Min Turnaround Alt. on Single Engine Aircraft-Engine Failure Question
ze...@home.com
average Altitude needed to turn back to the runway you took off from.
I fly a PA-181 and Cessna 172
What are others experiences with how much altitude loss when turning
around. What altitude do you chose to turn around verses tryig to make an
alternate choice.
Just for fun I need to go up and simulate a engine out then do a 180 and
see how much alt i lose, and I was wondering others experiences with their
aircraft.
Mackfly
>see how much alt i lose,
Do a 180 huh----you plan to land on a taxi way, IF you get it back to the
airport? Or even off the airport? It takes more than a 180 to get back to
the runway. Think this through a little. Mack
phil cohen
Did a "return to the numbers" and landed after a simulated engine
failure at about 400 ft just as I began turning crosswind in a 172. It
was night and there were obstacles. Fortunately it was a very familiar
airport. The fact that I had about 45 degrees into the crosswind turn
helped a lot. Just kept the turn going and made a teardrop back to the
numbers, then slipped it in.
I don't recommend trying this. I am working on my CFI and I told my
instructor that I wanted to try this demo AT ALTITUDE.
I was real surprised when he did it "for real" just as I was turning
crosswind below 500 feet.
Great, I thought after we landed. A little bit daring, but an intense
experience.
Then we took off again and he pulled it at 300 feet! This time I was
expecting it even less! Wouldn't have make it. Had to add power and
climb back out.
I would think that the PA-181 would not glide as well as the 172. It's
a bit heavier, no?
ze...@home.com
from.
Mackfly <mac...@aol.com> wrote:
:>Just for fun I need to go up and simulate a engine out then do a 180 and
Ron Rosenfeld
Please don't forget that in your simulation, the engine was still producing
a bit of power. So with a dead engine and windmilling prop, you'd likely
have needed more altitude to make it back.
-- ron
phil cohen wrote in message <36D239...@worldnet.att.net>...
luc...@metrowerks.com
ze...@home.com wrote:
As others have suggested, try this at altitude. You'll be quite surprised at
how much altitude you'll actually need to do this 8). I've done this
"teardrop" turn numerous times in my Quicksilver and the minimum is
approximately pattern altitude (approx. 300 to 400' AGL), depending on how
far away from the runway I've travelled before I try it. The bottom line on
that is, if the far end of the available deadstick glideslope (minus the
altitude lost doing the 200+ deg turn) is on the runway, I can make it.
Otherwise, I go into the several fields straight ahead.
A few weeks ago, this practice saved me a lot of money (and possible injury)
when my prop belt drive spun loose on takeoff. The prop was still spinning
fast enough to maintain a little bit of a climb and that was about it. I
throttled back to idle and executed a teardrop turn-back and landed downwind,
with no damage. Fortunately, I'd already done this maneuver, simulated,
without using the instruments, many times before, so it was uneventful.
I say go ahead and practice it. There's no harm in having extra options in
your emergency procedures - just do it carefully! 8)
Lucien S.
PP-ASEL.
> I know every aircraft is different but I am just wondering what the
> average Altitude needed to turn back to the runway you took off from.
>
> I fly a PA-181 and Cessna 172
>
> What are others experiences with how much altitude loss when turning
> around. What altitude do you chose to turn around verses tryig to make an
> alternate choice.
>
> Just for fun I need to go up and simulate a engine out then do a 180 and
> see how much alt i lose, and I was wondering others experiences with their
> aircraft.
>
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James Goddard
doing some t&g's with a pretty strong headwind. I had turned left
crosswind and was probably about 700 feet when my CFI pulled the power.
I hesatated, and he suggested I turn RIGHT doing a 270 and landing with
the wind (ok approx. 270 for the anal retentive ones among us). I was
slightly surprised to find myself landing very long. It was a great
experience that taught me 2 things. 1. Sometimes the best solution is
not the most obvious one. 2. How to land with a strong tailwind.
Tim Bengtson
>
> I know every aircraft is different but I am just wondering what the
> average Altitude needed to turn back to the runway you took off from.
>
> I fly a PA-181 and Cessna 172
>
> What are others experiences with how much altitude loss when turning
> around. What altitude do you chose to turn around verses tryig to make an
> alternate choice.
>
> Just for fun I need to go up and simulate a engine out then do a 180 and
> see how much alt i lose, and I was wondering others experiences with their
> aircraft.
If you see http://web.usna.navy.mil/~dfr/technical_flying.html
you'll find a rather erudite discussion of the turn-back issue.
Tim Bengtson
John Clarke
phil cohen <phi...@worldnet.att.net> wrote:
>******DO NOT TRY THIS YOURSELF******
>
>Did a "return to the numbers" and landed after a simulated engine
>failure at about 400 ft just as I began turning crosswind in a 172. It
>was night and there were obstacles. Fortunately it was a very familiar
>airport. The fact that I had about 45 degrees into the crosswind turn
>helped a lot. Just kept the turn going and made a teardrop back to the
>numbers, then slipped it in.
Uh, this is simply idiotic. You need to switch instructors
before he gets you killed.
Seriously.
The "turn back" experiment should be done at altitude. If, for
some reason, you want to try it out on a real runway, at least do
it where you have some options, and you can clearly judge the
situation. I would expect that you had to crank in some serious
bank attitude to make it back from 400' (ideally 45 degrees).
What is your stall speed in that config? And you want to do
this at night, with obstacles?
Mike Rapoport
Mike
John Clarke wrote in message <7auijm$s5i$1...@bcarh8ab.ca.nortel.com>...
John Clarke
And that changes the scenario in what way? He either
expects the student to push the throttle back in, or he
expects him to try and make the turn back at 400' to an
obstacled runway at night.
Any of these factors has increased the danger level exponentially,
and provides no extra training beyond what could be done in a
more controlled daylight environment, or at altitude.
Or am I missing something?
Michael
John Clarke <jcl...@nortel.ca> wrote in article
<7auijm$s5i$1...@bcarh8ab.ca.nortel.com>...
> In article <36D239...@worldnet.att.net>,
> phil cohen <phi...@worldnet.att.net> wrote:
> >Did a "return to the numbers" and landed after a simulated engine
> >failure at about 400 ft just as I began turning crosswind in a 172.
>
> Uh, this is simply idiotic. You need to switch instructors
> before he gets you killed.
> Seriously.
Practically speaking, if you are flying a typical fixed
gear/fixed pitch single, you can return to the runway once
you are well into your crosswind turn. I know that's not
incredibly precise, but it's a useful rule of thumb.
If you are taking off from a runway where a landing straight
ahead will leave you dead, you may want to consider flying
a pattern even if your on-course departure is straight out,
because you will need more altitude to make the return
from a straight-out departure for reasons that have
already been pointed out many times.
In sailplanes we practice the return to the runway from
low altitude (200ft) pretty routinely. What's more,
while in a power plane pulling the engine to idle is a
simulated emergency (probably - after all, the engine
may not restart) in a glider the emergency is real once
you pull the release. I was required to do it before I
could solo, along with every other glider pilot I know.
Thus I find it hard to take people who think practicing the
maneuver from 400 in a power plane is suicidal seriously.
The risk of losing the engine during the few seconds at
idle that it takes to complete the maneuver AND the
risk of simultaneously botching the maneuver is pretty
small.
Certainly doing it at night adds an element of challenge -
but this maneuver SHOULD be practiced at night. We
don't do it in gliders because we don't generally fly
gliders at night. But night is exactly when returning to
the runway is most useful, because you can't see
ahead and the emergency landing ahead becomes more
dangerous.
The principal problem involved is really not so much
physical as mental. Few people get killed in emergencies
because they had a plan, executed the plan, but just
didn't quite have the skill to pull it off. Most die
because they choke. So doing this unexpectedly under
difficult conditions is a really good idea - it gets the
student used to the idea that it can happen and allows
him to practice the maneuver under realistic conditions.
At altitude, the conditions are not realistic.
I've seen more than one student glider pilot botch an
instructor-induced low altitude rope break. The solution
is to keep doing them until he gets it right, not to
decide that they are too dangerous. And yes, some
gliders have been bent. On the other hand, I can't
remember the last time a low altitude rope break
resulted in a fatality. They happen with some
regularity and yet pilots seem to handle them just
fine. Coincidence? Hardly. Good training.
We could use more of that sort of training in power
flying.
Michael PP-ASEL, G
Leonard Wojcik
Ron Rosenfeld wrote:
> Please don't forget that in your simulation, the engine was still producing
> a bit of power. So with a dead engine and windmilling prop, you'd likely
> have needed more altitude to make it back.
To the contrary, the windmilling prop causes more drag than a still one. While
windmilling the propeller creates resistance over the entire disk of rotation
(not equivalent to a solid disk, but none the less unstalled and
aerodynamically active). The stopped propeller is stalled (aerodynamically)
and is effectively just a draggy object the size of a propeller with the
accompanying air flow around it. To demonstrate: with a controllable prop,
check out the effect on glide angle between minimum pitch and maximum pitch
while the engine is idling. This is why twins have featherable propellers, to
reduce drag on the failed side.
John Clarke
Michael <cre...@flash.net> wrote:
>
>Thus I find it hard to take people who think practicing the
>maneuver from 400 in a power plane is suicidal seriously.
>The risk of losing the engine during the few seconds at
>idle that it takes to complete the maneuver AND the
>risk of simultaneously botching the maneuver is pretty
>small.
Are those the only risks you can see in this scenario?
What about the risk of disorientation during a fairly steeply
banked manouever at night and at low speed. The return
to the runway turn from 400' would require a fairly precise
45 degree bank, and speed somewhere near best glide, which
means that you don't have a large margin above stall. Getting
into a spin wouldn't be particularly hard, and would be fatal.
Not only that, but the student is trying to return to a
runway with obstacles at night. During the day, I have
no problem spotting treetops, but at night, its a completely
different story.
>Certainly doing it at night adds an element of challenge -
>but this maneuver SHOULD be practiced at night.
Why should practising this manouever at ground level at
night be required? Do we require spin practice at pattern
altitude, since that is where someone is most likely to stall/spin?
Understanding how much altitude is required can be safely done
at altitude over a suitable reference point, and keeps the
margin of safety intact.
I have absolutely no problem with practising engine out scenarios
to the runway, given the right conditions. I will argue strenuously
that the conditions described are not the right conditions.
Even worse, it seems that the student hadn't yet practised this
scenario (which is why he requested the exercise), which means
that this training was virtually without a point. They hadn't
determined what a suitable altitude for a turnback is, likely
hadn't discussed the correct procedure for a turnback, and
all the exercise showed was that from a particular point in
the pattern and a particular altitude, the student could get
the plane back on the ground. 100' lower? Who knows? Still
on climbout? Who knows? The point of trying this at altitude
is to determine fairly precise guidelines for that particular
plane. You can repeatedly try the manouever, changing initial
altitude, initial direction, relative winds, all without risk.
Pointless and dangerous equals dumb in my book. I know to
others it sounds like fun. Boot camp for pilots, I suppose.
George R. Patterson III
>
> I know every aircraft is different but I am just wondering what the
> average Altitude needed to turn back to the runway you took off from.
I would not attempt it at a strange field at less than 800' AGL. At my
home base, the pattern is such that I would not try it below 1,000' AGL
(we have a left turn for noise abatement procedure in effect).
George Patterson, N3162Q.
Ron Rosenfeld
Unless the engine seizes, the propellor in a SE light a/c WILL be
windmilling. Phil's message, to which I was responding, spoke of doing the
maneuver in a 172 -- no feather capability. In order to STOP the propellor
in a SE a/c that does not have feather capability, you need to bring the a/c
to just about stall speed -- this would not be a maneuver I would carry out
in the event of a take-off engine failure, although I might do it with a
high altitude engine failure.
-- ron
Leonard Wojcik wrote in message
<36D2ED8C...@dontspamme.wojciktech.com>...
John Clarke
>> before he gets you killed.
>> Seriously.
>
>maneuver from 400 in a power plane is suicidal seriously.
Actually, I never claimed that this was suicidal. It, in
my opinion is an unnecessarily dangerous manouever. It indicates
a willingness to push the envelope which I think will lead to
trouble in the future. I think there could have been serious
problems while attempting this in the situation described.
Training shouldn't be about who is macho. It can certainly
include expanding peoples limits, but I don't see this exercise
proving a whole lot. Or teaching much.
Did the student (was it Phil?) learn much about the turnback
from this?
John
Michael
> banked manouever at night and at low speed. The return
> to the runway turn from 400' would require a fairly precise
> 45 degree bank, and speed somewhere near best glide, which
> means that you don't have a large margin above stall. Getting
> into a spin wouldn't be particularly hard, and would be fatal.
Then don't spin. For that matter, don't stall. Personally,
I find it a challenge just to get a C-172 into a spin. To do
it inadvertently indicates a pilot who got way behind the
airplane. If you're going to get way behind the airplane,
no flying is adequately safe.
Besides, he's got a CFI who is NOT flying the plane, but is
instead watching carefully and will presumably step in to
correct the student's blunder before he does something as
extreme as spinning at low altitude.
> Not only that, but the student is trying to return to a
> runway with obstacles at night. During the day, I have
> no problem spotting treetops, but at night, its a completely
> different story.
There are always obstacles. Above 200' AGL they are lit
and no problem to spot. Below 200' AGL the aircraft should be
turning onto final.
> Why should practising this manouever at ground level at
> night be required? Do we require spin practice at pattern
> altitude, since that is where someone is most likely to stall/spin?
No, because (1) there is generally not enough altitude
available to recover a spin on the base-to-final turn no matter
how much you practice and (2) you shouldn't spin in the
pattern anyway. Engine failures on takeoff do happen regardless
of what you do.
> Understanding how much altitude is required can be safely done
> at altitude over a suitable reference point, and keeps the
> margin of safety intact.
As I said before, the major problem with the maneuver is not
physical, it is mental. A coordinated 45 degree bank turn at
several knots over stall speed is a maneuver that every
private pilot should be able to do, regardless of his altitude
over the ground. It is a maneuver every private glider pilot
can do. The problem is that if you have not had to do it
before under pressure, you may choke.
> I have absolutely no problem with practising engine out scenarios
> to the runway, given the right conditions. I will argue strenuously
> that the conditions described are not the right conditions.
Here we disagree.
> Even worse, it seems that the student hadn't yet practised this
> scenario (which is why he requested the exercise),
Here we do NOT disagree. I think this maneuver SHOULD be
done at 400 AGL at night - but only after it has been practiced
at 2000 AGL, day and night. And that should come first.
> which means
> that this training was virtually without a point.
That may not be true. The fact that the student successfully
completed the maneuver would suggest otherwise.
> They hadn't
> determined what a suitable altitude for a turnback is, likely
> hadn't discussed the correct procedure for a turnback, and
> all the exercise showed was that from a particular point in
> the pattern and a particular altitude, the student could get
> the plane back on the ground.
The order of doing these exercises is at the discretion of the
instructor. I would not choose the order he chose, but the
fact that the student completed the maneuver and did not
choke suggests that he may not have been wrong.
> 100' lower? Who knows? Still
> on climbout? Who knows? The point of trying this at altitude
> is to determine fairly precise guidelines for that particular
> plane. You can repeatedly try the manouever, changing initial
> altitude, initial direction, relative winds, all without risk.
Absolutely. But it sounds like the instructor already had a good
idea of what an acceptable altitude was. Gee, I wonder how he
determined it...
> Pointless and dangerous equals dumb in my book. I know to
> others it sounds like fun. Boot camp for pilots, I suppose.
I agree that there is an element of danger in the exercise, but
I don't think it's pointless.
> Did the student (was it Phil?) learn much about the turnback
> from this?
Sure sounds to me like he did...
Michael
Herbal
>Any of these factors has increased the danger level exponentially,
>and provides no extra training beyond what could be done in a
>more controlled daylight environment, or at altitude.
>
>Or am I missing something?
John, you're not missing anything. Beyond the ability to recover
from that scenario, I seriously question the CFI's ability to
recognize, communicate and correct an airwork error that
would quickly deteriorate at 400 feet, wrapped up, at night,
with airport obstacles.
There's nothing that requires that much "pucker factor" just for
the sake of training. Not even landing on boats.
Herbal
>correct the student's blunder before he does something as
>extreme as spinning at low altitude.
I wouldn't bet my life on it, as a student or instructor.
>Engine failures on takeoff do happen regardless
>of what you do.
No need to mort with the engine running.
>The problem is that if you have not had to do it
>before under pressure, you may choke.
If you've practiced the maneuvers at altitude, odds are
you won't choke. If you practice the maneuvers near
the deck, you toying with tying the low altitude record.
>> Did the student (was it Phil?) learn much about the turnback
>> from this?
>
>Sure sounds to me like he did...
Hopefully he learned something NOT to do as a CFI.
Rod Farlee
>Understanding how much altitude is required can be safely done
>at altitude over a suitable reference point, and keeps the
>margin of safety intact.
This exercise will teach a number of things which cannot be
learned "at altitude over a suitable reference point". It really
requires that one get lined up on the runway. It shows that the
problem is landing long and overrunning the end of the runway
(especially if there's any wind), and thus that the obstacles off
the departure end of the runway are irrelevant. One can practice
stalls and steep turns at altitude, but turnbacks at altitude are not
realistic, and can lead to the dangerous conclusion that they will
require less altitude than they really do.
Is practicing this more dangerous at night? Well, why is a power
failure more dangerous at night? Because you cannot see off-
field emergency landing areas. If one flies at night, perhaps this
is when this should best be practiced, because it is when it'll be
most needed.
p.s. An idling engine does produce thrust, and slightly lengthen
the glide, relative to a an engine that is not firing. C-172 prop
will windmill at glide speed, and stop in the flare. That can also
be disconcerting to a pilot who is not expecting it, and might cause
him to botch the landing, so perhaps should be included in the
practice. To make it realistic, rather than pulling the throttle to
idle, pull the mixture to idle cutoff.
- Rod Farlee
Vincent Norris
>a bit heavier, no?
The distance an airplane can glide from a given altitude depends on lift and
drag, not its weight. A Boeing 747 is much heavier than a PA 181 or a 172,
but will glide several times as far because it's cleaner.
vince norris
r...@xmission.com
light than it will heavy due to the fact that the amount of lift needed to
support the increased weight is greater. Thus, the angle of attack needed to
maintain level flight or a chosen glide speed will also be greater, resulting in
a steeper glide slope and less distance covered over the ground. Couple this
with the deadly Aardvark Effect and you have a recipie for terror!
mary-anne & tom
Michael wrote in message <01be5f55$02afff20$8301010a@mike-s-desktop>...
>SNIP
>In sailplanes we practice the return to the runway from
>low altitude (200ft) pretty routinely.
>Thus I find it hard to take people who think practicing the
>maneuver from 400 in a power plane is suicidal seriously.
There is a BIG difference between a simulated rope break at 200 ft and a
simulated engine failure at 400 ft. First, the sailplane probably has an
L/D of around 28 to 1 compared to an L/D of 8 to 1 (if that) in your powered
plane. The altitude loss in the sailplane is far less than the power plane.
Second, if the CFI-G and towplane pilot are smart the towplane will know
what's coming and will purposely allow the towplane with glider to drift
downwind from the runway (assuming some crosswind component) so that the
turn to the runway is only 180 degrees, lessening the risk of the manuveur
somewhat. Third at the time of rope break the sailplane is in all
likelihood travelling somewhat faster than its best glide speed and
definitely faster than stall speed; so, if some speed is lost in the
manuveur no real harm done; the powered plane at 400 ft is probably at Vy
which is about the same as best glide speed; any loss in airspeed brings the
powered plane closer to stall; add the effect of bank and a stall/spin is
the most likely outcome.
If a CFI pulled the throttle on me at 400 ft and tried to turn back to the
runway I would (assuming I lived) call the local FSDO and report him for
reckless operation. I seriously believe that this type of behaviour is
totally uncalled for.
Regards,
Tom PP-ASEL, Glider
John T. Lowry
same for the same airplane at two different weights.
--
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
r...@xmission.com wrote in message <36D3A143...@xmission.com>...
Tom Turton
the best L/D AOA. However, your speed will change.
Rich Carr
: There is a BIG difference between a simulated rope break at 200 ft and a
: simulated engine failure at 400 ft.
Furthermore, with a decent towplane, the glider climbs at a steeper
angle on tow than it descends at Vbg, so each second it spends on tow
improves its glide angle to the runway.
At my field elevation (5000' MSL), it's a rare airplane that climbs at a
steeper angle at Vx than it descends power-off, so each second of climb
puts it at a worse glide angle back to the runway, assuming it climbs on
runway heading.
- Rich Carr
Michael
> There is a BIG difference between a simulated rope break at 200 ft and a
> simulated engine failure at 400 ft.
Yes - the most important one being that pulling the throttle
in an airplane is simulating an emergency - if things don't
go too well you can push it back in. In a glider pulling the
release is CREATING an emergency - once you pull the
release the emergency is just as real as if the rope broke.
> First, the sailplane probably has an
> L/D of around 28 to 1 compared to an L/D of 8 to 1 (if that) in your
powered
> plane. The altitude loss in the sailplane is far less than the power
plane.
I'll grant you that - the altitude loss in a glider is likely about 85 ft -
figure
a sink rate of 170 fpm at best glide (I'm using numbers from an L-23
Blanik for the glider in the rest of this, and numbers from a PA-22 for
the airplane) and 30 seconds to complete the 180. In a plane it will be
closer to 200 ft (800 fpm down at 70 mph - stall is about 50) in the
15 seconds you will need to complete the crosswind turn you
already started.
> Second, if the CFI-G and towplane pilot are smart the towplane will know
> what's coming and will purposely allow the towplane with glider to drift
> downwind from the runway (assuming some crosswind component) so that the
> turn to the runway is only 180 degrees, lessening the risk of the
manuveur
> somewhat.
That's a good thing to do anyway and does make things more
convenient in the event of a low rope break.
But it still won't be as convenient as completing the crosswind
turn. At my glider field when we launch to the South, the tow
plane makes a 90 degree turn to the left at about 100 AGL. I
watch the altimeter and once the turn begins I drop my turnback
altitude to 150 ft because I don't need to do as much. Of course
we have a VERY wide field. Tailoring your emergency
procedures to what you have available is a good thing, IMO.
> Third at the time of rope break the sailplane is in all
> likelihood travelling somewhat faster than its best glide speed and
> definitely faster than stall speed; so, if some speed is lost in the
> manuveur no real harm done; the powered plane at 400 ft is probably at Vy
> which is about the same as best glide speed; any loss in airspeed brings
the
> powered plane closer to stall; add the effect of bank and a stall/spin is
> the most likely outcome.
My best climb airspeed is a published 84 mph; my stall speed clean
is a published 53 but I have droop tips which reduce it. Best glide is
not published but I'm guessing somewhere around 75-80. Stall
speed at 45 degrees of bank is about 60. 70 (published Vx) seems
like a reasonable speed for the maneuver.
In a Cessna the situation is not as nice. In a low wing Piper you
are right - there will not be much if any extra airspeed to play
with. On the other hand, power planes in this class are much
more stall-resistant and give you far more warning than a
typical glider (SGS 2-33's excepted) so do you really need as
much margin over stall?
Given all that, I think pulling the throttle at 400 ft on the crosswind
turn is really safer than pulling the release at 200 going straight
out.
Michael
jga...@hotmail.com
vp...@psu.edu (Vincent Norris) wrote:
> >I would think that the PA-181 would not glide as well as the 172. It's
> >a bit heavier, no?
>
> The distance an airplane can glide from a given altitude depends on lift and
> drag, not its weight. A Boeing 747 is much heavier than a PA 181 or a 172,
> but will glide several times as far because it's cleaner.
>
OK, I'm confused here. A 747 will glide (assuming power off) several times
as far as a Piper or Cessna? I recall that the glide ratio of a 172 was
somewhere in the neighborhood of 9:1. Assuming "several" means more than
two, are you saying that a 747 has a glide ratio of at least 27:1? That
would make it a pretty decent sailplane.
I was discussing engine out glide performance with a 747 captain several
years ago and he told me that the glide performance of his airliner was,
"slightly better than the glide performance of a rock".
John Galban=====>N4BQ (PA28-180)
John T. Lowry
from the Cessna 172 POH, by the way, is somewhat too conservative. Actual
measurements give about 10:1. I believe the discrepancy is due to the fact
that Cessna Aircraft employs lawyers.
John.
--
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
jga...@hotmail.com wrote in message <7b23be$hv8$1...@nnrp1.dejanews.com>...
JStricker
Actually, that 17:1 sounds about right from some stories I've heard back
when airline captains used to try some of these things. Then, think about
that number. Flying into a coastal airport somewhere at FL350. Glide for
100 NM with no power.
John Stricker
--
Remove the "nosp..........." Oh hell, you folks know what to do and
why I had to put it in. If one of you real humans wants to contact me:
"I didn't spend all these years getting to the top of the food chain
just to become a vegetarian"
John T. Lowry wrote in message <7b2643$osv$1...@news.mcn.net>...
Ron Natalie
> as far as a Piper or Cessna? I recall that the glide ratio of a 172 was
> somewhere in the neighborhood of 9:1.
I don't know about 747's but I believe the number on 727's is
up around 17:1, so it's only about twice a 172 glide. But the
issue is that it's the drag not the weight that decides the
issue.
The issue however, is that the 747 is moving substantially
faster that the 172 at Vbg, so it's coming down a lot faster
too, it's just covering a lot of ground in the process.
Dave Mould
farther
>light than it will heavy
AFAIK, this is not true, though the speed needs to be higher in order to
obtain the optimum glide angle. This is why sailplanes carry water
ballast - they can glide the same distance from a given altitude, but they
get there faster (takes longer to climb though, so it's a compromise).
It's counter-intuitive at first glance, but not if you think a bit deeper.
Sure, more lift is needed to hold the extra weight, but there is also an
equal increase in the stored potential energy of the aircraft (weight times
height). The increased weight means more energy is required in the climb -
so you climb slower, burning more fuel to get to the given altitude, so
there's no "free lunch" involved and the law about conservation of energy is
not broken (otherwise you'll go to jail!).
Dave Mould
Michael
> OK, I'm confused here. A 747 will glide (assuming power off) several
times
> as far as a Piper or Cessna? I recall that the glide ratio of a 172 was
> two, are you saying that a 747 has a glide ratio of at least 27:1? That
> would make it a pretty decent sailplane.
20:1 is about the norm for the big jets, and no it wouldn't make
a decent sailplane. 20:1 is actually tolerable in a sailplane, but
the 20:1 sailplanes usually have their best glide speed somewhere
around 45 kts with a minimum sink speed somewhere around
40 kts. The big jets glide almost that well, but at 200 kts.
That gives them a minimum sink rate of about 1000 fpm or
thereabouts - stronger than any thermal I've ever seen. Now if
you were to catch some good mountain wave, I bet you COULD
soar a jumbo jet...
Michael
mary-anne & tom
Michael wrote in message <01be6015$07144060$8301010a@mike-s-desktop>...
>SNIP
>My best climb airspeed is a published 84 mph; my stall speed clean
>is a published 53 but I have droop tips which reduce it. Best glide is
>not published but I'm guessing somewhere around 75-80. Stall
>speed at 45 degrees of bank is about 60. 70 (published Vx) seems
>like a reasonable speed for the maneuver.
>
>In a Cessna the situation is not as nice. In a low wing Piper you
>are right - there will not be much if any extra airspeed to play
>with. On the other hand, power planes in this class are much
>more stall-resistant and give you far more warning than a
>typical glider (SGS 2-33's excepted) so do you really need as
>much margin over stall?
Given the number of people that kill themselves every year turing back to
the airport after an engine failure I'd say yes, indeed, you really need as
much margin over stall to accomplish it.
I'm not saying its impossible to do; I fly a J-3 Cub which I suspect could
make the turn at 400 ft or so...but as far as I am concerned in single
engine aircraft other than the J-3 if the big fan stops turning on me at low
altitude I am taking my chances with the swamp at the end of the runway and
not trying to pull off a 180 return to the airport. With the J-3 Cub an
engine failure at 400 ft would leave about 2,000 ft runway in front of me so
no problem ;-)
Tom Turton
John T. Lowry wrote:
> I recall a 747 Captain telling me the glide ratio was about 17:1. The 9:1
> from the Cessna 172 POH, by the way, is somewhat too conservative. Actual
> measurements give about 10:1. I believe the discrepancy is due to the fact
> that Cessna Aircraft employs lawyers.
...And Boeing DOESN'T, John??? ;-)
Michael
> the airport after an engine failure I'd say yes, indeed, you really need
as
> much margin over stall to accomplish it.
Then why don't all those glider pilots who do it at 10 kts over stall
get themselves killed? That's the big question to me. In a power
plane you only need to simulate the emergency (by pulling the
throttle) to practice the maneuver and yet we don't - and a bunch
of people seem to kill themselves when they try it. I a glider we
have to create the emergency (by pulling the release) to practice
the maneuver - and yet we do, and people seem to learn it and
use it and do just fine.
Michael
Mike Rapoport
compared to the climb angle with the tow. When you really think about it
what is required is a climb angle which is high enough to give you
sufficient altitude to turn around while still close enough to the airport
to make the final strait-in glide. Glider pilots are also undoubtedly
better at gliding than there powered counterparts. Hopefully they get more
experience!
I have been reading this thread for a while and surprised at the number of
pilots who think that they can execute this maneuver. I had a Turbo Lance
which is a good climber (1300fpm @92kias) with a climb gradient of
848feet/nm. THe published glide was 1.2nm/1000ft which is a gradient of
833ft/nm. In other words, in a no-wind situation there is no way that the
airplane could reach the lift-off point EVEN IF IT WAS ALREADY POINTED BACK
AT THE RUNWAY.
The only way the maneuver could be accomplished is if there is a strong wind
aligned with the runway (higher climb angle) or if the runway was very long
and there was a large distance from the liftoff point to the end of the
runway (shorter distance to return).
Mike
MU-2
Michael wrote in message <01be60d2$57e0c6e0$8301010a@mike-s-desktop>...
Michael
> I have been reading this thread for a while and surprised at the number
of
> pilots who think that they can execute this maneuver. I had a Turbo
Lance
> which is a good climber (1300fpm @92kias) with a climb gradient of
> 848feet/nm. THe published glide was 1.2nm/1000ft which is a gradient of
> 833ft/nm. In other words, in a no-wind situation there is no way that
the
> airplane could reach the lift-off point EVEN IF IT WAS ALREADY POINTED
BACK
> AT THE RUNWAY.
>
> The only way the maneuver could be accomplished is if there is a strong
wind
> aligned with the runway (higher climb angle) or if the runway was very
long
> and there was a large distance from the liftoff point to the end of the
> runway (shorter distance to return).
That's an excellent observation. I'm glad you published numbers - now
let's add one more. How much distance do you need to lift off? I'm
guessing your published ground roll on takeoff is under 1000 ft.
Working with a typical 3500 ft runway and assuming you made your
turn to crosswind at 500 and then your engine quit - that puts you
just over 3000 ft from your touchdown point but only about 700 ft from
the threshold. Even if you burn 350 ft making the turn back, you can
still do it.
That's neglecting any boost you get from the headwind on climbout
and tailwind on return. The problem really is not landing short of
the runway - it's landing long.
So the real question here is not best glide ratio - it's minimum
sink rate. The critical parameter that makes a turnback from
200 ft going straight out comfortable in a glider and suicidal
in a power plane is the difference in sink rates. A typical
training glider has a sink rate of about 200 fpm. A typical
light single will be closer to 600 fpm at the speeds used.
Thus the straight-out distance for most light singles is in
the 600ft+ range if you want a safety margin comparable to
gliders.
For high performance singles the numbers may well be
worse. Most that I've seen develop an absolutely
wicked sink rate when flown power-off. I would not be
surprised if your T-Lance needed 500 ft just to make the 180
(1000 fpm for the 30 seconds required to make the turn)
making straight-out minimum altitude 1000 ft.
You can cut the altitude requirement some by making the
turn to crosswind under power sooner - 400-500 ft - not because
it leaves you closer to the runway (that's a liability, not an
asset) but because it leaves you less of a turn to do.
You made a point about glider pilots being better at gliding -
that may actually have some bearing on the matter. As a
novice glider pilot I typically thermal at 30-45 degrees of
bank about 5 knots over stall in turbulent air. This is not
some stunt - it's what soaring is all about. I was required
to demonstrate 45 degree banked turns to headings at
a few knots over stall to pass my private-glider checkride.
The last instructor I flew with is obviously far more experienced
and in order to stay in the core of best lift he will typically
thermal at 60-70 degrees of bank, again a few knots over
stall in turbulent air.
On the other hand, a typical power pilot will very rarely use
45 degrees of bank these days - this is considered a
very steep turn in power flying, and I have even heard flight
instructors say that more than 30 degrees of bank in the
pattern is a bad thing. How many power-only pilots out
there have done a 45 degree banked turn at 5-10 kts over
the stall speed corrected for bank (18% higher)?
Michael
snowb...@my-dejanews.com
jcl...@nortel.ca (John Clarke) wrote:
> In article <36D239...@worldnet.att.net>,
> phil cohen <phi...@worldnet.att.net> wrote:
> >Did a "return to the numbers" and landed after a simulated engine
> >failure at about 400 ft just as I began turning crosswind in a 172. It
> >was night and there were obstacles. Fortunately it was a very familiar
> >airport. The fact that I had about 45 degrees into the crosswind turn
> >helped a lot. Just kept the turn going and made a teardrop back to the
> >numbers, then slipped it in.
> Uh, this is simply idiotic. You need to switch instructors
> before he gets you killed.
> Seriously.
Seriously John, did you miss this part of Phil's post?
"I am working on my CFI and I told my instructor that I wanted to try
this demo AT ALTITUDE. I was real surprised when he did it "for real"
just as I was turning crosswind below 500 feet. "
While I don't think this sort of exercise is appropriate as a "first pass"
introduction for a student pilot, don't you think it's a Good Thing for a
CFI to have tried at least once, esp. with a CFI on board monitoring the
situation?
One just doesn't get the same "picture" of whether this is a good idea,
or a bad idea, at altitude as one does close to the ground.
Regards,
Snowbird
jga...@hotmail.com
Ron Natalie <r...@sensor.com> wrote:
> > OK, I'm confused here. A 747 will glide (assuming power off) several
times
> > as far as a Piper or Cessna? I recall that the glide ratio of a 172 was
> > somewhere in the neighborhood of 9:1.
>
> up around 17:1, so it's only about twice a 172 glide. But the
> issue is that it's the drag not the weight that decides the
> issue.
>
> The issue however, is that the 747 is moving substantially
> faster that the 172 at Vbg, so it's coming down a lot faster
> too, it's just covering a lot of ground in the process.
>
Thanks Ron and all for the education. When you think about it, it makes
sense. Even though the 747 is coming down at a much greater rate than the
172, it's also covering large chunks of territory in the process.
John Galban=====>N4BQ (PA28-180)
Mike Rapoport
probably close to your 1000ft number. Fortunately my current plane has more
engines and turbine ones at that, so presumably I won't face the issue
myself. My comments were however, directed at the single engine topic of
the thread. When the thread started the question involved a failure before
any turns were made. Obviously if you are already crosswind or downwind you
are much better off!
If the best glide sink rate is over 800 fpm, then the sink in a steep turn
is going to be well above that figure, probably 1500+fpm. So in your 3500ft
runway, no wind, senario with failure at 500agl you won't even be able to
make the turn back before reaching the ground! At 1000ft you MIGHT make the
turn (remember you must turn more than 180 deg to realign with the runway)
but that is about it. You really can't use minimium sink speed in the turn
and turn steeply at the same time as the (power off) stall speed in a 60deg
turn is about 50% above the unaccelerated stall speed.
Another consideration is that the plane doesn't leave the ground at its max
climb rate, it must accelerate to Vy and then vertically from 0fpm to what
ever the max rate is. And it takes additional time to retract the gear
raise flaps ect. So you cannot assume that the plane climbs at max rate as
soon as it becomes airborn.
Also, he published ground roll distance is assuming that you hold the brakes
while building up full power. Who does this in a single piston engined
airplane on a 3500ft runway? Additionally the minimium ground roll is
usually with a short field technique with liftoff well before Vy.
I know of no GA piston single with a climb angle greater than its glide
angle. I'm sure they exist but are probably motor-gliders.
In the example of the Lance which has almost equal climb and sink angles you
would lose 500-1000ft in the turn which would have given you 3600-7200ft
(.6-1.2nm) of glide range. So you would need to have 3600-7200ft of runway
remaining after liftoff, gear retraction ect. to make the runway.
In short, unless you have an EXTRAORDINARY climb angle(P-51 Mustang type
climb rate), I don't think you can return from a failure if you are
straight out from the runway without a VERY long runway or a lot of wind. I
am interested to know if anyone has actually accomplished one (not simulated
as the engine is still producing power at idle.
Mike
MU-2
Michael wrote in message <01be60f0$b3295300$8301010a@mike-s-desktop>...
Vincent Norris
>from the Cessna 172 POH, by the way, is somewhat too conservative. Actual
>measurements give about 10:1. I believe the discrepancy is due to the fact
>that Cessna Aircraft employs lawyers.
>John T. Lowry, PhD
I said a 747 would glide "several" times as far as a 172 because I didn't
know the precise number, but I'm very surprised it's only about twice as far.
A 747 (or any jet transport) looks so clean and slippery, and a 172 so
clunky with struts and gear hanging out in the breeze; can you, John, or
anyone, tell me why there isn't a greater difference? Where is all that
747's drag coming from?
vince norris
Vincent Norris
>45 degrees of bank these days
I respectfully disagree. I'm asked to do 360s in both directions, with 70
degrees of bank, on every BFR I take. And I'm expected to do them with no
noticeable change of altitude, and I'm disappointed if I don't hit the
"bump" as I complete the turn.
Isn't that a common requirement?
I would not want to do them at 100 feet agl but would not object to doing
them at 500 feet.
Forty-five degrees of bank has been recommended as the most efficient to use
in a turnaround after takeoff. I've practiced that with two persons in a
PA 28-161 with two persons aboard.
I'd recommend the practice to everyone who hasn't done it. It may save your
life someday.
vince norris
andrew m. boardman
> OK, I'm confused here. A 747 will glide (assuming power off) several times
>as far as a Piper or Cessna? I recall that the glide ratio of a 172 was
>two, are you saying that a 747 has a glide ratio of at least 27:1? That
>would make it a pretty decent sailplane.
If I remember right, a 747 can do 19:1, but some of the newer transports
that are slicker can do well over 20:1. There was a lot of talk about
this when the 'Gimli Glider' incident happened, including numbers from
Boeing which I only vaguely remember...
Yeah, it probably does better than my local club's ratty 2-33s, but I'd
hate to try and stay in a thermal at 300 knots in an aircraft structure
that weak!
andrew
Mike Rapoport
>
>> If the best glide sink rate is over 800 fpm, then the sink in a steep
>turn is going to be well above that figure, probably 1500+fpm.
>
>You're kidding, right? If a 45 degree bank turn doubled the sink rate,
>how in the world would gliders ever thermal???
No I'm not kidding. I was thinking about a 60deg turn. Try it. The spiral
descent used to be on the comercial checkride. you lose altitude fast but
you turn around faster also
>> You really can't use minimium sink speed in the turn
>> and turn steeply at the same time as the (power off) stall speed in a
>60deg
>> turn is about 50% above the unaccelerated stall speed.
>
>Where did you get 60deg? In a 45 degree bank turn (which is
>optimal) the stall speed is only 18% over the unaccelerated
>stall speed.
Why is 45deg optimal in this case? Remember you need to align with the
runway. If you choose a wider turn you will have to turn a lot more (in
degrees) to align with the runway. REMEMBER IF THIS HAPPENS AT 1000FT YOU
HAVE ONE MINUTE TO EXECUTE THE TURN AND LAND.
>
>> Another consideration is that the plane doesn't leave the ground at its
max
>> climb rate, it must accelerate to Vy and then vertically from 0fpm to
what
>> ever the max rate is. And it takes additional time to retract the gear
>> raise flaps ect. So you cannot assume that the plane climbs at max rates
as soon as it becomes airborn.
>
>Nor can you assume that it flies at max speed as soon as it become
>airborne. Wanna use the 'distance to clear 50 ft obstacle' from the
>book and redo the calculation? Dollars to doughnuts it doesn't come
>out much different.
Please send the dollars. In my flight manual, which admittedly is for the
MU-2, the 50 distance is over 1000ft longer than the ground roll. If
acceleration is constant (I admit its not) then speed varies with time but
distance varies as the square of time (d=1/2att).
>
>> Also, he published ground roll distance is assuming that you hold the
>brakes
>> while building up full power. Who does this in a single piston engined
>> airplane on a 3500ft runway?
>
>Well, if your options in case of EFATO are so bad you're considering
>turning back to the runway, maybe you should?
True
>
>See, the point I'm making here is not that you should always turn
>back to the runway, nor that it is always possible - but that it is
>possible in enough cases and necessary in enough cases that you
>ought to know the maneuver and practice it.
I agree. But I contend that practice will demonstrate that it isn't
possible in the vast majority of cases to return to the takoff runway with
an engine failure while strait out. The accident statistics bear this out I
believe. Pulling the power back to idle doesn't really duplicate a failure
either.
>> I know of no GA piston single with a climb angle greater than its glide
>> angle. I'm sure they exist but are probably motor-gliders.
>
>Right, but that's not the point. You don't need to climb more
>steeply than you glide to execute the maneuver in most cases.
>Gliders generally DO climb steeper than they glide, and the
>number one problem with a low altitude rope break is dumping
>all the extra altitude.
>
>> In the example of the Lance which has almost equal climb and sink angles
>you
>> would lose 500-1000ft in the turn which would have given you 3600-7200ft
>> (.6-1.2nm) of glide range. So you would need to have 3600-7200ft of
>runway
>> remaining after liftoff, gear retraction ect. to make the runway.
>
>Assuming you had no headwind on takeoff and did not make a turn.
>And I agree with you - if that is the case you need 600+ ft even in
>something like a C-172 to do the maneuver and I haven't even
>considered what it would take in a Lance but it would not surprise me
>if it was well over 1000 ft.
>
>> In short, unless you have an EXTRAORDINARY climb angle(P-51 Mustang type
>> climb rate), I don't think you can return from a failure if you are
>> straight out from the runway without a VERY long runway or a lot of wind.
>
>I agree with you - though what constitutes very long and a lot
>varies with the type aircraft. But yes - if you want to do the
>straight-out thing in your Lance, it's not really a practical
>maneuver. In a C-172 it's just barely doable. In my PA-22
>on a no wind day, it's just possible from 600 ft with no margin
>for error onto a 3500ft runway. It would have to be an awful
>bad situation to make me want to try it.
How do you know you can make it from 600ft? Short of actually shutting down
the engine there is no way to know. A plane with a failed engine with a
windmilling prop does not glide like an engine idling. If you doubt this
try turning over the prop 600RPM by hand. It takes a lot of power!
Mike
MU-2
Mike Rapoport
Wow 70deg=3Gs!!! Another 5 deg of bank and the wings on a normal catagory
airplane fold. I didn't think that a cherokee had enough power to maintain
a 70 deg level turn.
Mike
MU-2
Mike Rapoport
Mike
Michael
> When the thread started the question involved a failure before
> any turns were made. Obviously if you are already crosswind or downwind
you
> are much better off!
No argument there.
> If the best glide sink rate is over 800 fpm, then the sink in a steep
turn
> is going to be well above that figure, probably 1500+fpm.
You're kidding, right? If a 45 degree bank turn doubled the sink rate,
how in the world would gliders ever thermal???
> You really can't use minimium sink speed in the turn
> and turn steeply at the same time as the (power off) stall speed in a
60deg
> turn is about 50% above the unaccelerated stall speed.
Where did you get 60deg? In a 45 degree bank turn (which is
optimal) the stall speed is only 18% over the unaccelerated
stall speed.
> Another consideration is that the plane doesn't leave the ground at its
max
> climb rate, it must accelerate to Vy and then vertically from 0fpm to
what
> ever the max rate is. And it takes additional time to retract the gear
> raise flaps ect. So you cannot assume that the plane climbs at max rate
as
> soon as it becomes airborn.
Nor can you assume that it flies at max speed as soon as it become
airborne. Wanna use the 'distance to clear 50 ft obstacle' from the
book and redo the calculation? Dollars to doughnuts it doesn't come
out much different.
> Also, he published ground roll distance is assuming that you hold the
brakes
> while building up full power. Who does this in a single piston engined
> airplane on a 3500ft runway?
Well, if your options in case of EFATO are so bad you're considering
turning back to the runway, maybe you should?
See, the point I'm making here is not that you should always turn
back to the runway, nor that it is always possible - but that it is
possible in enough cases and necessary in enough cases that you
ought to know the maneuver and practice it.
If I normally flew multiengine, I would spend my time working out
and practicing the twin procedures for engine failure on takeoff -
identify, verify, secure, etc - as I assume you do. It would be a
lot easier to just feather both engines and crash straight ahead -
and under some conditions of runway length, loading, and
density altitude that really is the right thing to do. But the fact is
that twin pilots practice the more difficult procedure and modify
their normal operating procedures accordingly.
Do you rotate below Vmc? Of course not - because if would
hurt your options in the event of an engine failure. But what if
the strip is too short to allow you to accelerate to Vmc? Well,
you have some decisions to make, don't you?
I'd say that if you are at a strip where an EFATO will put you
into unsurvivable terrain, you owe it to yourself to plan for
the engine failure - and if that means making a maximum
performance takeoff, that's a small price to pay. If there's
a sod farm off the end of the runway then maybe it's not
worth it.
> I know of no GA piston single with a climb angle greater than its glide
> angle. I'm sure they exist but are probably motor-gliders.
Right, but that's not the point. You don't need to climb more
steeply than you glide to execute the maneuver in most cases.
Gliders generally DO climb steeper than they glide, and the
number one problem with a low altitude rope break is dumping
all the extra altitude.
> In the example of the Lance which has almost equal climb and sink angles
you
> would lose 500-1000ft in the turn which would have given you 3600-7200ft
> (.6-1.2nm) of glide range. So you would need to have 3600-7200ft of
runway
> remaining after liftoff, gear retraction ect. to make the runway.
Assuming you had no headwind on takeoff and did not make a turn.
And I agree with you - if that is the case you need 600+ ft even in
something like a C-172 to do the maneuver and I haven't even
considered what it would take in a Lance but it would not surprise me
if it was well over 1000 ft.
> In short, unless you have an EXTRAORDINARY climb angle(P-51 Mustang type
> climb rate), I don't think you can return from a failure if you are
> straight out from the runway without a VERY long runway or a lot of wind.
I agree with you - though what constitutes very long and a lot
varies with the type aircraft. But yes - if you want to do the
straight-out thing in your Lance, it's not really a practical
maneuver. In a C-172 it's just barely doable. In my PA-22
on a no wind day, it's just possible from 600 ft with no margin
for error onto a 3500ft runway. It would have to be an awful
bad situation to make me want to try it.
But if your landing options on takeoff are so limited that you're
even considering turning back to the runway at low altitude,
why in the world aren't you making your crosswind turn at
400 or 500 or so, when the maneuver becomes pretty
comfortable? That changes the whole nature of the maneuver.
Michael
mary-anne & tom
Michael wrote in message <01be60d2$57e0c6e0$8301010a@mike-s-desktop>...
>get themselves killed? That's the big question to me. In a power
According to the January 1999 issue of Soaring 14.7% of glider accidents are
"premature termination of the tow" and 11.3% are stall spin accidents. No
breakdown as to what percentage are specifically rope breaks followed by
attempted return to airport, but clearly the 180 degree turn is hardly a
risk free maneuver, even for a glider pilot. There are only 20,000
certificated glider pilots in the USA so the number of accidents are low but
the fatality record as a percentage of certificated glider pilots isn't much
different from the fatality record as a percentage of certificated powered
pilots.
The 200 ft 180 degree turn is not necessarily the best move in a rope break;
why try it if there is a decent field in front of, or off to the side of,
the runway? Also, in a strong headwind (in a glider) after completing the
turn and applying full spoilers you now have a strong tailwind and have a
good chance of smacking into whatever is at the OTHER end of the runway.
Regards,
Tom
mary-anne & tom
>I respectfully disagree. I'm asked to do 360s in both directions, with 70
>degrees of bank, on every BFR I take. And I'm expected to do them with no
>noticeable change of altitude, and I'm disappointed if I don't hit the
>"bump" as I complete the turn.
>
>Isn't that a common requirement?
70 degrees bank? Are you sure? Private standards for steep turns are 45
degrees bank plus or minus 100 feet altitude change. Commercial standards
for steep turns are 50 degrees bank plus or minus 5 degrees with altitude
plus or minus 100 feet. As I read the standards, a 70 degree bank would
result in a failure for the task.
Regards,
Tom
Henrik Soderstrom
Very good points. And we can add yet another factor. Due to the
higher minimum-sink speed of the powered aircraft at a given
angle of bank (eg. 45 degrees) its rate of turn will be lower
ie. it will take longer and lose even more heiqht completing
the turn of 180+ degrees.
<snipped a number of other good points>
/Henrik
Henrik Soderstrom
>
> jga...@hotmail.com wrote
<snip>
> > two, are you saying that a 747 has a glide ratio of at least 27:1? That
> > would make it a pretty decent sailplane.
>
> a decent sailplane. 20:1 is actually tolerable in a sailplane, but
Depends on what you mean by tolerable. Some of the vintage types
still flying may have glide angles around 20:1 but among modern ships
(say aprox. last 20 years or newer) even the modest performing ones
are in the 30:1 neigborhood or better. The "hot ships", of course,
are in the 50-60:1 range.
/Henrik
Henrik Soderstrom
>
> Simply not true. Weight has nothing to do with glide distance IF you are flying at
> the best L/D AOA. However, your speed will change.
You are absolutely correct, assuming calm air. When there is a wind
blowing, increased weight will improve your best angle into wind and
worsen it downwind.
But in the turnaround after takeoff case the glide angle is not
necessarily the only issue.
Lower weight *will* mean that:
a. Your best glide occurs at a lower speed and consequently at a lower
rate of sink. You stay airborne for a slightly longer time.
b. Your rate of turn at a given angle of bank is greater.
You need less time to complete the turn.
c. Your best glide angle downwind is slightly better which might help
a little in actually reaching the runway, assuming you were able
to complete the turn in the first place.
(though I suspect that if the wind was strong enough for this to
matter you'd already be close enough anyway)
So, considering the above, it would seem you are better off with
less weight.
Cheers /Henrik
John T. Lowry
For the single engine-out return-to-airport maneuver, all the various
parameters (aircraft weight and flaps settings, runway length and elevation,
wind speed and direction) matter. But a crucial performance number is,
instead of just best glide ratio (which is important once the turn is made)
or minimum sink rate, the maximum turn rate PER altitude lost, dTheta/dh. As
close to (banked) stall as possible. That rate is:
Max(dTheta/dh) = -g*Rho*S*CLmax*sin(theta)*sqrt(cos^2(theta)+k^2)/(2*W*k)
where g is 32.2 ft/sec^2, Rho is density, S wing area, W weight, and
k = CD0/CLmax + CLmax/(Pi*e*A)
where CD0 is the parasite drag coefficient, e the airplane efficiency
factor, and A the wing aspect ratio. The optimum bank angle is just a little
(except for flamed-out jets) OVER 45 degrees and is given by
cos(phi_bta) = sqrt(2)*sqrt(1-k^2)/2
You'll find a full discussion in Chapter 9, Glide Performance, of my
forthcoming Performance of Light Aircraft published by AIAA.
John.
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
Henrik Soderstrom wrote in message <36D68A56...@rioja.ericsson.se>...
Tom Turton
Well, don't overlook those four big engines (cowlings, pylons) hanging out there
in the breeze. Those struts and landing gear on the 172 are (somewhat)
streamlined so not as draggy as they look (if they were really drag monsters, I
think Cessna would've gone the low wing Piper route). My aero book knowledge is
fast sublimating away off my brain cells, but I remember seeing comparisons of
round struts vs streamlined and the streamlined struts really do cut down on
drag. Sorry I don't have any hard numbers to offer you.
---Tom
Vincent Norris wrote:
> >I recall a 747 Captain telling me the glide ratio was about 17:1. The 9:1
> >from the Cessna 172 POH, by the way, is somewhat too conservative. Actual
> >measurements give about 10:1. I believe the discrepancy is due to the fact
> >that Cessna Aircraft employs lawyers.
>
> >John T. Lowry, PhD
>
> I said a 747 would glide "several" times as far as a 172 because I didn't
> know the precise number, but I'm very surprised it's only about twice as far.
>
John T. Lowry
last post should have been phi_bta (bank angles for best turn around)
instead. By the way you can see that weight W DOES matter in maximizing
dTheta/dh (rate of change of turn angle (not rate, another oops) with
altitude h).
John.
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
John T. Lowry wrote in message <7b68j6$hso$1...@news.mcn.net>...
Michael
> Why is 45deg optimal in this case? Remember you need to align with the
> runway. If you choose a wider turn you will have to turn a lot more (in
> degrees) to align with the runway.
It's an optimization problem, and was already solved quite
adequately by Dr. Dave Rodgers (sp?) - I refer you to hs work.
> Please send the dollars. In my flight manual, which admittedly is for
the
> MU-2, the 50 distance is over 1000ft longer than the ground roll.
That's a big difference - but then the MU-2 is a twin. I bet you
could do MUCH better by climbing at a slower airspeed - but
then if you lost an engine you would be hosed.
I'm sure a T-Lance can do better, but my TriPacer can
make 50'AGL in 1600' horizontal on a standard day, so
let's work from there. I seem to remember you quoted
800+ ft per nm, which is 80+ ft vertical for 600' horiz.
But now you're at 50 ft and climbing at Vx, not Vy.
Comes out just about the same.
> I agree. But I contend that practice will demonstrate that it isn't
> possible in the vast majority of cases to return to the takoff runway
with
> an engine failure while strait out.
Not if you want a safety margin, no. In a glider we do this trick
from 200 and that gives about a 100% or better safety margin.
In a power plane you can maybe do it from 500 or so with no
safety margin at all. Unless you make the crosswind turn at
500 or so - then it looks a lot better. So the point I'm making is
if your options for EFATO are so bad that you are considering
turning back at low altitude, don't be straight out.
> How do you know you can make it from 600ft? Short of actually shutting
down
> the engine there is no way to know. A plane with a failed engine with a
> windmilling prop does not glide like an engine idling. If you doubt this
> try turning over the prop 600RPM by hand. It takes a lot of power!
Well, I did do some testing at altitude with the engine shut down
with the mixture control, both with the prop windmilling and the
prop stopped.
You're right - unless you check real altitude loss that way, you
can't know. But you can do the maneuver both ways at altitude
and see the difference (that's where the 600' comes from - I can
manage it with the engine idling in 500).
The problem with the straight-out turnback is there is just no
margin for error. I would advocate learning it anyway, but there's
also no particular reason to when you can just turn crosswind
at 500 and turn a very marginal maneuver into a comfortable one.
Michael
Henrik Soderstrom
>
> Dear Mike, Henrik, and All:
> For the single engine-out return-to-airport maneuver, all the various
> parameters (aircraft weight and flaps settings, runway length and elevation,
> wind speed and direction) matter. But a crucial performance number is,
> instead of just best glide ratio (which is important once the turn is made)
> or minimum sink rate, the maximum turn rate PER altitude lost, dTheta/dh. As
> close to (banked) stall as possible. That rate is:
Well said.
> Max(dTheta/dh) = -g*Rho*S*CLmax*sin(theta)*sqrt(cos^2(theta)+k^2)/(2*W*k)
>
> where g is 32.2 ft/sec^2, Rho is density, S wing area, W weight, and
>
> k = CD0/CLmax + CLmax/(Pi*e*A)
>
> where CD0 is the parasite drag coefficient, e the airplane efficiency
> factor, and A the wing aspect ratio. The optimum bank angle is just a little
> (except for flamed-out jets) OVER 45 degrees and is given by
>
> cos(phi_bta) = sqrt(2)*sqrt(1-k^2)/2
>
> You'll find a full discussion in Chapter 9, Glide Performance, of my
> forthcoming Performance of Light Aircraft published by AIAA.
>
Much as I'd hate to bring you any bad news, it looks like you may
be repeating work already done by somebody else (?).
Check the following link, which was already provided by another
poster:
http://web.usna.navy.mil/~dfr/possible.html
/Henrik
Roy Smith
> Those struts and landing gear on the 172 are (somewhat) streamlined so not
> as draggy as they look (if they were really drag monsters, I think Cessna
> would've gone the low wing Piper route).
The decision to go high vs. low wing and the decision to go stuts vs
cantelevered have very little to do with each other. Cessna made several
high-wing models with no struts. I think they even made a low-wing model
with stuts (AgCat, no?).
Take away the struts and you need a much stronger main spar, which adds
weight. Everything is a compromise.
> I remember seeing comparisons of round struts vs streamlined and the
> streamlined struts really do cut down on drag.
Indeed. It makes a huge difference.
--
Roy Smith <r...@popmail.med.nyu.edu>
New York University School of Medicine
Henrik Soderstrom
<snip>
> cantelevered have very little to do with each other. Cessna made several
> high-wing models with no struts. I think they even made a low-wing model
> with stuts (AgCat, no?).
Yes, AgWagon actually - looks almost the same as the Piper Pawnee
and it can be hard to tell one from the other unless you know what
to look for: The trailing edge of rudder and elevators are a rounded
shape on the Pawnee and rectangular on the Cessna.
You can often see Pawnees, and occasionally an AgWagon, being used
as tugs at gliding sites.
/Henrik
Vincent Norris
>Regards,
>Tom
I mispoke (mistyped?), Tom; I should have typed 60. It was 70, IIRC, in the
military.
I've been flying with the same CFII for my checkrides for 30-some years;
he's ex-military too, and I guess he likes to give me my money's worth.
vince norris
Mike Rapoport
>That's a big difference - but then the MU-2 is a twin. I bet you
>could do MUCH better by climbing at a slower airspeed - but
>then if you lost an engine you would be hosed.
Actually neither Vx or Vy is reached at 50ft so climbing at a lower airspeed
wouldn't help. But I agree that in a low performance airplane this is less
of an issue.
>
>I'm sure a T-Lance can do better, but my TriPacer can
>make 50'AGL in 1600' horizontal on a standard day, so
>let's work from there. I seem to remember you quoted
>800+ ft per nm, which is 80+ ft vertical for 600' horiz.
>But now you're at 50 ft and climbing at Vx, not Vy.
>Comes out just about the same.
Actually the Lance takes more because
OK, you are 1600 feet from the beginning of the runway at 50ft at Vx. That
50ft will get you 375 feet going the other way (no wind) which is 1225 feet
from the beginning of the runway. The ascent and descent angles are nearly
equal in the case of the Lance. So the problem becomes: can the turn be
completed with an altitude loss of less than that required to glide 2275ft
(3500-1225). The altitude required to glide 2275 is 455ft (the descent
gradient is 1.2nm/1000ft or about 7.2/1). So you have 315 verticle ft
availible to get turned around and aligned with the runway. At Vbg (92kt,
wings level, about 800fpm) that is 24seconds to make the turn and realign
with the runway. So you need to do a lot of turning pretty fast!
Additionally the sink rate will go up a lot with the turn so in reality you
have less time, but in any event, a 3x standard rate turn is going to eat up
a lot of altitude, so you won't make the runway in a Lance. We haven't even
considered that the drag on gear retraction/extension cuts the climb rate
and increases the descent rate. I'm sure John Lowry could tell us how far
out in the bushes we and our Lance would be.
The Lance turned out to be an interesting example because the climb angle is
the same as the descent angle so nothing is gained by going higher than the
height required for the turn. I admit that is isn't much of a glider but
that is just the point. Many, if not most, GA aircraft types can't make the
return. I agree that turning crosswind greatly improves the situation.
Practicing the maneuver will get you closer to the runway but once you get
out of the trainer/bush/STOL/motorglider class of airplane you won't make it
from straight out. It turns out that the MU-2 would fare much better than
the Lance due to both a better glide angle (1.9nm/1000ft=11.4/1) and a much
higher climb angle (1nm/1050+ft=5.7/1), demonstrating that it is better to
have 1550 horsepower than 300!
Mike
MU-2
Michael
> The Lance turned out to be an interesting example because the climb angle
is
> the same as the descent angle so nothing is gained by going higher than
the
> height required for the turn. I admit that is isn't much of a glider but
> that is just the point. Many, if not most, GA aircraft types can't make
the
> return. I agree that turning crosswind greatly improves the situation.
> Practicing the maneuver will get you closer to the runway but once you
get
> out of the trainer/bush/STOL/motorglider class of airplane you won't make
it
> from straight out.
Well, I've got one more factor to throw in - why not climb at Vx instead
of Vy? I would not do it normally - but again, if your options on
EFATO are so bad you're considering a you might try that until
you are at a sufficient altitude to reach something survivable.
My guess is that this would buy you just enough extra to make it.
A 180 degree turn in 375 vertical feet is tight in a C-172.
I've never flown a Lance - if you tell me that's beyond the
aircraft's capabilities I believe you. It sure sounds like it
might be. Climbing at Vx might buy you an extra 100 ft at
that distance.
Of course the bigger airplanes don't like that kind of
handling - I don't worry too much with my O-320 but it's
about bulletproof.
Once you get into something bigger and heavier than the C-172
class aircraft I can see how it might be a problem to
to make an average-sized (3500') runway on a
no-wind day with a straight-out departure. As I mentioned before,
it's a very marginal maneuver even in the C-172 class of aircraft.
As you move into a high-performance single you have less
runway to spare, higher power-off sink rates (which is really
the critical parameter for that turn), and you get less of a
benefit from the headwind on takeoff and tailwind on a
return. Everything works against you.
I will quibble with your "Many if not most GA aircraft" - most aircraft
in the fixed-gear, fixed-pitch, 4 or fewer seats and 180 or fewer hp
CAN just barely make it - with the advantage going to the older,
slower-flying aircraft.
> It turns out that the MU-2 would fare much better than
> the Lance due to both a better glide angle (1.9nm/1000ft=11.4/1) and a
much
> higher climb angle (1nm/1050+ft=5.7/1), demonstrating that it is better
to
> have 1550 horsepower than 300!
Yeah, no kidding. Too bad we can't all afford 775 hp in each wing.
Michael
PA-22-150
Rod Farlee
>I know of no GA piston single with a climb angle greater than its
>glide angle. I'm sure they exist but are probably motor-gliders.
Huh? Many common piston singles do. Even at max gross weight.
C-172 (160/180 hp models), C-177B, PA-28-180/181, Bonanza, Tiger,
Mooney, etc. Even the C-150/152 achieves that, solo, at sea level.
However, this is not a criterion that decides whether a turnback can
be accomplished. For a discussion of what does, see:
http://web.usna.navy.mil/~dfr/technical_flying.html
The determining factors are more pilot, than airplane, and are
addressed by training, not engineering.
>I am interested to know if anyone has actually accomplished one
>(not simulated as the engine is still producing power at idle.
If you pull the mixture, the prop will windmill and accurately simulate
engine failure. However, this will not change the glide ratio as
dramatically as you might imagine.
I am interested to see the number of rather emotional responses to
this thread. I guess it's like the "spin debate"... another manuever
that seems scary in prospect, fun in retrospect, that everyone should
do in training (pre-solo, BFRs, etc).
- Rod Farlee
John T. Lowry
I typically DO climb out at Vx, for just that reason.
--
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
Michael wrote in message <01be61ce$da659440$8301010a@mike-s-desktop>...
>Mike Rapoport <rapo...@ix.netcom.com> wrote
Mike Rapoport
>I will quibble with your "Many if not most GA aircraft" - most aircraft
>in the fixed-gear, fixed-pitch, 4 or fewer seats and 180 or fewer hp
>CAN just barely make it - with the advantage going to the older,
>slower-flying aircraft.
I knew you would quibble. That is why I said: "most GA aircraft TYPES". I
recognize that the fleet is composed of mostly fixed gear 4 place singles.
Of course the guy in the retractable 6 seater is the one who will stall/spin
on the return. This is also the guy/gal who owns the plane and will try to
return. Hell, if I rented a plane and the engine failed on takeoff, I'd
crash straight ahead and return to the FBO to demand a better one!
>> It turns out that the MU-2 would fare much better than
>> the Lance due to both a better glide angle (1.9nm/1000ft=11.4/1) and a
>much
>> higher climb angle (1nm/1050+ft=5.7/1), demonstrating that it is better
>to
>> have 1550 horsepower than 300!
>
>Yeah, no kidding. Too bad we can't all afford 775 hp in each wing.
I can't be certain, but if you lost an engine on takeoff, I'd bet that you
would consider any price to be affordable for a second one!!!
Mike
MU-2
Mike Rapoport
Are You sure about this? The 172 that I learned in climbed 700fpm at 65kts
(this is from memory) this is a climb angle of 646/mn. I don't recall the
glide for a 172 but Barry Schiff's book has 8.5/1 for a 152 which is 705/nm.
I wouldn't think that a 172 is much better (It needs to be about 10%
better). I don't know about the others but with the retractables one needs
to consider that the max climb angle is not reached until the gear is up and
the sink goes way up after extension.
>>I know of no GA piston single with a climb angle greater than its
>>glide angle. I'm sure they exist but are probably motor-gliders.
>
>Huh? Many common piston singles do. Even at max gross weight.
>C-172 (160/180 hp models), C-177B, PA-28-180/181, Bonanza, Tiger,
>Mooney, etc. Even the C-150/152 achieves that, solo, at sea level.
>
>However, this is not a criterion that decides whether a turnback can
>be accomplished. For a discussion of what does, see:
>http://web.usna.navy.mil/~dfr/technical_flying.html
>The determining factors are more pilot, than airplane, and are
>addressed by training, not engineering.
>
Everyone on this newsgroup has the "Right Stuff" and is willing to try
anything if it is even remotely possible!!!
>>I am interested to know if anyone has actually accomplished one
>>(not simulated as the engine is still producing power at idle.
>
>If you pull the mixture, the prop will windmill and accurately simulate
>engine failure. However, this will not change the glide ratio as
>dramatically as you might imagine.
OK
>I am interested to see the number of rather emotional responses to
>this thread. I guess it's like the "spin debate"... another manuever
>that seems scary in prospect, fun in retrospect, that everyone should
>do in training (pre-solo, BFRs, etc).
>- Rod Farlee
If you think that this topic is emotional then go to the "shock-cooling"
thread!!!
Mike
A. Little
behind it.
There has been a lot of theorising over minimum turn around altitudes,
some of which seems to be very esoteric to me.
So far, I have seen no factoring in of other real world problems. Nor
any emphasis on the wisdom of carrying out steep turns at very low
altitude, power off, in a highly unusual, high stress situation whilst
simultaneously endeavouring to advise those now using the runway behind
you that you are returning for a down wind landing, carrying out engine
failure drills and pre landing checks, adjusting the turn to align
yourself with the runway......GEAR!!!
I would suggest that for the sake of any inexperienced/low houred pilots
who may be lurking in on this, you might consider including in your
discussion the highly probable consequences of failing to pull off this
manoeuvre.
I would go on to suggest that in almost all real world situations, with
an unanticipated engine failure, much below 700-800ft above ground
level, involving the most common single engined trainers & tourers,
you are almost certainly not going to be able to realign yourself with
the runway if you try to turn back.
A 180 won't do it, and any significant wind is going to eat up any
manoeuvring space you might have theorised about.
Took off with a crosswind? Did you turn up wind or downwind initially?
Why?
--
A. Little
John T. Lowry
You're right there are lots of factors to consider. All the more reason
to practice, calmly, first at altitude and only later down low.
Also, what some of us do is add an item to our pre-takeoff check list
which, in action, goes something like this: "Today, at this altitude with
this terrain and this airplane at this weight, if the engine fails soon
after takeoff I'll only consider a return-to-airport maneuver if I'm between
500 and 800 ft AGL (actually, one translates this to altimeter readings) and
then, since there's a left crosswind, I'll bank to the left..."
Somebody once asked Tom Landry what was the secret of producing a
championship football team. He responded: "Just practice one thing at a
time. And do it until you get it right." So there's no need to throw up
one's hands just because things can get complicated.
John.
--
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
A. Little wrote in message ...
Rod Farlee
>Are You sure about this?
Yes. Please note that C-172s have come with four different engines
from 145 to 180 hp over the years.
But this is irrelevant. Turnbacks can be done safely in any of them. The
higher power ones actually make turnbacks more difficult, to me at least.
They climb so well that, in typical wind conditions, at sea level, after the
turnback one can end up with too much altitude and overrun end of the
runway. After the simulated engine failure, one may have to continue
straight out, away from the airport, into the wind, for several seconds, to
avoid this outcome.
I am surprised to see this topic discussed on such a "hypothetical" or
theoretical plane. When I was a student, my CFI started pulling
simulated engine failures more and more frequently, before he would ever
let me solo. I expect them in BFRs. I find I need to do them every few
months to feel proficient. That's because I don't have the "right stuff".
Nothing hypothetical about it.
The benefits of practicing this extend to other situations, and may enable
you to save yourself, or at least avoid killing yourself by attempting the
impossible. I am surprised to see anyone argue against training. It works.
http://web.usna.navy.mil/~dfr/possible.html
- Rod Farlee
John T. Lowry
A. Little wrote in message <4wE$BCA2AR...@theedges.demon.co.uk>...
>>if the engine fails soon
>>after takeoff I'll only consider a return-to-airport maneuver if I'm
between
>>500 and 800 ft AGL (actually, one translates this to altimeter readings)
and
>>then, since there's a left crosswind, I'll bank to the left..."
>> Somebody once asked Tom Landry what was the secret of producing a
>>championship football team. He responded: "Just practice one thing at a
>>time. And do it until you get it right." So there's no need to throw up
>>one's hands just because things can get complicated.
>> John.
>
>I wonder why you turned left, with a crosswind from the left?
>
>--
>A. Little
Mike Rapoport
Mike
MU-2
Mike Rapoport
first rule of engineering is "Never guess when you can test". The accident
record contains many fatal crashes during attempts to glide back to the
departure runway followed by spins.
The point of the discussion was that some aircraft cannot make the
turnaround and glide back to the runway if they experience an engine failure
before turning crosswind. IMHO it is at least as important to recognize
that the maneuver is not always possible as it is to practice it.
In the book "Proficient Pilot" vol 1, author Schiff says that he and some
others experimented with a 172L (and some other types also) and found that
300 vertical feet were required to complete a 180deg turn with 45deg of
bank. Further testing revealed that another 50%, or 150 feet, were required
to realign with the runway (the 45deg bank at 5% above stall gives 854' of
lateral displacement). So they concluded that a minimium 450 feet was
required in a 172L (no wind).
Mike
MU-2
Rod Farlee wrote in message
<19990228091103...@ngol04.aol.com>...
snowb...@my-dejanews.com
"Mike Rapoport" <rapo...@ix.netcom.com> wrote:
[question of whether climb angle greater than glide angle. Rod Farlee
says "often true"]
> Are You sure about this? The 172 that I learned in climbed 700fpm at 65kts
> (this is from memory) this is a climb angle of 646/mn. I don't recall the
> glide for a 172 but Barry Schiff's book has 8.5/1 for a 152 which is 705/nm.
> I wouldn't think that a 172 is much better (It needs to be about 10%
> better).
First, small point:
I think there is an inaccuracy (albeit small for your example) in how
you are calculating climb angle? Talking trig, it seems you are using
the hypotenuse as the numerator of the climb ratio instead of solving for
the horizontal distance traveled across the ground at that climb speed
and rate of climb?? (this will of course make a larger difference for
planes with a better climb angle, which is why I mention it rather than
letting it go as a nit. It makes a difference of 4 ft for your example).
Gory details on request, but it's straightforward trig.
In addition, the POH gives rates of climb at Vy (76 not 65 kts for C172).
Note that while rate of climb will of course be lower at Vx, climb
angle (our real concern here) will be higher at Vx.
That said, AFAIK you are correct that POH-calculated climb angle (using
Vy) is typically smaller than the POH-calculated glide angle. However,
as we'll see, this comparison ignores the important factor of runway
length.
According to my C172 POH, the glide ratio is about 1:9 or 6.3 degrees.
From the same C172 POH, the rate of climb is 700 fpm at sea level Vy
of 76 kts. This works out to a climb angle of 5.2 deg or (in your
units) a mere 555 ft/nm--much worse than your numbers.
FTR, the same is true for my Grumman Tiger: Vy climb angle of 5.1
degrees is less than POH glide angle of about 5.7 degrees.
But, as I said, comparing POH glide angles and climb angles doesn't
tell the whole story.
Let's consider the effect of runway length. Suppose one is
using a 3000 ft runway. Supposing we lift off at 1500 ft, something
the POH alleges one can do even at full gross and quite high density
altitude. Supposing one climbs at an angle of 5 degrees (a bit
less than the POH claims for Vy climbout). By trig, at 400 ft altitude,
one has travelled ~4600 ft from one's liftoff point. However, to return
to the runway, one need only travel 3100 ft (4600-1500 ft). This requires
a glide ratio of less than 8:1 (7.4 degrees), less than the POH claims and
considerably less than some folks assert that their C172 achieves. Of course,
the altitude lost in the turn must also be considered, this example is just
to make the point that one can't simply compare glide and climb angles and
say "it can't be done because climb angle is less than glide angle".
Other issues are: what angle of climb can one actually achieve,
given current conditions of density altitude, wind, loading, and the
performance of this individual plane? What sort of takeoff did one
perform--short field with a Vx climb-out, or a lengthy ground roll
followed by Vy climb-out? How long is the runway and how much is needed
for takeoff? What sort of obstacles must be cleared at the end? What
glide ratio can one actually achieve in this individual plane?
None of these issues are IMO well addressed by the POH's I've
seen, nor (naturally) is the issue of pilot skill in turning back,
holding Vbg etc.
My personal opinion is that the only way to make an intelligent
decision about turnback altitudes is to go out and try it, *in a
specific plane and specific set of conditions*, then be aware
how changing planes and conditions may affect one's tests. Clearly
at some altitude and runway length under certain conditions, it is
possible to turn back easily, so a certain prohibition against any
turnback at any altitude seems to limit one's options unnecessarily.
Clearly at another altitude, it is not possible. In between is a
grey zone where the pilot had better have thought things through
carefully and maintained proficiency before thinking about turnback.
Snowbird
-----------== Posted via Deja News, The Discussion Network ==----------
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A. Little
Henrik Soderstrom
<snip>
> A 180 won't do it, and any significant wind is going to eat up any
> manoeuvring space you might have theorised about.
Actually, any significant wind is normally going to improve your
theoretical chances, not the reverse.
On the other hand gusts and wind shear factors would reduce your
precision and add to the dangers in an already critical high stress
situation. The real-world considerations you bring up are perfectly
valid.
> Took off with a crosswind? Did you turn up wind or downwind initially?
> Why?
Into wind: a couple of reasons already mentioned in other posts:
- steeper angle of climb relative to the ground
- helps by setting you back towards the centreline.
Another couple of factors:
- If you have already started to turn before the engine fails
the angle you have to turn through to get back is smaller.
- If you are already maintaining a crab angle against a
crosswind, and assuming you'll want to end up with a crab
angle on your final approach after completing the turn,
the angle you turn back through is smaller - in an extreme
case you may even need less than a 180 degree turn.
/Henrik
Rich Carr
is the effect of density altitude. At higher altitudes, climb rate is
reduced and sink rate is increased, which obviously makes the ratio of
the two worse for the turnaround.
- Rich Carr
St Stephen Ames
A great reason to go practice this at different altitudes...
--
Till the next time,
St Stephen Ames
54.0 Total hrs(34.8hrs dual, 19.2hrs solo, 231 landings!)
"When my abilities = my desire & commitment,
I will be one hell of a pilot!"
My flying site: http://www.stephenames.com/flying/flying.html
----------------------------------------------------------------
"St Stephen with a rose, in and out of the garden he goes,
country garden and the wind and the rain,
wherever he goes the people all complain!"
Michael
> I knew you would quibble. That is why I said: "most GA aircraft TYPES".
I
> recognize that the fleet is composed of mostly fixed gear 4 place
singles.
Right. That's what I own, and that affects my perspective.
> Of course the guy in the retractable 6 seater is the one who will
stall/spin
> on the return. This is also the guy/gal who owns the plane and will try
to
> return. Hell, if I rented a plane and the engine failed on takeoff, I'd
> crash straight ahead and return to the FBO to demand a better one!
Honestly, even though I own my plane, if I expected that I was going to
be able to get off with nothing worse than property damage, I'd let the
insurance company worry about it. You posted elsewhere that a 172
needs an absolute minimum of 450 ft to make it back on a straight
out departure - that leaves no room for error (and a TriPacer is worse
because of the shorter wings and higher power-off sink rate). I'm
not too into doing maneuvers with no margin for error in order to
avoid property damage I've already bought insurance to cover. You
can call it wimpiness.
The time to do this for real at minimum altitude is when landing
straight ahead puts you into freezing water or a factory or some
such thing - where your survival is very much in doubt regardless
of landing technique.
You don't do this maneuver to save your plane - you do it to save
your passengers - which is why I consider actually lining up on
the pavement a secondary matter. If I've avoided the factory and
put down on the grass by the runway after a 500 ft engine
failure, I feel the maneuver is a success.
Of course here again we have to contend with differences between
the 4-seat fixed gear and the 6-seat retract. With few exceptions
(Commanches?) the 6-seat retracts have higher stall speeds
and flimsier gear. So they both need the maneuver more because
they are less safe landing off the airport and are less able to
execute it because of greater runway requirements and higher
power-off sink rates.
> I can't be certain, but if you lost an engine on takeoff, I'd bet that
you
> would consider any price to be affordable for a second one!!!
Only if I could actually pay it. Most of us here can't afford a plane
that can actually climb on one engine at reasonable loading,
never mind the fuel, maintenance, and insurance. Most of us
here actually spend most of our disposable income on the
fixed gear 4-place singles that constitute most of the GA fleet.
There is a reason the fleet is mostly fixed gear 4 place singles.
Michael
PA-22
John T. Lowry
Right you are! About density altitude influencing the return-to-airport
maneuver.
Years ago I gave a talk at a Montana Aviation Conference, in Missoula
that year, which presented nine scenarios at various gross weights, density
altitudes, and headwind/tailwind situations. All for a Cessna 172 which
conked out at 500 ft AGL. On a paved 3000' runway. Of the nine, only three
could even conceivably (doing everything precisely correctly) could make it
back to the runway. Of course there are some other considerations, such as:
Is it better NEARER the runway rather than farther out?
Since there are so many aspects to the problem, it's fairly laborious to
go through each one in detail. Of course -- AD! AD! -- The Bootstrap
Approach makes it much simpler. I also presented some concrete details in an
article in Mountain Pilot magazine a couple of years back.
John.
--Rich Carr wrote in message <7befia$5nk$1...@fcnews.fc.hp.com>...
Rich Carr
: An additional factor I haven't seen discussed in this excellent thread
: is the effect of density altitude. At higher altitudes, climb rate is
: reduced and sink rate is increased, which obviously makes the ratio of
: the two worse for the turnaround.
I overstated the case a bit, since the descent *angle* is unaffected
by density altitude (ignoring the effect of wind and assuming Vbg is
flown). Climb *angle* is reduced along with climb rate.
Rather a serious oversight on the part of a glider pilot.
- Rich Carr
CFIG
A. Little
<rapo...@ix.netcom.com> writes
>To increase his angle of climb.
>
Regards,
--
A. Little
A. Little
writes
>That way the wind sets you back towards the runway centerline.
>-
And whilst you're at it, what is your normal approach profile in a
single engined a/c?
--
A. Little
Michael
> which is determined by sink rate - which does
> decrease with increasing density altitude.
^^^^^^^^^^^^
I meant increase of course.
Michael
Michael
<7beolm$8ka$1...@fcnews.fc.hp.com>...
> I overstated the case a bit, since the descent *angle* is unaffected
> by density altitude (ignoring the effect of wind and assuming Vbg is
> flown). Climb *angle* is reduced along with climb rate.
Yeah, but the descent angle is the LEAST important part of
the equation - the lion's share of altitude is lost in the
turn back, which is determined by sink rate - which does
decrease with increasing density altitude.
As a practical matter - I am not aware of ANY instances where
a pilot attempted a turnback and then got killed by landing
short of the runway but approximately on runway heading and
in the airport environment. When people get killed doing this,
they get killed because they do not land in control - they
run out of airspeed. I even know someone who has actually
seen the maneuver botched in such a way that the pilot
crashed ON the runway in C-182. Multiple fatalities resulted.
What makes the maneuver easier in a glider is not the
greater glide angle but the lower sink rate.
Michael
snowb...@my-dejanews.com
rodf...@aol.com (Rod Farlee) wrote:
> Yes. Please note that C-172s have come with four different engines
> from 145 to 180 hp over the years.
> But this is irrelevant. Turnbacks can be done safely in any of them.
I guess I have to horn in again here. Turnbacks can be done safely in
any of them, *given certain conditions of runway length, density altitude,
aircraft load, wind, and above-ground altitude achieved at the point of
engine failure.* Not to mention pilot proficiency, as you point out.
Mike's point that the climb angle of light singles is typically less
than their glide angle appears to me, from perusal of every POH I
could get my hands on, to be correct -- especially true if the climb
angle considered is that of the typical Vy climbout. I think this
relevant, and important to understand so that the effect of factors
such as density altitude and runway length can be properly appreciated.
To clarify, turnback is sometimes possible and may in fact necessitate
maneuvers to lose excess altitude, not because climb angle is greater
than glide angle, but because of other factors including da, rwy length,
aircraft weight, wind, and pilot proficiency.
> They climb so well that, in typical wind conditions, at sea level, after the
> turnback one can end up with too much altitude and overrun end of the
> runway.
And they climb so poorly that, in light wind conditions, at the 4000 ft
density altitudes which are not uncommon in the flat midwest mid-summer,
at max gross, on a 2000 ft runway, one had better not even think about
turning back below traffic pattern altitude, and then only if one has already
turned crosswind.
Yes, I'm exaggerating a bit here. It makes me uncomfortable to read general
"Do Not Ever Turn Back You Will Die" type statements because clearly at
some altitude one has enough 'glide range' to fly a tight pattern back
to the departure end of the rwy. But it makes me just as uncomfortable to
read general statements which seem to me to imply turnback always involves
a need to lose excess altitude. Under some conditions, it will. Under
others, from the same height AGL, there will not be enough altitude.
> I am surprised to see this topic discussed on such a "hypothetical" or
> theoretical plane. When I was a student, my CFI started pulling
> simulated engine failures more and more frequently, before he would ever
> let me solo.
While I'd never argue against training, I don't know why one would be
surprised by the hypothetical plane (pun intended?) of this discussion.
The fact is, due to the accident record, the current emphasis in most
training is "never turn back" and the procedure expected of a student
for a simulated engine failure on climbout is "land 60 degrees to either
side of straight ahead". So I suspect it's a regime many CFIs have not
encouraged their students to explore. I'm not agreeing with this philosophy,
simply pointing it out.
However, I think turnback is a subject where the theoretical is important,
as the pilot contemplating one must understand that the same turnback
scenario which was practiced successfully at sea level in spring on a
3800 ft runway, may fail from the same height agl if any of these conditions
are changed.
Regards,
John T. Lowry
turn, then it's NOT sink rate, but altitude-loss-per-degree-turned which is
the pivotal parameter. The formula for that is somewhat complicated, but I
think I gave it here a few days back.
--
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
Michael wrote in message <01be642b$2ee3b980$8301010a@mike-s-desktop>...
Dave Mould
A. Little wrote in message ...
No, I don't get it. I see no disadvantages with making the initial turn
into-wind excepting circumstances specific to the occasion (terrain, traffic
etc.) "Normal approach profile" wrt possible engine failure in a single has
been thrashed many times in this newsgroup - and has no bearing on an EFTO
scenario. Why not post what you mean straight out rather than present us
with riddles? There are few occasions where a paternalistic posting style
is either necessary or appropriate.
Dave Mould
Michael
> If you're interested in losing the least altitude in (say) a 180-degree
> turn, then it's NOT sink rate, but altitude-loss-per-degree-turned which
is
> the pivotal parameter. The formula for that is somewhat complicated, but
I
> think I gave it here a few days back.
John
I have no doubt in the accuracy of the mathematical
analyses you have done here - what I have been able
to follow has been good, and having a Ph.D. in
engineering allows me to follow quite a lot.
But please do consider the practical nature of the
problem - there are factors that are dominant, factors that
are minor, and factors that will for all intents and purposes
be constant.
For all practical purposes, the maneuver in question is
a turn back to the runway (or a completion of a turn
already begun, as in crosswind turn) that is flown
coordinated (whatever that may take - some may be
surprised to hear that this can mean lots of bottom
rudder and opposite aileron) at 45 degrees of bank
and several knots over the stall speed corrected for
45 degrees of bank (18% increase) with a rollout just
a little past the intended touchdown point on the
runway, followed by a correcting turn on final.
Given this as a constant, the dominant factor in the
altitude lost in the maneuver is the power-off sink
rate. The other factors are comparatively small,
affecting the total altitude required by well under
100 ft.
I understand as a physicist you feel the need to
account for all of them anyway; I'm sure you'll
understand that as an engineer I'll ignore them
unless it can be shown that they significantly
affect the final result.
Michael
Rod Farlee
Any analysis that attempts to "prove" the following incidents are
impossible is missing something... because they aren't even rare.
FAA INCIDENT DATA SYSTEM REPORT
Report Number: 841223070059G
12/23/1984 09:45 FRYEBURG, ME
Aircraft Damage: NONE
Aircraft Make/Model: CESSNA CE-172-N
POWER LOSS AFTER COMPLETING CLIMB. TURNED BACK TO AIRPORT
LANDING DOWNWIND OVERSHOT. STUD ON ROCKER ARM BROKEN.
Wind Direction (deg): 32
Wind Speed (mph): 08
Instructional flight, 2 aboard.
Report Number: 960323004909G
03/23/1996 15:16 HUNTSVILLE, AL 3M5
ENGINE QUIT ON CLIMBOUT TURNED BACK. LANDED FAST. RAN OFF
END RUNWAY. HIT DITCH AND NOSED OVER.
Wind Direction (deg): 15
Wind Speed (mph): 04
Report Number: 840630035469G
06/30/1984 11:30 WATERLOO, IA
Aircraft Damage: NONE
Aircraft Make/Model: PIPER PA-22-160
ENGINE QUIT ON TAKEOFF CLIMB DUE TO FUEL STARVATION. FUEL
SELECTOR ON EMPTY TANK. TURNED BACK LANDED NEAR RUNWAY.
Wind Direction (deg): 07
Wind Speed (mph): 09
Some factors you're neglecting are wind, weight below max gross, and
whether the power loss is partial or complete.
- Rod Farlee
Rod Farlee
>The accident record contains many fatal crashes during attempts to
>glide back to the departure runway followed by spins.
True, but I draw the opposite conclusion. For each turnback accident
in the NTSB database, one can find two or three successful turnback
incidents in the FAA database.
Some of the successful turnbacks are in the FAA incident database
because they involved overrunning the departure end of the runway,
hard landings, or loss of directional control after touchdown. I would
still consider those successes, if the alternative was crashing into
trees, lakes or homes.
None of us know how many uneventful turnbacks are never reported.
They probably far outnumber the reported ones.
The real lesson of the accident record is the need for turnback training.
Dave Roger's study clearly shows that a little training results in a big
improvement in safety.
Brett Rabe
> Of course here again we have to contend with differences between
> the 4-seat fixed gear and the 6-seat retract. With few exceptions
> (Commanches?) the 6-seat retracts have higher stall speeds
> and flimsier gear. So they both need the maneuver more because
> they are less safe landing off the airport and are less able to
> execute it because of greater runway requirements and higher
> power-off sink rates.
Why less safe landing off field? I'd just land gear up ....
putting my belly in the dirt is at least as safe (from an
injury perspective) as dropping those three little wheels
into the mud, no?
And, I wouldn't call you a wimp. :-)
> > I can't be certain, but if you lost an engine on takeoff, I'd bet that
> > you
> > would consider any price to be affordable for a second one!!!
Nonsense. I'd consider any price to be affordable
for training so that I could deal with the emergency
appropriately. But a second engine? No thanks.
Brett
--
Brett Rabe Email : br...@uswest.net
Systems Administrator - U S West Phone : 612.664.3078
Interact - 3S Pager : 612.613.2549
600 Stinson Blvd. Fax : 612.664.4770
Minneapolis, MN 55413 USA Pager : page-...@uswest.net
Four minus two is one and the same.
A. Little
>into-wind excepting circumstances specific to the occasion (terrain, traffic
>etc.) "Normal approach profile" wrt possible engine failure in a single has
>been thrashed many times in this newsgroup - and has no bearing on an EFTO
>scenario. Why not post what you mean straight out rather than present us
>with riddles? There are few occasions where a paternalistic posting style
>is either necessary or appropriate.
>
>Dave Mould
>
>
I don't know you from Adam, nor the others who are involved in these
related threads. How else would I be able to asses what level of
competence is brought to the debate, either by yourself or others?
If you personally feel slighted, I do apologise for that. It was not my
intention to upset anyone.
There is so much of a practical nature missing from this debate, and so
much potentially dangerous theorising being thrust forward, that I had
hoped to be able to influence some move towards the real world.
Not entirely without failure, either.
I see you have now qualify your previous bald statement that you would
turn into the wind, to take into account something of the real world.
I would suggest that very few professionals climb out at best angle
other than for terrain avoidance or minimum noise routings.
Nor would they make initial turns into wind after take off, to cover the
possibility of engine failure.
Traffic pattern, not wind direction will determine the direction of
turn, if staying in the circuit.
If not, then most will be looking for en route climb, at best speed for
economy, as laid down in SOPA's.
Unless of course they are very low houred, looking to build up hours!
Equally, and particularly in view of the US propensity for giving
landing clearance to aircraft at some distance out on the approach,
irrespective of whether or not the runway is clear, other traffic should
be a factor in any decision to make an immediate return to a down wind
landing.
If the general belief is that aircraft performance is the limiting
factor for a return to a downwind landing after engine failure, then I
think people are being mislead, into a very dangerous area.
Factors other than the aircraft will almost always decide the limits of
what can and can not be achieved. Failure to acknowledge this is fool
hardy and it is going to continue to cause unnecessary deaths.
Might I suggest an acknowledgement of the real world in this debate? For
the sake of we mortals.
--
A. Little
Mike Rapoport
Brett Rabe wrote in message <36DC2DFE...@uswest.net>...
>> > I can't be certain, but if you lost an engine on takeoff, I'd bet that
>> > you
>> > would consider any price to be affordable for a second one!!!
>
>Nonsense. I'd consider any price to be affordable
>for training so that I could deal with the emergency
>appropriately. But a second engine? No thanks.
The emergency, even if properly and perfectly dealt with, may not result in
your survival. IMHO the second engine AND the training to use it eliminates
the potential emergency altogether. To me this is preferable to perfecting
the ability to salvage the situation some of the time.
Mike
Michael
> putting my belly in the dirt is at least as safe (from an
> injury perspective) as dropping those three little wheels
> into the mud, no?
If it's mud, yes. If it's knee-high brush or rocks, I doubt it.
And that only deals with the retract portion - stalling at
60 kts rather than 40 doubles the energy on impact and
there's not a thing you can do about that.
> Nonsense. I'd consider any price to be affordable
> for training so that I could deal with the emergency
> appropriately. But a second engine? No thanks.
I'd love to have a second engine. If I could afford a twin
that could carry 4-5 hours of fuel and 600+ lbs of people
and cargo and still get in and out of 2500 ft of grass or
gravel AND climb on one engine on a hot Texas summer
day, you can be sure I would own one. But that's way
more airplane than I can afford.
Michael
Dave Mould
>
>I don't know you from Adam, nor the others who are involved in these
>related threads. How else would I be able to asses what level of
>competence is brought to the debate, either by yourself or others?
Ditto with yourself. Read what we say and how we say it, and judge for
yourself. That's what I do, anyway. No need for quizzes - most will come
out and say what we think anyway!
>
>If you personally feel slighted, I do apologise for that. It was not my
>intention to upset anyone.
No personal slight taken. Simply an observation on general tone. I suspect
that you have a wide wealth of experience to share. Realise that many other
posters are equally (but differently) experienced. It's surprising how many
long-cherished beliefs are debunked and modified after conversing with other
knowlegable folk, so long as you keep an open mind. No less so whether you
are 18 or 81.
>
>There is so much of a practical nature missing from this debate, and so
>much potentially dangerous theorising being thrust forward, that I had
>hoped to be able to influence some move towards the real world.
>
Most of us have exactly the same wish. Some theoretical observations from
qualified posters is welcome though. You'll usually find that amongst all
the theory, there are some sound practical caveats tucked away.
>I see you have now qualify your previous bald statement that you would
>turn into the wind, to take into account something of the real world.
No, I did not make the original statement to that effect - you are reading a
post from a different person. FWIW, I am not a "turnback" proponent, as my
previous posting history will show. OTOH, there are no hard and fast rules
to this, and if a pilot is in practise and well set up for a turnback, it
would be foolish not to take the opportunity. If the pilot is not certain
of the outcome, my feeling is that an off-field landing in a direction that
can be attained with assurance is the safest course of action. In r.a.s. I
am far more vociferous in arguing against a turnback - it takes a fair bit
of experience to know when it is possible and when not. A mistake of *not*
turning back will usually (IMHO) have a better outcome than a mistake the
other way, but it's not something to be dogmatic about.
>
>I would suggest that very few professionals climb out at best angle
>other than for terrain avoidance or minimum noise routings.
>
ISTM that in a typical GA aircraft the climbout is not *that* far off best
angle. Others will no doubt be able to put figures to it.
>
>Nor would they make initial turns into wind after take off, to cover the
>possibility of engine failure.
>
Well, maybe I'm an exception. If there is a particularly strong X-wind,
I'll usually deliberately plan my turnout into wind. At the airport I fly,
the prevailing wind is usually from the right, so this means a turn against
the usual traffic, which is quite acceptable 99.9% of the time. If I want
to ultimately head the other way, doing a 270 instead of a 90 degree turn
adds only a minute to the flight time, by which time I'm high enough to have
better options. We're talking GA VFR, not heavy metal on a SID.
>Traffic pattern, not wind direction will determine the direction of
>turn, if staying in the circuit.
>
True, circuit bashing leaves few options in this regard. OTOH the %
exposure over the "lifetime" of flying is pretty small unless you are an
instructor.
>If not, then most will be looking for en route climb, at best speed for
>economy, as laid down in SOPA's.
In my case, only after I'm high enough to have some breathing space. What
difference are we talking about anyway? A minute? Two minutes?
>
>Unless of course they are very low houred, looking to build up hours!
>
You can do that by throttling back at altitude. Why fly around at cruise
setting for a local sightseeing trip? In a hired aircraft, I don't get a
better price rate by doing so, but ISTM to be a benefit for the club that
has no adverse effects. I've taken 1.5 hours to fly to a destination I
could have made an hour, because for me, the flight is the main thing, and I
want to enjoy it as long as possible!
>Equally, and particularly in view of the US propensity for giving
>landing clearance to aircraft at some distance out on the approach,
>irrespective of whether or not the runway is clear, other traffic should
>be a factor in any decision to make an immediate return to a down wind
>landing.
>
That would depend to an extent on whether an off-runway landing is feasable.
It would be unlucky to hit an aircraft taking off or landing under these
circumstances - and I would not think of a high probability. Call "Mayday"
ASAP, and most other pilots on freq. would get themselves into gear pretty
quickly and have time to get out of the way one way or another before your
arrival. I'm not saying that it's no risk at all - just that overall it's
not the highest risk IMHO. Having said that, I am personally of the opinion
that a land-ahead in whatever reasonably open area is available is usually
the best decision unless the pilot is really on the ball and experienced. I
suspect that that is what I'd do below - say - 1000 feet. OTOH my aircraft
glides like a brick doesn't.
>If the general belief is that aircraft performance is the limiting
>factor for a return to a downwind landing after engine failure, then I
>think people are being mislead, into a very dangerous area.
>
My belief is that the limitation is a combination of aircraft performance
and pilot capability - which includes a real-world knowlege of what the
pilot is capable of achieving in that particular aircraft - aka experience.
If not sure - don't do it. Many posts advocate specifically training for
the event, and I concur with this. It's not the number of hours that count,
it's what you do with them!
>Factors other than the aircraft will almost always decide the limits of
>what can and can not be achieved. Failure to acknowledge this is fool
>hardy and it is going to continue to cause unnecessary deaths.
>
Factors *as well as* the aircraft performance will determine the overall
limit. My options in a Cub are far different to my options in the Provost.
IMHO, failure to acknowlege the aircraft performance would be equally
foolhardy. An EFTO in a Cub will see me behaving significantly differently
to a failure at a similar point in the Provost, yet everything *except* the
aircraft characteristics are the same. Do you honestly think this is the
wrong attitude?
>Might I suggest an acknowledgement of the real world in this debate? For
>the sake of we mortals.
>
Both theory and practice are important. Not too long ago you were
expounding a variation of the "downwind turn" myth. Theory explains both
why it doesn't happen and also why it often appears to be the case, and what
to watch out for so that you don't fall a victim. Yes - the downwind turn
can be a killer, but not for the reasons usually cited. Stick and rudder
skills are very important, and are actively assisted by a complete
understanding of all the theoretical as well as the real-world factors that
are involved. Theory differs from real-world only in that it usually takes
a simplified model and often fails to take into account the human factors
involved.
Dave Mould
TMetzinger
<cre...@flash.net> writes:
>With few exceptions
>(Commanches?) the 6-seat retracts have higher stall speeds
>and flimsier gear. So they both need the maneuver more because
>they are less safe landing off the airport and are less able to
>execute it because of greater runway requirements and higher
>power-off sink rates.
>
I agree. The POH for the Trinidad I fly specifically says to land gear-up on
an unprepared surface. The PC12, on the other hand, is built like a tank, so
unless I was landing in a forest or in the water, I might lower the gear if
landing on a decent field.
Clear Skies!
Timothy Metzinger
Private Pilot - ASEL - IA!!!! AOPA Project Pilot Mentor
DOD # 1854 '82 Virago 750 - "Siobhan"
TB-9s, TB-10s, C172Rs at FDK (No Names)
PGP Public Key Available on Keyservers
John Robbins
> "John T. Lowry" <jlo...@mcn.net> writes:
> > Somebody once asked Tom Landry what was the secret of producing a
> > championship football team. He responded: "Just practice one thing at a
> > time. And do it until you get it right." So there's no need to throw up
> > one's hands just because things can get complicated.
>
> A music teacher of mine used to tell me to practice, and keep practicing
> until I get it right. Then keep practicing until I don't get it wrong.
> Managing any manouevre once isn't a sign of proficiency (I know that's not
> what you meant, John). Managing it every time makes it more likely that you
> will be able and ready to do it if (when?) you need to.
>
> a.
> --
> Angus Duggan, Harlequin Inc, 1201 Third Ave, | INET: an...@harlequin.com
> Suite 2380, Seattle, WA 98101, U.S.A. | FAX: +1 (206) 447 8181
> http://www.dcs.ed.ac.uk/home/ajcd/ | U.K. PPL(A) IMC Night
> http://www.tardis.ed.ac.uk/~ajcd/ | Still learning, upside-down
When I coached a 10-12 year old girl's softball team I always told them
practice makes perfect only if you are practicing it the right way. After 25
years of flying I take advantage of the Wings program to fly with an
instructor and make sure I am practicing correctly.
John Robbins
EAA, AOPA, SPA