Turn Back Maneuver
Ron Rosenfeld
site on which he had posted the results of a scientific analysis of the
"turn-back" maneuver as well as some studies done using average pilots.
IIRC, the optimum maneuver was a 45 deg turn at stall speed.
Does anyone have the URL?
Thanks.
ron
PROF D. Rogers {EAS FAC}
click on technical flying.
Dave Rogers, PhD, ATP
E33A Bonanza
Have a look at
www.nar-associates.com/flying-adventures/flyadvm.html
if you have dreamed of flying to distant places.
In article <7vhks4$rcg$1...@ash.prod.itd.earthlink.net>,
Darrell Schmidt
least amount of lateral space would be an immelman which takes NO room. I
would think the next best manuever if your aircraft didn't have immelman
capability would be a chandelle. If a turn in level flight was required,
the manuever you list below would probably be the best.
Ron Rosenfeld wrote:
> One of the scientist participants in these NG's had a reference to a web
> site on which he had posted the results of a scientific analysis of the
> "turn-back" maneuver as well as some studies done using average pilots.
> IIRC, the optimum maneuver was a 45 deg turn at stall speed.
>
> Does anyone have the URL?
>
> Thanks.
>
> ron
--
Home Page: "B-58 HUSTLER" http://members.home.net/dschmidt1/
E-Mail: dsch...@home.com
John
>Ron Rosenfeld <ronros...@earthlink.net> wrote:
>>One of the scientist participants in these NG's had a reference to a
web
>>site on which he had posted the results of a scientific analysis of
the
>>"turn-back" maneuver as well as some studies done using average
pilots.
>>IIRC, the optimum maneuver was a 45 deg turn at stall speed.
>>
>>Does anyone have the URL?
>>
>>Thanks.
Ron....
The two URLs for Dr. Roger's articles are:
http://web.usna.navy.mil/~dfr/possible.html
http://web.usna.navy.mil/~dfr/aiaa1col.pdf
These are interesting reading, but nothing new. He published this
stuff in, I think, 1982. I was taught the same when working on my
commercial certificate in 1971. We found that the optimum for us was
about 55-60 degrees of bank in a 172. The whole point is that rate of
turn outweighs rate of descent, so you actually get back pointed
toward the runway with the minimum lost altitude. It also presumes a
pilot who can keep control oh the airplane while near the edge of the
performance envelope, so it's not for everyone. JG
jack
> ...best manuever...would be a chandelle.
The turn back maneuver IS a chandelle.
You just have a LOT less power than usual.
Jack
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Chuck Forsberg
Darrell Schmidt <dsch...@home.com> wrote:
>If your aircraft had the capability, the "turn back" manuever taking the
>least amount of lateral space would be an immelman which takes NO room.
If the engine isn't running how are you going to perform the loop entry?
IIRC an Immelman is the first half of a loop then an aileron roll??
--
Chuck Forsberg WA7KGX PP-ASEL/HP Skylane N2469R c...@omen.COM
Omen Technology Inc The High Reliability Software www.omen.com
Author of YMODEM, ZMODEM, RZ, SZ, Pro-YAM, ZCOMM, GSZ, and DSZ
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Hans-Georg Michna
>If your aircraft had the capability, the "turn back" manuever taking the
>least amount of lateral space would be an immelman which takes NO room. I
>would think the next best manuever if your aircraft didn't have immelman
>capability would be a chandelle. If a turn in level flight was required,
>the manuever you list below would probably be the best.
Darrell,
would you mind describing these two maneouvres briefly?
I have seen people demonstrate a simple maneouvre in which the
nose is pulled up high, about 60 degrees (almost vertical, then
rudder is kicked in (have to do that in time, as long as there's
still airspeed). The plane falls over to the side and turns with
very little sideways room and ideally without losing any height.
Some people do this with full flaps, but I wonder if it doesn't
work at least as well without flaps.
Hans-Georg
[No mail please]
Roy Smith
> If your aircraft had the capability, the "turn back" manuever taking the
> least amount of lateral space would be an immelman which takes NO room. I
> would think the next best manuever if your aircraft didn't have immelman
> capability would be a chandelle.
Turn-back is usually thought of in the context of an engine failure. I
don't know of too many planes that can do a chandelle with the engine
dead.
jack
> Darrell Schmidt <dsch...@home.com> wrote:
> > If your aircraft had the capability, the "turn back" manuever taking the
> > least amount of lateral space would be an immelman which takes NO room. I
> > would think the next best manuever if your aircraft didn't have immelman
> > capability would be a chandelle.
***********************************
First, a correction to my previous post, in which I said that a turn back
maneuver IS a Chandelle, but with no real gain in altitude. A Chandelle, as
taught in most civilian training, is done at 30 degrees of bank, and is
therefore different from the turn back maneuver at issue, in which a bank of
~45 degrees is used.
***********************************
Now, a response to RS's post:
> Turn-back is usually thought of in the context
> of an engine failure. I don't know of too many
> planes that can do a chandelle with the engine
> dead.
Didn't Bob Hoover do a routine in the AeroCommander where he did a LOOP with
both engines feathered?
I guarantee I can do a Chandelle with the engine at idle, for example, but it
won't have the vertical profile it would have if the engine were putting out
all the available hp. And that is the ONLY difference.
If I do two in a row, power off, the second will bottom out well below the
level that the first one did, etc., etc.
The ability of any aircraft to do any maneuver has to do with the available
energy. Energy is available to the pilot in three forms:
1) thrust;
2) altitude;
3) airspeed.
If all of it came from thrust, we could do an Immelmann from brake release in
our Decathlon. As it is, we need to have about 126 KIAS going for us first. So
momentum is a BIG factor where thrust is limited.
If we lose thrust at altitude, we can still do any maneuver, which we could
have done with thrust, by sacrificing altitude if necessary, to get the energy
for the maneuver.
Since thrust is REALLY limited and drag is increased with engine wind milling
after a failure on the takeoff leg, and there is no altitude which we wish to
sacrifice unnecessarily, we are dependent on the momentum we have accumulated
in order to get through any subsequent maneuver.
If we are climbing out in the Decathlon, for example, at Vy, 66 KCAS (Vs is 47
KCAS), and experience a loss of thrust, and we decide to turn back, we reduce
that energy surplus immediately by transitioning to ~45 degrees of bank. This
results in a stall speed of 56 KCAS, giving us a surplus of 10 KCAS. How you
choose to use that extra energy is up to you. This is the point at which it
pays to have done your homework!
In the real world, particularly if we have not practiced this maneuver, we will
use up that 10 kts with sloppy execution.
How many feet of altitude will we need in order to execute this maneuver? Read
the technical paper, get to know your airplane (in the books and, most of all,
in the cockpit) and you'll have a fighting chance.
We can't make a claim for what can NOT be done in an airplane with out a great
deal of analysis. Otherwise some joker will promptly go out and do it.
Ron Rosenfeld
couldn't find it.
Best wishes,
ron
PROF D. Rogers {EAS FAC} <d...@diamond-bf.usna.navy.mil> wrote in message
news:7vhvbc$s99$1...@diamond-bf.usna.navy.mil...
> G'day,
>
> www.nar-associates.com
>
> click on technical flying.
>
> Dave Rogers, PhD, ATP
> E33A Bonanza
> Have a look at
> www.nar-associates.com/flying-adventures/flyadvm.html
> if you have dreamed of flying to distant places.
>
> In article <7vhks4$rcg$1...@ash.prod.itd.earthlink.net>,
> Ron Rosenfeld <ronros...@earthlink.net> wrote:
> >One of the scientist participants in these NG's had a reference to a web
> >site on which he had posted the results of a scientific analysis of the
> >"turn-back" maneuver as well as some studies done using average pilots.
> >IIRC, the optimum maneuver was a 45 deg turn at stall speed.
> >
> >Does anyone have the URL?
> >
> >Thanks.
> >
> > ron
> >
> >
> >
>
>
Ron Rosenfeld
degrees. I did note that Dr. Roger's article did not mention testing of
bank angles greater than 45 deg.
And I didn't mean to imply that what he wrote was "new". But someone wanted
the URL and I couldn't find it.
Best,
ron
John <jga...@ici.net> wrote in message
news:Fs1T3.534$Pf.7...@news.goodnet.com...
> >In article <7vhks4$rcg$1...@ash.prod.itd.earthlink.net>,
> >Ron Rosenfeld <ronros...@earthlink.net> wrote:
> >>One of the scientist participants in these NG's had a reference to a
> web
> >>site on which he had posted the results of a scientific analysis of
> the
> >>"turn-back" maneuver as well as some studies done using average
> pilots.
> >>IIRC, the optimum maneuver was a 45 deg turn at stall speed.
> >>
> >>Does anyone have the URL?
> >>
> >>Thanks.
>
>
St Stephen Ames
angels and found the best balance(between loss of altitude, turn radius
and stall speed) to be at 45 degrees also...
--
Blue skies,
St Stephen Ames
PP-ASEL
N16402
PA-28-180
My flying site: http://www.stephenames.com/flying/flying.html
---------------------------------------------------------------
- Another part of my pre-flight passenger briefing -
'We’ll be flying at an altitude of 3500 feet today, in theory;
should the plane’s altitude drop precipitously, please check to
ensure that the pilot is awake and in an upright position.'
Hans-Georg Michna
>How did you determine that 55-60 degrees was optimum, as opposed to 45
>degrees. I did note that Dr. Roger's article did not mention testing of
>bank angles greater than 45 deg.
Ron,
it's a compromise between having a newbie stall-spinning out,
crashing into the bottom of the valley and the average pilot
crashing into the trees at the left side of the valley <grin>.
If fact it's kind of stupid to prescribe a certain bank angle.
If I see that I'm not going to make it at 45°, I would actually
steepen the turn, rather than going into the trees.
Hans-Georg
[No mail please]
Hans-Georg Michna
>Turn-back is usually thought of in the context of an engine failure.
Roy,
I always thought it is the maneouvre you want to perform when
you find yourself in a mountain valley that rises more steeply
than you can climb.
Hans-Georg
[No mail please]
Chuck Forsberg
jack <bar...@earthlink.net> wrote:
>Didn't Bob Hoover do a routine in the AeroCommander where he did a LOOP with
>both engines feathered?
When he does that loop he's screaming. I'm amazed at how much
wind noise I hear on the ground. Maybe that's why he calls his
routine "energy management".
IIRC Bob once had an engine failure on takeoff (mis-fueled) and
he did not have enough energy for an RTLS. Off airport crunch
landing but he walked away.
Ron Rosenfeld
I think you're talking about a different maneuver than I. As I raised the
concept, it is a maneuver used to get back to the runway in the event of
engine failure on takeoff. I believe you are talking about a chandelle used
to get out of a tight valley -- with the engine still running. And I would
agree that in that event, a 55-60 deg bank would likely be optimal.
Best,
ron
Hans-Georg Michna <Hans_Georg_Mich...@cis.com> wrote in message
news:nj8dOClXcEsVGI...@4ax.com...
Ron Rosenfeld
I reread your articles (let me say I only skimmed the second -- a bit beyond
me), and passed the URL's on to my friend.
In another discussion in a different forum, some are saying that they use a
steeper than 45 degree bank for this maneuver. In light of your studies and
background, what are your feelings regarding this recommendation.
Thanks.
ron
PROF D. Rogers {EAS FAC} <d...@diamond-bf.usna.navy.mil> wrote in message
news:7vhvbc$s99$1...@diamond-bf.usna.navy.mil...
> G'day,
>
> www.nar-associates.com
>
> click on technical flying.
>
> Dave Rogers, PhD, ATP
> E33A Bonanza
> Have a look at
> www.nar-associates.com/flying-adventures/flyadvm.html
> if you have dreamed of flying to distant places.
>
> In article <7vhks4$rcg$1...@ash.prod.itd.earthlink.net>,
> Ron Rosenfeld <ronros...@earthlink.net> wrote:
> >One of the scientist participants in these NG's had a reference to a web
> >site on which he had posted the results of a scientific analysis of the
> >"turn-back" maneuver as well as some studies done using average pilots.
> >IIRC, the optimum maneuver was a 45 deg turn at stall speed.
> >
> >Does anyone have the URL?
> >
> >Thanks.
> >
> > ron
> >
> >
> >
>
>
John T. Lowry
through) for a gliding airplane is given by:
cos(phi) = (sqrt(2)/2)*sqrt(1-k^2)
where k = CD0/CLmax + CLmax/(pi*e*A)
where CD0 is the parasite drag coefficient, CLmax is the maximum lift
coefficient for the airplane's flaps configuration, e is the airplane
efficiency factor, and A is the wing aspect ratio. I know most ng readers
hate those darned formulas, but that's the way the world works.
For GA propeller-driven airplanes, k is a small number (0.116 for a Cessna
172, flaps up) and so the best turnaround bank angle is very closely the 45
degrees cited by Rogers and, much earlier, by Langewiesche (Stick and
Rudder, p. 358). For the above Cessna, for instance, it's 45.4 degrees. For
a flamed-out jet fighter, however, things are considerably different.
The formulas above, along with formulas for the banked stall speed, for
banked gliding flight path angle, and for the minimum altitude loss in a
180-degree turn, can all be found in my recent book Performance of Light
Aircraft, pp. 294-296. The following seven pages then treat the
return-to-airport maneuver, from start of the takeoff roll to contact with
the runway or terrain, in excruciating detail. Including wind effects, the
typical four-second hesitation when the engine stops, etc.
John.
--
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
Matthew Majka
> In article <381C8982...@home.com>,
> Darrell Schmidt <dsch...@home.com> wrote:
> >If your aircraft had the capability, the "turn back" manuever taking the
> >least amount of lateral space would be an immelman which takes NO room.
>
> If the engine isn't running how are you going to perform the loop entry?
> IIRC an Immelman is the first half of a loop then an aileron roll??
You remember correctly. I can't think of anything
non-military that can build up enough energy on takeoff to
be able to perform an Immelman with the engine inop.
jack
> jack <bar...@earthlink.net> wrote:
> >Didn't Bob Hoover do a routine in the AeroCommander where he did a LOOP with
> >both engines feathered?
>
> When he does that loop he's screaming. I'm amazed at how much
> wind noise I hear on the ground. Maybe that's why he calls his
> routine "energy management".
Exactly the point. Everybody's "routine" is energy management, every time they
release breaks. It would broaden a lot of aviatin' minds if they thought of it that
way.
Jack
--
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<http://home.earthlink.net/~baron58/ga.html>
Roy Smith
> You remember correctly. I can't think of anything
> non-military that can build up enough energy on takeoff to
> be able to perform an Immelman with the engine inop.
Fail the engine on takeoff, and most pilot's can generate enough
pucker-power energy to launch the seat cushion into an Immelman!
--
Roy Smith <r...@popmail.med.nyu.edu>
New York University School of Medicine
Matthew Majka
> In article Matthew Majka <mma...@cs5.dasd.honeywell.com> wrote:
> > You remember correctly. I can't think of anything
> > non-military that can build up enough energy on takeoff to
> > be able to perform an Immelman with the engine inop.
>
> Fail the engine on takeoff, and most pilot's can generate enough
> pucker-power energy to launch the seat cushion into an Immelman!
I stand corrected...
Don Tuite
and a power-off wing-over?
Don
Darrell Schmidt
best "Turn back maneuver". The need for a maximum effort turn back can be the
result of many different flight aspects. Caught flying into a narrow, blind canyon
could require a turn back using minimum lateral displacement. With the engine
running, the immelman (if enough power is available) would be best.
A climbing max turn (chandelle) would be next best. Slowing, extending flaps, then
making a max rate turn using power would be next.
Engine failure throws in a whole new deal. If that was the intent of the original
post all of the above ideas go out the window.
Chuck Forsberg wrote:
> In article <381C8982...@home.com>,
> Darrell Schmidt <dsch...@home.com> wrote:
> >If your aircraft had the capability, the "turn back" manuever taking the
> >least amount of lateral space would be an immelman which takes NO room.
>
> If the engine isn't running how are you going to perform the loop entry?
> IIRC an Immelman is the first half of a loop then an aileron roll??
>
> --
> Chuck Forsberg WA7KGX PP-ASEL/HP Skylane N2469R c...@omen.COM
> Omen Technology Inc The High Reliability Software www.omen.com
> Author of YMODEM, ZMODEM, RZ, SZ, Pro-YAM, ZCOMM, GSZ, and DSZ
> TeleGodzilla BBS: 503-617-1698 FTP: ftp.cs.pdx.edu pub/zmodem
> POB 4681 Portland OR 97208 503-614-0430 FAX:503-629-0665
>
> -----------== Posted via Newsfeeds.Com, Uncensored Usenet News ==----------
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> ------== Over 73,000 Newsgroups - Including Dedicated Binaries Servers ==-----
--
Kestrel
3000 AGL. Simulated takeoff set up - airspeed 100, no gear, no flaps, then
throttle all the way back. Did the 45 degree bank, 180 degree turnback with
a loss of about 400 feet. Kept the stall horn just on the edge. ( the
blaring gear warning horn was an added distraction). At this low speed
there was not much G force associated with the steep turn and control forces
remained light. I did not feel any buffett of impending stall. My
opinion - the manuver is worth practicing. I may decide to lower my no
turnback altitude from 800 AGL to 600 AGL.
Rich Carr
I wouldn't. Your maneuver doesn't account for many factors present
during the real thing, the biggest of which is that a 180 lines you
up with the beacon tower, not the runway. You have another 60-90 degrees
of turning to do if you want to get back to the runway you took off
from. Of course, you may be lucky enough to have another runway
that's more reachable than the one you departed from, but that's not
typical. Or you may have allowed yourself to drift with the
crosswind, in which case your 180 might get you lined up.
- Rich Carr
jack
>
> Everybody's "routine" is energy management, every time they
> release breaks.
OOPS! Should be "...brakes...."!
How many of you did not catch that?
Jack
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jack
>
> Just for curiosity, is there a difference between a power-off chandelle
> and a power-off wing-over?
Disregarding the power off part, as I remember it, the wing-over is just
an extreme Lazy Eight, where we look for 90 degrees of bank with the
nose coming down through the horizon at the 90 degree turn point instead
of using a max. bank of 30 degrees.
Jack
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Kestrel
some more.
James Bieker
>
>How many of you did not catch that?
About the same number that confuse "lose" and "loose"
Ron Rosenfeld
Best,
ron
John T. Lowry <jlo...@mcn.net> wrote in message
news:s1r7s5...@corp.supernews.com...
John
Ron Rosenfeld wrote in message
<7virt1$gr$1...@birch.prod.itd.earthlink.net>...
>How did you determine that 55-60 degrees was optimum,
Flight testing. This took place just outside of Denver. There were
about six of us working on commercial certificates simultaneously with
the same instructor. We flew in pairs, using a variety of bank angles
to effect a 210 degree turn followed by a 30 turn, to simulate a
return to the runway. We did this at altitude, recording results to
determine minimum altitude loss for the exercise. All three pairs
reached the same conclusion. If I recall correctly, we needed about
450 to 500 feet to make the turnback. Never tried it on an actual
takeoff, nor have I ever tried it at sea level. JG
Ron Rosenfeld
angle closer to 45 degrees posted by Dr. Lowery, and the work previously
published by Dr. Rogers.
What airspeed did you fly the maneuver's at? If you flew the maneuver's
considerably above stall speed, maybe that accounts for the differeing
results.
Best,
ron
John <jga...@ici.net> wrote in message
news:cItT3.56$6%3.6...@news.goodnet.com...
mike regish
approach to land, I found myself dealing with a crosswind. I made a low
approach to mentally rehearse the rudder inputs I would need to land. On
the go around I ran out of gas at about 300' AGL. I had started a
climbing turn to downwind when it happened. I leveled the wings and put
the nose down pretty steep and then rolled the ac in a nose down
attitude until I was headed for the runway at an angle. I had lots of
airspeed which I knew I could bleed off in the aerodynamically dirty
ultralight and a lot of ground speed since I was now going with the
wind. I aligned with the runway with about 10" altitude. I had to
momentarily pick up my right wing to get it over a runway light and
flared landing at a slight angle to the runway. I hit the brakes and got
it stopped just at the far edge of the runway.
In this situation, a lot of the turn was roll at a steep angle. I wonder
if something like this has been tried in heavier ac. I realize you'd
need more altitude and runway for a light single, but the principle is
there.
Any comments or opinions?
mike regish
PP-ASEL
John
Ron Rosenfeld wrote in message
>That's interesting, especially in view of the theoretical backing for
a bank
>angle closer to 45 degrees posted by Dr. Lowery, and the work
previously
>published by Dr. Rogers.
>
>What airspeed did you fly the maneuver's at? If you flew the
maneuver's
>considerably above stall speed, maybe that accounts for the
differeing
>results.
>
except to say that in my fifty years I've seen a few things that
worked differently in real life than they did on paper.
Seems that we would fly just above stall....we didn't have the horn on
constantly, I think we targeted something like stall plus five --I
can't recall now almost thirty years later. The whole thing was an
exercise in learning what your aircraft will and won't do......an
essential frame of mind for one who would be a professional, not just
an academic enquiry. Having considered the problem, and worked out
the [supposed]solution, in thirty years I've never had to turn back to
an airport with such pressing need that this type of turnback would be
warranted. JG
Ted Timmons
How you may ask? Depart at a 30-45 degree angle from the runway heading
until you are far enough from the runway that a 180 degree turn will end
with you lined up with the runway.
When far enough from the runway return to runway heading.
If the engine quits, the 180 degree turn will line you up with the runway.
At one time I had the formula for calculating the turn radius for a given
speed and bank angle. That is what is needed to know the required distance
from the runway. With a little practice, it could probably be guesstimated
with reasonable accuracy.
Even if the engine quit before you had the required distance from the
runway, the turn back would still be a simpler turn.
Any comments? Flaws in my reasoning?
Lou Sanchez-chopitea
Ted Timmons wrote:
> I think this turn back maneuver can be further enhanced.
>
> How you may ask? Depart at a 30-45 degree angle from the runway heading
> until you are far enough from the runway that a 180 degree turn will end
> with you lined up with the runway.
Unfortunately many airports I've seen have noiseabatement that specifies
something like
"no turns below 600 AGL".
OTOH, at RHV off of 31R noise abatement specifies
"20 degree right turn at boundary".
> When far enough from the runway return to runway heading.
>
> If the engine quits, the 180 degree turn will line you up with the runway.
>
> At one time I had the formula for calculating the turn radius for a given
> speed and bank angle. That is what is needed to know the required distance
> from the runway. With a little practice, it could probably be guesstimated
> with reasonable accuracy.
>
> Even if the engine quit before you had the required distance from the
> runway, the turn back would still be a simpler turn.
>
> Any comments? Flaws in my reasoning?
Someone I saw the other day continually started the aforementioned
turn at about midfield and was all over the sky instead of in the pattern.
It sure bugged me. I don't know if anyone else would feel the same way
about non-standard patterns, and I would only try at uncontrolled fields
when noone was around (and there can always be that pesky NORDO).
Might be a good little piece of insurance to have under safe
conditions, though.
Cheers
Lou
--
Lou Sanchez-Chopitea EMail: lou.sanche...@xilinx.com
Senior Software Engineer SnailMail: 2100 Logic Drive
SpeakMail: (408) 879-5059 San Jose, CA 95124
FaxMail: (408) 377-3259 #include
John T. Lowry
I think the additional turning needed, beyond the 180 degrees to reverse
course, is often exaggerated. For instance for a relatively low-powered
airplane like the Cessna 172 (160 hp), by the time it gets to sufficient
altitude (say 500 ft AGL) to even consider turning around if the engine
fails, it's quite a ways from the end of the runway. In one common scenario
(Performance of Light Aircraft, pp. 296-303), the airplane was about 5000 ft
past the end of the 3000 ft long runway and, after turning around, was less
than 500 feet off to the side. That means it only needs about 6 degrees of
turn past the course reversal to point at the end of the runway. And then
another 6 degree turn when it gets there (IF it gets there) to line up with
the runway centerline. Not a big deal.
That formula is R = V^2/(g*tan(phi)*cos(gamma))
where R is the turn radius, V the air speed, g the acceleration of gravity,
phi the bank angle, and gamma the flight path angle, all in consistent (say
British engineering) units. Most times we leave out the cos(gamma) factor in
the denominator.
John.
--
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
Ted Timmons wrote in message ...
>I think this turn back maneuver can be further enhanced.
>
>How you may ask? Depart at a 30-45 degree angle from the runway heading
>until you are far enough from the runway that a 180 degree turn will end
>with you lined up with the runway.
>
PROF D. Rogers {EAS FAC}
!: I tried the 45 degree turnback this morning in my E Model Mooney at
!: 3000 AGL. Simulated takeoff set up - airspeed 100, no gear, no flaps, then
!: throttle all the way back. Did the 45 degree bank, 180 degree turnback with
!: a loss of about 400 feet. Kept the stall horn just on the edge. ( the
!: blaring gear warning horn was an added distraction). At this low speed
!: there was not much G force associated with the steep turn and control forces
!: remained light. I did not feel any buffett of impending stall. My
!: opinion - the manuver is worth practicing. I may decide to lower my no
!: turnback altitude from 800 AGL to 600 AGL.
!
!I wouldn't. Your maneuver doesn't account for many factors present
!during the real thing, the biggest of which is that a 180 lines you
!up with the beacon tower, not the runway. You have another 60-90 degrees
!of turning to do if you want to get back to the runway you took off
!from. Of course, you may be lucky enough to have another runway
!that's more reachable than the one you departed from, but that's not
!typical. Or you may have allowed yourself to drift with the
!crosswind, in which case your 180 might get you lined up.
!
!- Rich Carr
Actually Rich, the turn angle is about 210 degrees total.
You might want to look at
to see why.
Dave Rogers
Rich Carr
: Actually Rich, the turn angle is about 210 degrees total.
In the dozens of turnbacks I've done in glider training, I guess I've
never tried to put a number on the amount of realignment heading
change. I guess 15 degrees each way sounds about right.
One measure of success, though, is that the pilot doesn't just point
at the threshold and expect to make the final 15 degree turn at
ground level. I'd rather do a little more turning in order to
complete the turns at a reasonable height.
- Rich Carr
Steve
place?!
Darrell Schmidt <dsch...@home.com> wrote in message
news:381DDA86...@home.com...
Kestrel
aircraft and currency dependent. And, that in an unfamiliar airplane it
should be kept conservative. Also, the manuver is a perfect set-up for a
deadly low altitude un-recoverable accelerated stall if air speed is not
controlled very carefully. Again, practice. And practice first at high
altitude.
Peter Gottlieb
I had to set the joystick sensitivity to full to get enough elevator
authority to get near stall speed in the steep turn.
Since visibility is terrible, I had to do the turn solely be reference to
instruments.
I needed about 600 feet to sometimes get back, 800 had much better odds.
Indeed, this is something that requires a lot of practice. I'm going to go
up and try this for real in the next few days (of course, at a safe
altitude) as soon as I can figure out how to set up a decent and accurate
reference point in the sky marking the end of my virtual runway.
The November Aviation Safety has an article on this. This seems like a good
thing to know how to do, another tool in the toolkit. At least then one can
know when it's foolhardy to attempt it or if it looks safe.
Kestrel <sj...@abts.net> wrote in message
news:s22n78...@corp.supernews.com...
Jim Sokoloff
> At this low speed there was not much G force associated with the
> steep turn and control forces remained light.
The G forces are identical for a given bank angle steep turn (*),
regardless of the airspeed. The control forces are another matter.
---Jim
(*) Assuming you aren't letting the airplane accelerate unbounded
downward, which you aren't in an emergency turn-back.
Larry Dighera
wrote:
[Best turnaround bank angle formula snipped]
>The formulas above, along with formulas for the banked stall speed, for
>banked gliding flight path angle, and for the minimum altitude loss in a
>180-degree turn, can all be found in my recent book Performance of Light
>Aircraft, pp. 294-296.
Does the data in your book corroborate the assertion of Dave Rogers'
article, that the optimal velocity in the turn is " Vturning =
1:05Vstall (clean) / cos (phi) in the turn, i.e., the unbanked stall
velocity divided by the cos (phi) multiplied by 1:05"?
Wouldn't a slightly higher speed in the turn reduce the sink rate?
John T. Lowry
per foot altitude loss would put V right at the banked stall speed (for
whatever flaps configuration is current). But one needs a slight safety
buffer. I usually suggest five knots and Rogers evidently suggests 5%. The
only real difference between our basic formulas is that mine includes the
fact that the airplane is gliding along a helix where Rogers's formula
ignores that (normally small, but watch out for flamed-out jet fighters!)
effect.
John
--
John T. Lowry, PhD
Flight Physics; Box 20919; Billings MT 59104
Voice: 406-248-2606
Larry Dighera wrote in message <7vv801$60q$1...@bgtnsc03.worldnet.att.net>...
mike regish
turn. Another factor was that I was a 145 lb. pilot in an ultralight
designed for a fairly large pilot.
I brought mine up to Vne on another occasion just to see what would
happen. There was a pretty strong buffeting. It definitely let me know
that it didn't like it and wouldn't put up with it very long.
Just seems that all the examples given are maneuvers in the horizontal
plane. I was wondering if anybody had done any tests using the vertical.
I realize that a heavy (relatively speaking) clean plane wouldn't stand
a chance of this maneuver from 300', but was wondering about 6, 7, or
800'. I'm imagining maybe even a wingover type maneuver where the turn
radius would be so small as to leave you pretty much lined up for a
downwind.
Just running mental scenarios wondering if there's any test data.
mike regish
PP-ASEL
Peter Chapman wrote:
>
> You'll naturally realize that having a draggy and slow airplane helped
> to allow you the time to get turned around in the steep rolling and
> turning dive.
>
> An acquaintance tried a few different turnaround maneuvers in his
> Zenair Zodiac. The dive & turn didn't work well as the aircraft would
> get up close to Vne too quickly, despite starting at low speed. While
> the Zodiac isn't particularly slippery, its roll rate isn't any better
> than, say, a C-150. I don't think most pilots would have the
> opportunity you had.
>
> His intent was to explore ways to get turned 180 degrees quickly, not
> necessarily as if it were an engine failure on takeoff. For his
> aircraft, from cruise speed, he found a stall-turn resulted in a much
> faster turn around than doing a steeply banked turn. (At least for
> non-aerobatic type G loads -- perhaps under 2.5g.)
>
> Peter Chapman
> Toronto, Canada
Peter Chapman
wrote about a turn-around in an ultralight:
>approach to mentally rehearse the rudder inputs I would need to land. On
>the go around I ran out of gas at about 300' AGL. I had started a
>climbing turn to downwind when it happened. I leveled the wings and put
>the nose down pretty steep and then rolled the ac in a nose down
>attitude until I was headed for the runway at an angle. I had lots of
>Any comments or opinions?
Mackfly
>radius would be so small as to leave you pretty much lined up for a
>downwind.
>
>Just running mental scenarios wondering if there's any test data.
>
>mike regish
Mike I doubt the wingover would be a good option. Doing them in power planes
one finds the prop blast on the tail helps take the plane over the top. I have
done many in sailplanes that fly just fine at 37 to 49 kts but require 80 kts
to start the upside of the wingover so one has enough rudder to rotate the nose
over before airspeed reaches zero. An engine loss on takeoff would not find
you with near enough airspeed to pull up, rudder the plane over the top, and
dive out of it to the runway. In sailplane training we do a practice rope
break at 200' AGL and the only way back is, set min sink speed-or best glide,
start turn back ( into the wind), and fly the plane back to the runway. We use
about 30 to 40 degree bank in the turn. The math I've done on a ces 150 says
it can't do a turn back and make the runway unless there is a lot of headwind
on takeoff. Then I'd not want to do the downwind landing anyway. Just some
thoughts--Mack
Colin Wray
A highly respected and extemely experienced professional aerobatic
team member here in UK advocates the slipping turn as the best method
of turning back to land downwind after engine failure on take off. I
will try to summarise this controversial assertion:
1. The objective is to turn through (say) 200 degrees without losing
too much height OR increasing the airspeed unduly.
2. The rate of turn is dependant on angle of bank and airspeed, with
high bank angles and low airspeeds producing the highest rates of
turn. (To illustrate this, consider the rates of turn achieved by 45
degrees of bank in a/c travelling at 60 and 600 mph).
3. In a 60 degree balanced turn you need to pull 2g, and for this to
be successful, you need to increase airspeed considerably. All of
these factors (increasing the speed, and therefore also the duration
of the turn, and pulling g) increase the height lost in the manouver.
4. In a slipping turn, where you hardly pull any g, and hold the nose
up (to control the airspeed) with top rudder, the rate of turn is
enormous. OK, you may have quadrupled the rate of descent, but the
time spent in the turn is reduced such as to way more than compensate
for this, and your airspeed is correct for landing at the end of it.
With a lot of practice, he reckons he can land a Chipmunk from an
engine failure at 150 ft. using a 75-80 degree slipping turn at 70
knots. Of course, it is no use trying this if your aircraft has not
enough rudder to sustain a slip, but all else being equal, it is
something to practice at a safe height.
Colin.
Mike Rapoport
Mike
MU-2
Colin Wray wrote in message <382ed148...@goodnews.nildram.co.uk>...
John T. Lowry
turn-back-towards-airport, for a Cessna 172 at 2400 pounds at MSL with flaps
10, is only 163 feet. That was at the banked stall speed at the (again
*theoretical*) optimum bank angle, 45.5 degrees.
John.Web site: http://www.mcn.net/~jlowry
E-mail: jlo...@mcn.net
Colin Wray
>Why would a slipping turn be better than a coordinated one?
>
>Mike
>MU-2
Answer in section 2:
Section 1
>>A highly respected and extemely experienced professional aerobatic
>>team member here in UK advocates the slipping turn as the best method
>>of turning back to land downwind after engine failure on take off. I
>>will try to summarise this controversial assertion:
Section 2
>>1. The objective is to turn through (say) 200 degrees without losing
>>too much height OR increasing the airspeed unduly.
>>2. The rate of turn is dependant on angle of bank and airspeed, with
>>high bank angles and low airspeeds producing the highest rates of
>>turn. (To illustrate this, consider the rates of turn achieved by 45
>>degrees of bank in a/c travelling at 60 and 600 mph).
>>3. In a 60 degree balanced turn you need to pull 2g, and for this to
>>be successful, you need to increase airspeed considerably. All of
>>these factors (increasing the speed, and therefore also the duration
>>of the turn, and pulling g) increase the height lost in the manouver.
>>4. In a slipping turn, where you hardly pull any g, and hold the nose
>>up (to control the airspeed) with top rudder, the rate of turn is
>>enormous. OK, you may have quadrupled the rate of descent, but the
>>time spent in the turn is reduced such as to way more than compensate
>>for this, and your airspeed is correct for landing at the end of it.
Section 3