CH-53 made loops?
JasiekS
Many years ago, in early seventies, I saw in the Polish aviation magazine
'Skrzydlata Polska' series of photos from an experimental flight of H-53
making loops. I lost those pictures. Is there anybody who could help me and
tell some link to such pictures or (much better!) films on the Net? I am
sure it was not April Fool issue of 'Skrzydlata'.
Regards
JasiekS
Warsaw, Poland
redcar 303
The maneuver was legitimate. It was performed
in the late '60s by Col. Bob Guay, USMC, then
working in HQMarine Corps in Washington.
This wasn't an experimental flight, more a
publicity flight for the aircraft. At the time,
loops had been performed in several lighter
helos.
The CH-53 was "bailed" to Sikorsky for
development purposes. Movies of the
maneuver were taken by Sikorsky.
During pullout, that '53 pulled more
g's than were demonstrated during
structural trials of the aircraft. That
gave rise to some informal thinking
that the military should explore
something other than a rolling pull-out
to achieve max g during sturctural
demonstrations.
I imagine that Sikorsky aircraft
still maintains a video clip of the
maneuver. You might inquire of
them.
Cheers.............Paul.
PMH
posted with nr/2 v2.0
"redcar303" <paul.zzzuop1atcoxzzz.net>
Gordon
a flight deck full of alarmed/amazed deck apes (myself included).
No pictures taken that I know of - happened too fast.
v/r
Gordon
<====(A+C====>
USN SAR Aircrew
"Got anything on your radar, SENSO?"
"Nothing but my forehead, sir."
Dave Kearton
Dave K
"Gordon" <krzta...@aol.comint> wrote in message
news:20020415144816...@mb-cj.aol.com...
Gordon
>Was that intentional ?
Supposedly - the rumor (or rumour if you wish) was that he had done it once
before at/near Norfolk (Virginia).
Dave Kearton
privacy of your own home before trying it in public.
v/r (under licence) ;-)
Dave Kearton
krzta...@aol.comint (Gordon) wrote in message news:<20020415190003...@mb-cj.aol.com>...
redcar 303
Intentional -- yes. With the gross
weight toward the lower end of
its range, both the "aileron" and
barrel rolls stay within the
structural limits of the aircraft.
At all but "stripped empty" the
'53 isn't short on control power
in level (unaccelerated) flight.
However, both maneuvers are
beyond the published service
limits for normal aircraft
operation, therefore not legal.
Cheers........Paul
Charles Samardza
I found it in an old Aviation Week, I still have the issue, but it's in storage.
Devi Deveraux
could do loops all day long- MBB's ultra agile B0-105.
DV-D
D. Scott Ferrin
wrote:
>Very interesting stuff. But only one helicopter in the world really
>could do loops all day long- MBB's ultra agile B0-105.
>
>DV-D
Hey you forgot Blue Thunder ;-)
Ken Duffey
You haven't been to any UK airshows recently have you ??
The British Army Lynx does a very nice trick where it hovers head-on to
the crowd, then does a 'back flip' - essentially a loop - and ends up
diving towards the ground, facing forward.
And - it has been doing rolls for ages. All of these maneouvres of
course are not negative G at all - the rolls are barrel rolls and the
loops are not true loops - they are still pulling positive G at the top.
And - you want to see the little Russian piston-engined Mil Mi-34 !! Now
that IS agile !
And - I have been meaning to ask - we are talking loops here aren't we
?? A vertical climb, over the top and dive down. As in 'loop-the-loop'
- not a roll ?
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Ken Duffey - Flanker Freak & Russian Aviation Enthusiast
Flankers Website - http://www.flankers.co.uk/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Matthew G. Saroff
They barrel rolled a Chinook.
--
--Matthew Saroff
_____ * For a succesful technology, *
/ o o \ * reality must take precedence over *
______|_____|_____ * public relations, for Nature *
uuu U uuu * cannot be fooled." *
* - Richard P. Feynman *
JasiekS
Uzytkownik "Ken Duffey" <kend...@flankerman.fsnet.co.uk> napisal w
wiadomosci news:3CBDA2D3...@flankerman.fsnet.co.uk...
Yes, I meant loops, but rolls are interesting also. Simply ANY kind of
aerobatics made by helicopter of THAT size have to be interesting.
I saw loops and rolls made by two German teams on Bo-105 during Internationa
Helicopter Aerobatics Championship 1980 in Piotrkow Trybunalski, Poland.
These teams won 1st and 3rd award. The 2nd place was awarded by (then) USSR
team on Mi-1 (!) piston-engined helicopter. I saw the final day of the
championships. Russians did almost the same programme as Germans (minus
inverse aerobatics, of course) but in much more dynamic manner. It wasn't
surprise, because piston engine has smaller inertion in response to throttle
movement than turboshaft engine.
BTW according to redcar 303's advice i tried to fin some resources on
Sikorsky's official site. I found nothing. I sent ane e-mail to Sikorsky's
press officer - without response yet.
Best regards
JasiekS
Warsaw, Poland
robert arndt
complete confidence with its rigid rotor system. So could MBB's export
BK-117.
Rob
redcar 303
>Devi Deveraux wrote:
>
>> Very interesting stuff. But only one helicopter in the world really
>> could do loops all day long- MBB's ultra agile B0-105.
>>
>> DV-D
>
>You haven't been to any UK airshows recently have you ??
>
>The British Army Lynx does a very nice trick where it hovers head-on to
>the crowd, then does a 'back flip' - essentially a loop - and ends up
>diving towards the ground, facing forward.
>
>And - it has been doing rolls for ages. All of these maneouvres of
>course are not negative G at all - the rolls are barrel rolls and the
>loops are not true loops - they are still pulling positive G at the top.
>
>And - you want to see the little Russian piston-engined Mil Mi-34 !! Now
>that IS agile !
>
>And - I have been meaning to ask - we are talking loops here aren't we
>?? A vertical climb, over the top and dive down. As in 'loop-the-loop'
>- not a roll ?
>
Yes, honest-to-god loops
And the BO-105 / XH-51a was
singularly outstanding at the
manuever. Too bad it came
unglued at the wrong time !
With regards, PMH
"redcar 303"
<< paul.zzzuop1atcoxzzz.net >>
Posted with NR/2 v2.0
The Enlightenment
Wouldn't be suprised. Aparently the 53 is the most manoevarble
helicopter in the navy or marine inventory despite its size. It can
out turn a Cobra for instance.
Kristan Roberge
Devi Deveraux wrote:
> Very interesting stuff. But only one helicopter in the world really
> could do loops all day long- MBB's ultra agile B0-105.
>
False, British Lynx can do it all day long also, think its roll/loop
rate is 100 degrees a second.
And I've seen Hughes 500's doing tailslides. Plenty of agile helos out
there. Also considering the
Ah-56 had lockheed's then revolutionary rigid rotor system, which had
been proven in previous
development testing to be fully capable of rolls and loops, I don't
dount the Cheyenne was capable of
them too.
_Big_Mac_
What about the Eurocopter Tiger? That's an agile one. Can it do loops?
Peter Stickney
And you/ve all missed the fact tha the first helicopter to
successfully perform a loop was the lowly HUP (H-25), back in hte
early '50s. Of cource that one wasn't entirely on purpose -
It was just before or during the testing of the autostabilizer, and
the aircraft started pitching up. By the time the pilot had guidance
over the thing (not necessarily control) the nose was so high that
keeping the G on an pulling it through looked smarter than pushing over.
The H-53 was performing loops and rolls back in '65 or '66, The
Sikorsky S-67 Blackhawk, ht eGunship H-3 that they designed as an
AH-56 competitor - think of a Hind that's been working out - was lost
at the Paris Airshow after dishing out from the last of several
low-level rolls in fromt of the crowd.
--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster
Ken Duffey
As I understand it, in all these cases, the helicopter is not pulling
negative G - so the rolls are really barrel rolls and the machine is
actually 'flying downwards' at the top of the loop.
In other words, the rotors are still producing 'lift' underneath the blades
(towards the landing gear) when the machine is inverted.
Imagine the helicopter right side up - the air goes through the blades from
top to bottom. Now turn it upside down - and now the air goes from the
bottom to the top (i.e. the same both ways).
If this were not the case, the helicopter would be capable of inverted
flight - which it ain't !
Do I have it right ??
Steve Arnold
Peter Stickney <p-sti...@worldnet.att.net> wrote in message
news:8n73aa...@Mineshaft.att.net...
</snip>
> The H-53 was performing loops and rolls back in '65 or '66, The
> Sikorsky S-67 Blackhawk, ht eGunship H-3 that they designed as an
> AH-56 competitor - think of a Hind that's been working out - was lost
> at the Paris Airshow after dishing out from the last of several
> low-level rolls in fromt of the crowd.
> --
> Pete Stickney
> A strong conviction that something must be done is the parent of many
> bad measures. -- Daniel Webster
Peter, it was at Farnborough 1974 where the S-67 prototype crashed. I
remember seeing it before the crash, it was in desert camoflage because
Sikorsky were trying to sell it to the Israelis. I understand that they were
going to buy but the crash changed their minds and they went with AH-1
insread.
You were right about the nature of the loss however. Started his sequence
too low and hit the ground on exit from his last roll.
Steve.
Peter Stickney
Ken Duffey <kend...@flankerman.fsnet.co.uk> writes:
> Peter Stickney wrote:
>> And you/ve all missed the fact tha the first helicopter to
>> successfully perform a loop was the lowly HUP (H-25), back in hte
>> early '50s. Of cource that one wasn't entirely on purpose -
>> It was just before or during the testing of the autostabilizer, and
>> the aircraft started pitching up. By the time the pilot had guidance
>> over the thing (not necessarily control) the nose was so high that
>> keeping the G on an pulling it through looked smarter than pushing over.
> As I understand it, in all these cases, the helicopter is not pulling
> negative G - so the rolls are really barrel rolls and the machine is
> actually 'flying downwards' at the top of the loop.
Pretty much correct. Other than on television action-adventure shows,
helicopters don't like much negative G.
>
> In other words, the rotors are still producing 'lift' underneath the blades
> (towards the landing gear) when the machine is inverted.
Yep.
> Imagine the helicopter right side up - the air goes through the blades from
> top to bottom. Now turn it upside down - and now the air goes from the
> bottom to the top (i.e. the same both ways).
The problems aren't only with airflow, but mechanically/structurally
as well. No matter what type of rotor hum is used, the blades bend
because of the differing levels of lift across the span of the blade -
(Very little airspeed inboard, lots of airspeed outboard- and then you
add in the relative wind from forward motion - it gets Mondo
Complicated very quickly) even the so-called rigid rotor hubs rely on
blade flexibility for this. You may recall, or can Google for, a
discussion here a while back about UH-1/AH-1 tail strikes occurring
when pushing over at about 0.5G. Lots of helicopters have had
problems this way - later Sikorsky S.55s/H-19s/HRS had the tail boom
angled downward to get it firther from the main rotor. The H-43 Husky
started its career cutting its own tail off. There are many other
examples, but those are the ones that come to mind first.
>
> If this were not the case, the helicopter would be capable of inverted
> flight - which it ain't !
For a good view of all the coning and flapping and tilting and other
stuff that goes on with them, get a copt of hte James Bond movie "You
Only Live Twice". Tons of good views of helicopters, and the scenes
with the KV-107 show all the rotor dynamic stuff in plenty of detail.
(And lots of fun anyway.)
>
> Do I have it right ??
Yes, I'd say so. But I'd add the caveat that I won't fly 'em, I just
study them. (I've got two hours of stick time in helicopters. Never
was so nervous in all my life. Let's jsut say that I've got 100 time
more flight time in airplanes without engines than engines without
airplanes)
Peter Stickney
"Steve Arnold" <notfo...@email.com> writes:
>
> Peter Stickney <p-sti...@worldnet.att.net> wrote in message
> news:8n73aa...@Mineshaft.att.net...
<In Re: The Sikorsly Blackhawk crash >
> Peter, it was at Farnborough 1974 where the S-67 prototype crashed. I
> remember seeing it before the crash, it was in desert camoflage because
> Sikorsky were trying to sell it to the Israelis. I understand that they were
> going to buy but the crash changed their minds and they went with AH-1
> insread.
>
Thanks - I knew it was one of the Big European shows.
> You were right about the nature of the loss however. Started his sequence
> too low and hit the ground on exit from his last roll.
The four worst things - Altitude Above You, Runway Behind You, Fuel in
the Truck, and Airspeed you don't have.
Kristan Roberge
Ken Duffey wrote:
> top to bottom. Now turn it upside down - and now the air goes from the
> bottom to the top (i.e. the same both ways).
>
> If this were not the case, the helicopter would be capable of inverted
> flight - which it ain't !
something like that, but actually the only thing limiting a helicopter for
inverted flight is GETTING into that orientation while you reverse the pitch on
the main rotor. Scale-Model R/C helicopters for example are perfectly capable
of rolling inverted and then hovering, upside down.
Steve Davies
>
> In other words, the rotors are still producing 'lift' underneath the
blades
> (towards the landing gear) when the machine is inverted.
and
> Imagine the helicopter right side up - the air goes through the blades
from
> top to bottom. Now turn it upside down - and now the air goes from the
> bottom to the top (i.e. the same both ways).
Ken, the rotors produce lift from their upper surfaces - the heli does not
'thrust' itself skyward by pushing air towards the ground, it generates lift
just like an aerofoil. When you hover close to the ground, the air that is
thrust downwards can be used as a 'cushion', but this is simply a by-product
of the downwash. This is what you might have meant, but I wasn't sure so I
thought I'd say.
--
www.f-15e.net
Steve Davies
England
Steve Davies
> inverted flight is GETTING into that orientation while you reverse the
pitch on
> the main rotor
And how do you reverse the pitch on a real helicopter main rotor? I fly
helicopters and am not aware of a single bird that can do this. In any case,
there are several major issues which prevent SOME helicopters from *getting
into* inverted flight.
--
www.f-15e.net
Steve Davies
England
"Kristan Roberge" <krob...@ca.inter.net> wrote in message
news:3CC8A3F7...@ca.inter.net...
>
>
> Ken Duffey wrote:
>
> > top to bottom. Now turn it upside down - and now the air goes from the
> > bottom to the top (i.e. the same both ways).
> >
> > If this were not the case, the helicopter would be capable of inverted
> > flight - which it ain't !
>
> something like that, but actually the . Scale-Model R/C helicopters for
Steve Davies
I am not sure about the original discussion you refer to, but it sounds like
you are talking about 'mast bumping' which is a phenomenon only associated
with teetering head rotor systems. The solution is to keep the aircraft
under positive G. Lowering the tailboom seems more consistent with
facilitating better control authority at low speeds, when larger disk travel
is necessary to generate higher rates.
--
www.f-15e.net
Steve Davies
England
Unknown
>
>Ken, the rotors produce lift from their upper surfaces - the heli does not
>'thrust' itself skyward by pushing air towards the ground, it generates lift
>just like an aerofoil. When you hover close to the ground, the air that is
>thrust downwards can be used as a 'cushion', but this is simply a by-product
>of the downwash. This is what you might have meant, but I wasn't sure so I
>thought I'd say.
>
>
>
will take issue with you on your 'theory of flight' here.
All airfoils, ALL, produce lift by displacing air in the opposite
direction to that in which it is desired to move the airfoil.
Remember, 'For every action there's an equal and opposite
reaction'.
So 'both' the upper surface 'and' the lower surface act to move
this quantity of air, 'not' just the upper surface as you state.
Let the games begin... :)
--
Gord Beaman
PEI, Canada
"Old age is no place for sissies" -Bette Davis.
Ken Duffey
You're right Steve - I understand the principles of airfoils - I was just trying
to paint a simple mental picture of what I meant.
I know that the air sucks !!! And the earth repels.
Regards
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Ken Duffey - Flanker Freak & Russian Aviation Enthusiast
Flankers Website - http://www.flankers.co.uk/
Genuine E-mailers - Replace sukhoi with flanker
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Steve Davies
I think Ken knew what i was saying! But, yes, I appreciate that my post
iscertainly interesting to read. Oh dear... what have i started ;-)
--
www.f-15e.net
Steve Davies
England
"Gord Beaman" <ve...@rac.ca> wrote in message
news:3cc965b2...@198.164.200.20...
Peter Stickney
"Steve Davies" <ewanwhose...@ntlworld.com> writes:
> Peter,
>
> I am not sure about the original discussion you refer to, but it sounds like
> you are talking about 'mast bumping' which is a phenomenon only associated
> with teetering head rotor systems. The solution is to keep the aircraft
> under positive G. Lowering the tailboom seems more consistent with
> facilitating better control authority at low speeds, when larger disk travel
> is necessary to generate higher rates.
Mast Bumping is but one of the things that can go wrong with those
Hyperthyroid Propeller Beanies. Fully articulated rotors have their
own sets of problems, which was one of the reasons for changing the
tail on the S.55. The H-43 (and HOK) used to chop its tail off with
distressing regularity - It didn't use a teetering rotor, but a
semi-hinged design with no flapping hinges in the hub, just lag
hinges, and it used a flexible rotor (controlled by trim tabs) for
flapping and pitch control.
Basically, all helicopters are subject to having nasty things happen
to the plane (cone, actually) of the rotors when flying at anything
other than 1G level hovering flight. Much of this is compensated by
all the flexing and hinging, but there are limits. It is sometimes
useful to think of the fuselage and rotor(2) as two separate systems,
with the fuselage hanging from the rotor(s) at the shafts. (This can
be seen in shots of helicopters flying dead toward or away from the
observer - the rotor cone is canted to one side due to the aymmetrical
lift. Again, I refer you to ("You Only Live Twice).
John Keeney
Steve Davies <ewanwhose...@ntlworld.com> wrote in message
news:f88y8.2589$%k.11...@news6-win.server.ntlworld.com...
> only thing limiting a helicopter for
> > inverted flight is GETTING into that orientation while you reverse the
> pitch on
> > the main rotor
>
> And how do you reverse the pitch on a real helicopter main rotor? I fly
> helicopters and am not aware of a single bird that can do this. In any
case,
> there are several major issues which prevent SOME helicopters from
*getting
> into* inverted flight.
Hu? Excuse me, but I thought that part of making an
autorotation landing required "reversed pitch" on the
rotor to built up & store energy in the rotor.
Steve Davies
Not that I'm aware of, and I have 150 hours in heli's. When we autorotate,
we *reduce* the pitch of the blades (unload them). If you *reversed* the
pitch of the blades you'd generate lift in the opposite direction (i.e
downwards). I have heard of RC models being able to do this, but, AFAIk,
it's never been done in the real deal.
--
www.f-15e.net
Steve Davies
England
"John Keeney" <jdke...@iglou.com> wrote in message
news:3cca4...@news.iglou.com...
Steve Davies
I'd like to learn more about the H-43. I fly heli's (R-22, MD-500 and Bell
206) and, bar the usual phenomenon (RBS, Vortex Ring, Dynamic Roll Over,
Ground Resonance etc.), they are all very safe to fly, and most of the
accidents over here seem to be cause by other failures or problems (icing,
engine failure, fuel starvation, vortex ring). In the MD-500 you can be
aggressive on the stick at 90 knots without fear of tailstrike (I don't do
it, but my IP demonstrated it to me). I know an ex-Army aviator who led the
Sharks helicopter display team (Gazelle and Lynx), and he did say that there
used to be tail-scuffs as they manouvered the heli's with enough precision
to go right to the limits. However, he did say that when it happened the guy
would get the biggest bollocking of his life, so i don't imagine that they
were complacent about it.
Mast Bumping is THE thing that goes wrong with teetering head systems. I
don't know about the US, but it's possibly one of the most stressed safety
points to studs going through PPL here in the UK. I'm more than familiar
with coning as you see it from the cockpit when you pull pitch, you also see
the disk cant due asymmetrical lift.
--
www.f-15e.net
Steve Davies
England
"Peter Stickney" <p-sti...@worldnet.att.net> wrote in message
news:u6dbaa...@Mineshaft.att.net...
Unknown
Well Steve, am I to assume that I misread your explanation of how
rotors work (below)?...I must confess that I cannot decipher the
meaning of your answer here...sorry...
Steve Davies
wanted to explain that it was not the downwash from the disk which creates
the lift.
--
www.f-15e.net
Steve Davies
England
"Gord Beaman" <ve...@rac.ca> wrote in message
news:3ccb16b9...@198.164.200.20...
Peter Stickney
> 206) and, bar the usual phenomenon (RBS, Vortex Ring, Dynamic Roll Over,
> Ground Resonance etc.), they are all very safe to fly, and most of the
> accidents over here seem to be cause by other failures or problems (icing,
> engine failure, fuel starvation, vortex ring). In the MD-500 you can be
> aggressive on the stick at 90 knots without fear of tailstrike (I don't do
> it, but my IP demonstrated it to me). I know an ex-Army aviator who led the
> Sharks helicopter display team (Gazelle and Lynx), and he did say that there
> used to be tail-scuffs as they manouvered the heli's with enough precision
> to go right to the limits. However, he did say that when it happened the guy
> would get the biggest bollocking of his life, so i don't imagine that they
> were complacent about it.
The usual phenomena wer reason enough for me to back out :) Horses
for Courses, I guess. I know intellectually that helicopters are just
as safe as any other aircraft, but I'm just allergic to them.
The Intermeshing Kamans were/are (If they're still building Kmaxs)
very interesting birds. The Torque Cancellation was dead-on perfect,
and for the most part they were very easy to fly. In fact, the 2 seat
K-225/HTK model was rejected as a trainer because it was _too_ easy to
fly, and didn't prepare student pilots to fly "normal" helicopters.
They had a tremendous amount of lift- HOGE for an H-43B (Same engine
as an UH-1A/Bell 204, but derated to from 860 to 825 HP was 18,000'.
And, while they weren't fast, they sure were slow. A former Marine
HOK (Piston engined H-43)pilot I ran into described forward flight as
"Like pushing a sheet of plywood sideways in a windstorm." You'd top
out at about 85 kts.
The rotor comtrol system was, as for all early helicopters, unique.
The blades were wood, and quite flexible. The only hinges in the
rotor hubs were lag hinges. Blade pitch was controlled by "Servo
Flaps", basically trim tabs on the trailing edge of the blades, that
would twist teh blade to the appropriate angle.
With the counter-rotating rotors, there was no need for a tail rotor,
of course. The tail was a short twin-boom setup with a horizontal
stabilizer and vertical fins. Under conditions where extreme aft cyclic was
required, the early designs of the tail would be struck by the blades.
Wayne Mutza's H-43 book lists about 8 tail-strike incidents in 1960
alone. This led to all H-43s being grounded and a new tail designed.
>
> Mast Bumping is THE thing that goes wrong with teetering head systems. I
> don't know about the US, but it's possibly one of the most stressed safety
> points to studs going through PPL here in the UK. I'm more than familiar
> with coning as you see it from the cockpit when you pull pitch, you also see
> the disk cant due asymmetrical lift.
That, and the tendency to roll when flying fast.
Unknown
--cuts--
> I just wanted to explain that it was not the
>downwash from the disk which creates
>the lift.
>
But it -is- Steve (indirectly at least). Saying what you said is
akin to saying that, when a rifle is fired at you, it isn't the
rifle's recoil that kills you, and, strictly speaking, it isn't,
but you won't be killed (by the rifle) if there's no recoil, will
you now?.
So then, the lift is the reaction that the disk feels when it
creates the downwash. Therefore you can't say that the
downwash doesn't create the lift, can you?.
The act of creating the downwash is what creates
the lift, right?.
Ken Duffey
But - I thought all along that helicopters were so ugly that the earth
repels them !!
Is this not how they fly ??
Ken Duffey
Guy Alcala
> "Steve Davies" <ewanwhose...@ntlworld.com> wrote:
> --cuts--
>
> > I just wanted to explain that it was not the
> >downwash from the disk which creates
> >the lift.
> >
>
> But it -is- Steve (indirectly at least). Saying what you said is
> akin to saying that, when a rifle is fired at you, it isn't the
> rifle's recoil that kills you, and, strictly speaking, it isn't,
> but you won't be killed (by the rifle) if there's no recoil, will
> you now?.
>
> So then, the lift is the reaction that the disk feels when it
> creates the downwash. Therefore you can't say that the
> downwash doesn't create the lift, can you?.
>
> The act of creating the downwash is what creates
> the lift, right?.
And let's not forget the vertical drag of the downwash impinging on
the fuselage (and any wings that are present), which decreases the
hover weight capability. If the downwash didn't have anything to do
with lift, then the presence of fuselage/wings in the downwash flow
path wouldn't affect the weight-lifting capability in the slightest.
But it does.
Guy
Steve Davies
I agree with you. I don't know why you are arguing?
--
www.f-15e.net
Steve Davies
England
"Gord Beaman" <ve...@rac.ca> wrote in message
news:3ccca4e3...@198.164.200.20...
Steve Davies
My knowledge of aerodynamics is strictly limited to what I had to learn for
my PPLH. However, I believe that you are discussing hover weight IGE, which,
as I have already said, is a *direct* benefit of downwash and does effect
hover capability. I was never disputing this!.
--
www.f-15e.net
Steve Davies
England
"Guy Alcala" <g_al...@junkpostoffice.pacbell.net> wrote in message
news:3CCDAE0F...@junkpostoffice.pacbell.net...
Guy Alcala
> Guy,
>
> My knowledge of aerodynamics is strictly limited to what I had to learn for
> my PPLH. However, I believe that you are discussing hover weight IGE, which,
> as I have already said, is a *direct* benefit of downwash and does effect
> hover capability. I was never disputing this!.
Steve, vertical drag of the fuselage (and any wing in the rotor downwash)
affects hover weight in OR out of GE, decreasing the effective lift and thus the
hover weight (IGE adds some back). That's why the V-22 has those big, wide
chord and span flaps which deploy to about 80 deg. when fully out, to decrease
the Cd(v) in the hover. That's also why the Sikorsky R-6 (and virtually every
other helo designed since) had a curved top to the fuselage, instead of the more
or less flat plate surface on the R-4 - to improve the hover capability by
decreasing the download on the fuselage. That's also why rotor blades tend not
to have airfoils on their inner sections. Just wanted to make sure we all
agreed on the effects of downwash.
Guy
P.s. You've got far more practical experience of helos than I do; I'm just
reading the books and passing the info along. My practical understanding of
aero is probably similar to yours, and essentially fixed-wing. I've just been
doing a lot of helo-related reading lately, and am planning to take a
flight/lesson sometime this year just to see what I'm missing. Not that I can
afford to do it on a regular basis regardless, more's the pity.
Steve Davies
Thanks for your informative post. I was unaware that parasitic drag from the
fuse/downwash would decrease IGE & OGE hover performance.
I'd bet that your aerodynamic knowledge far exceeds mine, as i always seem
to put my foot in my mouth whenever i try and explain it!
Good luck with your lesson; I am sure that you'll see that flying them is
much more fun than reading or discussing them!
Cheers
Steve
--
www.f-15e.net
Steve Davies
England
"Guy Alcala" <g_al...@junkpostoffice.pacbell.net> wrote in message
news:3CCE486E...@junkpostoffice.pacbell.net...
Steve Davies
Thanks very much for the post; it's interesting to learn a little about the
guys who did the really interesting flying!
--
www.f-15e.net
Steve Davies
England
"Peter Stickney" <p-sti...@worldnet.att.net> wrote in message
news:15jgaa...@Mineshaft.att.net...
Guy Alcala
> Guy,
>
> Thanks for your informative post. I was unaware that parasitic drag from the
> fuse/downwash would decrease IGE & OGE hover performance.
Just as another example, when heli-logging companies buy used S-61L/Ns, they
usually have the two fuselage plugs (that Sikorsky added when they stretched the
original S-61 [SH-3] design to carry more passengers) removed. This adds useful
load two ways - it decreases the empty weight by removing structure irrelevant
to the external lift role, and it increases the max. hover weight (possibly with
some structural beefing up required) by decreasing the download, as there's less
fuselage under the airfoil section of the rotor.
> I'd bet that your aerodynamic knowledge far exceeds mine, as i always seem
> to put my foot in my mouth whenever i try and explain it!
Oh, so do I, unless I've got the books right there. Ask me to explain anything
beyond "angle of attack" and I start to get nervous;-) Fortunately, I've got a
friend who's comfortable with aero, and he can explain it in words even I can
follow.
> Good luck with your lesson; I am sure that you'll see that flying them is
> much more fun than reading or discussing them!
Always is, and I confess that I just like the utilitarian idea of the beasts
(but then I work in the trucking industry). Of course, since my uncorrected
vision prevents me from ever getting a commercial or ATP license (fixed or
rotary-wing), I can't ever have anyone else pay me to fly, which is a drag. I'm
debating between trying an R-22 or a 300; I'm told by people who've trained in
both that learning in a Robbie makes you a better pilot down the road (kind of
like learning in a tail-dragger), but since I'm never going to be able to do
this professionally that's moot, and I've never cared for the Robbie's cyclic -
it just doesn't fit the mental image I want. Kind of like I hate control wheels
and flying from the left side in GA a/c - I've always wanted to fly with a stick
in my right hand and the throttle in my left, with anyone else in tandem behind
me, so I can be Group Captain Mitty, ta-pocketa, pocketa, pocketa;-)
So, T-bar cyclics don't pass my fantasy test - how can I be a Loach or SAR pilot
with one?;-> I visited the Hiller Museum in San Carlos a few weekends back, and
got to 'fly' the FS98 (206) sim they'd hooked up to the controls of an old
UH-12. Sitting in the cockpit of that and flying around the (computer) Bay Area
felt perfect - why, below me I could almost see the anxious faces of Hawkeye,
BJ, Radar and Klinger looking up at me, waiting to unload the two stretcher
cases that the steely-nerved Casevac pilot was bringing them. Well, what the
hell, flying doesn't make any economic sense for me, so I might as well enjoy my
fantasies. Snoopy and I are both Root-Beer drinkers, too;-)
Guy
Steve Davies
Guy,
I'm with you 100% on the t-bar stick, but I have to say that it does have
its advantages. I've never flown the 300, and have done 90% of my flying in
various marks of the R-22 (I also have a Hughes 500 rating and 7 or 8 hours
p-u-t in the Bell 206). With my limited credentials out of the way, I'll
stick my neck out and say that I actually *prefer* the t-bar system :-) It's
was great to jump in the Hughes for the first time and play with this manly
stick, festooned with buttons reminiscent of and F-15 stick, but once the
sparkle wore off, the hassle of getting into and out of the cockpit with the
damn thing getting in the way began to get on my nerves. I could also very
comfortably rest my right hand on my right thigh as I flew in the R-22, a
technique which makes things far more relaxing and which, IMO, is less
effective in the Hughes and Jetranger due to the placement of the stick.
Initially at least, the centre stick was so alien to me that I'd PIO in the
hover because my muscle memory simply did not know what to make of it; it
was worse with the ultra smooth, hydraulically boosted '206 controls cyclic.
When i fly the Robbo, I too find it hard to take the machine seriously as it
fails to fit into my own ideas of what a 'real' helo is, but its a great
machine and I'd wager a bet that most IP's would state that it makes you a
better pilot form the start, not just further down the road. The
implication, for me at least, is that it doesn't matter if you go on to ATPL
or CFI, you want to be safe and to have good airmanship skills - I'd rather
fly a twitchy, unforgiving bird and stay sharp than a less demanding one and
become complacent.
Guy Alcala
<snip>
Guy,
> I'm with you 100% on the t-bar stick, but I have to say that it does have
> its advantages. I've never flown the 300, and have done 90% of my flying in
> various marks of the R-22 (I also have a Hughes 500 rating and 7 or 8 hours
> p-u-t in the Bell 206).
BTW, what model 500 do you have time in? I remember reading a discussion on
another forum some time back on the advantages and disadvantages for different
types of work of the various models with 2, 4 or no (520N) bladed tail rotors.
> With my limited credentials out of the way, I'll
> stick my neck out and say that I actually *prefer* the t-bar system :-) It's
> was great to jump in the Hughes for the first time and play with this manly
> stick, festooned with buttons reminiscent of and F-15 stick, but once the
> sparkle wore off, the hassle of getting into and out of the cockpit with the
> damn thing getting in the way began to get on my nerves.
If I had to do it all the time it might well bug me too, but for the kind of
very occasional flying I'd probably manage it wouldn't matter. Hell, I have
trouble sliding my legs under the steering wheel of my car owing to a long ago
groin muscle pull that never healed, but since I have to drive the thing rarely
(I can walk/bike to work/shopping/restaurants etc.) it's not a big deal.
> I could also very
> comfortably rest my right hand on my right thigh as I flew in the R-22, a
> technique which makes things far more relaxing and which, IMO, is less
> effective in the Hughes and Jetranger due to the placement of the stick.
I've heard others say much the same, although that seems to be a question of
cyclic length/location. I've also seen some of the newer (and definitely not
trainer) helo designs use a cyclic grip that's curved towards you instead of
away, where you hold it more like a tennis racket. I expect that wouldn't pass
my fantasy test either, but it might alleviate the problem you describe. If I'm
lucky, there may be a Robbie around here with the conventional cyclic mod, so I
could try it both ways.
> Initially at least, the centre stick was so alien to me that I'd PIO in the
> hover because my muscle memory simply did not know what to make of it; it
> was worse with the ultra smooth, hydraulically boosted '206 controls cyclic.
>
> When i fly the Robbo, I too find it hard to take the machine seriously as it
> fails to fit into my own ideas of what a 'real' helo is, but its a great
> machine and I'd wager a bet that most IP's would state that it makes you a
> better pilot form the start, not just further down the road.
Absolutely. By 'further down the road' I meant that learning on a Robbie would
make you a better pilot flying any helo, including when you'd moved on to your
work a/c.
> The
> implication, for me at least, is that it doesn't matter if you go on to ATPL
> or CFI, you want to be safe and to have good airmanship skills - I'd rather
> fly a twitchy, unforgiving bird and stay sharp than a less demanding one and
> become complacent.
If I was going to be able to do this professionally, I'd agree 100%. Knowing
me, what I think I'll probably wind up doing is get an hour each in the R-22 and
300, just for kicks and to compare them as much as I'm able (with that little
experience, probably not much). Considering how many years it's been since I've
flown anything, just getting up again should be great.
Guy
Peter Stickney
Guy Alcala <g_al...@junkpostoffice.pacbell.net> writes:
> Steve Davies wrote:
>
>> Guy,
>>
>> Thanks for your informative post. I was unaware that parasitic drag from the
>> fuse/downwash would decrease IGE & OGE hover performance.
>
> Just as another example, when heli-logging companies buy used S-61L/Ns, they
> usually have the two fuselage plugs (that Sikorsky added when they stretched the
> original S-61 [SH-3] design to carry more passengers) removed. This adds useful
> load two ways - it decreases the empty weight by removing structure irrelevant
> to the external lift role, and it increases the max. hover weight (possibly with
> some structural beefing up required) by decreasing the download, as there's less
> fuselage under the airfoil section of the rotor.
Sorry for jumping back in a bit late -
I've got a few shots of a CH-3E that was stationed in Alaska (Eielson
AFB) that had had the sponsons removed and the struts & wheels from
an S-61L put on, for the same reasons. (Less area under the rotor, and
adding lightness.) IIRC, some of these pictures are in the
Squadron/Signal "H-3 In Action" booklet.
>
>> I'd bet that your aerodynamic knowledge far exceeds mine, as i always seem
>> to put my foot in my mouth whenever i try and explain it!
>
> Oh, so do I, unless I've got the books right there. Ask me to explain anything
> beyond "angle of attack" and I start to get nervous;-) Fortunately, I've got a
> friend who's comfortable with aero, and he can explain it in words even I can
> follow.
>
A good source, and not super-hyper technical, (but you do need a
scientific calculator) is "Rotary-Wing Aerodynamics", by
W.Z. Stepniewski and C.N. Keys, Dover Publications, NY, ISBN
0-486-64647-5. Of course, there's always "Aerodynamics for Naval
Aviators" (a.k.a. "Aerodynamics for History Majors" :) ) which
provides a very good practical understanding of just what you're doing
when flogging the air.
>> Good luck with your lesson; I am sure that you'll see that flying them is
>> much more fun than reading or discussing them!
>
> Always is, and I confess that I just like the utilitarian idea of the beasts
> (but then I work in the trucking industry). Of course, since my uncorrected
> vision prevents me from ever getting a commercial or ATP license (fixed or
> rotary-wing), I can't ever have anyone else pay me to fly, which is a drag. I'm
> debating between trying an R-22 or a 300; I'm told by people who've trained in
> both that learning in a Robbie makes you a better pilot down the road (kind of
> like learning in a tail-dragger), but since I'm never going to be able to do
> this professionally that's moot, and I've never cared for the Robbie's cyclic -
> it just doesn't fit the mental image I want. Kind of like I hate control wheels
> and flying from the left side in GA a/c - I've always wanted to fly with a stick
> in my right hand and the throttle in my left, with anyone else in tandem behind
> me, so I can be Group Captain Mitty, ta-pocketa, pocketa, pocketa;-)
>
> So, T-bar cyclics don't pass my fantasy test - how can I be a Loach or SAR pilot
> with one?;-> I visited the Hiller Museum in San Carlos a few weekends back, and
> got to 'fly' the FS98 (206) sim they'd hooked up to the controls of an old
> UH-12. Sitting in the cockpit of that and flying around the (computer) Bay Area
> felt perfect - why, below me I could almost see the anxious faces of Hawkeye,
> BJ, Radar and Klinger looking up at me, waiting to unload the two stretcher
> cases that the steely-nerved Casevac pilot was bringing them. Well, what the
> hell, flying doesn't make any economic sense for me, so I might as well enjoy my
> fantasies. Snoopy and I are both Root-Beer drinkers, too;-)
You could be a Fantastically Brave French Organization Sanitaire
pilot, braving the flak to evacuate casualties from Dien Ben Phu.
They had a couple of Hiller 360s, and those had the T-bar cyclics.
Or Fred Piasecki, teaching himself to fly the PV-2 Dogship, and eaning
Helicoper Pilot's License #1.
Good luck with it though, and I hope you like it.
Guy Alcala
> In article <3CCF57C2...@junkpostoffice.pacbell.net>,
> Guy Alcala <g_al...@junkpostoffice.pacbell.net> writes:
> > Steve Davies wrote:
>
> >> I'd bet that your aerodynamic knowledge far exceeds mine, as i always seem
> >> to put my foot in my mouth whenever i try and explain it!
> >
> > Oh, so do I, unless I've got the books right there. Ask me to explain anything
> > beyond "angle of attack" and I start to get nervous;-) Fortunately, I've got a
> > friend who's comfortable with aero, and he can explain it in words even I can
> > follow.
> >
> A good source, and not super-hyper technical, (but you do need a
> scientific calculator) is "Rotary-Wing Aerodynamics", by
> W.Z. Stepniewski and C.N. Keys, Dover Publications, NY, ISBN
> 0-486-64647-5.
Volume I will quickly bog you down in equations unless you're really comfortable with
them, but Volume II offers practical examples (most based on one of Boeing's YH-61
UTTAS design iterations) and is much more accessible. Indeed, I based most of my
comments to Steve on it (and some judicious use of Vol. 1).
<snip recounting of my helo flying fantasies>
> You could be a Fantastically Brave French Organization Sanitaire
> pilot, braving the flak to evacuate casualties from Dien Ben Phu.
> They had a couple of Hiller 360s, and those had the T-bar cyclics.
Nah, nothing French would work. I don't smoke Gitanes or anything else;-)
> Or Fred Piasecki, teaching himself to fly the PV-2 Dogship, and eaning
> Helicoper Pilot's License #1.
More like Stan Hiller, flying the XH-44 inside Memorial Stadium in Berkeley, or that
360 pilot who rescued a 12 year-old kid in a coma from a fractured skull (fell off a
horse) from Benson Lake in the Yosemite backcountry in '49 ('48?), after a Bell 47
tried and failed. In one of life's little ironies, that 12-year old grew up to become
the current (and much reviled by police and those few conservatives that San Francisco
has, for his very liberal views) San Francisco District Attorney, Terence Hallinan.
Guy