Wingdrop while stalling

[drake]

Hi,

there is a HAL HPT-32 (pistonengined 2 seater trainer light a/c)
which, when attempting a stall, does not pitch down correctly. Instead
one of the wings (either port or starboard (50/50)... no gyro problems
due to engine) almost always drops, and this genreally results in the
a/c entering a spin (which the rookie pilots are unable to handle,
generally). There is no inherent imbalance in the c.g. location due to
the fuel tanks ot fuel flow. What could be causing such a wing drop
while stalling? Is it soem inherent instability in the roll axis?

Any help/advice/recollection of previous such problems and what you
did to fix it will be greatly appreciated.

Lars

[nafod40]

drake wrote:
> Hi,
>
> there is a HAL HPT-32 (pistonengined 2 seater trainer light a/c)
> which, when attempting a stall, does not pitch down correctly. Instead
> one of the wings (either port or starboard (50/50)... no gyro problems
> due to engine) almost always drops, and this genreally results in the
> a/c entering a spin (which the rookie pilots are unable to handle,
> generally).

Sounds like a great trainer aircraft! If this problem common to the
type, or just this particular A/C?

The 50/50 part is interesting. Normally, if a plane is bent, it'll favor
one side or 'tuther.

Stall strips are a common way to improve stall performance, so as to
keep the tips flying (and ailerons working) while the root stalls. Does
the type have them?

Good luck...

[Orval Fairbairn]

In article >,
Todd Pattist > wrote:

> (drake) wrote:
>
> >there is a HAL HPT-32 (pistonengined 2 seater trainer light a/c)
> >which, when attempting a stall, does not pitch down correctly. Instead
> >one of the wings (either port or starboard (50/50)... no gyro problems
> >due to engine) almost always drops, and this genreally results in the
> >a/c entering a spin
>
> A strong wing drop that occurs on either side can be caused
> by the wing tips stalling too early. As the tip stalls, the
> wing with the stalled tip begins to drop, the AOA increases
> on the dropping wing and the entire wing stalls. Washout
> (wing twist to reduce tip AOA) or a carefully selected
> airfoil for the tip (that stalls at a higher AOA than inner
> parts of the wing) may be used by the designer to prevent
> this undesirable phenomenon. Careful comparison of washout
> angle and/or the airfoil at the tip with the plans might
> detect some rigging or construction problems. Any tendency
> of the wing to twist, while in flight, can exacerbate the
> problem.
> Todd Pattist
> (Remove DONTSPAMME from address to email reply.)
> ___
> Make a commitment to learn something from every flight.
> Share what you learn.

If the wing drop is 50/50 L/R on the same plane, I would think that
somebody is holding in a little aileron or rudder, without knowing it.

I am not familiar with the type, so I cannot speculate further.

I would attach some stall strips to the inboard leading edges of both
wings, so they would induce turbulence at high angles of attack. They
need be 4" to 6" long, which would induce root stall before tip stall.

[ChuckSlusarczyk]

In article >, drake says...
>
>Hi,
>
>there is a HAL HPT-32 (pistonengined 2 seater trainer light a/c)
>which, when attempting a stall, does not pitch down correctly. Instead
>one of the wings (either port or starboard (50/50)... no gyro problems
>due to engine) almost always drops, and this genreally results in the
>a/c entering a spin (which the rookie pilots are unable to handle,
>generally). There is no inherent imbalance in the c.g. location due to
>the fuel tanks ot fuel flow. What could be causing such a wing drop
>while stalling? Is it soem inherent instability in the roll axis?
>
>Any help/advice/recollection of previous such problems and what you
>did to fix it will be greatly appreciated.
>
>Lars

Bet you don't have any wash out in the wings.If it was always the same wing then
it could be rigging. That's a starting point .

See ya

Chuck

[Dan Thomas]

nafod40 > wrote in message >...
> drake wrote:
> > Hi,
> >
> > there is a HAL HPT-32 (pistonengined 2 seater trainer light a/c)
> > which, when attempting a stall, does not pitch down correctly. Instead
> > one of the wings (either port or starboard (50/50)... no gyro problems
> > due to engine) almost always drops, and this genreally results in the
> > a/c entering a spin (which the rookie pilots are unable to handle,
> > generally).
>
> Sounds like a great trainer aircraft! If this problem common to the
> type, or just this particular A/C?
>
> The 50/50 part is interesting. Normally, if a plane is bent, it'll favor
> one side or 'tuther.
>
> Stall strips are a common way to improve stall performance, so as to
> keep the tips flying (and ailerons working) while the root stalls. Does
> the type have them?
>
> Good luck...

Some airplanes might have some nasty stall characteristics
caused by wing design, and sometimes such design is intentional to get
good aerobatic performance and to teach advanced flight maneuvers.
Most training airplanes are designed to have straightforward stalling
behaviour, some so forgiving that there is no real stall at all.
Newbie pilot students can get into big trouble real quick with stall
behaviour that drops one wing or the other.
Any certified airplane will have a straight-ahead stall break.
Wing drop is caused by one wing stalling slighty earlier, or the stall
on that side has progressed more than on the other, and if the wing
isn't out of rig, it's caused by uncoordinated flight. The nose of the
airplane isn't pointing straight ahead so that the airplane is sliding
slightly sideways as it stalls, and the wingtip that's farther aft
will stall first and drop. The same holds true for skidding turns; the
inside wing will drop first.
A power-on stall will most often drop the wing on the side that
has the upgoing prop blade; in North America, that's the left wing.
The rotating propwash strikes the wing root and causes a higher angle
of attack on that side, causing an earlier stall.

Dan

[Tim Ward]

"Todd Pattist" > wrote in message
...
> (drake) wrote:
>
> >there is a HAL HPT-32 (pistonengined 2 seater trainer light a/c)
> >which, when attempting a stall, does not pitch down correctly. Instead
> >one of the wings (either port or starboard (50/50)... no gyro problems
> >due to engine) almost always drops, and this genreally results in the
> >a/c entering a spin
>
> A strong wing drop that occurs on either side can be caused
> by the wing tips stalling too early. As the tip stalls, the
> wing with the stalled tip begins to drop, the AOA increases
> on the dropping wing and the entire wing stalls. Washout
> (wing twist to reduce tip AOA) or a carefully selected
> airfoil for the tip (that stalls at a higher AOA than inner
> parts of the wing) may be used by the designer to prevent
> this undesirable phenomenon. Careful comparison of washout
> angle and/or the airfoil at the tip with the plans might
> detect some rigging or construction problems. Any tendency
> of the wing to twist, while in flight, can exacerbate the
> problem.
> Todd Pattist
> (Remove DONTSPAMME from address to email reply.)
> ___
> Make a commitment to learn something from every flight.
> Share what you learn.

It occurs to me that they might want to check the aileron rigging.
If both ailerons were "drooped", it would reduce the washout.

Tim Ward

[Bill Daniels]

I once heard a neat story about stall spin characteristics.

It seems that a light airplane manufacturer wanted a piece of the two seat
training market that Cessna dominated with the C150/152. They designed and
built a nifty little low wing prototype that flew real nice with much better
performance than the 150/152 with the same power. Then they invited a bunch
of CFI's to fly it and asked, "How'd you like it?" "It doesn't spin - we
want to teach spins", they said.

The manufacturer hired some engineering consultants and said, "Make it
spin". The consultants added stall strips on the outboard wing to make the
wing tips stall first - and boy, did it spin. The manufacturer brought the
CFI's back and let them fly it again. The CFI's said, "Boy, does it spin".
"We like it", they said.

So, the manufacturer built some little airplanes and the CFI's and their
students started making smoking holes in the ground as they spun in.

"Wow", said the manufacturer, "we got to fix this". So, they hired another
bunch of aeronautical consultants who looked up "how to fix bad stall/spin
characteristics" in their "how to design little airplanes" book. The book
said, "add stall strips to the inboard wing", so that's what they did. Now
the little airplane would still spin, but not as enthusiastically as before.
With FOUR stall strips on the wing, it didn't perform worth a damn either.

Still, the manufacturer built a bunch of them before exiting the market.

Makes you wonder.

Bill Daniels

[Tim Ward]

"Morgans" > wrote in message
...
>
> "Tim Ward" > wrote
> >
> > It occurs to me that they might want to check the aileron rigging.
> > If both ailerons were "drooped", it would reduce the washout.
> >
> > Tim Ward
> >
> >
> I believe you have it backwards. Droop decreases overall AOA, and acts as
> washout, right?
> --
> Jim in NC
>

I don't think so. I'm using "droop" here to indicate that the trailing
edges are lower than normal.
If it's lower in back, the AOA should be larger, and the washout less.
If they were both _reflexed_, it would be higher on the trailing edge, and
increase the washout.

Tim Ward

[Morgans]

"Tim Ward" > wrote
>
> It occurs to me that they might want to check the aileron rigging.
> If both ailerons were "drooped", it would reduce the washout.
>
> Tim Ward
>
>
I believe you have it backwards. Droop decreases overall AOA, and acts as
washout, right?
--
Jim in NC

[Morgans]

"Tim Ward" > wrote in message
...
>
> "Morgans" > wrote in message
> ...
> >
> > "Tim Ward" > wrote
> > >
> > > It occurs to me that they might want to check the aileron rigging.
> > > If both ailerons were "drooped", it would reduce the washout.
> > >
> > > Tim Ward
> > >
> > >
> > I believe you have it backwards. Droop decreases overall AOA, and acts
as
> > washout, right?
> > --
> > Jim in NC
> >
>
> I don't think so. I'm using "droop" here to indicate that the trailing
> edges are lower than normal.
> If it's lower in back, the AOA should be larger, and the washout less.
> If they were both _reflexed_, it would be higher on the trailing edge, and
> increase the washout.
>
> Tim

Right. I had to do some hand flying to get that figured! <g>
--
Jim in NC

[john smith]

drake wrote:
>
> Hi,
> there is a HAL HPT-32 (pistonengined 2 seater trainer light a/c)
> which, when attempting a stall, does not pitch down correctly. Instead
> one of the wings (either port or starboard (50/50)... no gyro problems
> due to engine) almost always drops, and this genreally results in the
> a/c entering a spin (which the rookie pilots are unable to handle,
> generally). There is no inherent imbalance in the c.g. location due to
> the fuel tanks ot fuel flow. What could be causing such a wing drop
> while stalling? Is it soem inherent instability in the roll axis?

Sounds like a good rudder trainer.

[Albert]

Lars,
Fit wedges on the leading edges at the wing roots to force a root
stall. Some WW2 era military trainers tip stalled to enhance training
experience and the root wedge fix is used to remove the characteristic
(and surprise) for civilian warbird use.
Albert

(drake) wrote in message >...
> Any help/advice/recollection of previous such problems and what you
> did to fix it will be greatly appreciated.
>
> Lars

[Roger Halstead]

On Sat, 10 Jan 2004 00:03:57 GMT, john smith >
wrote:

>drake wrote:
>>
>> Hi,
>> there is a HAL HPT-32 (pistonengined 2 seater trainer light a/c)
>> which, when attempting a stall, does not pitch down correctly. Instead
>> one of the wings (either port or starboard (50/50)... no gyro problems
>> due to engine) almost always drops, and this genreally results in the
>> a/c entering a spin (which the rookie pilots are unable to handle,
>> generally). There is no inherent imbalance in the c.g. location due to
>> the fuel tanks ot fuel flow. What could be causing such a wing drop
>> while stalling? Is it soem inherent instability in the roll axis?
>
>Sounds like a good rudder trainer.

Sounds like my Debonair. And...no it doesn't have wedges on the wing
roots although it does have the little 1/4 inch stall strips about 6
inches long. I don't think the first 60 or so had any washout either,
but I'd have to dig deeper on that.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

[Wright1902Glider]

Ditto Chuck's response. On one of my experimental gliders, I designed a
delta-wing using a reflex airfoil (M-178 I think.) However, I did not wash out
the tips, and I used wingtips that terminated in a sharp points. Big mistake.
When tested at high AOA's, massive tip stalls caused the wing to roll 45
degrees and yaw 180 degrees about every 3 seconds.

Curiously enough, the Wright boys (yep, them again) used washed out wingtips on
the 1902 glider.

Harry "flies under polyethylene too" Frey

PS: Funny what you can learn from watching the (stress) hawks fly. Isn't it?

[Dave Hyde]

Wright1902Glider wrote:

> When tested at high AOA's, massive tip stalls caused the wing to roll 45
> degrees and yaw 180 degrees about every 3 seconds.

Was this a model or was it piloted?

Dave 'bowling balls' Hyde

[nafod40]

Dave Hyde wrote:
> Wright1902Glider wrote:
>
>
>>When tested at high AOA's, massive tip stalls caused the wing to roll 45
>>degrees and yaw 180 degrees about every 3 seconds.
>
>
> Was this a model or was it piloted?
>
> Dave 'bowling balls' Hyde

Yea, that'd be heck in a dog fight. You could fly a tight landing
pattern, though.

Nafod "nafod" 40

[drake]

Hi all,

Thanks for your replies.

The a/c in question is:
http://www.bharat-rakshak.com/IAF/Images/Current/Deepak.html

The wingdrop problem has been solved (some years back). Just learnt
that all the engineers did was to replace the counter-sunk flat top
rivets on the wing-top (holding the skin to the ribs) were replaced by
protruding pan-head rivets, which apparently energised the flow (made
it more turbulent?). There were rivets all over the wing, but more
towards the wing-root side. This solved the wing drop problem i.e. the
wing drop while stalling was then gentle enough to be handled by
novice pilots. I still am not completely satisfied with the turbulence
explaination... why should a more "energised" flow make the wing drop
less violent?

One character who worked on this kite several years ago said that the
stall actually started mid-wing, and progressed very quickly, so that
one wing (entire wing, not just the tip or root) stalled and dropped.
Dunno if he was farting or not.

Has anybody used the protruding rivet approach before to solve wing
aerodynamic problems before? Quite a minimalist solution!

Drake Lars

[Richard Lamb]

drake wrote:
>
> Hi all,
>
> Thanks for your replies.
>
> The a/c in question is:
> http://www.bharat-rakshak.com/IAF/Images/Current/Deepak.html
>
> The wingdrop problem has been solved (some years back). Just learnt
> that all the engineers did was to replace the counter-sunk flat top
> rivets on the wing-top (holding the skin to the ribs) were replaced by
> protruding pan-head rivets, which apparently energised the flow (made
> it more turbulent?). There were rivets all over the wing, but more
> towards the wing-root side. This solved the wing drop problem i.e. the
> wing drop while stalling was then gentle enough to be handled by
> novice pilots. I still am not completely satisfied with the turbulence
> explaination... why should a more "energised" flow make the wing drop
> less violent?

Sounds like the round head rivets are acting like turbulators.

If the boundry layer is not attached to the surface, none of the
"energy" in the flow is transfered to the surface.

Basically, tickling the boundry layer like that causes it to reattach
to the surface. That's what they mean by "energizing" the flow.

Make more sense?

Richard (the new improved)Lamb

Hi ya'll!

[Wright1902Glider]

Separation bubbles?


OT: BTW, my experimental glider was a full-sized HG, and I tested it both
clipped-in and unclipped. The second method was preferable, as the first
allowed the glider to drag me all over the beach at Kitty Hawk. I should note
that when I designed this machine, I had very little understanding of the fine
points of non-rigid delta-wing aerodynamics. There's a photo of it on my
website. Its the "Stormy Petrel 3" photo. The "Stormy Petrel 2A" was a
modified "Batso" glider and flew fairly well.

Harry
http://hometown.aol.com/wright1902/page3.html

[Big John]

Todd

Further on your experience.

A number of model airplanes I have seen had very rapid roll off as the
airspeed was reduced approaching the stall. On landing this caused the
wing to drop and bird cartwheel.

One solution was to glue a piece of string along the crown of the air
foil.

Another was to put a wedge shaped piece of balsa on the wing leading
edge near the fuselage.

Both seemed to work ok and made the birds flyable by new bees.

Same techniques will work on full size aircraft.

Big John
Pilot ROCAF


On Thu, 15 Jan 2004 14:51:10 -0500, Todd Pattist
> wrote:

>Richard Lamb > wrote:
>
>>Sounds like the round head rivets are acting like turbulators.
>
>My glider uses a strip of tape that looks like Dymo labeling
>tape with a string of periods punched into it to turbulate
>the flow.
>Todd Pattist
>(Remove DONTSPAMME from address to email reply.)
>___
>Make a commitment to learn something from every flight.
>Share what you learn.

[Dave Hyde]

Wright1902Glider wrote:

> OT: BTW, my experimental glider was a full-sized HG, and I tested it both
> clipped-in and unclipped.

You are a brave, brave man. :-)

Dave 'pirouette' Hyde

[Roger Halstead]

On Thu, 15 Jan 2004 17:01:06 GMT, Richard Lamb >
wrote:

>drake wrote:
>>
>> Hi all,
>>
>> Thanks for your replies.
>>
>> The a/c in question is:
>> http://www.bharat-rakshak.com/IAF/Images/Current/Deepak.html
>>
>> The wingdrop problem has been solved (some years back). Just learnt
>> that all the engineers did was to replace the counter-sunk flat top
>> rivets on the wing-top (holding the skin to the ribs) were replaced by
>> protruding pan-head rivets, which apparently energised the flow (made
>> it more turbulent?). There were rivets all over the wing, but more
>> towards the wing-root side. This solved the wing drop problem i.e. the
>> wing drop while stalling was then gentle enough to be handled by
>> novice pilots. I still am not completely satisfied with the turbulence
>> explaination... why should a more "energised" flow make the wing drop
>> less violent?
>
>Sounds like the round head rivets are acting like turbulators.

They have done this in Bonanzas for years.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
>
>If the boundry layer is not attached to the surface, none of the
>"energy" in the flow is transfered to the surface.
>
>Basically, tickling the boundry layer like that causes it to reattach
>to the surface. That's what they mean by "energizing" the flow.
>
>Make more sense?
>
>Richard (the new improved)Lamb
>
>Hi ya'll!

[Cy Galley]

It must be poor wing design if you have to modify the airfoil with a flow
disrupting rivet head.

My Bellanca doesn't have a wing drop problem and doesn't have any rivet
heads either.

Wonder what the Glass plane builders are doing?
Designing the wing correctly?
--
Cy Galley - Bellanca Champion Club
Newsletter Editor-in-Chief & EAA TC
www.bellanca-championclub.com
Actively supporting Aeroncas every day
Quarterly newsletters on time
Reasonable document reprints

"Roger Halstead" > wrote in message
...
> On Thu, 15 Jan 2004 17:01:06 GMT, Richard Lamb >
> wrote:
>
> >drake wrote:
> >>
> >> Hi all,
> >>
> >> Thanks for your replies.
> >>
> >> The a/c in question is:
> >> http://www.bharat-rakshak.com/IAF/Images/Current/Deepak.html
> >>
> >> The wingdrop problem has been solved (some years back). Just learnt
> >> that all the engineers did was to replace the counter-sunk flat top
> >> rivets on the wing-top (holding the skin to the ribs) were replaced by
> >> protruding pan-head rivets, which apparently energised the flow (made
> >> it more turbulent?). There were rivets all over the wing, but more
> >> towards the wing-root side. This solved the wing drop problem i.e. the
> >> wing drop while stalling was then gentle enough to be handled by
> >> novice pilots. I still am not completely satisfied with the turbulence
> >> explaination... why should a more "energised" flow make the wing drop
> >> less violent?
> >
> >Sounds like the round head rivets are acting like turbulators.
>
> They have done this in Bonanzas for years.
>
> Roger Halstead (K8RI & ARRL life member)
> (N833R, S# CD-2 Worlds oldest Debonair)
> www.rogerhalstead.com
> >
> >If the boundry layer is not attached to the surface, none of the
> >"energy" in the flow is transfered to the surface.
> >
> >Basically, tickling the boundry layer like that causes it to reattach
> >to the surface. That's what they mean by "energizing" the flow.
> >
> >Make more sense?
> >
> >Richard (the new improved)Lamb
> >
> >Hi ya'll!
>

[C.D.Damron]

"Cy Galley" > wrote in message
news:69SNb.79462$I06.340710@attbi_s01...
> It must be poor wing design if you have to modify the airfoil with a flow
> disrupting rivet head.

Are you kidding?

Airfoil selection and wing design is about making priorities and
compromises.

The majority of planes have some external flow control and I wouldn't
consider every one a case of poor wing design.

[Wright1902Glider]

Dave,

I could send ya a few photos of Chuck S. flying the same kinda gliders back in
the 70's. I may be a nut, but I'm not the only nut. ;-)

By the way, my Wright 1902 is also airworthy. I haven't tried flying it yet
though. It'll be a while before I have the financial and logistical resources
(and spare parts) to mount an expedition to Kitty Hawk with it.

Harry

[Corrie]

Deja vu all over again - wasn't there a 90-post thread on this topic
(need for thingies sticking up != bad wing design) a couple months
back? Save your fingers and check the archives....

The Deepak is a nifty-looking little trainer, though. Side-by-side
seating, right?

"C.D.Damron" > wrote in message news:<s0WNb.81800$na.43654@attbi_s04>...
> "Cy Galley" > wrote in message
> news:69SNb.79462$I06.340710@attbi_s01...
> > It must be poor wing design if you have to modify the airfoil with a flow
> > disrupting rivet head.
>
> Are you kidding?
>
> Airfoil selection and wing design is about making priorities and
> compromises.
>
> The majority of planes have some external flow control and I wouldn't
> consider every one a case of poor wing design.

[Dave Hyde]

Cy Galley wrote:

> It must be poor wing design if you have to modify the airfoil with a flow
> disrupting rivet head.

Do you consider any airplane with vortex generators,
washout, or stall strips a poor design? Round-head rivets
sound like a pretty slick and cheap way of adding
vortex generators to me. The list of 'poor designs'
(your words, not mine) that have flow-disrupting
devices to address stall characteristics is long and
distinguished.

> My Bellanca doesn't have a wing drop problem and
> doesn't have any rivet heads either.

Give any decent aero guy ten minutes with your Bellanca
and he/she could come up with some ugly external mod that
could improve performance in some part of the envelope.
Doesn't mean it's a poor design - nor does adding an
aerodynamic 'band-aid' rather than redesigning an
entire wing when flight test doesn't match predictions.

> Wonder what the Glass plane builders are doing?
> Designing the wing correctly?

Or maybe just accepting the compromises that were designed
in from the start? Should a designer faced with a 'wing drop
problem' scrap the entire wing design altogether and start from
scratch when a simple fix will suffice?

Dave 'trade study' Hyde

[Roger Halstead]

On Fri, 16 Jan 2004 14:01:38 GMT, "Cy Galley" >
wrote:

>It must be poor wing design if you have to modify the airfoil with a flow
>disrupting rivet head.
>
>My Bellanca doesn't have a wing drop problem and doesn't have any rivet
>heads either.
>
I don't think the early Debs had any washout either.

Sure it drops a wing if you aren't on it, or aren't too sharp
yourself, but with a bit of practice using rudder only you can hold
it in a stall with the nose way up there while wobbling around. Just
don't try to center the ball while doing that. It'll roll over every
time.

I'm so used to it I never figured dropping a wing a bit was anything
to worry about. A little rudder stops it right away. OTOH a lot of
rudder can make for an exciting day<:-))

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
>Wonder what the Glass plane builders are doing?
>Designing the wing correctly?

[drake]

(Corrie) wrote in message >...
> Deja vu all over again - wasn't there a 90-post thread on this topic
> (need for thingies sticking up != bad wing design) a couple months
> back? Save your fingers and check the archives....
>
> The Deepak is a nifty-looking little trainer, though. Side-by-side
> seating, right?

Yes side-by-side seating. The canopy looks cool! (More on the Deepak
below, but is skippable)
Never flew in it though (Infact, flew for the 1st time (ever) in a
Saratoga(sedate plane, though several people did get airsick) and then
in a Supercub (what a sexy old bird!) about 20 days back.(Hey, is
there a '1st time in the air' thread?? )


Is there any refernce to Bonanzas using pan-head rivets at turbulators
anywhere?

And why would a more turbulent airflow prevent tip stalling?(leading
to wing drop) Wont it mean that the tip will stall at a higher AoA? Or
the fact that there were more such rivets towards the root side have a
stablizing effect while stalling?

Boring stuff on the HAL HPT-32 Deepak:(U may skip)
Specs:http://www.bharat-rakshak.com/IAF/Aircraft/Specs/Deepak.html
Pics:http://www.bharat-rakshak.com/IAF/Images/Current/Deepak.html
http://www.airshowreport.com/india/008.htm

The Indian fedral audit doomsayers report on the plane and the
problems it had:
(Says the Textron Lycoming engine is causing too much pain)
http://www.cagindia.org/reports/defence/1998_book1/chapter3.htm
Goto "7.6.2 Unreliability of trainer aircraft 7.6.2.1 HPT-32 aircraft"


The Indian Parliamentary committee invetigates above report:
(The problem is not the engine but...)
http://164.100.24.208/ls/committeeR/PAC/29th/report.html
Goto "5.2.1 HPT-32 aircraft"

Apparently, all problems solved now, the Indian Air Force has ordered
even more Deepaks.

Blue skies y'all,
Lars

ObAeroJoke(from http://iron-eagles.tripod.com/jokes.html):
ATC: "HPT-32, what are your intentions?"

HPT 32: "To get my wings and become a fighter pilot sir."

ATC: "I meant in the next 5 minutes, not ten years!"