Spin testing of large aircraft

[Trim Stab]

What is the largest/heaviest aircraft that has been spun intentionally?

[sycamore]

Unless it`s a requirement for Service(mil) or Certification I would doubt that anything larger than say an F-14 or Sukhoi would get spun due to the inertia effects,fuel surges in wings,podded engines,etc.Probably most aircraft will have had `spin tunnel` testing of models,and similar free flight dynamic model testing. Some large aircraft may have had `spin `chutes` attached during testing,but probably more to assist in recovery at some of the envelope `corners` rather than deliberate spinning.
Other large aircraft have probably been spun inadvertently,possibly recovered,but usually larger aircraft will have a large test crew and equipment on board,and that would not be very pleasant.Also you would have a real problem with escaping in the event it all went `pear-shaped`...Not a good idea.....

[Fitter2]

Under the EASA replacement reguilations for JAA-22 (sailplanes) Open Class gliders have to demonstrate spin recovery with one wing full of ballast, and the other empty. Wingspan up to 30 meters.

On an Eta (one of the 30metre wingspan types) it was discovered during this test that the fuselage composite construction was defective, and had structural failure. Expensive eror..........

Certainly not the heaviest - AUW weight limit 850kg.

[Trim Stab]

Unless it`s a requirement for Service(mil) or Certification


That is a secondary question I was hoping to uncover, partly inspired by reading the incident report into the unintentional spin of a USN P3 Orion.

Which aircraft would require spin certification these days?

I can understand that basic training aircraft would require spin certification, due to the possibility of entering unintentional spin. Previously aircraft that flew near the edge of the aerodynamic envelope (eg air defence aircraft) required spin certification. But nowadays, with advanced envelope protection, is spin certification still a requirement for even military aircraft?

[sycamore]

Very true that trainers are shown to be spin `compliant` so that students get the benefit,and are capable of recognising a spin,and recovering,because there is no way they will be allowed to spin an operational aircraft,as a regular exercise. However,a lot of work will go into any new aircraft`s `characteristics` in a spin,in the simulator,as the `real` aircraft parameters are `fine-tuned`,so that the aircrafts FCS/computers etc can go to a `spin-prevention ` mode,so that in any flight condition/configuration the aircraft will be `spin-resistant`,no matter how `ham-fisted` the pilot behaves.Of course,there will be points around that envelope that need verification,by the Manufacturer and accepting Service TPs,so it will still have to be a real flight-test. There is a programme on `Discovery` of the guys at Pax.River spin-testing the F-18E/F; it also shows some Typhoon stuff as well--called `Test Pilot` ,I think,but not the one about ETPS from the `70s..

[Pilot DAR]

Trim Stab,

I'm presuming that you have familiarized yourself with the prevailing design requirements for the aircraft in question - (by certification basis, in civil aircraft terms). I claim no knowledge of military requirements, so will not offer an opinion in that respect.

Expecting that you have read from the civil perspective, what must demonstrate spin compliance, and what need not, you probably won't be surprised to be reminded that manuafacturers and modifiers are not eager to demonstrate capability much beyond the requirement (in regard of spins anyway), unless doing so is a contractual requirement beyond the civil requirements (military? I have no idea).

For me to re-present the civil certification requirements here is probably redundant. In brief, I don't think that there is a requirement to demonstrate spins for "part 25" aircraft, but there is for single engine "part 23" aircraft. There are not a lot of "large" single engine part 23 aircraft. Most are twins, which are not required to demonstrate spins.

As such, the largest common civil aircraft I am aware must demonstrate spins, are the Cessna Grand Caravan, and probably the PC-12. I know little about the PC-12, but I have done these tests in the Grand Caravan. It is a beautiful spinning aircraft, though takes you to the limits in getting it out.

C208 spin clip.m4v - YouTube

[Trim Stab]

Was the Caravan floatplane also spin-tested?

[Exascot]

....takes you to the limits in getting it out :eek:

OK, we wont do that then!

[Pilot DAR]

Was the Caravan floatplane also spin-tested?

I would presume so, as it is a requirement for that configuration too. When I test flew a modified Caravan Amphibian it was not required for the mod I was testing. Many other float planes I have test flown have had to be spun. Though generally a little more lethargic getting out, they don't accelerate in the dive so much, and that's nice.

The Caravan is obviously a spins prohibited aircraft, because of the exciting ride in the recovery. The recovery was smooth and predictable, though I did get to Vne, and 2.8 G in the resulting dive. There's not a lot of margin beyond that. I did 14 spins in three configurations. Without an accelerometer, it would be a attention getting recovery.

[deagles]

The Company spun (span?) the Tornado to gather data used for development of the SPILS (Spin Prevention, Incidence Limiting System).

[Wwyvern]

In the mid 60s, I served in Malaysia, and there was a rumour going around that the RNZAF had deliberately and successfuly spun a Bristol Freighter.

Slight thread drift - during a more recent preparation for a microlight amphibian certification flight test programme, we obtained a copy of a World War 2 flight test report of spin testing a Spitfire floatplane. The test pilot's conclusion was that there was no difference from the spin characteristics of a normal Spitfire.

[mat777]

I cant vouch for their accuracy but I have heard mentions in the past of Vulcans being spun for crew training... must have been somewhat of a sight! :eek:

[TBM-Legend]

RAAF C-130A inadvertently entered a developed spin in the early '60's and was recovered OK..

[pacrat]

RAAF C-130A inadvertently entered a developed spin in the early '60's and was recovered OK..

The RAAF inadvertent stall spin departure from a botched Vmca demonstration did not.

With many hundreds of spins flown in development and certification of the P750 XSTOL. I would like to make the point that FAR 23 spin testing is intended to give a pilot some margin to recover a stall before a stable spin develops. It is debatable whether the term spin testing should really be used here. In the normal or utility category recovery is initiated after just one turn. As such the spin axis is not likely to be vertical and the nose will oscillate around the horizon. The oscillatory nature of the forces improves the likelihood of recovery over a spin left for about 4 turns, that has the likelihood of now being fully developed about a vertical axis. An aircraft demonstrating recoverable characteristics after one turn may, if left beyond one turn, still be totally unrecoverable with use of aerodynamic controls alone.
This is why aerobatic type certification requires the recovery to be initiated from a 4 turn stable state and not the incipient one turn entry point, which I would contend is not yet a spin.

[Arm out the window]

The RAAF inadvertent stall spin departure from a botched Vmca demonstration did not.

That's the 707 you're talking about, I assume. I know we had some close calls in the C130.

[pacrat]

Yes indeed I was referring to the B707. What a tragedy. The report was sobering but full of good lessons for many reasons.

[Centaurus]

I know we had some close calls in the C130.

I knew the instructor pilot who inadvertently found himself in a spin in a RAAF C130A Hercules. The story is on Pprune archives I believe. If I recall correctly, he found himself in three full turns before recovering using standard Tiger Moth procedures.

Later the USAF contacted him to find out more about how he got into the spin but more importantly how did he recover successfully. Seems there had been inadvertent spins in USAF C130 and not recoverable. Hence the keen interest

[safetypee]

Centaurus, was there any follow up explaining the difference?
Were there similar standards of training / experience, flight situation, etc; or were the USAF entry conditions different (configuration / power) or remained applied, e.g. gross asymmetric power.

[TBM-Legend]

36 Sqn C-130A. Stall demos to a trainee by Flt Lt Bruce Clarke Sqn QFI...

Many packets of fags smoked after that!

[goldfish85]

Sycamore:

The television series where the German student at Empire Test Pilot School spun the light airplane was made in the mid=80's The airplane was a prototype SAH-1 airplane which had been approved for spins. While it was certified by the UK, it never went into production. I was in the UK evaluating the design for a US compnay and saw the videos from the series. I later ran into the student, now a Luftwaffe test pilot in Sweden at a meeting.

The airplane had interesting spin characteristics and spun more like a T-37 than a Cessna. I was surprised in reading the certification flight test report to see that the UK had only required about 90 spins for certification. A more typical number for US approval for intentional spins would be about 500 spins.


Goldfish

[Kitbag]

Pedantry mode on:

T-37 is a Cessna

Pedantry mode off:ok: