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Inadvertent Spin- wheels up or down?


Raptor05121

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Andy,

I have no good answer... but, to add to the depth of your question....

Have you seen the picture of the fifth person sitting in the baggage compartment of the fully loaded M20C before the off-field landing..?

Fortunately, somebody has done this test flight already, shared the visuals of it, and now we have an answer to 'what happens if I do this...'  :)

Best regards,

-a-

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Speed brakes may delay recovery- but honestly they are relatively small for the size of the wing- probably wouldn’t effect your spin recovery- but would delay your return to a net neutral attitude.

They would slow you down giving you more time to recover, if standard recovery procedure wasn’t working. Why would they delay return to level attitude?
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19 minutes ago, jetdriven said:

IAS in the spin is very low.  Remember the airplane is stalled.  I’m not sure if the drag from the gear extending will make any difference. 

Byron, this in contrast to a so called grave yard spiral where IAS is high. Do you feel gear would make a difference in that scenario?

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47 minutes ago, teejayevans said:


They would slow you down giving you more time to recover, if standard recovery procedure wasn’t working. Why would they delay return to level attitude?

They aren’t really speed brakes in the traditional sense (fuselage mounted drag devices).  They really are more spoilers.  They won’t slow you down in the spin, just decrease lift off both the stalled and lift producing wing- thus delaying spin recovery and would actually probably increase your sink rate thus giving you less time to recover.  On return to level attitude, you’ll require more power to increase lift to command the AoA to get the nose up to return to level attitude.

keep in mind I haven’t “run the numbers” on this- so it might literally be fractions of a second... again the speed brakes are relatively small... but that is the aerodynamic ramification of deploying spoilers during a spin.  The only possible good reason to deploy the spoilers during a spin would be to change your attitude during the spin...  but that’s just speculation- deploying the spoilers may not change the attitude of the spin at all- I’d have to run numbers and simulations to get data out of that.

Edited by M016576
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19 minutes ago, PTK said:

Byron, this in contrast to a so called grave yard spiral where IAS is high. Do you feel gear would make a difference in that scenario?

In a graveyard spiral, you’re still in controlled flight- I think the biggest risk recovering from that would be over stressing the plane, and structurally destroying it (in flight break up).  The gear would act as a big speed rake- so if altitude was a consideration, I think deploying the gear (knowingly over speeding it in the process) could actually be a smart decision and allow you to get below corner velocity (maneuvering speed), thus allowing a safe recovery of the airplane.  

The biggest problem with a graveyard spiral, though, is typically the pilot doesn’t realize they are in one (inadvertent flight into imc, then “listening” to your vestibular system as opposed to flying the instruments).  It’s the moment you pop out of the goo and see that you’re 60 degrees nose low in a turn that you snatch the controls and destroy your plane.  AOPA safety institute has an awesome and terrifying video about a pilot of a pilatus with his family on board that does just this... the autopilot kicks off and he didn’t recognize what was going on until it was too late- then snatched the yoke back and tore the tail and wings off the plane... at 18000’.  He had the rest of his life (about 45 seconds) to contemplate how he’d killed himself and his family.

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46 minutes ago, M016576 said:

In a graveyard spiral, you’re still in controlled flight- I think the biggest risk recovering from that would be over stressing the plane, and structurally destroying it (in flight break up).  The gear would act as a big speed rake- so if altitude was a consideration, I think deploying the gear (knowingly over speeding it in the process) could actually be a smart decision and allow you to get below corner velocity (maneuvering speed), thus allowing a safe recovery of the airplane.  

The biggest problem with a graveyard spiral, though, is typically the pilot doesn’t realize they are in one (inadvertent flight into imc, then “listening” to your vestibular system as opposed to flying the instruments).  It’s the moment you pop out of the goo and see that you’re 60 degrees nose low in a turn that you snatch the controls and destroy your plane.  AOPA safety institute has an awesome and terrifying video about a pilot of a pilatus with his family on board that does just this... the autopilot kicks off and he didn’t recognize what was going on until it was too late- then snatched the yoke back and tore the tail and wings off the plane... at 18000’.  He had the rest of his life (about 45 seconds) to contemplate how he’d killed himself and his family.

Yes, I’ve read that NTSB report. That’s a hell of a horrific 45 second ride...

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1 hour ago, PTK said:

Byron, this in contrast to a so called grave yard spiral where IAS is high. Do you feel gear would make a difference in that scenario?

It makes the difference between living and dying in a clean airplane like this. Nobody recovers from a 350 knot, 8-g vertical barrel roll. If the gear was already down, it greatly reduces this outcome  

But this thread was about lowering the gear in a spin to help recover.  I think I would have rather used my additional brain power to first avoid a spin, and second, to recover using the PARE technique which is sound and works. 

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3 hours ago, Andy95W said:

Antares, I know it wasn't your video, so this isn't directed at you, but why would someone post a video where they are:

1.) breaking an FAR (not wearing an installed shoulder harness during takeoff and landing)

2.) allowing their airplane to get into a spin

and 3.) executing an improper spin recovery (didn't retard throttle to idle, especially because his incipient spin was to the left)

What a dumbass.

I guess the shoulder belts being off made the spin recovery easier....sheeesh...

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That is a great video of what not to do!  I have had a student handle a power-on stall demonstration poorly in a Mooney and that got my attention.  And as an instructor and occasional aerobatic pilot, I have done many deliberate spins in my career!

The key in a Mooney, if you don't want to become a test pilot, is to quickly recognize an incipient spin entry and recover properly at the first sign.  Recovery is not as brisk as in a Cessna 172, 152 or Citabria/Decathalon, but if initiated immediately and correctly, will not do what we saw in the video....

Keep the shiny side up ;)

-Mike

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4 hours ago, Andy95W said:

Antares, I know it wasn't your video, so this isn't directed at you, but why would someone post a video where they are:

1.) breaking an FAR (not wearing an installed shoulder harness during takeoff and landing)

2.) allowing their airplane to get into a spin

and 3.) executing an improper spin recovery (didn't retard throttle to idle, especially because his incipient spin was to the left)

What a dumbass.

I would say it was the kid in the right seat or his buddy in the back seat who posted that online, not the pilot. After recovery you can just barely hear the pilot laugh and say that they recovered from a spin. He didn't seem too upset about it either. 

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16 hours ago, Piloto said:

When a single engine is certified it needs to be recoverable within one turn after anti-spin controls are applied. The spin test is done with full aft cg and full fuel as was the case for the long range tanks STC. The test was done at 10,000ft on 49 possible configurations. Even though the Mooney recovered within a 1,000ft I found this test of little value since most spin accidents occur on approach or departure at low speed and low altitude.

José

I don't think that is what the certification is saying though. The certification is that you can delay recovery for 1 full turn. I dont think its required to stop spinning within one turn because lots of planes don't.

The delay is there assuming it takes the pilot 1 turn to figure out its spinning.

-Robert

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8 hours ago, takair said:

Jose

I seem to recall that you situated yourself in the back seat for the aft CG test, while the FAA pilot flew and the plan was to move forward if she could not recover.  Did you ever test the theory that moving the CG forward, while spinning, would assist in recovery?  I still think you may be one of the most spun Mooney people still around to talk about it. As a side note, did you ever test the relief tube while spinning?  Seems like that could be a mess.

There were a few configurations that Lucy Young could not recover within the turn at first  but she retried again and passed the test. I never moved forward during the spin. On most cases the Mooney will drop a wing, flip upside down and spin but will recover if you held anti-spin controls until rotation stop, just be patient. It is important that you have the seat belts well strapped. It minimize the floating sensation and assures a good grip on the controls.

Another in-flight test was for wing flutter at over red line on a dive. Even though I have proven no flutter speed change by GVT test. The Mooney wing may flutter at over 400kts. Wonder how much the flutter speed is affected on other planes when adding tip tanks.

José

Edited by Piloto
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8 hours ago, bluehighwayflyer said:

Thanks, Rob, and good point  I suppose the J’s lower gear doors could also differentiate our two models. I’ll look forward to your findings. 

Jim

Well, I was wrong.  20 years flying this thing and I never noticed the natural pitch up.  So, today, I trimmed the airplane level at 120mph, let go of the yoke and put the gear down....the airplane pitched up and climbed at about 500fpm initially.  I guess I have always been holding the yoke and subconsciously keeping the nose down.  Will have to think about the “why”.

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Well, I was wrong.  20 years flying this thing and I never noticed the natural pitch up.  So, today, I trimmed the airplane level at 120mph, let go of the yoke and put the gear down....the airplane pitched up and climbed at about 500fpm initially.  I guess I have always been holding the yoke and subconsciously keeping the nose down.  Will have to think about the “why”.

I would think the drag on the gear below CG would cause a pitch downward (like braking causing the nose of a car to dip)?
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If you are in a spin, you are stalled. Your priority is to reduce the angle of attack to get the wing flying again. That means full down elevator and some patience. Stopping the autorotation if you can with full opposite rudder and idle power will help with that process but you may not be able to stop the rotation until you break the stall. No matter what, you need LOTS of altitude below you. If you need to be tinkering with drag or c/g items like speed brakes or gear (which have little or no impact on AOA) you are probably already dead.
When I started my aviation career as a CFI almost 40 years ago, full spins were part of the PPL test in Canada. I believe they still are but I have been out of that world for a long while. C150s would spin all day and pop out as soon as you applied the correct recovery. C172s were a lot harder to spin but would pop out if you just let go. The scariest was the brand new Piper Tomahawk. If you didn't recover in the first 2 turns it would go flat and the airflow over that silly T-tail was partially blanked by the wing, making the standard full nose down ineffective. I experienced this once and was able to recover after about 7 turns by alternating between full up and down elevator synchronized with the pitch oscillations until the nose dropped enough to break the stall. After a change of underwear I never went past 1 turn again, but in the next few years there were several "unexplained" stall/spin crashes and the Tomahawk kind of faded away as a trainer.
These techniques don't change much with aircraft type. Some are just harder (or impossible) to recover from a spin. Many years later, instructing on USAF F-16s we still taught that rocking technique for recovery from a deep stall. Only difference was we didn't go out and try it for real. (practicing bleeding) We just showed the students a HUD tape of an Edwards AFB test pilot soiling HIS underwear instead.
Mark


Sent from my iPhone using Tapatalk

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1 hour ago, teejayevans said:


I would think the drag on the gear below CG would cause a pitch downward (like braking causing the nose of a car to dip)?

Me too, but it seems not to be the case, but I can’t quite figure out why.  Even when I start thinking of dirty air over the tail, one would think it would pitch down.  It must be transient, when dropping gear for an ILS, I never re-trim, but I must be compensating.  Will need to get more data points.  Wonder what other planes do?

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If you are clean and level at a given airspeed, when you drop the gear you will get a slight nose up pitch. If you maintain the same airspeed instead of letting the airspeed bleed off with the nose up pitch, you should be in about a 500'/min decent. Handy when you have your power settings correct at glide slope intercept. No re trimming required to capture the glideslope and ride it down, simply drop the gear, and prevent the nose up pitch. The extra drag will keep the speed the same at the 3 deg decent.

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On the topic of it ain’t over until it’s over... and stalls at TPA...

We have one known survivor...  crashed into a house near, but not in line with the airport...

He openly detailed the wild ride in the following days after the accident.

Searchable if interested in the details...

Also Mentioned a few times in this thread...  https://en.m.wikipedia.org/wiki/PARE_(aviation)

Best regards,

-a-

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5 hours ago, Piloto said:

Aerostar' s demand good pilot skills.

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On 12/10/2017 at 4:07 PM, takair said:

Well, I was wrong.  20 years flying this thing and I never noticed the natural pitch up.  So, today, I trimmed the airplane level at 120mph, let go of the yoke and put the gear down....the airplane pitched up and climbed at about 500fpm initially.  I guess I have always been holding the yoke and subconsciously keeping the nose down.  Will have to think about the “why”.

My 231 always pitches up when I lower the gear, but the effect is temporary.  As soon as the gear is down and locked it is neutral. I don’t think you would want to try this during a spin because the aerodynamics of the wing is changing,  That’s the last thing you need at that point.

Edited by jlunseth
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