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RV-6 Spins... Yeah this again.

ssmdive

Well Known Member
So I am now flying an RV6 around. I have lots of practice spinning my sold Citabria (vanilla upright, L&R) and spinning my Pitts S1S (all modes).

https://www.youtube.com/watch?v=ZG-mlDhRt_A&list=PLaG50Nso598AO-s4hGjljOSgwF7TOm9Zw&index=2

So now that I am starting to fly this RV6, I will of course be doing some light acro when people want to get their acro cherry popped. The RV6 has a reputation as being difficult to start a spin and possibly difficult to recover. Well, I buy into the theory that you don't do acro in a plane you have not spun since many botched maneuvers end in a spin. So the question becomes what EMERGENCY recovery is recommended? I understand that the incipient phase is different that an established spin. Many aircraft will recover with just a reduction in power and neutralizing the controls.

The three major spin recoveries: PARE, Beggs, and Finagin it seems PARE is the one that Vans recommends. Has anyone tried the other two?

I have read up on how some consider an RV6 and a spin to be stupid. I have read that Vans recommends staying at fewer than 2 revolutions. But I am looking for advice because if I can't spin the plane, I will not be taking people up for light acro in it and that was one of the best things about my Citabria.
 
I have spun the six up to 1.5 turns with "normal" recovery using PARE. It will typically take 1 additional rotation to recover after PARE inputs. No problem.

The problem in the six is the aerobatic gross weight of 1375 pounds. That essentially precludes aerobatics in a six with two people. Search the forums for the MANY discussions on this.

Have fun, be safe.
 
Transition Syllabus Resource

Hi Ron,

Don't know if you've looked, but you might find some info in the emergency out-of-control/spin discussion in the transition syllabus linked in the sticky at the top of this (Safety) page to be helpful in your research. It begins on page 283 of the current version (3.1). There is also quite a bit of discussion in the Handling Characteristics section (page 316) that may be useful before you start spin testing your airplane. Intentional spin discussion begins on page 357. Appendix B has an advanced handling briefing that provides a 30,000 foot overview of basic RV aerobatics (page 393). If you download the pdf version of the document, the table of contents is hyperlinked to help with navigation.

Side-by-side types have slightly different spin characteristics than the tandem airplanes (perhaps due to the shape of the forward fuselage and it's aerodynamic effect at high yaw rates), but all RV's are sensitive to static margin (CG) as regards spin characteristics and recovery. Differences between individual aircraft may also affect post-stall handling characteristics, including vertical tail configuration/size on different RV-6's. The easiest way to ensure conventional handling characteristics is to operate the airplane within the design envelope as Gary said and confirm the flight controls are rigged in accordance with the design instructions. Be mindful of the aft aerobatic CG limit and understand that things can get sporty in the aft 25-30% of the usable aerobatic envelope when conducting sustained auto-rotation in side-by-side RV-types. If you didn't build your RV, you might also consider re-weighing it before conducting post-stall test to ensure you have accurate weight and balance data.

You may have already read it, but if not, the "Final Inspection and Flight Test" chapter in the builder's manual has some very helpful information you might find useful as you experiment with post-stall handling characteristics.

One point to ponder is that I noticed on your youtube video you used the expression "stomp" as regards rudder application during spin recovery. To avoid damaging the metal airframe (especially the tail), Van is always careful to point out that smooth flight control application is the best way to fly an RV-type. So if the definition of "stomp" is smooth application of rudder sufficient to stop yaw, then it's all good!

Fly safe and add any "lessons learned" to this post!

Cheers,

Vac
 
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Try this...

With a few thousand spins under my belt I thought I had a pretty good idea about how to handle spin recoveries in my RV. That is until about four years ago when I took an upset recovery training course offered by a highly respected pilot named Bill Finigan. Bill is an accomplished aerobatic competitor and IAC chief judge. As a sales representative for Aviat Aircraft he travels the country and hosts upset recovery training courses which involve a morning of classroom instruction and afternoon flights in his Pitts S-2C.
During the morning session Bill asked the handful of pilots assembled to tell him what methods of upset recovery they had come upon out there in the real world. (Keep in mind that we are talking about upset recovery which involves recovery from any unusual attitude, not just a normal upright spin.) I offered that if you don't know what type of unusual attitude you are in, just apply pro-spin controls and any wild gyration would quickly revert to an upright spin. Then you simply apply normal anti-spin controls to recover (ie: throttle idle, rudder opposite the spin, release back pressure and recover from the dive.) Bill smiled and said we would try that during my afternoon flight. The gleam in his eye told me I was probably in for a whooping of some sort!
Bill went on to talk about accelerated spins and inverted spins. He drew an analogy concerning accelerated spins that sticks with me today: Consider an ice skater who is doing a slow spin with his arms extended. As he brings his arms in close to his body the spin rapidly accelerates. Similarly, an aircraft in a flat spin with the nose and tail at a great distance from the axis of the spin will accelerate when the nose is lowered, bringing the weight of the nose and tail closer to the axis of the spin.
Following a hearty lunch of nearly nothing I found myself strapped into the front seat of Bill's Pitts and we were climbing through 7000 feet. As briefed, Bill put the Pitts into an inverted, right turning flat spin and said "your aircraft". I applied the unusual attitude recovery method that I had mentioned in class that morning (pro normal spin controls): Throttle idle, left rudder, full aft stick. You can probably guess what happened. Since we were in an inverted spin, the application of left rudder, which acts in reverse when inverted, did nothing to slow the spin rotation. As I moved the stick aft the nose lowered dramatically and the spin accelerated to an astonishing rate! (I had brought the skater's arms close to his body!) I swear that I heard Bill laughing over the sound of the Lycoming IO-540.
Following that entertaining display of airmanship, Bill went on to demonstrate his 4-step recovery technique and allowed me to try it on a number of out-of-control situations, including the dreaded inverted flat spin. The premise of his recovery techniques supposes that the pilot has no idea if he is spinning right or left or tumbling fore or aft. (I have a fair amount of aerobatic experience and I admit that I was hard pressed to identify the direction of turn during some of the situations I experienced during that flight with Bill.)
To get to the point, here's Bill's unusual attitude recovery technique:

1. THROTTLE - IDLE
2. FORCE THE CONTROLS TO NEUTRAL
3. WAIT FOR 100 KNOTS
4. RECOVER FROM THE DIVE


Step one takes the influence of engine thrust, torque and P-factor out of the picture and reduces the engine's influence to that of a dead weight at the front of the airplane.
Step two takes the influence of all controls out of the picture and allows that dead weight (engine) to pull the airplane into a dive just like a dart. (Note that this step requires that you FORCE the controls to neutral. Releasing the controls does not necessarily mean that they will go to a neutral position. I have found that in a fully developed upright spin my RV-8 stick will stay nearly full aft when I release it!)
Step three makes you wait until sufficient airspeed develops so you can safely apply flight controls without entering a secondary spin.
Step four keeps you from hitting the ground! (Duh!)

To answer your first question: Yes, this recovery procedure may take longer than a normal spin recovery (no rudder opposite the spin!). But remember, you may not know which direction you are spinning and if you are guessing you have a 50% chance of getting it right.

I climbed out of Bill's Pitts with a slightly deflated ego and a foolproof procedure for upset recovery that I think of every time I fly. Thanks, Bill.

 
Hi Ron,

Don't know if you've looked, but you might find some info in the emergency out-of-control/spin discussion in the transition syllabus linked in the sticky at the top of this (Safety) page to be helpful in your research.

I did not know of that document... I'll DL and read it, thanks.

You may have already read it, but if not, the "Final Inspection and Flight Test" chapter in the builder's manual has some very helpful information you might find useful as you experiment with post-stall handling characteristics.

Didn't build, so I'll also look for this doc and read it.

One point to ponder is that I noticed on your youtube video you used the expression "stomp" as regards rudder application during spin recovery. To avoid damaging the metal airframe (especially the tail), Van is always careful to point out that smooth flight control application is the best way to fly an RV-type. So if the definition of "stomp" is smooth application of rudder sufficient to stop yaw, then it's all good!

"Stomp" to me means "full application". Partial application can really delay the recovery. I can see how it could be read as fast... But in a Pitts that is also OK. I'll stomp to full application, but smoothly in the RV - Thanks!
 
Consider an ice skater who is doing a slow spin with his arms extended. As he brings his arms in close to his body the spin rapidly accelerates. Similarly, an aircraft in a flat spin with the nose and tail at a great distance from the axis of the spin will accelerate when the nose is lowered, bringing the weight of the nose and tail closer to the axis of the spin.
Bill's unusual attitude recovery technique:

1. THROTTLE - IDLE
2. FORCE THE CONTROLS TO NEUTRAL
3. WAIT FOR 100 KNOTS
4. RECOVER FROM THE DIVE

In my Pitts, I did PARE

1. Power - off
2. Ailerons - Neutral
3. Rudder - Opposite the Yaw
4. Elevator - Fwd (or back if inverted)

Beggs Muller
1. Power - Off
2. Let go of the stick
3. Rudder - Opposite the Yaw

Finigin... Which you described.

I found Beggs Muller was actually a bit faster. When you let go of the stick it floats to a bit of in spin aileron which is anti spin and just enough up elevator to still present as much rudder as possible while also going towards neutral. In addition it has fewer steps than PARE.

I tried Beggs in my 7ECA and found that it 'snapped' nose down. I think it actually did an outside snap. The G meter read -2. Since the plane was rated -2, I didn't do any more attempts at Beggs in the Citabria.

What I plan when flying is to use Finigain's recovery technique since pulling the power and neutralizing all the controls will also prevent a plane from departing. If it does spin, then I modify Finigin to add in anti yaw input.

I'll try some spins in the 6 after I do a new W&B.
 
OP, you're not going to find broad experience among the RV community with the emergency recovery techniques you show in your video - especially in the RV-6. Few RV pilots are tuned into emergency spin recovery as those in the dedicated acro world are. On the advice of Vans against spinning the side by sides, few RV-6 pilots report spinning more than 1.5 turns - which is not yet fully developed. But this airplane is known to recover with normal PARE inputs once fully developed, but with a faster than normal rotation rate, and a somewhat delayed response to normal anti-spin inputs.

Seems you are qualified to spin test these techniques in your RV-6. The Vans recommendation against spinning the 6 is primarily due to the fact that your average pilot has little experience and a low comfort level with spins. Those who do spins all the time and are comfortable with them will likely not be freaked out by the airplane.

I'm sure folks here will read your findings with interest.
 
I have explored spins quite a bit in my -6A, up to and including 14-turn upright spins both left and right along with flattened and inverted spins (sucks cleaning quarts of oil off the belly, but I wanted to validate recovery from that situation).

No issues with either PARE or Finigan (which is what I usually use) but not a fan of Beggs-Mueller in my -6A. It's the slowest to recover from a fully developed spin, taking three rotations or more. PARE or Finigan each took slightly less than two rotations.

With less than half-full fuel tanks, expect the engine to start windmilling after 6-8 turns because to fuel starvation due to fuel moving to the outboard sides of the fuel tanks.
 
Seems you are qualified to spin test these techniques in your RV-6. The Vans recommendation against spinning the 6 is primarily due to the fact that your average pilot has little experience and a low comfort level with spins. Those who do spins all the time and are comfortable with them will likely not be freaked out by the airplane.

I plan on testing them. I am just in the "get educated from others mistakes first" phase. If someone has tried Beggs and it didn't work (It does not work in all planes) then I can know that going into the series.

I already got some good advice when advised that "stomp" with gusto might be bad.

But this airplane is known to recover with normal PARE inputs once fully developed, but with a faster than normal rotation rate, and a somewhat delayed response to normal anti-spin inputs.

And this helps. I don't want to go into a series without knowing the recovery I KNOW will stop the Earths rotation before impact. And knowing it will speed up first (which most flat spins will do) and that it will take a revolution or two to stop is also good info. The first time I did a flat spin and it sped up before recovering, well it was eye opening.

I'm sure folks here will read your findings with interest.

If I get around to it.... I'll do a video like I did with the Pitts. But it will be months away since I am still feeling the plane out. Only have about 10 hours in it and most of that was learning the 430, auto pilot, and GRT.
 
Oh My !

So much to choose from....

I did some transition training for a guy in a 6 some years ago.

We tried normal, Muller/Beggs and then nothing....

When you do nothing and after a 2 turn spin, just let go - well guess what, it recovers.

Darn fine Mr VanGrunsven !
 
I have explored spins quite a bit in my -6A, up to and including 14-turn upright spins both left and right along with flattened and inverted spins (sucks cleaning quarts of oil off the belly, but I wanted to validate recovery from that situation).

No issues with either PARE or Finigan (which is what I usually use) but not a fan of Beggs-Mueller in my -6A. It's the slowest to recover from a fully developed spin, taking three rotations or more. PARE or Finigan each took slightly less than two rotations.

With less than half-full fuel tanks, expect the engine to start windmilling after 6-8 turns because to fuel starvation due to fuel moving to the outboard sides of the fuel tanks.

Interesting on the fuel starvation part, never thought about that before....I use to go out and spin the little 152 all the time, can I expect similar recovery characteristics in my 7a? or will it just be a faster rotation rate?
 
Spins

Regarding hands on recovery, I really dislike the technique of recovery with rudder and forward stick applied simultaneously. If one gets mixed up and inadvertently leads with forward stick the spin may accelerate quite rapidly. There is the potential, especially with relatively inexperienced pilots, to apply forward stick and then become so surprised by the results that full opposite rudder is not applied.
 
Interesting on the fuel starvation part, never thought about that before....I use to go out and spin the little 152 all the time, can I expect similar recovery characteristics in my 7a? or will it just be a faster rotation rate?

Faster rotation rate, delayed recovery when fully developed, and much quicker acceleration when pulling out of the dive during spin recovery. I remember it being difficult to keep a Cessna in a proper spin at times since it wouldn't always want to stay stalled. My -6A isn't like that *at all*.
 
1. THROTTLE - IDLE
2. FORCE THE CONTROLS TO NEUTRAL
3. WAIT FOR 100 KNOTS
4. RECOVER FROM THE DIVE

This will NOT work for all aircraft, the dHC1 Chipmunk springs to mind, recovers fine using PARE but often will NOT recover until you have FULL forward CC!
Also of interest was the spin tests on our RV7, recovery was fine to the left, first spin to the right the prop stopped (at height with full rich mixture), recovery was not possible with ANY of the methods discussed with the engine stopped, as soon as I restarted the engine recovery was almost instantaneous!
 
What???

Also of interest was the spin tests on our RV7, recovery was fine to the left, first spin to the right the prop stopped (at height with full rich mixture), recovery was not possible with ANY of the methods discussed with the engine stopped, as soon as I restarted the engine recovery was almost instantaneous!

Something is wrong here! :eek: Normal spin recovery is accomplished with the engine at IDLE power. There should be no difference in the recovery with the prop stopped. I would like to hear more about your spin test methods.
 
What??? (again)

1. THROTTLE - IDLE
2. FORCE THE CONTROLS TO NEUTRAL
3. WAIT FOR 100 KNOTS
4. RECOVER FROM THE DIVE

This will NOT work for all aircraft, the dHC1 Chipmunk springs to mind, recovers fine using PARE but often will NOT recover until you have FULL forward CC!

Did you mean to say "FULL forward stick"? If you meant to say "FULL forward CG" I don't know how you would change CG in flight. Any other Chipmunk pilots care to chime in here?

This might be a good time to reinforce the importance of FORCING the controls to neutral in this recovery method authored by Bill Finagin. If you simply release fore/aft pressure on the stick this will not always put the elevator in the neutral position. (In a well-developed spin my RV-8 stick will stay nearly full aft when released!) You must FORCE the stick to a neutral position such that the elevator is aligned with the horizontal stabilizer. One way to insure this in your RV is to notice the actual stick position when the elevator is neutral and note this position relative to the instrument panel.
 
1. THROTTLE - IDLE
2. FORCE THE CONTROLS TO NEUTRAL
3. WAIT FOR 100 KNOTS
4. RECOVER FROM THE DIVE



Did you mean to say "FULL forward stick"? If you meant to say "FULL forward CG" I don't know how you would change CG in flight. Any other Chipmunk pilots care to chime in here?

This might be a good time to reinforce the importance of FORCING the controls to neutral in this recovery method authored by Bill Finagin. If you simply release fore/aft pressure on the stick this will not always put the elevator in the neutral position. (In a well-developed spin my RV-8 stick will stay nearly full aft when released!) You must FORCE the stick to a neutral position such that the elevator is aligned with the horizontal stabilizer. One way to insure this in your RV is to notice the actual stick position when the elevator is neutral and note this position relative to the instrument panel.

I took full forward cc to mean "full forward Control Column".
 
This will NOT work for all aircraft, the dHC1 Chipmunk springs to mind, recovers fine using PARE but often will NOT recover until you have FULL forward CC!

Yes, there are aircraft that will not recover all spin modes using this 'Finagin' technique. The Yak 52 is another well known example that will not recover a developed flat spin using this technique. This neutral control technique as advocated by Bill Finagin was specifically developed for use as an emergency recovery technique for any possible spin mode in a properly loaded Pitts. He never advocated it as a guaranteed universal spin recovery technique in all aircraft. To your point, this is worth noting. I suspect this technique would work for all spin modes in RVs, but have not seen a flight test report using this technique across the entire spin matrix in an RV.
 
Something is wrong here! Normal spin recovery is accomplished with the engine at IDLE power. There should be no difference in the recovery with the prop stopped. I would like to hear more about your spin test methods.

Spin was IMHO very standard - at light buffet, full rudder and up elevator, the prop stopped as the aircraft autorotated, when I restarted it was at low power and recovered immediately on engine restart, following this I leaned the mixture and recovery was normal with engine at idle.
 
Spin was IMHO very standard - at light buffet, full rudder and up elevator, the prop stopped as the aircraft autorotated, when I restarted it was at low power and recovered immediately on engine restart, following this I leaned the mixture and recovery was normal with engine at idle.

Just to clarify, you're saying that the -7 won't recover using the PARE method with the prop stopped, correct? How many turns before the recovery was attempted? Is this with a fixed pitch prop? I suspect that the difference between having some idle residual thrust and true zero thrust with the prop stopped makes just enough difference with rudder and/or elevator effectiveness, that more positive (than PARE) spin recover inputs are needed when the prop is stopped on this particular aircraft.

In my -8 with a fully developed (3 turns or more) spin to the right, using positive (opposite rudder) recovery techniques, I need the elevators farther forward than neutral to stop the spin.

Skylor
 
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This will NOT work for all aircraft, the dHC1 Chipmunk springs to mind, recovers fine using PARE but often will NOT recover until you have FULL forward CC!
Also of interest was the spin tests on our RV7, recovery was fine to the left, first spin to the right the prop stopped (at height with full rich mixture), recovery was not possible with ANY of the methods discussed with the engine stopped, as soon as I restarted the engine recovery was almost instantaneous!

Not sure I understand...are you saying that the engine stopped *during* the spin to the right? Or you had stopped the engine prior to entering the spin, and the prop windmilled when going to the left, but not to the right?

I can't imagine why the engine would stop during a spin...so I must be reading this wrong.
 
I can't imagine why the engine would stop during a spin...

I only know of two reasons - one...that you are running a wood/composite prop and your idle setting is too low for the lack of relative wind through the prop to keep the prop windmilling. During a spin, the relative wind develops a higher angle of attack as the spin develops. Been there more than once. Two...that your fuel level in the wing tanks is insufficient to cover the fuel port as the fuel is forced outward during the spin.
 
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Just to clarify, you're saying that the -7 won't recover using the PARE method with the prop stopped, correct? How many turns before the recovery was attempted? Is this with a fixed pitch prop?

I am not saying the -7 will not recover, just that THIS -7 will not, I would be very interested if anyone else has had the prop stop on entry and the result! Recovery was initiated after 2 turns and took 12 and yes, a metal fixed pitch prop.

Not sure I understand...are you saying that the engine stopped *during* the spin to the right? Or you had stopped the engine prior to entering the spin, and the prop windmilled when going to the left, but not to the right?

I can't imagine why the engine would stop during a spin...so I must be reading this wrong.

Engine stopped as I entered, I just closed the throttle, I think it was probably a combination of airflow, spin direction and mixture setting (at 8,500' with full rich and partially leaning meant this did not happen on subsequent spins)
 
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I can't imagine why the engine would stop during a spin...so I must be reading this wrong.

Fuel migrates to the outboard side of the tank, depriving the engine of fuel. This can result in the prop stopping, especially if a low mass (wood or composite) prop is installed.

Also, I think Ron asked why prop stopped or not would make any difference in recovery. Consider the gyroscopic precession forces associated with a spinning prop - I could see how such would have an impact on recovery.
 
I have recovered my RV-8 from spins with prop stopped due to fuel migrating away from pickups during extended spins. Recovery of MY airplane is same with prop stopped or with idle power. Not sure why your experience is different.
 
I have recovered my RV-8 from spins with prop stopped due to fuel migrating away from pickups during extended spins. Recovery of MY airplane is same with prop stopped or with idle power. Not sure why your experience is different.

The side-by-sides are known to have different spin characteristics than the tandems, for starters. That combined with the lack of precession forces and/or the unique characteristics of a given airframe could very well present different spin characteristics.
 
The side-by-sides are known to have different spin characteristics than the tandems, for starters. That combined with the lack of precession forces and/or the unique characteristics of a given airframe could very well present different spin characteristics.

Different, maybe...but...unrecoverable with the prop stopped? That sounds not good to me. If that's the case, then the plane should probably be placarded for no aerobatics, perhaps?
 
I am not saying the -7 will not recover, just that THIS -7 will not, I would be very interested if anyone else has had the prop stop on entry and the result! Recovery was initiated after 2 turns and took 12 and yes, a metal fixed pitch prop.



Engine stopped as I entered, I just closed the throttle, I think it was probably a combination of airflow, spin direction and mixture setting (at 8,500' with full rich and partially leaning meant this did not happen on subsequent spins)

I'm still trying to clarify your answer: When you say your plane won't recover with the prop stopped, was that using only the Finnegan method (neutral controls) , or did you try anti-spin control inputs as well (PARE)?

Skylor
 
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Different, maybe...but...unrecoverable with the prop stopped? That sounds not good to me. If that's the case, then the plane should probably be placarded for no aerobatics, perhaps?

+1. If it were my airplane I would ground it. Something definitely wrong with it.
 
This will NOT work for all aircraft, the dHC1 Chipmunk springs to mind, recovers fine using PARE but often will NOT recover until you have FULL forward CC!
Also of interest was the spin tests on our RV7, recovery was fine to the left, first spin to the right the prop stopped (at height with full rich mixture), recovery was not possible with ANY of the methods discussed with the engine stopped, as soon as I restarted the engine recovery was almost instantaneous!

Does this RV7 have the riveted TE rudder(9) or the (smaller) folded TE rudder (8)?
 
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Good question, Bill. Sorry for being late to the party, but here is another data point. When testing my -7, I had the prop stop in a right upright spin after two or three turns. The recovery, with standard anti-spin inputs, was normal. In the recovery, as I pulled to level, the increased airflow caused the prop to windmill and the engine to restart. I have a composite (MT-2 blade) prop and the riveted TE -9 rudder.

Merrill
 
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Different, maybe...but...unrecoverable with the prop stopped? That sounds not good to me. If that's the case, then the plane should probably be placarded for no aerobatics, perhaps?

Maybe. There's still a lot of things to explore though:
1) Where was the CG? Was it towards the front or towards the rear of the acro envelope?
2) How to the control throws compare with what is listed in the builders manual? In spec or out of spec? Towards the low end of the range or high end of the range?
3) Are there any airframe mods which may have added surface area in front of the CG?
4) What, exactly, was the recovery technique? Maybe have a second pilot fly it to get an additional perspective.

I feel like there are too many variables to make any real determination on an internet forum. Figuring out stuff like this is usually what should happen in phase one testing, but that's a whole 'nother bucket of worms.
 
Maybe. There's still a lot of things to explore though:
1) Where was the CG? Was it towards the front or towards the rear of the acro envelope?
2) How to the control throws compare with what is listed in the builders manual? In spec or out of spec? Towards the low end of the range or high end of the range?
3) Are there any airframe mods which may have added surface area in front of the CG?
4) What, exactly, was the recovery technique? Maybe have a second pilot fly it to get an additional perspective.

I feel like there are too many variables to make any real determination on an internet forum. Figuring out stuff like this is usually what should happen in phase one testing, but that's a whole 'nother bucket of worms.

You're right...I was assuming that the plane was properly constructed, with the rigging verified to be in spec, CG within aerobatic limits per Van's, etc.

If any of that is not true, then all bets are off...but I, for one, wouldn't want to do any aerobatics in a plane that can't recover from a normal upright spin without having the engine turning (unless it's a glider :) ).

As stated above...suppose the reason it stopped was unporting of the pickup? There'd be no way *to* restart it, and if the spin is unrecoverable without the engine running...that's all she wrote.

I'd find the root cause and either fix it, or placard it.
 
You're right...I was assuming that the plane was properly constructed, with the rigging verified to be in spec, CG within aerobatic limits per Van's, etc.

As we all (hopefully) know.... in aviation, assumptions can be risky.

Generalizing the spin recovery characteristics of all RV's based on this one would be a bad thing to do because this is not typical.

If a tank is so low on fuel that the pick-up un-ports during a spin, hopeful the opposite tank isn't quite so empty and simply switch tanks would resolve the problem?
 
Spins

I can't resist this one:
many years ago my supervisor and mentor said: John Doe will be here tomorrow to fly with you in the SuperXXX. He is a very accomplished aerobatic pilot but most pilots of that era don't know much about spins. John Doe: I've never done a flat spin, my airplane will not do a flat spin. me: I'm quite sure it will, let me show you how to do it. So we did a few flat spins and a lot of other stuff. He went home for a few days and came back to fly some more. JD: you were right, my airplane flat spins just fine.
My only suggestion about the stopped prop is the remote possibility that with the prop stopped, hands off the stick, the elevator may be in a slightly more up position than with the engine at idle. hands on the controls there should be little difference. An argument could be made that with a stopped prop the airflow over the tail is slightly cleaner than with engine at idle.
After thousands of spins in a lot of different airplanes I still consider myself a student when it comes to spins.
 
Consider the gyroscopic precession forces associated with a spinning prop - I could see how such would have an impact on recovery.

There is very little gyroscopic precession associated with an idling prop - even a metal one. With a wood/composite prop, it's practically non-existent at idle. But in theory, a left spin would be slightly more prone to prop stoppage since the gyroscopics of a left spin cause a degree of nose up precession. Nose down for a right spin (Lycoming CW turning motor). The nose up precession of a left spin flattens the spin slightly and increases the angle of attack of the relative wind (less air keeping the prop windmilling). Many airplanes spin more smoothly to the right due to this lack of gyroscopic flattening effect.

So I guess my point is that it seems that the poster should not find this phenomenon limited to right spins only. Once the prop is stopped, the dynamics of a left vs. right spin are practically symmetrical, assuming proper aircraft rigging. Too many variables here, including piloting technique.
 
spin engine quit?

I just returned from our annual IAC Chapter meeting and we had 4 pilots that are or have been on the US World Teams, and one was elected into the IAC Hall of Fame this year, and they have never heard of any difference in any aircraft with spin recovery, engine idle or stopped. Of course that is a rare event with the engine off anyway.:eek: By the way, the maximum number of allowable turns in IAC contest is 2, and I've never seen or heard of more than 1 1/2 in a Known or Unknown sequence. We also discussed the increase in RV participation, and everyone was THRILLED, and hoped we could encourage more to participate. Had to drive to the meeting since it was 23 degrees, and I won't even crank my toy till it's 40 degrees.:p
Cheers,
Bill McLean
RV-4 slider
lower AL
 
I'm still trying to clarify your answer: When you say your plane won't recover with the prop stopped, was that using only the Finnegan method (neutral controls) , or did you try anti-spin control inputs as well (PARE)?
If you read my posts you will see that I used PARE. For those questioning the aircraft setup this is a UK built aircraft and is pretty standard - mods are much harder to get accepted here, and yes, control thows are within design parameters
 
If you read my posts you will see that I used PARE. For those questioning the aircraft setup this is a UK built aircraft and is pretty standard - mods are much harder to get accepted here, and yes, control thows are within design parameters

Ah yes, I see you said it wouldn't recover with ANY of the methods discussed.
 
CG was at 82.6", so towards the back as you would expect with an RV7 but well within limits. Weight was 1530lbs on start and had flown about 15 mins.
 
Where was the CG? Not just "within the envelope", but what was it *precisely* as far as you can determine?

Also is the W&B accurate? I remember seeing at least one RV that was re-weighed on aircraft scales and was significantly (tens of pounds and around an inch) off from what the W&B said it was.
 
Also is the W&B accurate? I remember seeing at least one RV that was re-weighed on aircraft scales and was significantly (tens of pounds and around an inch) off from what the W&B said it was.

Again, more heavily controlled in the UK so unlikely to be out by anything significant.
 
Again, more heavily controlled in the UK so unlikely to be out by anything significant.

Well, as Scott said, assumptions can be dangerous. Something is amiss, because that's not normal RV behavior. If it was mine, I'd check everything again, including re-weighing it myself, to rule those things out.

I'd also have another pilot fly it for a different perspective.
 
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