Author Topic: A tale of two spins  (Read 9378 times)

Offline Traveler

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Re: A tale of two spins
« Reply #120 on: January 11, 2012, 03:09:33 PM »
Ailerons absolutely have authority, they just work against you. But when using  ailerons you are increasing or decreasing a wings camber. This has the effect of changing the MAX AOA of the wing section containing the aileron. And hence why many planes snap when trying to correct with ailaron. They stall the outer wing section.

But using aileron  in the direction of the spin can hookup a section of the wing again when very close to the spin being stopped.
What happens when you try to do this? Normally it makes for a very nice snap. It's even more fun doing it for real when in an inverted stall.


Not true, a spin is around both axis, the pitch angle determines how much is yaw, how much is roll. Or more precisely.

The difference in lift between wings creates a roll, the difference in drag of the wings creates the yaw. The ratio of these will determine the nose up attitude.

I agree.

HiTech

If you are telling that you are able to recover from the spin to the right by only applying left rudder. But I thought I had read where you had to apply aileron to stop the rotation for the spin to the right.  

That you were able to stop the rotation for the left spin alone with just right rudder, but you had to use aileron and rudder to stop the rotation for the spin to the right?  That sounds different to me.   Others have said that they used power to recover not just rudder.  

If it is just my system, wow, I’ve tried several different sticks and even using just the mouse, same result.  Other then calibration not sure what is available to me to check or correct it.   I can recovery every other type of aircraft that I’ve tried just not the P38L.

Here is what  Soulyss and others said earlier in this thread:

You can stop a spin to the right in the P-38L under the conditions you describe by bringing up a little power on the right engine while leaving the left throttle all the way back and using left rudder.

The stall to the right does seem to behave differently than the stall to the left, why I couldn't say but you can recover from it.

I too wasn't able to recover from a right-hand spin, but had no trouble with a left-hand spin.
I had the same results at Traveler with the P38L; recovered without difficulty left and right required differential throttle control to recover.

I tried it in the J and I had no problem either way... I wonder if the drag on the christmas tree rocket rails on the L isn't the same on both sides?
Just spent some more time in the TA doing spins in the 38L.

You guys that are able to recover, any chance you're using some aileron in your recovery technique?

If I used the standard spin recovery of throttles idle, ailerons neutral, opposite rudder and forward stick the spin rotation would increase slightly and did not recover from the spin.

If I used the standard anti spin controls PLUS aileron INTO (left spin, left aileron) I got consistent recovery withing 5 or 6 additional turns. (Pro spin aileron makes sense IF adverse yaw is modeled, but what I'm seeing in the spin is a bank away from spin rotation -- once the bank is neutralized with aileron you get immediate recovery)

I'm seeing this with or without bombs loaded, both left and right spins.

Spins were started at 20K, slow deceleration and allowed to go until spin stabilized (3-5 turns) before recovery.  Recovery was from 10 to 13K.

HiTech not sure you read the entire thread, I understand that you are a busy man and perhaps you didn’t .  But it isn’t just me that is encountering this issue.  If you did read the entire thread, then it bothers me that you came away feeling that is was just me having this problem.
« Last Edit: January 11, 2012, 03:16:37 PM by Traveler »
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Offline hitech

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Re: A tale of two spins
« Reply #121 on: January 11, 2012, 03:29:44 PM »
Traveler read those post again.

Only cactuskooler is saying there is a difference left and right.

Do you have manual trim on or off.

What fuel load?

HiTech

Offline Traveler

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Re: A tale of two spins
« Reply #122 on: January 11, 2012, 04:03:17 PM »

Traveler read those post again.

Only cactuskooler is saying there is a difference left and right.

Do you have manual trim on or off.

What fuel load?

HiTech


You don’t feel that Soulyss is stating that there is a difference?

The stall to the right does seem to behave differently than the stall to the left,

or that Delirium by having the same results as me is not saying there is a difference ?

I had the same results at Traveler with the P38L; recovered without difficulty left and right required differential throttle control to recover.
 

You really believe that it is only cactuskooler and me???

Tests were performed with different fuel loads and with combat trim both on and off.
« Last Edit: January 11, 2012, 04:08:28 PM by Traveler »
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Offline Ack-Ack

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Re: A tale of two spins
« Reply #123 on: January 11, 2012, 04:05:30 PM »
And yet others that have tried haven't had the same problem either.

ack-ack
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Offline colmbo

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Re: A tale of two spins
« Reply #124 on: January 11, 2012, 04:18:50 PM »
Again I was playing with spins in the 38L.

This time without bombs and rockets, 75% fuel load.  Still no recovery in spin to right unless I either use power on right engine OR us pro spin aileron.

FYI I used the CH control manager and confirmed that my controllers are getting full throw in all axes -- it's not a controller issue.  I do not have combat trim on.

I did find a nasty spin mode in the left spin -- I guess it's going very flat.  Using the same slow deceleration entry as in the spins to right when doing spins to left the nose doesn't slice down leaving me in slightly nose low attitude while spinning.  IAS is 36-42 (stabilized spin to right has IAS of 92).  If I applied power I could "push" the nose down and spin would normalize.  Able to recover from the "flat" spin with power and anti-spin controls.

I wonder if entry technique is making a difference in the spins?
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Offline Traveler

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Re: A tale of two spins
« Reply #125 on: January 11, 2012, 04:21:44 PM »
And yet others that have tried haven't had the same problem either.

ack-ack

Yes, very strange indeed.  one has to wonder why for me the only stall/spin that I can't stop the rotation to the right in is in the P38L.  That is the only aircraft.   Have you given it a try, seems to me that you enjoy flying the P38L once in a while. Do a spin to the left and recover by using right rudder and then try one to the right and see if you can recover with just using left Rudder or do you have to add power or aileron?  so no mistake , also using all normal stall recovery techniques, stickforward and that stuff.
« Last Edit: January 11, 2012, 04:29:43 PM by Traveler »
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Offline Traveler

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Re: A tale of two spins
« Reply #126 on: January 11, 2012, 04:24:25 PM »
Again I was playing with spins in the 38L.

This time without bombs and rockets, 75% fuel load.  Still no recovery in spin to right unless I either use power on right engine OR us pro spin aileron.

FYI I used the CH control manager and confirmed that my controllers are getting full throw in all axes -- it's not a controller issue.  I do not have combat trim on.

I did find a nasty spin mode in the left spin -- I guess it's going very flat.  Using the same slow deceleration entry as in the spins to right when doing spins to left the nose doesn't slice down leaving me in slightly nose low attitude while spinning.  IAS is 36-42 (stabilized spin to right has IAS of 92).  If I applied power I could "push" the nose down and spin would normalize.  Able to recover from the "flat" spin with power and anti-spin controls.

I wonder if entry technique is making a difference in the spins?

CG would be the deciding factor , I guess???
« Last Edit: January 11, 2012, 04:37:13 PM by Traveler »
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Offline Ack-Ack

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Re: A tale of two spins
« Reply #127 on: January 11, 2012, 04:51:14 PM »
Yes, very strange indeed.  one has to wonder why for me the only stall/spin that I can't stop the rotation to the right in is in the P38L.  That is the only aircraft.   Have you given it a try, seems to me that you enjoy flying the P38L once in a while. Do a spin to the left and recover by using right rudder and then try one to the right and see if you can recover with just using left Rudder or do you have to add power or aileron?  so no mistake , also using all normal stall recovery techniques, stickforward and that stuff.


As noted in a previous post I tried it both it in the P-38J and the P-38L and I had no issues at all recovering.

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Offline Seanaldinho

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Re: A tale of two spins
« Reply #128 on: January 11, 2012, 05:22:14 PM »
Just tested the L with a twisty stick and 25% fuel. Let it rotate once then just used engine power and rudder to stabilize no big deal either direction.

Offline Traveler

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Re: A tale of two spins
« Reply #129 on: January 11, 2012, 05:26:50 PM »
As noted in a previous post I tried it both it in the P-38J and the P-38L and I had no issues at all recovering.

ack-ack

I’m sorry Ack-Ack, I completely missed it.  

I tried offline and I couldn't reproduce the right side stall induced spin that was unrecoverable.  Each time I was able to recover within a turn without having to use differential throttle control.

ack-ack

 I do have a question, when you say that you were able to recover within a turn, does that mean from the time the spin started, or from the time  you applied full left rudder to stop the rotation to the right ?  
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Offline Traveler

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Re: A tale of two spins
« Reply #130 on: January 11, 2012, 05:38:05 PM »
Just tested the L with a twisty stick and 25% fuel. Let it rotate once then just used engine power and rudder to stabilize no big deal either direction.
You are 100 % correct,  and yes, we know the recovery can be accomplished with power , now try the conditions of the original test. 

Power off, Stall, at 5K wings level, apply right rudder to spin to the right.

Now using S.T.O.P to recovery:

S= Stick forward ailerons neutral,
T= Throttle closed,
O= Opposite rudder to stop the rotation then center ball
P= Power, slowly raise the nose and add power to climb back to altitude
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Offline Seanaldinho

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Re: A tale of two spins
« Reply #131 on: January 11, 2012, 05:55:47 PM »
You are 100 % correct,  and yes, we know the recovery can be accomplished with power , now try the conditions of the original test. 

Power off, Stall, at 5K wings level, apply right rudder to spin to the right.

Now using S.T.O.P to recovery:

S= Stick forward ailerons neutral,
T= Throttle closed,
O= Opposite rudder to stop the rotation then center ball
P= Power, slowly raise the nose and add power to climb back to altitude


Thats what I did guess I just worded it badly.

Offline icepac

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Re: A tale of two spins
« Reply #132 on: January 12, 2012, 10:05:12 AM »
Try these tests without the trim in the near full up positon and it's much easier.

Offline FLS

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Re: A tale of two spins
« Reply #133 on: January 13, 2012, 05:49:28 PM »
FWIW I spun a P-38L left and right and recovered both directions power off with stick forward and opposite rudder. I didn't use ailerons.

Offline colmbo

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Re: A tale of two spins
« Reply #134 on: January 13, 2012, 07:29:23 PM »
FWIW I spun a P-38L left and right and recovered both directions power off with stick forward and opposite rudder. I didn't use ailerons.

Weird.  Any chance you had some/lots of nose down trim in?  In my spin tests I hit auto-angle to "center" things up before doing the spin...so I'm basically trimmed for level flight, low power setting and 150-180IAS.  That's going to be a nose-up trim setting more than likely.

I'm confident that my controllers are working properly and I'm confident in my ability to apply the correct control inputs to recover from the spin.

I really have to wonder why some have no problem with the recovery yet there are some of us that are having to do a bit more to recover.

There is some variable we haven't picked up on.

Off to the TA for some spin tests.
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