Author Topic: 38 Problems  (Read 1061 times)

Offline OLtos

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38 Problems
« on: April 17, 2006, 12:41:51 AM »
Had a problem with the 38L departing controlled flight last week.  Came here and found out why.   Then I went back online upped a 38G for one flight.  Killed 3 P47Ns and a Spit 16 and landed the kills.  At this point I am not having any problems.

However, here are some observations.  I always flew it with the stall limiter engaged.  I have ALWAYS suffered in the P-38 with out it.  Up untill the SL was added to the game my 38s were always departing controlled flight and crashing.  The departure was always a snap roll into a spin.  SL came out, I tried it, and the a-historical snap rolling in turns stopped.  I was happy and lived in 38s of various models ever since.

The new change came out and I noticed that first incident with 38L.  It acted like my SL was disengaged.  I checked flight settings and there was the usuall X in the usual spot.  I checked the arena settings under FlightModeFlags and LO and BEHOLD the SL was disabled in the arena settings.

I turned off the feature off line so I could test my 38s there.  As of this post I was unable to force any model of 38 into a snap roll to departure from controlled flight under any turning regimen.  Deploying flaps or not.  It may be that a lot of old problems I used to have are now gone.  Along with the SL.  SL is NOT active in the Main Arena anymore.  It's disabled in the arena settings.

As of this post the 38 flys fine for me.

OLtos

Offline Delirium

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38 Problems
« Reply #1 on: April 17, 2006, 03:04:13 AM »
1. The FM is a real step back... the fact you can't make it depart and you can't tell the difference between Stall limiter on or off proves that. Add that to the fact that there is no difference between having manual or combat trim, and the 'flying on rails' is complete.

2. I've done some time with you showing you some things in the P38 and honestly, that constantly departing was likely either your stick settings (too sensitive) or you were just a little too rough on the stick. Having Stall Limiter on is (and as I told ya in person) is a real crutch for advancement in any aircraft, no matter what you're flying.

3. P38s could and did snap-roll historically... and we received this in exchange for a P38 in AH that can't manuver at all. Bad exhange unless you're just going to keep it fast...

Sorry Oltos, you're a good guy, but I really disagree with you.
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Offline OLtos

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Snap Rolls
« Reply #2 on: May 30, 2006, 12:23:50 AM »
38s snap rolled out of stalls historically?  Love to read that source.  Which one is it?   And, dont quote the MaQuire thing at me.  No one knows exactly how he lost control.  I have heard everything from snap rolls induced by drop tanks to boost regulator failures caused assymetrical thrust ( which would and did do uuuugggglllly things to you roll wise ).  But boost regulators do not fail in AH.

As for it just being me.  I wouldn't have said it if a I hadn't checked that detail.  I have a couple of friends close who have flown it on my system then used the same settings and stick on their system.  They see the same thing.  Different system, plane handles differently.  Saw that on the P51 as well.  Where it would be nice and sweet on my system it was all tweaky and unstable on his.  So it just being me is ruled out there.  

On the other hand I did find the bug with the uber drag happening on full flaps.  That will definitely take some getting used to.   BUT the 38 seems to be more stable now!  So I am not really missing the stall limiter as much as I thought I would.  In fact, I was up in the FWD9 to day and IT seemed more stable as well.  Maybe the FM change is having an overall benefit to the game that is outweighing its negatives on the 38.  Still.  I am not quite ready to call it quits with the 38.  

You showed me loud and clear, and I have never questioned since, that the SL was making me fly at a disadvantage.  Maybe my playing field just got leveled for me.  That would make me GRINN NN NNNNN a lot.  Even though I know its not really true.

Thanks again for all your input.  Really has helped my understanding of the game.

OLtos

Offline Tac

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38 Problems
« Reply #3 on: May 30, 2006, 12:43:09 AM »
The 38 did have a tendency to snap roll. Something to do with the windspeed at the wingtips if I recall correctly. I think you're confusing the snap roll caused by torque at stall speeds with the 38's 'wing dip' snap stall.

Offline Captain Virgil Hilts

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38 Problems
« Reply #4 on: May 30, 2006, 07:30:07 AM »
I'm unaware of any "wing dip" on the P-38. No test pilot nor combat pilot with sufficient experience mentions it anywhere. You can stall any wing if you get it slow enough.
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Offline Hazard69

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38 Problems
« Reply #5 on: May 30, 2006, 09:39:04 AM »
Im no history guru and dont really have any idea about the actual camber, CL, wingwash etc. of the REAL 38's wing...but I am an aerospace engineer and heres what I think.

Any wing can stall at low enough speeds.....as stated earlier.
Looking at the rather long wingspan of the 38 and some rather aggressive manoevering, I think it should be possible to get one wing to stall, the effect being most pronounced at the tip. Thereby causing the 38 to enter a snaproll.
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Offline Widewing

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38 Problems
« Reply #6 on: May 30, 2006, 10:05:40 AM »
Quote
Originally posted by Hazard69
Im no history guru and dont really have any idea about the actual camber, CL, wingwash etc. of the REAL 38's wing...but I am an aerospace engineer and heres what I think.

Any wing can stall at low enough speeds.....as stated earlier.
Looking at the rather long wingspan of the 38 and some rather aggressive manoevering, I think it should be possible to get one wing to stall, the effect being most pronounced at the tip. Thereby causing the 38 to enter a snaproll.


According to what I've read of P-38 stall behavior, the wing center section stalled first, allowing the aircraft to retain roll control deep into the stall. There was a slight tendency to dip a wing, but this self-corrected as soon as the aircraft gained some speed after mushing. Accelerated stall behavior can vary according to multiple factors in place at the time.

Lockheed used different NACA airfoils for the inner and outer wings, NACA 23016 for the inner, NACA 4412 for the outer wing section. Both had an incidence of 2 degrees.

My regards,

Widewing
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Offline Lazerr

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38 Problems
« Reply #7 on: May 30, 2006, 10:13:07 AM »
wow... Tac lives...:aok

Offline Hazard69

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38 Problems
« Reply #8 on: May 30, 2006, 02:08:18 PM »
Originally posted by: Widewing
According to what I've read of P-38 stall behavior, the wing center section stalled first, allowing the aircraft to retain roll control deep into the stall. There was a slight tendency to dip a wing, but this self-corrected as soon as the aircraft gained some speed after mushing. Accelerated stall behavior can vary according to multiple factors in place at the time.

Bingo!.......
Wing washing is where angle of incidence of wing is varied from max at root to min at near tip (also called a twisted wing) but thats mainly to prevent tip stalls. Used on all highspeed airliners today (although I believe some have two opposite twists).
Aileron conrol effectivenes is typically maintained by using vortex generators.

In this case the root stall was ensured to occur before the tip stall by using a thicker aerofoil. However in a sharp turn at low speeds, the difference in linear velocity is sufficient to cause a root and a tip stall. Accelerated stalls are more difficult to predict since they depend on aircraft movement at that instant (climbing, skidding, slipping, diving etc.)
Imagine after that slight wing dip, the aircraft speed was not allowed to recover (for e.g. by someone yanking the stick) that slight wing dip will eventually grow until......TIP STALL, which then causes the snap roll.
<S> Hazardus

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Is no blonde or brunette from a Hollywood set, but an escort of P38s.

Offline bozon

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38 Problems
« Reply #9 on: May 30, 2006, 04:19:40 PM »
Quote
Accelerated stalls are more difficult to predict since they depend on aircraft movement at that instant

If stalled while in a banked turn the outer wing with respect to the turn direction will stall first since it has higher angle of attack (due to aileron deflection). The wing will drop, but pilot instincts will be to counter with more stick deflection making the stall worse and snaping the plane inverted.

Bozon
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Offline Krusty

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38 Problems
« Reply #10 on: May 30, 2006, 06:42:51 PM »
I don't think that's right. The outer wing is travelling faster, as it's on the end of the lever. The inner wing will stall first because it's moving slower because it's closer to the fulcrum. The inner wing will stall first.

Add to that, the ailerons will be : inner wing deflected up, outer wing deflected down.

The outer wing's aileron is acting as a flap (creating more lift, to roll that wing up) and the inner wing's aileron is acting as a spoiler (disrupting lift to make that wing roll down).

Add that to the direction of the turn, and the inner wing should stall first.

Offline bozon

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38 Problems
« Reply #11 on: May 31, 2006, 09:05:39 AM »
stall does not happen due to low air velocity over the wing. It relates (almost) soley to the angle of attack.

When you roll left, you increase the angle of attack on the right wing. On high torque planes even flying level requires one wing to produce more lift then the other (by aileron deflection) to counter the engine's torque roll. This is why most planes drop the left wing when stalled level.

The latter case is not a problem in the P38 as torque is near zero, but if you fly near stall and deflect ailrons trying to roll, you will stall the wing that is supposed to lift - causing it to sink instead. The pilot will try to counter by deflecting more ailrons sending the one wing deeper into the stall and the other farther away from the stall.

Do that violently by pulling hard on the stick and trying to roll sharply and from here a strong yaw tendancy kicks in since the stalled wing produce a lot more drag than the other one - the plane both flips and yaws. Might send you into a flat inverted spin even in a zero-torque plane.

Bozon
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Click!>> "So, you want to fly the wooden wonder" - <<click!
the almost incomplete and not entirely inaccurate guide to the AH Mosquito.
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Offline Kweassa

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Perhaps an entirely different reason...?
« Reply #12 on: May 31, 2006, 11:23:53 AM »
Guys,

 Maybe the perceived 'problem' comes from an entirely different reason than suspected (although other pilots like AckAck comment that he feels nothing different with the P-38s).

 I remember an explanation by Hitech that was on the old Aces High webpage. He was explaining on some difficulties in modelling the planes on a "1:1 scale" in maneuvering tendencies.

 He said that the real Spitfire would stall when achieving something like 20 degrees of elevator deflection, and when this is modelled on a 1:1 scale in the game, the AH Spits would be stalling all over when our game joystick was just half-way deflected. IIRC, it was because real life pilots maneuvered with a totally different stick-feel and force/resistance to our joysticks. Therefore, the ratio between the elevator input and stick deflection in the game, would have to be augmented somewhat arbitrarily, so the plane would reach stall AoA when the joystick was almost pulled back to the max.

 
 Perhaps, the new P-38s have some problems in that very aspect?

 Many P-38 pilots say the new AH P-38 is very unstable and stalls out easily during turns. Others say that they don't feel anything different. If both parties are telling the truth, then maybe it's because the people who feel no differences are more accustomed to fine-controlling the P-38 with less stick pull, so they can manage it more easily, but the people who are having problems with it may habitually pull the stick a lot harder than the P-38 can take.

 What I mean by this, is perhaps the stick-to-elevator-deflection ratio on the AH P-38 may be much more larger than other AH planes... so most of AH planes might stall out when the pilot pulls maybe about 3/4 th of the stick, but the P-38 is set up differently/wrong or something, so the elevator deflection reaches stalling AoA a lot faster than other aircraft, maybe something like only 1/2 of stickpull and the elevator is already deflected too much.

 If this be the case, then regardless of the individual pilot skill, a pilot may be led to think that the plane is much unstable - since habitual bias is a very strong temptation. Everybody knows how different planes react differently even with the same amount of stickpull in the game, but in most cases those differences are clearly manageable and adaptable. But perhaps, the P-38 stick/elevator scale is off radically (than compared to other planes), so pilots who usually don't have any problems flying different types of planes, might suddenly have big problems in not "pulling the stick too much" when they fly the P-38.
 
 One evidence of this, might be how OLtos had no problems with the stall limiter engaged. As everyone knows, the SL keeps the plane a certain margin away from the critical AoA - elevator deflection is forcibly halted by the buffer set by SL, so a pilot is forbidden to enter stalling AoA. OLtos is a good pilot, so I'm sure he wouldn't need to use the SL in any other plane, no matter how "tricky" the plane is. But if he needed to use the SL in the P-38, then that would mean that something's wrong with the amount of stickpull in the P-38. If OLtos would habitually pull a certain amount of stick in all the other planes, and they'd react under his control, but if that same amount would always cause over-deflection in case of the P-38, then clearly he would be led to think that the P-38 is modelled wrong, when in reality, the FM concerning how the plane flies could be right (but the stick/elevator scale might be too high).

 Therefore, this theory would explain why people say different things about the recent AH P-38s. Maybe both of the parties are right.


 The solution, in that case, would probably be adjusting the stick scale for the P-38 only, so it uses only about 50% of elev. deflection with the same amount of stick pull than compared to the settings other planes are using. Then the 'stick authority' would be dulled, and people would be able to pull the stick around at the same levels of other aircraft without stalling the P-38.


 Just a guess.

Offline Hoarach

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38 Problems
« Reply #13 on: May 31, 2006, 02:42:15 PM »
Kweassa also when using the 5th notch flap on the 38 now its like attaching an anchor to the plane.
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Offline Lazerr

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38 Problems
« Reply #14 on: May 31, 2006, 06:10:26 PM »
I don't think a p38 with full flaps would fall out of the sky in real life...