Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: SFRT - Frenchy on March 24, 2014, 04:48:47 PM
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Were were sharing POVs on an another thread about stalling/spin/rudder. Created my own not to highjack the other one. I was talking about the plane I mostly fly and how the Thunderbolt nose would get 'stuck' nose up on wing overs. Or just wobbeling around not abruptly and significantly droping. Here's a quick vid for discussion. And bear with me, that was done quickly for demonstration purposes, I don't have a 'obvious' vid of what I was describing but that's close enough.
In the vid, I have a nice tail slide even if the nose doesn't drop fast enough I think. Then I have that ' nose high wobbeling around' example, and finally I cannot make a dam Spitfire spin. I'm pretty sure they did when stalled while full rudder is applied. :P
I think as good as the FM is, something gets all screewy in the low speed department.
https://www.youtube.com/watch?v=uSzvthRnx8o (https://www.youtube.com/watch?v=uSzvthRnx8o)
What you guys think?
Edit : I'm learning :aok I learned that what I perceive as 'the screewy behavior' is generated by having the engine on even when at idle. I'm surprised the forces generated by the prop of an engine at idle have so much influence on the FM :
https://www.youtube.com/watch?v=586lFSpIxsw (https://www.youtube.com/watch?v=586lFSpIxsw)
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What you guys think?
about sex mostly.
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Are you using combat trim? The 38 can get it's nose stuck in the air when rolling over at the top of a loop when you get it real slow. I knock off combat trim when Im in a loop just to be sure not to get it stuck.
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Ahh .. no combat trim, no stall limiter.
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about sex mostly.
You must not have enough then :lol
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my lady is 7 months pregnant.. you remember that time I am sure. :rock
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I can spin anything right into the floor no problem ;)
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Ahh .. no combat trim, no stall limiter.
How much fuel?
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my lady is 7 months pregnant.. you remember that time I am sure. :rock
You poor devil, saddly the worst is yet to come :t
I can spin anything right into the floor no problem ;)
:lol I still bet you can't spin a Spitfire.
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did you push the I button to push the nose down??????? :joystick:
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my lady is 7 months pregnant.. you remember that time I am sure. :rock
lol.
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Fuel ... 75% I think on both, maybe only 50 on the Spit. Does fuel really matter? On the Spit 16 between 25% and 100% it's only 600 lbs. On the Jug it's 1,300lbs. Which is 10% of the total weight on the Jug, 6% on the Spit.
In the Pilatus I fly, full fuel or low fuel doen't affect 'how' the plane stalls, but more like 'when'. But all the fuel is in the wing. Since it's a debate on 'how', I don't think it's that relevant except maybe if the Spit has way backward fuselage tanks.
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:lol I still bet you can't spin a Spitfire.
How is this?
https://www.amazon.com/clouddrive/share?s=NmuGIPTyTMgiNKw75MrjVQ
The Spitfire pilot manual states that a full rear fuselage tank will cause the nose to go up near the stall.
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Is the 'can't spin a spit' thing serious, or am I missing some in-joke?
Just put the stick to 4-5 o'clock and apply full right rudder. You're spinning.
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Do you "spin" as in it stays spinning when you let the controls go neutral or that you can't get one wing to stall before the other?
Per Boscombe Down testing the Spitfire had to be held in a spin otherwise it would stop on its own. IIRC the Mk XIV would do about 1080 degrees before ceasing to spin.
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In the vid, I have a nice tail slide even if the nose doesn't drop fast enough I think. Then I have that ' nose high wobbeling around' example, and finally I cannot make a dam Spitfire spin. I'm pretty sure they did when stalled while full rudder is applied. :P
https://www.youtube.com/watch?v=uSzvthRnx8o (https://www.youtube.com/watch?v=uSzvthRnx8o)
What you guys think?
I've been wondering the same thing for quite a while. My personal hypothesis of it is that there might be excessive gyroscopic precession of the prop working together with the aerodynamic forces at play during a tail slide that cause this somewhat weird behavior. I doubt there's anything wrong with gyroscopic precession code itself but I'm suspecting that the parameters fed into the model might be the cause. For example, a case where the prop mass is too great or the angular velocity of the prop is too high (say, the crankshaft rpm instead the rpm of the prop end of the reduction gear) would cause greater precession force than what would occur in real life.
I want to emphasize that this is just a hypothesis and it would be pretty hard for me to explicitly prove it. One way to test the theory is to try tail slides with the I-16 which seems to have the worst symptoms of this. As the I-16 starts fall backwards at the top of the tail slide, without any control input, it takes a long while for the I-16s nose to drop close to parallel of the velocity vector when the engine is running at idle. With the engine off and prop stationary, the nose swings down quickly and uneventfully.
Before the prop mass of the Brewster was reduced, the plane could fall ~4000-5500ft down more or less tail first from a tail slide maneuver before the nose came down. After the reduction of the prop mass (granted, other changes were made as well) the nose drops down rather uneventfully.
The planes that in my opinion seem to suffer from this problem the most are:
I-16
Spit14
Ta152
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Is the 'can't spin a spit' thing serious, or am I missing some in-joke?
Just put the stick to 4-5 o'clock and apply full right rudder. You're spinning.
I'd love to see your video of it, or catch me in the MA, I'll observe you. By a spin I mean, nose down about 30 degrees doing a couple of rotations like you see at airshows.
Do you "spin" as in it stays spinning when you let the controls go neutral or that you can't get one wing to stall before the other?
Per Boscombe Down testing the Spitfire had to be held in a spin otherwise it would stop on its own. IIRC the Mk XIV would do about 1080 degrees before ceasing to spin.
Did you look at the video? : I can't get to make it spin when stalling with full rudder deflection. I'll make a video for the P47 to explain (geezbus you guys are killing me). :angel:
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At work, can't see videos. :p
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I've been wondering the same thing for quite a while. My personal hypothesis of it is that there might be excessive gyroscopic precession of the prop working together with the aerodynamic forces at play during a tail slide that cause this somewhat weird behavior. I doubt there's anything wrong with gyroscopic precession code itself but I'm suspecting that the parameters fed into the model might be the cause. For example, a case where the prop mass is too great or the angular velocity of the prop is too high (say, the crankshaft rpm instead the rpm of the prop end of the reduction gear) would cause greater precession force than what would occur in real life.
I want to emphasize that this is just a hypothesis and it would be pretty hard for me to explicitly prove it. One way to test the theory is to try tail slides with the I-16 which seems to have the worst symptoms of this. As the I-16 starts fall backwards at the top of the tail slide, without any control input, it takes a long while for the I-16s nose to drop close to parallel of the velocity vector when the engine is running at idle. With the engine off and prop stationary, the nose swings down quickly and uneventfully.
Before the prop mass of the Brewster was reduced, the plane could fall ~4000-5500ft down more or less tail first from a tail slide maneuver before the nose came down. After the reduction of the prop mass (granted, other changes were made as well) the nose drops down rather uneventfully.
The planes that in my opinion seem to suffer from this problem the most are:
I-16
Spit14
Ta152
Nice observation. I've never tried it with the prop stopped.
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I think Wmaker as a good point, exploring further the engine runing at idle is what's screewing up the deal.
When I shut off the engine of the Spitfire I have a very nice spin either directions. When I leave the engine runing at idle, she does spin to the right but it's very choppy, like she's trying to get out of the rotation even when I keep the rudder full in. On a left spin, it's total nonsense to me. (vid loading up).
Maybe in AH, the idle power of the aircrafts and forces associated with them are far too strong, and they interfere with the aerodynamic laws? I wonder if it's why the nose acts all weird in wingovers and hamerheads.
https://www.youtube.com/watch?v=586lFSpIxsw (https://www.youtube.com/watch?v=586lFSpIxsw)
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I agree the Spit acts pretty weird when trying to spin it using a "standard" spin entry of aft stick to stall with full rudder in direction of desired spin. Seems to only want to yaw in one direction regardless of rudder input. Once "spinning" it hesitates as Frenchy noted, kind of like I've heard some flat spin modes described where rotation varies and the nose pitches up and down. Occasionally it has gotten stuck settling nose high, otherwise recovery is consistent.
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Watch vid above Colmbo, so far on the planes I tries, the F4UD is the most magnificiant. On a stall/left rudder it will enter a very nice 'roll into the spin'. On a stall/right rudder she will not enter a spin, you can maintain her wings level-ish. That idle prop forces thingy.
The Ensign Eliminator syndrome I couldn't replicate it. I was ridding the stall full left rudder and jammed the throttle forward with no superhuman skill needed to accelerate straight and level.
For the old timers, I think it was Beta 4 maybe when the big FM change came? I liked it before better because you could actually run a stall fighter like a spitfire out of energy in a stallfight. But I disgress :rolleyes:
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I think I remember something in my P-47 manual about the aircraft stalling tail down. I'll have to take a look tomorrow and see if I can find it.
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Can't spin a Spit? Tried it in the Spit 1?
Once I had it in a spin from hi alt, had time to try everything twice, read the manual, try it again, make coffee, try it again, answer the phone, try it all again and still couldn't stop it.
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Maybe you were in space? :devil
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I'm not really 100% sure of what frenchy is saying but if its a nose up stall and u are trying to bring the nose back down quickly u have to glimpse at the true air speed and average the plane that u are in when exactly is it going to stall. Before u are about to stall use your engine torque and rudder to catch back the air speed and true air speed at the same time so the aircraft will not struggle to retain back its normal stall speed. From the vids posted I think that's what the problem was. Most of u might not get what I am saying but from my experience and my flying point of views that is what I will assume. :salute
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Can't spin a Spit? Tried it in the Spit 1?
Centre of gravity too far aft bug is my hypothesis for that one.
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On the P47 wing-over, with hard rudder, the timing of the throttle seems to be critical. Too soon and it mushes out as you noted. I do use manual trim. I can't hit it every-time. If it mushes, you are in deep po-po. I know that. Might as well be a Christmas ornament, at a BB gun convention.
Maybe some of the P47 specialist can offer some good advice. What I said is all I've got.
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On the P47 wing-over, with hard rudder, the timing of the throttle seems to be critical. Too soon and it mushes out as you noted. I do use manual trim. I can't hit it every-time. If it mushes, you are in deep po-po. I know that. Might as well be a Christmas ornament, at a BB gun convention.
Maybe some of the P47 specialist can offer some good advice. What I said is all I've got.
A wing-over is not a stall maneuver. It's simply a steep climb - turn - dive. Did you mean hammerhead?
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Maybe you were in space? :devil
Certainly felt like I was falling at a constant rate. If I'd managed to get my speed up to 25,000 mph or so before the stall, I'd have gone comfortably into orbit.
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I see spits spin all the time.
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Played around with the Spit I this morning using a standard spin entry of idle power, full rudder and full aft stick at the stall.
Using full left rudder the nose first yawed left and bit then hard back to the right, nose staying pretty much on the horizon. After 90-180 degrees of turn the nose popped up to about 60 degrees nose high, airspeed fell to zero and I fell tail first. Managed to work the airplane inverted and ended up 40 degrees nose low, IAS 30, elevator had no effect on pitch. Ailerons would provide roll opposite to correct direction, using aileron and rudder I was about to "rock" the airplane and get the nose to drop more, once airspeed gained it recovered.
Above is pretty standard for what I'm seeing with the Spit spins.
If accelerated at entry and some aileron used it spins more reliably in a more realistic manner. Even then however it will revert to a spin to the right even with left rudder used.
Spin to right was more normal, "jerky" in yaw rate, nose down 45 degrees or so.
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A wing-over is not a stall maneuver. It's simply a steep climb - turn - dive. Did you mean hammerhead?
I was sure enough. My bad.
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On the P47 wing-over, with hard rudder, the timing of the throttle seems to be critical. Too soon and it mushes out as you noted. I do use manual trim. I can't hit it every-time. If it mushes, you are in deep po-po. I know that. Might as well be a Christmas ornament, at a BB gun convention.
Maybe some of the P47 specialist can offer some good advice. What I said is all I've got.
The critical timing is in the speed where you initiate the yaw. When you are too fast you will skid instead of pivot and the skid will kill your rotation and leave you with your nose high. When you are too slow you won't create enough rotation with the rudder. When you go up make sure it's your wings that are vertical not your fuselage.
When you are on the runway go to F3 and look at your rudder. Note that you can turn your controller faster than the rudder will respond. Controls are affected by high speed and joystick settings but the rudder is always damped regardless of settings so you never get full instant deflection.
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When you are on the runway go to F3 and look at your rudder. Note that you can turn your controller faster than the rudder will respond. Controls are affected by high speed and joystick settings but the rudder is always damped regardless of settings so you never get full instant deflection.
But is the input into the flight model correct, and just the graphics delayed, or is the input also delayed?
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The control surface graphics come from the flight model. You can see that in high speed dives. The input is delayed and/or limited in order to be correct. Our rudder controllers being easier to move than real rudder pedals.
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Our rudder controllers being easier to move than real rudder pedals.
Hmmmm.
Sitting on the ground in the B-24 you can slap the rudder back and forth easily….same in the B-17. Moves as easily as the pedals hooked to my computer. The rudder is over damped in game…one of the reasons it's a bit harder to track during takeoff or landing since you're just "this much" behind the airplane….real life little stabs left and right keep you tracking the center line. At higher speeds I can see some reduction in rate (it takes more muscle) as well as a possible reduction in throw (again, muscle needed).
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FLS what's the story behind that motherdiddlying avatar?
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I've been wondering the same thing for quite a while. My personal hypothesis of it is that there might be excessive gyroscopic precession of the prop working together with the aerodynamic forces at play during a tail slide that cause this somewhat weird behavior. I doubt there's anything wrong with gyroscopic precession code itself but I'm suspecting that the parameters fed into the model might be the cause. For example, a case where the prop mass is too great or the angular velocity of the prop is too high (say, the crankshaft rpm instead the rpm of the prop end of the reduction gear) would cause greater precession force than what would occur in real life.
I want to emphasize that this is just a hypothesis and it would be pretty hard for me to explicitly prove it. One way to test the theory is to try tail slides with the I-16 which seems to have the worst symptoms of this. As the I-16 starts fall backwards at the top of the tail slide, without any control input, it takes a long while for the I-16s nose to drop close to parallel of the velocity vector when the engine is running at idle. With the engine off and prop stationary, the nose swings down quickly and uneventfully.
Before the prop mass of the Brewster was reduced, the plane could fall ~4000-5500ft down more or less tail first from a tail slide maneuver before the nose came down. After the reduction of the prop mass (granted, other changes were made as well) the nose drops down rather uneventfully.
The planes that in my opinion seem to suffer from this problem the most are:
I-16
Spit14
Ta152
Interesting.
I've noticed this most on the Ki-84.
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Interesting.
I've noticed this most on the Ki-84.
Just turn your motor off for a sec dude and she'll come back into line.
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Just turn your motor off for a sec dude and she'll come back into line.
I will try that. :salute
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Hmmmm.
Sitting on the ground in the B-24 you can slap the rudder back and forth easily….same in the B-17. Moves as easily as the pedals hooked to my computer. The rudder is over damped in game…one of the reasons it's a bit harder to track during takeoff or landing since you're just "this much" behind the airplane….real life little stabs left and right keep you tracking the center line. At higher speeds I can see some reduction in rate (it takes more muscle) as well as a possible reduction in throw (again, muscle needed).
It does seem odd that it's delayed with no airflow. Small corrections are quick but the full travel is noticeably delayed.
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Edit : I'm learning :aok I learned that what I perceive as 'the screewy behavior' is generated by having the engine on even when at idle. I'm surprised the forces generated by the prop of an engine at idle have so much influence on the FM :
https://www.youtube.com/watch?v=586lFSpIxsw (https://www.youtube.com/watch?v=586lFSpIxsw)
If the forces generated by prop so strong that they prevent plane falling into left spin normally the plane should entered the right spin with no problem. Is it right?
BTW I tested Spitfire stall/spin behavior in WarThunder and the plane entered left/right spin with no problem at all with engine idling at low rpm at near-stall speeds and full left/right rudder applied.
To recover from left spin it was enough to release controls to neutral position. To recover from right spin full rudder counterclockwise had to be applied.
https://www.youtube.com/watch?v=IikIyblYxkA (https://www.youtube.com/watch?v=IikIyblYxkA)