Speed bleeding while turning Fixed-Wing aircraft

[hailstorm 4]

Bugtracker Listing:

0002789: fixed-wing aircraft lose too much speed during turns

This is a fairly easy one, seeing that anyone whose flown one of ArmA's aircraft has noticed it.

why is it that when you turn a plane, at any speed and at any throttle setting, the airspeed will bleed off till you fall out of the sky and crash?

coming from an aerobatics background, i know this isn't the case - true, if your're flying mach 1 in your whiz-bang jet and throw it into a 90 deg. bank and pull, you'll lose speed.

what i disagree with is how i can be flying at 300kmh, push the throttles to the max, bank my plane over 30 deg. and see my speed drop on something as innocuous as a 2G level turn.

basically, what i'm asking is that when flying at 'slow' speeds, with maximum thrust, i shouldn't see my plane lose speed during turning, even with full backpressure on the controls - it makes no sense, and it dosen't happen in real life.

if you think that it needs changing, then please vote on the issue on the bugtracker page.

[Beagle 684]

Problem is..there is no such thing as thrust with ArmA planes.

It's just a speed setting...brake, slow, normal, fast.

There simply is no control over the engine RPM.

[xav 0]

Yes I do think it needs changing too.

Do I need to register and be logged in to vote?

[BraTTy 0]

Its not actually a bug.It is a setting in the config. It can be set so it doesn't lose any speed while turning. It wouldn't be very realistic then. Are you holding shift while turning?

Sorry I haven't flown it lately so I am not sure how much speed it loses.

[malick 0]

The problem I see, though I completely see your point, is how to correct this 'bug' ?

I think it's more or less an engine limitation. Vehicles have 'gears' : neutral (stop), forward, fast forward and reverse. That's all, and it also applies to how the planes, AI controlled or not, are handled.

In order to correct such a bug would require a quite severe overhaul of the way fixed wing aircraft are coded.

However, having played quite a lot of simulations in my gaming life, I can safely say that ArmA representation of flying is inappropriate, even at this scale.

Some basic physics vectorized equations should do the trick :<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Code Sample </td></tr><tr><td id="CODE">thrust + lift + friction + gravity = mass*acceleration

without being too complicated to elaborate or to implement.

It's still BIS call in the end.

Malick

[hailstorm 4]

yeah, to vote you need to have an account in the bugtracker:

Topic: How do I create a BTS account?

Problem is..there is no such thing as thrust with ArmA planes.

It's just a speed setting...brake, slow, normal, fast.

There simply is no control over the engine RPM.

that's a seperate issue, which is also in the bugtracker and needs votes:

0002507: More direct control of the various vehicles.

Its not actually a bug.It is a setting in the config. It can be set so it doesn't lose any speed while turning. It wouldn't be very realistic then. Are you holding shift while turning?

Sorry I haven't flown it lately so I am not sure how much speed it loses.

well see that's the problem - it's not a constant value, at high speeds and max thrust, turning aircraft should slow down, at low speeds it should speed up, or maintain initial speed, depending on aircraft and bank of turn.

at the moment you can turn a plane at any speed and it'll decay the airspeed till it either equals zero or you crash, both of which arn't realistic by any degree.

[BraTTy 0]

Clip from OFP commented config for Air vehicle class

<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Code Sample </td></tr><tr><td id="CODE">

noseDownCoef = 1; // how much goes nose down during turns

Obviously setting it to 0 ...you wouldn't loose speed in turns

No major engine changes needed.

Not sure if same/diff Arma config. I haven't toyed with addons yet

[malick 0]

Is this still in effect for ArmA or is it OFP-only ?

Maybe worth a try if it can improve the AI flying ability...

Malick

[suma 8]

Clip from OFP commented config for Air vehicle class

<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Code Sample </td></tr><tr><td id="CODE">

noseDownCoef = 1; // how much goes nose down during turns

Obviously setting it to 0 ...you wouldn't loose speed in turns

No major engine changes needed.

Not sure if same/diff Arma config. I haven't toyed with addons yet

I am not sure what is obvious with that - speed bleeding is not caused by nose going down. I am afraid something deeper in flight dynamics calculations is done wrong, perhaps too high AoA in turns, or too strong drag as a result of AoA.

(And besides, noseDownCoef is no longer supported for ArmA anymore.)

[BraTTy 0]

Ah well there you have it, something that would need patching.

Weird that in OFP I lessen that and the nose would drop less and you wouldn't lose as much speed after turning

[Shashman 0]

Problem is..there is no such thing as thrust with ArmA planes.

It's just a speed setting...brake, slow, normal, fast.

There simply is no control over the engine RPM.

You obviously haven't flown with a throttle equipped joystick then

[-ZG-BUZZARD 0]

I just hope this bug gets fixed in 1.09... I really do...  

[max power 21]

AoA rightly causes huge drag. The problem might lie in a lack of pitch stability... I haven't noticed too much energy bleed, though... but from flight simulators, I fly in such a way as to maintain a maximum possible energy state, so yanking and banking for no reason doesn't really factor in to it.

[Beagle 684]

Problem is..there is no such thing as thrust with ArmA planes.

It's just a speed setting...brake, slow, normal, fast.

There simply is no control over the engine RPM.

You obviously haven't flown with a throttle equipped joystick then

No in fact I use a X-52 TQS and Flightstick Combo.

In ArmA there is no real control, just go to three quarter throttle and nose down...engine will run at idle and spools up as soon as you climb.

Like with Helicopter the throttle doestn control engien power or cellective...it's just an basically a variation of the keyboard input. Up-down, forward-fast forward.

[subs17 9]

I have a few issues with the A-10,

centre pylon has a Maverick IRL only 2 pylons carry AGM65s. Idle throttle causes the brakes to open, could the airbrakes have a key assignment along with the flaps and landing gear?

The FFAR can carry smoke as well as HE so you can have one fly as FAC and mark targets with smoke.

Check this out:

Quote[/b] ]A-10A

1. Stations 3 and 9 are the only stations that can carry the AGM-65 Maverick either as singles or in pairs on the outboard and bottom racks of TER(Triple Ejector Racks).

2. Stations 1 and 11 can carry the AIM-9 Sidewinder, ALQ-131 ECM pods, Mk-20, CBU-97, and Mk-82 iron bombs.

3. Stations 4 and 8 can carry Mk-82s and Mk-20s on TER's.

4. Stations 4 and 8 can carry LAU-61 Hydra launchers on TER's.

5. Stations 3 and 9 can carry SUU-25 illumination flares.

6. All stations can now carry single CBU-97 Cluster bombs. Mr. Wolf has released a great new skin for the CBU-97 found here: http://www.lockonskins.co.uk/index.php?page=downloads. For those with Flaming Cliffs v1.11 a new model and skin was included for the CBU-97 so this one is not required.

7. The ability to carry Mk-20 Rockeye's on TER's has been re-introduced but note that due to scaling or the TER model, the landing gear will pass through the outboard weapon.

From here

Real weapons load

I've also found that the altimeter should be in feet not meters for western aircraft such as the A-10 and Av8B.

[max power 21]

The above poster must realize that that is an aircraft related plight and not flight model related in any way?

One of the gripes the TOP was making was that if you yank back on the stick you will eventually stall... that is quite true to life. The stall behaviour in ArmA is what pilots would roughly refer to as mushing. How it may be exaggerated in ArmA, I don't know. I'm fairly certain that if you give an a10 maximum backward stick, it will eventually stall and will not recover until you release the control input.

The mere presence of that behaviour doesn't signify an error in the flight model. How and when it happens might be.

[subs17 9]

The aircraft can stall in Arma but it requires high AoA at lower speeds I notice that the nose dosen't drop. Try comparing it to lockons A-10 and how that handles. And yes I am aware that this is a FM thread however my points relate directly to the A-10.

[hailstorm 4]

The above poster must realize that that is an aircraft related

One of the gripes the TOP was making was that if you yank back on the stick you will eventually stall... that is quite true to life.  The stall behaviour in ArmA is what pilots would roughly refer to as mushing.  How it may be exaggerated in ArmA, I don't know.  I'm fairly certain that if you give an a10 maximum backward stick, it will eventually stall and will not recover until you release the control input.

i think everyone needs to realise something - stalling an aircraft is not related to speed in any way - it is related to the angle of attack the wing makes with it's relative airflow - namely, if it exceeds 16 degrees. the reason everyone assumes it has to do with speed is that when flying slow the relative airflow will angle to this amount, and further if the plane keeps slowing down.

due to the fact it's angle-related and not speed-related, it's possible to stall at high speed in a VERY sharp turn, where the pilot pulls so hard back that the relative airflow exceeds the wings' attitude by more than 16 degrees and it falls out of the turn, which is what i believe plaintiff1 is referring to - but, like i said, it's not speed related, so a plane does not, and will not, slow down to stalling speed of 'x' before entering a stall.

The mere presence of that behaviour doesn't signify an error in the flight model.  How and when it happens might be.

exactly my point. planes will have an increased drag coefficient during turns, increasing with airspeed (parasitic drag) + backpressure (induced drag). that's a fact. the problem that i see is that ArmA's effects happen at too early an airspeed, and too early a backpressure, in addition to there being not enough excess thrust (on maximum settings) to combat it.

by the way, this happens with ALL ArmA's planes, from the Su34 to the Camel. it's an overall problem, not just related to the A-10.

[hailstorm 4]

bumping.

I am afraid something deeper in flight dynamics calculations is done wrong, perhaps too high AoA in turns, or too strong drag as a result of AoA.

i don't think the AoA gets to big, to be honest, but it does need a lot more stability. the drag issue is probably true, but without actually seeing the value in the code it's hard to tell exactly how much. it might be that the value is correct but the thrust value is wrong.

[mattxr 9]

If you pull the stick of an excraft fully to the right, you are bound to pull some serious G and loose speed. I think ArmA potrays this perfect, and the AI seems to get along fine also..

i have no problems, i could make a million and 1 videos of how to turn in a plane for arma but its easy as eating cake soo.

[hailstorm 4]

If you pull the stick of an excraft fully to the right, you are bound to pull some serious G and loose speed.

at high initial speed, yes.

at low initial speed and at full power? no. there is no way that can happen - and that's what i want changed.

i'm not saying i don't know how to fly the ArmA planes, i'm just saying that currently it's not a real representation of flight dynamics through the whole speed range.

Bugtracker Listing 0002789

[subs17 9]

If you pull the stick of an excraft fully to the right, you are bound to pull some serious G and loose speed. I think ArmA potrays this perfect, and the AI seems to get along fine also..

i have no problems, i could make a million and 1 videos of how to turn in a plane for arma but its easy as eating cake soo.  

All you are doing when you pull the stick to the right is an aileron roll to the right...hardly any g compared to a turn at max g on corner speed. Hailstorm is right the FM(and avionics) needs alot of work before it could be considered to be a fair representation of the aircraft and how it is used in the battlefield. Other things I don't like are the sluggish responses to joystick input which doesn't allow for precise aiming whilst straffing. BTW remember when you mention thrust that the A-10 and SU34 both have 2 engines. I also think that its probably a good idea to get a real A-10 pilot to assist in making it closer to the real deal. There is a few A-10 pilots on the internet if you look in the right places.

[max power 21]

i think everyone needs to realise something - stalling an aircraft is not related to speed in any way - it is related to the angle of attack the wing makes with it's relative airflow - namely, if it exceeds 16 degrees. the reason everyone assumes it has to do with speed is that when flying slow the relative airflow will angle to this amount, and further if the plane keeps slowing down.

Planform AoA and stall speed is quite related to airspeed, and the stall angle relates the design of the aerofoil. You're overstating your point and neglecting some very important facts in order to make your argument. I think a better statement would be that aircraft, under the right circumstances, can be made to stall at any speed by manipulating their angle of attack.

[frederf 0]

A stall is, by what I remember, is strictly by definition a delamination of airflow over the wings. An airplane going slowly through the air with a high AoA is the classic version of the stall, but pulling a 3000 G turn is another way to stall an airplane wing (known as a performance stall). A stall is asking the air to stick around the wing and the air not doing that, airspeed and AoA playing the key roles in the stall/no-stall condition.

Funnily enough, the faster the air is going over the wings, the less it will tolerate a high AoA before delaminating (or stalling). Think of sticking your hand over the side of a speed boat. Going slow and with your hand surface parallel with the direction of the water's movement, the water flows and conforms to your hand just fine. At a higher speed tilting your hand can cause an air cavity to form behind your hand. The higher the speed the less you have to tilt your hand to make the cavity.

As far as I know it's impossible to stall an airplane wing that's say falling and pointing straight down at a really slow speed since the AoA is zero, as an odd example.

Most aircraft respond with a noticeable nose drop when in a straight ahead stall. This is because the plane's center of lift is aft of the center of gravity and therefore it's "nose heavy." Most horizontal stabilizers / elevators on such aircraft are designed to provide negative lift to push the tail down and nose up in normal flight. I'd bet dollars to donuts that the horizontal stabilizer of the real A-10 stalls just a smidgen before the main wings do.

[NoRailgunner 0]

FYI - Stall and Spin Awareness

..maybe some "real" simulated blackouts and redouts are possible too?