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View Full Version : Torque effect on double engine aircrafts [4.02]



gabriele_82
11-24-2005, 03:07 PM
Hi,
Actually on on double engine aircrafts, one engine runs clockwise, the other counter-clockwise. So that the total torque effect is zero (if the two engines run at the same rmps). In the game, however, this is not true, i.e. we have torque effect on double-engine aircrafts. take for examble Bf-110.

I think this is a big mistake that should be corrected.

Daiichidoku
11-24-2005, 03:23 PM
this is an old and well chewed subject, gabby...

especially when twins with same-turning props had as much, or even sometimes less torque than the contra-rotatng P 38


the game was made with the IL2 only in mind, originally, hence the engine was not made with any concessions for lack of torque

there is supposedly absolutly nothing that can be done about it, we will have to wait until BoB come out...no, wait, we will have to wait until BoB comes out and is developed past the time period summer 1940, and contra-rotating prop types are included


besides, doesnt the 110 have same-turning props?

VW-IceFire
11-24-2005, 03:26 PM
Originally posted by gabriele_82:
Hi,
Actually on on double engine aircrafts, one engine runs clockwise, the other counter-clockwise. So that the total torque effect is zero (if the two engines run at the same rmps). In the game, however, this is not true, i.e. we have torque effect on double-engine aircrafts. take for examble Bf-110.

I think this is a big mistake that should be corrected.
Not true...only some aircraft have this feature. Of the WWII twins, the only one I know that has this feature is the P-38 Lightning. The Bf110, B-25, A-20, and other aircraft we have have two identical engines that rotate in the same direction...the P-38 has two engines mirrored and spin in opposite directions.

Contrary to what Daiichidoku said, the 4.01 patch introduced a new FM model that infact now accounts for twin engined aircraft torque and do indeed factor in the P-38's lack of torque.

If you fly a P-38, you will essentially not need rudder trim. The aircraft is completely stable from torque.

An aircraft like the A-20 on the other hand has quite a bit of torque because both engines spin the same way. Ground handling behavior is an instant indicator of this in the FM model.

Kuna15
11-24-2005, 03:27 PM
Every 2-engined user plane in FB has rotating props in the same direction; Beaufighter counterclockwise (both engines) while every other 2-engined plane rotates clockwise.

Exception is P-38 the only one that has counter rotating props and thus negating torque effect (if both engines are running on the same settings).

Daiichidoku
11-24-2005, 03:49 PM
if the 38 has no torque, then why wont it stall correctly, instead of flop one way or another?

danjama
11-24-2005, 03:54 PM
Got Track?(TM)

Daiichidoku
11-24-2005, 11:52 PM
dont need one

go fly a 38 and stall it

if there is really no torque, it should "flat stall", no wing drop

you can even see it taking off...if there is no torque, why does the 38 pull to one side when you give it throttle with both engines selected and running at same rpm's?

im sure the torque effect has been reduced, but not elimated

rnzoli
11-25-2005, 06:39 AM
if there is really no torque, it should "flat stall", no wing drop
The wings are never fully symmetrical in RL, so normally one wing will stall just a little bit earlier. So even with a dead engine, you should have a stall rolling you to one or the other side, instead of dropping both wings at the same time.

WOLFMondo
11-25-2005, 07:00 AM
Originally posted by Daiichidoku:
dont need one

go fly a 38 and stall it

if there is really no torque, it should "flat stall", no wing drop

you can even see it taking off...if there is no torque, why does the 38 pull to one side when you give it throttle with both engines selected and running at same rpm's?

im sure the torque effect has been reduced, but not elimated

Weather. Set the weather to the worst you can then try to land or take off in a really light plane.

Chadburn
11-25-2005, 08:25 AM
To further illustrate the odd behaviour of the P38, kill one of the engines and you'll see that there is no additional torque.

If the two engines cancel each other's torque, then when one dies, you should experience the torque of the remaining engine.

tomtheyak
11-25-2005, 08:47 AM
Originally posted by Chadburn:
To further illustrate the odd behaviour of the P38, kill one of the engines and you'll see that there is no additional torque.

If the two engines cancel each other's torque, then when one dies, you should experience the torque of the remaining engine.

Theres a strange characterstic going on here that I've reported to the bug team at 1C. If you fly a single engine a/c and turn off the motor, you'll find that if the prop windmills you'll get a very strong rotational force in the opposite direction to the direction of torque. I find this a bit suspect...

However, it gets worse.

For when the prop actually stops windmilling (whether jammed or low airspeed) suddenly that mysterious anti-torque force completely disappears, nay, REVERSES and you are suddenly forced to throw the stick around in counteraction.
It gets very tedious when deadstick gliding around the speed at which this change happens; its not always easy to prevent it especially if you're making quick adjustments to make it into a field...

"Hmm, a bit high here, I'll drop the nose and lose some of that alt," speed picks up, prop starts to windmill and *bang!*; sudden reversal in lateral stick force!

I think this is where your no torque on dead engine 38 issue lies - the fact that there is still force acting in the way torque does.

Have to say tho that I tried it myself in a P-38L on NWE map and got full torque effects (i.e crabbing into dead engine that had to be corrected with rudder trim).

F16_Neo
11-25-2005, 09:19 AM
Been wondering about this windmilling stuff...
This is how I *think* this windmill-torque phenomenon works:
Engine running= torque-effect is positive, ie plane want to roll in opposite prop direction. More power, more torque.

Engine windmilling= prop is running in the wind as if the engine got no friction, and plane do not torque.

Engine stops/jams= the windmill effect no longer rotates the prop, instead, torque makes the whole plane want to windmill.

Solution:
Plane-torque while windmilling should take engine friction into the calculation. If the engine stops due to low airspeed, that only means that engine friction force got higher than the windmill force, and no abrupt change in plane-torque should happen in the transition.
Unless, ofcourse, the prop stops due to jamming; then there would be an abrupt torque change. (Jamming= infinite engine friction).
It's simple physics when you think about it, would guess the 1C team didn't bother to pay time/performance for proper windmill-modelling...

vincemagda
11-26-2005, 11:09 PM
I have a problem taking off with the TB-3 in FB v1.22. The aircraft veers off to the right halfway down the runway. All engines are selected and the weather is good. Could it be the torque?

bolillo_loco
11-27-2005, 02:03 AM
Originally posted by rnzoli:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">if there is really no torque, it should "flat stall", no wing drop
The wings are never fully symmetrical in RL, so normally one wing will stall just a little bit earlier. So even with a dead engine, you should have a stall rolling you to one or the other side, instead of dropping both wings at the same time. </div></BLOCKQUOTE>

I suggest reading the pilots manual on this aircraft. In clean condition the aircraft has no tendency to drop a wing when it's stalled; in dirty condition with wheels and flaps extended there is a slight tendency to drop a wing, but at no time does the aircraft fall off into a spin. This is corroborated by much anecdotal pilot evidence both past and present. When you stall a P-38 in this game it usually falls off into a weird end over end flip. This is one easy aircraft to get into a spin considering it had very docile stall characteristics.

IL2-chuter
11-27-2005, 03:26 AM
Most of the planes in the game should have a straight ahead (flat) stall. They should also drop their noses instead of sitting on there asses as if they were grossly aft loaded. The result in the game is more like a snap roll (but a goofy snap roll at that). Best climb and dive speeds are also a bit goofy. The best glide speed for the Jug is 170 knots (loadout makes no difference) or about 190 mph. Compare a glide at this speed with one done at about 120 mph, a speed at which the Jug should be sinking like the Titanic. One of the first things I learned in flight training back in the mid seventies was how the glide slope could be dramatically steepened without picking up the speed caused by dropping the nose. Simply raise the nose a bit and bleed off speed and watch out below. The greater the wing loading the greater the effect.

Um . . . http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif . . . ya, stalls are a wee bit odd.