You THOUGHT you knew how good FB is...

[Zak33]

but its not until Zakky the sick twisted boy decides to play experiments do you really realise

Engine torque...makes the plane twist....right?

Well....the STARTER MOTOR must twist the opposite way.....right? cos it turns the flywheel.

And German and Russian planes engines rotate opposite directions, right?

Well....take a FW190 and a BF 109 and a Yak 3....

trim for level flight.......hit smoke...

cut engine........throttle to zero.....wait for props to stop (except for air movement)

Start Engine....throttle up.....

now as the Starter Motor kicks in the plane rolls the OPPOSITE way to the normal twist because the engine is resisting....AND it does it is "spasms" as the cylinders compress....

Taking the pee...right?

BF109 G6 http://homepage.ntlworld.com/cuppaso...r%20Torque.wmv

FW 190 A9 http://homepage.ntlworld.com/cuppaso...r%20Torque.wmv

Yak 3 http://homepage.ntlworld.com/cuppaso...r%20Torque.wmv


so...next time someone tells you just how good the physics is on their new game.....point them my way

and BE AWARE....no JOYSTICK INPUT AT ALL....not even for recovery....

and that is why Deckard loves the Yak 3......she pulls straight out on her own....

Enjoy

[[MA]DanglyBob]

You definitely need to get out more m8

But yes it's impressive.
Even to the point where you take it for granted really....
Nice to have it pointed out sometimes though.

[Dakaras]

Zak mate you think different to other people never would have worked that out in a million S!

[TiG]

See now all we need to do is move this understanding on one more level, you understand that, and its not that much more of a step to start predicting how to get yourself to a kill point for killing an enemy plane

Its nice to see these thought of threads too.

Thanks matey

TiG

[turkster]

Ok I didnt think most of those planes had starter motors.
I thought they used some kind of cartridge starter?

Also I would have thought that considering the relatively small mass of the starter motor the effect on the plane would be quite minimal?

[MA_Moby]

My understanding of torque is this ~

It is the tendancy of the plane to want to roll in the opposite direction of the rotation of the prop. So, in the instance of the G6, and most planes, the prop swings clockwise (when looking out of the cockpit) so the plane rolls anti-clockwise.

So what about power? Increased RPM will increase the effect.

I've just been playing with this myself in FB. I noticed that even with the engine off, the prop just windmilling, there was a slight tendancy for the G6 to want to roll left when I took my hands off the stick. The wind was turning the prop and the engine slightly, so the plane wanted to roll anti-clockwise. In theory adjusting the pitch should alter this yaw slightly (i think) - though I didn't see any noticable effects when I tried this.

When the starter motor is then engaged, turning the prop more vigourously, there is then a more noticable anti-clockwise roll. Anti-clockwise again, because that's the opposite direction to the way the prop turns. The direction of the starter motor movement doesn't really come into it at all. (bear in mind that the wind is still turning the prop and engine, as well as the starter motor as it kicks in - the combined effects of which are a more powerful influence over the plane than the direction of the starter motor).

Of course, once the engine is started again the slipstream/propwash effect comes into play. This causes yaw to the left, the secondary effect of yaw is roll, which will again be anti-clockwise.

So in my opinion the physics of FB seem to be pretty correct. Though the roll when the prop is windmilling does seem a little exaggerated to me.

I reckon Deckard will be able to put me right on anything I've missed or got wrong

[Nick]

Nah. Moby, you got it all in there I reckon.

I would expect to see a very slight roll effect due to torque resistance with engine off and prop windmilling, purely cos the engine is resisting being pushed around by the prop. The bigger factor would be drag and the direction of airflow caused by the shape of the blades... again, they're both pretty small.

I'm just wondering if the physics modellers ACTUALLY programmed this in or if it is just a side-effect of a detailed physics engine. I can't believe that they thought about air-starts... but if the physics engine deals with torque/relative motion and opposing forces, then the kick of a starter motor would slot in there nicely.

Turkster, you're right, a starter motor is tiny, but its not about relative mass. It about opposing forces and if you factor in the engine resistance plus the force needed to turn a dirty great metal prop as well, thats a fair amount of force acting on the plane. The force needs an equal and opposing force to act against, so the plane rolls.

I'd like to see this in effect at slower speeds where the airflow has less effect on keeping the wings level, that'd really show it up.

ps. You can actually see this in action in real life... when turning of a C152, they ALWAYS drop their right wings a tad in time with the starter.... if you an find a stubborn to start one it becomes really clear.

[MA_Moby]

I'm just wondering if the physics modellers ACTUALLY programmed this in or if it is just a side-effect of a detailed physics engine. I can't believe that they thought about air-starts... but if the physics engine deals with torque/relative motion and opposing forces, then the kick of a starter motor would slot in there nicely.

Yeah - i wondered that too. It could well be the case.