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Von Target

Here's the TOOOOOOOOOOOOOOOOORQUE!

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Eheh... :Silly:

 

http://www.youtube.com/watch?v=bsuFUZ-S7Is

 

In this movie, I can see pretty much what are my usual inputs in the LES Sundowner, on takeoff, on a go-around... etc...

 

Just look at the yoke and see how, svereal times during climb, go-around, the pilot has to input right yoke to keep wings straight... And... the way things happen, even taking into consideration some turbulence / wind.. are consistent with him countering torque from the engine / prop, IMO...

 

Actually, if you observe carefully, sometimes he makes his inputs a little bit late, and the aircraft starts banking to the left...

 

Or... is it because that pilot is really fat?

 

Does X-Plane model Torque or Fat effects? 

 

Maybe both?

 

And... my new RealAir has lot's of torque too ( has to be tunned down in the FM realism settings according to the manual...), the A2A C172 has it too, very intense - worse than the default C172 in X-plane...

 

I even had lot's of torque effects on my last glider flight !!!! Yes, had to use a LOT of left manche to counter it :-)

 

 

:Cry:

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My only comment is..........I must have missed the torque.

As to RealAir, do I need to find my old controls, and plug them in again? Otherwise, being a non-current flight simmer, I can't comment. I don't remember the RealAirs torquing to the left, even at 100% instead of 50. Never the less, a Sundowner won't be rolling to the left. If so, you'd see a nice left wing dip, at rotation.

 

edit: To expand on this thought, I don't think some people realize how much torque effect there can be on a takeoff roll......if it's a high power, low airspeed situation such as some touch and goes. You can litterly feel the push against the left wheel on the runway, and you'll be countering that with right aileron. For normal takeoffs, you usually won't see and feel that effect. Never the less, once those wings are airborne, the torque/roll effect, has been overcome by more powerful forces........unless it's truely a case of high power & low airspeed, as is seen with high powered military applications, for go arounds.

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I liked the video, nice find.

 

But I for one can't see him counter an excessive left roll like seen in XP.

 

So I would still suggest there's something not fully modelled in XP's FDM.

Don't want to blame Austin here. Not an easy task for sure to get everything close to 100% correctly modelled.

 

I accepted the fact that I need aileron trim in XP to fly comfortably and in PlaneMaker I add a little bit of artificial stability to make the trimming easier and quicker. And I set up custom ROG's to retain what makes the aircraft feel realistic to me.

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FWIW.  ...take what you will from it.  Note copilots left hand when he flies...most of the time when he moves it down......he's adjusting trim.  MU2 a busy plane to fly.

 

TK

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I think the main issue is with the user controllers. The same happens with Racing Simulators.

 

I used to use a Logitech Drive GT, which had the movement of 90 degrees to each side, totaling 180 degrees of movement. Not even close to a real car. So I would have to make minor corrections for the car to turn medium corners. Then I got a Logitech G27, with total range of 900 degrees!! Totally different feel. You have so much more control and precision over the car.

 

Until Saitek, or other not so expensive brand start making Yoke with some real control range, 90 degrees each side, and forward and backward motion much greater than what they do now, we will always have this issue of proper control of the airplane.

 

Although, from the video Jcomm posted, I noticed very very little movement required to keep the aircraft from rolling. In X-Plane we seem to need much more than that, as other user has already confirmed.

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Here's the POH of the Rutan Varieze:

 

http://www.ez.org/downloads/varieze_poh.pdf

 

Page 7, "Trim Systems": "Roll trim is available to offset trim changes due to engine power"

 

Page 15, "Descent": "You will need to reset roll trim for the descent when power is reduced"

 

However the Varieze is a canard with push prop, so propwash does not hit wings, fuselage and tailfin and there may be more roll due to torque compared to a Cessna etc.

 

But the interesting thing is, on X-Plane.org there was a Varieze pilot saying he noticed no roll tendency on power changes.

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Yes Murmur,

 

and in X-Plane 10 it really makes a difference when fying a pusher!!! A lot more roll due to torque, which is consistent, and supoorts that X-plane 10 already accounts for the slipstream / propwash effects on aircraft surfaces, and it probably just needs some adjustments in this particular area...

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Hi Jcomm.

I know you are a fan, as am I, of Denker's "See How it Flies". If I am reading it right (Chapter 9, especally sections 9.5 9.6) these aren't engine torque effects  (as these would only be apparent when altering the throttle) but propellor drag effects. It wounld be interesting to see if these could be reduced as in real life by asymmetrical wing incidence.

 

TIM

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Yes, TIM, you're right, but we tend to mix both effects in what we call the prop troque effects.

 

There's actually that engine torque that should only play it's part when throttle settings are changed ( there's a negative / positive acceleration ...), and the prop "drag" effects, which also play the opposite effect, sometimes called reverse or inverse torque, when you reduce power for a high speed descent and it's the airflowthat "wants" to drive your prop...

 

I believe asymmetric incidence or even airfoil is not used in modern aircarft (?) but rather engine and / or fin cant.

 

In X-plane 10 we can model this as well as an additional method of countering the prop effects, but X-plane's FDM just as it is now needs some additional modeling of effects over aircraft surfaces.

 

It is already accounting for the asymmetric effect of slipstream/ propwash on the wings, and you can see on a prop aircraft with a single engine in the nose, and considering a CW rotating prop, that there is an additional aerodynamic component near the root of the left wing, but it's not yet sufficient to lessen the roll due to torque under most circumstances.

 

I believe e can end up with an "almost perfect" prop model if Austn finds the time to dedicate to this particular aspect of X-Plane's FDM...

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Hi Jcomm.

I know you are a fan, as am I, of Denker's "See How it Flies". If I am reading it right (Chapter 9, especally sections 9.5 9.6) these aren't engine torque effects  (as these would only be apparent when altering the throttle) but propellor drag effects. It wounld be interesting to see if these could be reduced as in real life by asymmetrical wing incidence.

 

TIM

 

Propellor drag is linked to engine torque. The torque produced by the engine is entirely used to overcome the prop drag. But if the engine produces a torque upon the propeller, law of physics state that the propeller produces on the engine (and hence on the entire airframe) an equal and opposite torque.

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Propellor drag is linked to engine torque. The torque produced by the engine is entirely used to overcome the prop drag. But if the engine produces a torque upon the propeller, law of physics state that the propeller produces on the engine (and hence on the entire airframe) an equal and opposite torque.

Easy to see, if you hang an airplane by it's prop, and watch it spin around. Best to do with a small R/C model. Preferably electric......and don't push the throttle too high. Once there is enough air flowing past the wings & flight surfaces, the reaction is totally different. That opposite torque, is now overpowered by other forces. Torque is still there. It just can't do much.

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