J Rollon's Mentor

[scotchegg 4,168]

Very interested in this. Any comments from people who own it?

 

http://www.x-aviation.com/catalog/beechcraft-mentor-t34c-p-60.html

[Old_As_Dirt 160]

Looks great - except for the tires that run flat on the pavement!

[anthony_d 32]

I must get my eyes fixed, I thought for a moment the title said j_comm's mentor!

[pryoski 84]

Looks great - except for the tires that run flat on the pavement!

I believe there's a way to fix that in plane maker. Something about terrain elevation corrections if I recall and mapping runways to terrain ... but I haven't the foggiest where that information is!

[Old_As_Dirt 160]

Used to fix it in FSX with "contact points" in .cfg. Thought those days were over!

[scotchegg 4,168]

Really not sure. Looks great but then again it seems to be an update of a model originally made in 2010? $30 seems a bit steep.

 

Maybe if it gets discounted...

[Phantom88 3,284]

I have it and like it,It's one of the most beautifully aircraft done texture wise,It's not really in depth system wise as it's getting a little dated.But it's a very nice aircraft.

[scotchegg 4,168]

Couldn't resist it any more so bought it last night. Only to wake up this morning and find the B25 I'd been waiting for had just been released :angry: :lol:

 

Great little plane texture wise - the cockpit reflections are great and really help the immersion.

 

However I'm finding it a real pain to trim. Even at lower power settings with fuel in the right tank only and trim for right wing down, it's still rolling to the left! Is that normal?

[LAdamson 240]

However I'm finding it a real pain to trim. Even at lower power settings with fuel in the right tank only and trim for right wing down, it's still rolling to the left! Is that normal?

Of course it isn't normal.....

 

Just an X-Plane physics problem. Torque is present, but X-Plane doesn't deal with forces to override it.

 

I don't even own this one. Have not flown the real one either. Haven't even looked up real pilot reports.

It's just that with a multitude of pilot reports for so many aircraft, that I've read in the last three months.......and not one reference of support for actual "trim, trim, trim, torque roll".........I can say with 100% thought, that no, it's not normal.

 

As far as I'm concerned, X-Plane has formed a new generation of piloting thoughts. It's wrong though...

And, I hope the B-25 does all right. Just spent a few hours looking up pilot reports on that one. Watched a good pre-flight and takeoff video too. Nothing about intense torque. Just rudder.

[Murmur 3,941]

Just an X-Plane physics problem. Torque is present, but X-Plane doesn't deal with forces to override it.

 

Torque is present, but real aircrafts always use various devices to counter it: engine cant, differential wing incidence, etc. So the right question is: has the aircraft author tweaked the flight model to account for those effects?

[maple-syrup 40]

It's a really fun plane to fly! I've had it for a while now and I really enjoy taking it for a spin every so often. It's a wonderful plane for both beginners and experienced flyers.

[LAdamson 240]

Torque is present, but real aircrafts always use various devices to counter it: engine cant, differential wing incidence, etc. So the right question is: has the aircraft author tweaked the flight model to account for those effects?

It's certainly my impression, that the X-Plane program itself, isn't sufficent enough, to use engine cant, or the force of prop wash, as well as lift itself.........to overcome the torque. So, you use the "torque fix", to lower the torque values, or hidden aileron settings & varying wing incidences to counter the problem.

 

Or, you just fall into the belief, that this is how real airplanes fly, and that I don't have a notion of what I've been complaining about. But then you have to wonder. Would real airplane manufactures just expect you to use drag forming aileron trims, just to save some dollars on counter rotating engines for twins, or contra rotating props for singles? Would you really want to leave the runway, and have the plane seriously dip its wing on every takeoff?

 

We can feel the need for rudder on takeoff, to remain on the runway's centerline. We can feel the need for aileron to counter cross winds. How do we judge a torque value that wants to roll the airplane the second we leave the runway? Thank goodness, in real life, we don't have too.

 

edit: One more observation. I've experienced plenty of torque on the takeoff roll. Usually with a touch and go. The left wheel really pushes down on the pavement. You can see it and feel it. But if it continued at rotation time, I'd say holy crap and abort the takeoff. BTW-- since I have not tried the particular airplane, that this thread addresses........I don't know what effects are actually present, or how strong they are.

[jcomm 5,890]

I've actually given up on the "torque fix".

 

It's a very interesting way of fixing whatever is causing that overdone rolling moment on prop aircraft in X-Plane 10, but it doesn't come without side effects, and those side effects reflect themselves on aircraft preformance. Affecting the torque output will turn your aircraft into a rather different one, and if it's a carefully designed model, trying to nail the performance down to the real counterpart figures, that is going to have an impact, and that impact is certainly bigger than the consequences of setting aileron trim manually or, using what I have restarted to use - artificial stability.

 

On one of my preferred twins - the Mu2-J - I decided to use the artificial stability section of Plane-Maker to successfuly set the parameters that allow me to fly the model using what I think should be plausible control inputs, without having to constantly set aileron trim.

 

I am using this same approach with all of the prop aircraft.

 

Strangely the default C172 behaves in as far as that rolling moment goes, better than my reference in FSX, which is the A2A C172. As I pointed out at another thread, the A2A crew which flies two of those for real, confirmed in their forums that the model really has that rolling moment due to engine torque effects, as well as the yaw of course, but that in fact the roll is more pronnounced than the yaw!

 

They ( A2A ) are still fine tuning their prop effects routines that run outside of FSX to override FSX's prop effects based only on torque and p-factor, and not taking into account any spiraling slipstream effects, which A2A is trying to model externally.

 

Asymmetric slipstream effects over the root of the left wing on a CW single prop in X-Plane are evident when we enable the flight model view mode ( CTRL-M ). X-Plane is clearly ahead of FSX in this area and it just needs further tunning from Austin to take into account whatever compensates torque in RL.

 

I will gladly explain my art stab settings for the MU2J to anyone willing to try it.

 

Attached my current settings. The 0.15 on "fraction deflection per degree" can easily be increased to 0.25...  (click on the image to see the whole menu)

[scotchegg 4,168]

After getting used to it it's not as bad as I first thought. I have no idea if it's realistic but it's actually kind of fun having to think more carefully about fuel allocation and making regular trim adjustments. More involving...

[LAdamson 240]

Strangely the default C172 behaves in as far as that rolling moment goes, better than my reference in FSX, which is the A2A C172. As I pointed out at another thread, the A2A crew which flies two of those for real, confirmed in their forums that the model really has that rolling moment due to engine torque effects, as well as the yaw of course, but that in fact the roll is more pronnounced than the yaw!

When we read these lines, we can certainly begin making some conclusions. But "roll" in a Cessna 172, more pronounced than "yaw"???

 

If that's so, then something is out of wack, rigging wise. Flight instructors will have to start warning students about yanking the yoke to the right, instead of worrying about the right foot on the rudder pedal.

 

One can read a multitude of text on the internet, in which torque is described as nothing to worry about, in these small GA Pipers, Cessnas, etc. The effect is just to small. I've personally flew all of these small Pipers and Cessnas to also know that the effect is just to little to even think about.

 

On a side note: I've developed my mini "non wind tunnel" to check the effects of torque. I was holding a small electric powered R/C plane, with a tube fusealage, lightly with two fingers, as a four way gimbal. With the prop turning clockwise from behind, the plane easily wanted to rotate to the left from torque. With no wind, except prop wash over the wing, it would roll and roll, if it could. The torque effect is certainly strong enough. When I applied left rudder, the airplane actually righted itself to level. This is soley from the prop wash hitting the left side of the deflected rudder. In flight, since this little plane has no ailerons, left rudder will actually roll the plane to the left, since it uses dihedral to initiate a bank with rudder. But.........with no added airflow over the wing in a static condition, it's now the opposite, with left rudder rolling the plane right.

 

My scientific conclusion :smile: The vertical tail and rudder, are overpowering "torque", with prop wash. Even though torque is enough to easily roll the plane, once we add some other forces, it's overrun. And we haven't even added the lift of the wing, yet. In flight, this prop wash, as a slip stream, will be hitting the top of the right wing, the bottom of the left, and left side of the vertical tail. In addition to lift on the wing, these forces will be offsetting torque, that just the slip stream hitting left rudder, was doing itself.