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sdflyer

CH rudder directional control

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Hi,

Just wonder if anyone else having directional control with CH rudder pedals during the take off? It seems like TDM 900 has a bit oversensitive rudder input during  take off roll and veering left and right - very hard tp stabilize.

I have flown similar airplane size real life and can't remember a such a bit erratic behavior. Perhaps it's my hardware that has to be tweaked?

 

Thanks!

 

P.S. Awesome airplane, superb system modeling!

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Same thing here... I don't use X-Plane much so I thought it was just me. Even setting the augmentation/sensitivity to 100% doesn't help much.

1 minute ago, sdflyer said:

Hi,

Just wonder if anyone else having directional control with CH rudder pedals during the take off? It seems like TDM 900 has a bit oversensitive rudder input during  take off roll and veering left and right - very hard tp stabilize.

I have flown similar airplane size real life and can't remember a such a bit erratic behavior. Perhaps it's my hardware that has to be tweaked?

 

Thanks!

 

P.S. Awesome airplane, superb system modeling!

 

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I did couple tests, I think a rudder authority it too great on take off. In real life rudders designed to be pretty stiff (unless it’s aerobatic airplane ). I pretty sure developers can tweak it

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Yes, it is definitely way too twitchy on takeoff and landing roll.  Granted, the X-Plane prop wash weirdness doesn't help; but compared to similar aircraft, the TBM is extremely touchy with power applied.  Taxis and flies great though... I absolutely love the prop beta range implementation.

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What I've been doing is on the MFD, there's an indication of your trim settings. I ensure that the elevator trim is set on the green notch. Then I ensure rudder trim is set on the green notch. It takes a lot of right rudder trim. Once those are set, the takeoff roll is pretty stable. Just have to apply very minor rudder input to track the centerline.

Edited by xterminator24
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29 minutes ago, xterminator24 said:

What I've been doing is on the MFD, there's an indication of your trim settings. I ensure that the elevator trim is set on the green notch. Then I ensure rudder trim is set on the green notch. It takes a lot of right rudder trim. Once those are set, the takeoff roll is pretty stable. Just have to apply very minor rudder input to track the centerline.

I'm doing exactly that and it's still nearly impossible to control. I've almost gone off the runway on nearly every take off. What hardware are you using?

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12 minutes ago, AirBadger said:

I'm doing exactly that and it's still nearly impossible to control. I've almost gone off the runway on nearly every take off. What hardware are you using?

I've got MFG Crosswind rudder pedals. Sensitivity on Yaw is set to 5%. Closer to the left you are, the more linear control you have. I always found that when I move those sliders to the right, I start having to make larger control inputs and find it harder to control. It is sensitive and could most likely be tuned but I've watched a number of Twitch streams with planes moving all over the runway and they didn't add any rudder trim before takeoff roll.

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1 hour ago, xterminator24 said:

What I've been doing is on the MFD, there's an indication of your trim settings. I ensure that the elevator trim is set on the green notch. Then I ensure rudder trim is set on the green notch. It takes a lot of right rudder trim. Once those are set, the takeoff roll is pretty stable. Just have to apply very minor rudder input to track the centerline.

In the doc you will find the recommendation for ruddertrim: Trim right betwenn the blue and green mark for take off. That will help.

 

Peter

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While trimming right rudder for takeoff definitely helps for a normal departure, it will aggravate the yaw over-sensitivity even more if the takeoff needs to be aborted.  Cutting power on the roll will quickly result in S-turns across the runway (if not into the grass)... adding some reverse thrust into the mix will make it even more "exciting".  I have not had the pleasure of trying out the MFG Crosswind pedals; but I feel pretty confident that they are orders of magnitude better than CH pedals when it comes to precise control inputs.  Setting a (nearly) linear control response with the CH pedals is just a bad idea under any circumstance (full right slider for the win :-)).

Speaking of trim... has anybody noticed any issues with elevator trim?  Setting recommended takeoff trim results in a pretty pronounced nose up tendency after rotation. Flying a standard 3 degree ILS glideslope with full flaps requires over 90% nose-down trim to stabilize.  Seems like it could also benefit from a little fine-tuning.

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I believe the real counterpart is very stable IFR platform. So yes it feels like airplane require tweaking with static stability

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2 hours ago, wodyfox said:

In the doc you will find the recommendation for ruddertrim: Trim right betwenn the blue and green mark for take off. That will help.

 

Peter

Peter it's not a trimmer issue but a directional stability. If you don'y trim airplane correctly  for take off, you would have problem with either elevator or rudder authority. This is not the case. What most of us struggle  with is  stability control  - meaning aircraft constantly overact on rudder input during take off roll . 

Actually in this sense TDM behavior it reminds me call "V1 cut " in twin engine aircraft. It happens when during take off roll one engine get shut down before liftoff  and aircraft looses discretional control instantly. To stabilize it requires swift rudder work as well as promptly cutting thrust of remaining "good" engine.

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I still struggle with directional control whether I land or take off. Sloping runway or crosswind condition are really screwing things up.

Now I'm thinking that rudder sensitivity during take/landing or in flight should have been reduced. Does anyone come up with some tweak for CH rudder?  

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Not sure if it's too touchy or if there's a small time lag between input (pedals) and reaction (aircraft), which can lead to over controlling because the pilot pushes the rudder even further because the plane seemingly doesn't seem to react immediatly,  and then it just get's worse as one tries to counter the initial over controlling and the ocillation just snowballs until you're all over the place.  :D

I've learned to be more careful and developed a little muscle memory keeping the lag in mind. Not saying it is a lag, but at least that's how it feels to me. By being aware of it , it has helped me stay on track and not over-react. But unless the real aircraft behaves this way then I think there's room for improvement in this department. Less squirrely would be nice.

Edited by scarp

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Well LOL I have to fight leg  my muscle memory a lot with sim flight. The closest aircraft I put my hands on in real life was Piper Malibu PA-46-500TP and it was nothing like TBM 900 on take off roll. Of course real rudders are not CH but I get by with other AC no problem

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On 10/21/2018 at 1:09 PM, WaarEagle said:

While trimming right rudder for takeoff definitely helps for a normal departure, it will aggravate the yaw over-sensitivity even more if the takeoff needs to be aborted.  Cutting power on the roll will quickly result in S-turns across the runway (if not into the grass)... adding some reverse thrust into the mix will make it even more "exciting".  I have not had the pleasure of trying out the MFG Crosswind pedals; but I feel pretty confident that they are orders of magnitude better than CH pedals when it comes to precise control inputs.  Setting a (nearly) linear control response with the CH pedals is just a bad idea under any circumstance (full right slider for the win :-)).

Speaking of trim... has anybody noticed any issues with elevator trim?  Setting recommended takeoff trim results in a pretty pronounced nose up tendency after rotation. Flying a standard 3 degree ILS glideslope with full flaps requires over 90% nose-down trim to stabilize.  Seems like it could also benefit from a little fine-tuning.

I must agree that the MFG's are a world above anything I have flown with in almost 30 years of simulation. They mimic the real world better than anything I have put my feet on. I have used the CH pedal and Saitek Pros, all good, but, MFG gives you the sense and feel of RW flying. Now before I get yelled at for recommending such high priced pedals, it's all in what you want from your simulator. And yes, they are not cheap - about the cost of two sets of decent pedals. You can "tweak" better performance out of CH and Saitek, but due to design they are limited to what you will get. 

Edited by dvlourie

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I disabled the simulate control stiffening at high airspeed in the airframe manager, and I gain much control on the rudder with full throttle at T/O.

Hope it will help some guys here.

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15 hours ago, danhenri said:

I disabled the simulate control stiffening at high airspeed in the airframe manager, and I gain much control on the rudder with full throttle at T/O.

You shouldn't do this unless you have force-feedback flight controls, as it will make the aircraft extremely sensitive at high speeds.

We are working on some improvements for the rudder handling on the takeoff and landing roll. However, it is important to follow these crucial steps:

  1. Keep your inputs small and quick. Big and slow inputs will just make you zig-zag across the runway.
  2. Predict required rudder inputs, don't just react. If you are waiting until you are through the centerline before adjusting your inputs, then you are waiting too long.
  3. ALWAYS put aileron inputs into the wind. On a 20 knot crosswind, you can require as much as 2/3 aileron input into the wind to keep the upwind wing from lifting.
  4. Trim properly. On takeoff, pitch trim in the green band and rudder in between the white and green marks (depending on aircraft weight, the heavier, the closer to the green mark). On landing, rudder and aileron trim should be neutral
  5. On crosswind landings consider using the wing-low/sideslip landing technique, instead of the crab & kick-over technique. This allows you to get used to the inputs before you get down to the runway.

Quick demonstration video of some testing I did with the adjusted crosswind handling. The wind was set 10 knots higher than the maximum demonstrated crosswind value for the TBM and the aircraft was very light, so pretty much worst-case scenario.

 

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Thank you very much for all these advices that I will try to put in practice. 

I'm getting also much better results by following the recommendations of Daher's POH, avoiding to increase ou decrease too rapidly the power on take-off and landing.  Actually, the problem comes in large part from the CH Pro pedals, that do not move like in a real plane (I am a private pilote in real life) : they oppose much less resistance when moved from one side to the other, so that light planes are much more difficult to control in XP than in reality (except when flying a tail dragger like the Piper Cub !).

I thought I got an issue with the simulate control at high speed, because I had to make large movements of my joystick to change the aircraft's attitude. I recalibrated my joystick, set all sensitivity controls to 0 and after some tests, it's really a very nice pleasure to fly your plane. 

After many other guys here, I am very grateful to you for your creativeness, your support and reactivity.

Edited by danhenri
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last night I did some experiments with my CH pedal, by previous yaw sensitivity setting is 100% which works good with most of XP planes. but not TBM.

I tried %0, %10, %20, %30, %50, %100 those sensitivity settings, finally I found < 50% will dramatically  ease your high speed ground handling.

my testing steps:

1. advance my throttle smoothly, keep ~30% TRQ, wait for air indication speed alive

2.  when speed is around 50knots, I cancel my throttle to flight idle, then taxi range, then reverse range gently.

roughly I can follow a long straight line. finally I select 10% yaw sensitivity setting for this TBM. hope it works on your side  

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I also get by with similar take offs as shown on the video for now. But  in the real life  it definitely would  be a good reason terminate take off immediately. Runway centerline is a must unless of course there is  heavy gusty crosswind or desire to destroy runway edge lights :)

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I did two hours of touch and go's last night in the hopes of memorizing the rudder "feel" for this wonderful plane in X-Plane. Unfortunately I struggled each time on the take-off part. The slightest touch on the rudder pedal required another (lesser) counter touch and within a couple of seconds I was zigzagging. By the end of my two hour session I hadn't got any better.

I don't have this problem in any other add-on.

I don't have the 11.3 beta where I believe there is a sensitivity control and curve option, but I feel that will solve this rudder issue for me at least.

 

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Leinsters , there are ways to modify the behaviour of your control axis .

If you already know or tried this, ignore what follows.

Open the main Laminar Configuration window , open the  joystick window , open the control sensitivity window . Slide the yaw control response slider all the way to the left . This gives linear control to the rudder . Move your rudder pedals a little bit results in a little bit of rudder movement.  Try a take off/landing . If this is not enough try sliding the yaw stability augmentation slider to the right as well .

I ended up with the control response sliders all the way to the left for all axis., yaw, pitch ,roll. 

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