Rudder and Nose Wheel out of sync?

[Tom_G_2010]

I fly mostly GA aircraft so, of course, my rudder pedals control both the rudder and the nose wheel. On some aircraft I'm finding that the two seem out of sync. With the pedals centered (I checked this physically on my pedals, visually in the 3d cockpit, and the calibration values in FSUIPC seem to agree) the planes rudder shows centered, but while taxing (with winds calm) the plane is pulling to one side quite a bit and I have to kick in a fair amount of rudder to taxi straight.

Is it possible to get separate calibration for each function? Could I assign both the rudder and the tiller function to the same axis and calibrate each differently?

[Pete Dowson]

I fly mostly GA aircraft so, of course, my rudder pedals control both the rudder and the nose wheel. On some aircraft I'm finding that the two seem out of sync. With the pedals centered (I checked this physically on my pedals, visually in the 3d cockpit, and the calibration values in FSUIPC seem to agree) the planes rudder shows centered, but while taxing (with winds calm) the plane is pulling to one side quite a bit and I have to kick in a fair amount of rudder to taxi straight.

Sounds like normal prop wash effect -- this increases with prop RPM. When I was flying in a real Cessna 152 i was surprised how much rudder you need and not just for countering wind effects. The prop effectively creates a crosswind pressure on the tailfin because of its rotation. You can reduce these effects (propwash and torque) quite substantially in the FS aircraft realism settings. For light GA aircraft like the Cessna I found the centre values best for more of those settings.

Is it possible to get separate calibration for each function? Could I assign both the rudder and the tiller function to the same axis and calibrate each differently?

FSUIPC supplies a separate assignment and calibration option for a steering tiller axis. You'd need a separate axis for the tiller. maybe a separate lever on your quadrant?

The only alternative is to use the "slopes" facility in FSUIPC to flatter the response near centre, to give your rudder control nice gentle effects in the normal flying range but with really effective angles when pressed firmly. But this is really what you say you are needing to do in any case.

Regards

Pete

[Fritz]

FSUIPC supplies a separate assignment and calibration option for a steering tiller axis. You'd need a separate axis for the tiller. maybe a separate lever on your quadrant?

But you always controls nose wheel and rudder together. Not separated.

[Pete Dowson]

But you always controls nose wheel and rudder together. Not separated.

Yes. So?

I naturally assumed that the inquirer was wanting a different calibration for operating the nose wheel -- i.e. steering on the ground -- to that used for rudder operation at higher speeds. If both rudder and tiller are assigned in FSUIPC "direct to calibration" then FSUIPC gradually switches control from the tiller input to the rudder input as speed increases between 0 and 60 knots (defalut setting), and vice versa on slowing down after landing.

Pete

[Fritz]

That does not sound bad but how does FSUIPC distinguishes between the rudder and tiller?

[Tom_G_2010]

Peter,

Thanks for the info. Until yesterday it had been 29 years (to the day) since I logged my last hour in the left seat. I'm another one who started but never finished their Private Pilot's license. Yesterday, as a birthday gift my wife booked me an hour in a 172SP with a CFI. Having gotten back in a real plane yesterday much about control reaction, feel. and feedback, including rudder feel and action while taxiing have come back to me. As you suggest I think much of what I'm feeling is prop wash and perhaps some less than convenient winds.

After yesterday I am am convinced of a couple things:1. I will be looking for the cash to finish my pilots license; 2. For any Sim pilots who've never been in the left seat for real, an hour or two with a CFI in a real plane will make a HUGE difference in how they configure and use their SIM. Yesterday now has me thinking about Force Feedback for my flight controls and how to further enhance the out the window view so I can reduce my tendency to overuse of instruments. Of course the new twist is how to do that without taking cash away from my new Private Pilot's fund...

I do think a couple of my planes have less than realistic modeling related to rudder and nose wheel interaction and you've given me an idea of how I might deal with it. I'll be adding a second potentiometer to my rudder pedals (the advantage of DIY flight controls) to allow for splitting of the function/calibration where needed while still maintaining the realizm of sterring from the pedals.

Tom G.

[Pete Dowson]

That does not sound bad but how does FSUIPC distinguishes between the rudder and tiller?

Different axes assigned "Direct to FSUIPC calibration" via FSUIPC's Axis Assignments dialogue.

Pete

[Pete Dowson]

I'll be adding a second potentiometer to my rudder pedals (the advantage of DIY flight controls) to allow for splitting of the function/calibration where needed while still maintaining the realizm of sterring from the pedals.

Actually there's one easier way you could try first. I never thought of it before, but with the one rudder pedal input, in FSUIPC's axis assignments, select "Direct to FSUIPC calibration", then assign the axis to both Rudder AND Steering Tiller in the first two assignment dropdowns below. You should then be able to calibrate them separately. FSUIPC will gradually switch between the two calibrations as you accelerate or decelerate, and it might feel rather odd, but it should be gentle enough to cope with. Worth a try, anyway, and really not much different to using two pots on the same physical axis when really you want a separate lever for each. (I use a steering tiller by my left hand in my 737NG cockpit). If you do add a "steering" pot, best make it a more sensitive (i.e. lower impedence? I think) one, or possibly a log-type rather than linear so you can get that fiercer correction with less pressure. You'd need to experiement.

Regards

Pete

[Tom_G_2010]

Great, that's much simpler than adding a second pot. I'll be doing some experimentation with that to see what it does.

Any chance the transition threshold between the tiller and rudder is something that I could get at to tweak as a parameter someplace?

[Pete Dowson]

Any chance the transition threshold between the tiller and rudder is something that I could get at to tweak as a parameter someplace?

The maximum tiller speed is a parameter, defaulting to 60 knots. This isn't a sudden changeover though. At 0 knots it's 100% tiller 0% rudder. At 30 it's 50:50. at 60 and over, or off the ground at any speed, its 100% rudder 0% tiller.

Pete