rudder issue on take off roll and very intensive left turn tendency duration all legs of flight

[CubPilot]

Hi

I am having this issue of rudder is ineffective during take off roll and plane always weather-cock. During climb and cruise left turn tendency is way too high.

I tried to capture these problems in following videos.

One can see that at 12:23 aileron is neutral but plane keep turning left at very high bank angle.

I have also captured some of reference data related to aileron, rudder and elevator for reference.

Plus difference in ground traction  between grass and tarmac is huge, more than 2000 rpm is required to very slowly move along grass but on tarmac this is way too much power for normal taxi.

I tried to open account in discord but it is very temperamental.

Ps. First try at Qamdo Bamda Airport (BPX) in the mountains of Tibet didn't work, (I chose that to practice take off roll as it has longest run way in world but may be altitude of this airport is way to high for this a/c limit and so it was quite under power) so I decided to try it out at Heathrow.

I watched few videos of real plane and either pilot is way too adept pilot or in RL weathercock effect is not that intense.

Now I have seen Graham from ReflectedReality youtube channel (in fact inspired by his video I bought this aircraft) and he had no difficulty at all, also he mentioned about rudder trim I don't think this plan has rudder trim. I wonder is there any settings to fine tune this effect???

I use MFG Crosswind V2 rudder pedals also tried, Thrusmaster T20 Sidestick twist axis for rudder but no luck. 

I think I have latest version of this aircraft as I bought it in 2021 ( so must have update 1.02)  

 

 

 

 

[Uncle Jack Simulations]

Hey there, CubPilot!

From what I could see, it seems to me you are trying to steer the aircraft while its tailwheel is unlocked. The PT-19 has this tailwheel locking mechanism, which may seem odd at first, but a breeze once you get the hang of it. Too much rudder input will cause the tailwheel to "snap" out of its locked position and will free castor. This is useful for tight turns on the ground, but it makes everything else pretty much impossible. To lock the tailwheel back in its place, you must first bring it under its "lockable amplitude" (which means it must not be too far left or too far right from the center of the rudder), and then push the stick back in order for the locking mechanism to work. You'll hear an audible, metallic "clank" when locking occurs. After this, taxiing the aircraft should be done with moderate rudder input if you don't wish to unlock it again. Using differential braking makes this a lot easier, even though it seems very hard at first!

If you don't want to deal with this, you can simply go to the 3D menu and select to have the tailwheel always locked. This will make the PT-19 behave just like any other addon you're familiar with, and the tailwheel will never be unlocked again. This is a convenience feature.

About imbalances: If the aircraft is fully repaired and functional, one thing that often takes pilots by surprise is the fact that fuel tank management must be done manually. The aircraft has 4 fuel tank selector positions: 2 Both OFF, Left and Right. After about 15 minutes of flight or whenever applicable, you should manually change the fuel tank switch position to the other tank, as it may become out of balance otherwise. Other than that, the PT-19's flight model does take into account the natural yaw tendency of the real aircraft. This means that, even if perfectly balanced and trimmed (elevator trimmed), you must always give it a little rudder input here and there in order to have a smooth flight. Flying this antique aircraft requires way more hand-feet coordination than modern GA aircraft, but it is a worthwhile endeavour!

And finally about grass vs pavement performance... This is a known issue with how X-Plane sees grass and pavement. Unfortunately, the PT-19 does require more RPM than it should in order to start moving on grass, and extensive testing show that it does require about 150-200 more RPM than it should in order to break inertia and start rolling. The PT-19 in real life does behave like this on grass, but not to THAT extent. Unfortunately, this is a limitation on the simulator's end and how it "sees" the ground friction values, and changing this behaviour would break the accuracy of the aircraft's landing performance.

 

I hope this helps you somehow! Please feel free to follow up with questions or comments!

Respectfully,

Dan.

Edited November 9, 2021 by Uncle Jack Simulations