v2.0.1 Update Torque % and Throttle observations.

[XST]

Just observations, not sure if this is right or wrong, using in legacy throttle mode:

1. In flight range, throttle never goes under 40% in lower position and in higher position goes all the way up till Torque % label... 150/160%? is this right?

2. All the way down to 40% again, when sim/engines/reverse_toggle pressed, it sometimes starts under 40% so beta can be handled from 39% torque to 0 with the throttle lever. But sometimes it goes to 0 directly and no way to go through  the beta range.... not found a rule or reason of why this sometimes happen.

I'm not sure but in previous version torque was much lower than 40% just in the limit of the flight to beta range... and not that overpowered in the top high throttle position.

Just observations, I'm not a real pilot so maybe above way is the right way to work.

Thank you for such an amazing progress!

[Bulva]

It is completely broken in this version. Propellers never stay in the "Locks" position after startup.
I tried both with Honneycomb Bravo and without external equipment - there is a bug.

[tkyler]

Quote

In flight range, throttle never goes under 40% in lower position and in higher position goes all the way up till Torque % label... 150/160%? is this right?

The torque does seem a bit high.  I tweaked the prop blade angles slightly to yield a bit more thrust accuracy in the 'taxi regime', but this seems to have affected the torque adversely at flight idle.   Becuase we don't get detailed "prop geometry" information, tweaking the prop / angles is a bit of a empircal process.  Captain Crash has begun tweaking the prop with some flight testing and I expect to keep tweaking these till we converge on well rounded behavior.

As far as the 150/160%,  I can't say I've observed / measures the needle over 120, so unsure the exact representation of the needle position....but the engine is capable of 140% at sea level and does not have any kind of automatic limiting.  It is up to the pilot to keep the power under 100% on takeoff.  I should probably put a virtual stop on the torque gauge at 120.  I don't know if the real one does this because I've never found an MU2 owner willing to push his engine past 100%.  ....and the shops I've talked with who work on TPE-331s haven't really ever tried to "see what the gauge does" over 120.

-TomK

[sardilli]

Just a few additional observations related to the torque at flight idle. I have observed this occurring with both the legacy throttle setup and the new "lift levers" setup. When the throttles are at flight idle (both on the ground and in the air) the minimum torque seems to be at least 30% which is too high. As a practical example, if you maintain altitude at 150 knots and flight idle, the aircraft does not slow at all which I do not believe is supposed to be the case. In the previous version the torque would be just a bit above 0% at flight idle which seemed to result in performance that was similar to other turboprops. Hope this helps in troubleshooting, thanks for a fantastic product!

[Kimo]

Flight idle indeed seems a bit high. It's hard to slow down the MU-2 in flight.
 

Edited July 26, 2022 by Kimo

[tkyler]

Sorry about this gents.  I'm in agreement.  As soon as I get back home next week, I'll tweak this back to something reasonable.

-TomK

 

[XST]

Since an image is worth a thousand words, let me add some images to show what I'm experiencing:

1. Flight idle position on ground keeps torque somewhere between 38-40%... It doesn't go lower.

2. Pressing beta toggle in that position torque goes to 30%... it is OK... but there is no range to handle a torque between 31 %to 37%. Its like a dead zone.

3. Throttle lever all the way up test... no words....

4. Since min torque in flight range is 38-40%... I pressed beta range to go lower... not trying to do inflight reverse... just trying to lower the 40%... then it goes to 0%... same action on ground goes to 30% but on air it goes straight to 0%. Lever is in the beta limit not in the reverse range...

Summary:

1. Full throttle is very overpowered.

2. No way to go lower than 38% torque on flight range unless pressing beta... then dead zone in 31%-37%, this happens only on ground.

3. If beta button is pressed on air (inflight) to go lower than 38% torque... it goes straight to 0%... this doesn't happen on ground.

Don't hesitate to ask for any clarification if needed.

This aircraft is going to be great... just a bit of tuning to be done.

Thank you!!!

[tkyler]

thanks XST, I'm in agreement.  X-Plane TPE implementation is new and I'm the only dev using it to my knowledge (but there are probably others).   ...but they did not program an overspeed governor.  This put me in a bit of a quandry as weaving one in to the existing behavior is fickle and tricky....and the alternative is completely rewriting the engine code, which is no easy or quick task.  So....I'm going to keep fiddling with what we have to try and come up with a best compromise and on the side, begin playing with my own engine modelling. ...BUT...XP12 may surprise.  I haven't tested any improvments there yet.

Thanks for input....need another week to finish enjoying this Oshkosh trip and I'll be right back at it.

-Tom

[XST]

3 minutes ago, tkyler said:

Thanks for input....need another week to finish enjoying this Oshkosh trip and I'll be right back at it.

Enjoy your trip... that is important too!

Thanks!

[sardilli]

Yes, definitely enjoy the show! I used to work for Avidyne and really enjoyed the annual trips to Oshkosh, such an amazing event.

For what it's worth on the torque stuff, I think it's totally fine to go back to the v2.0 blade angles while you work on a longer term solution but I realize there are probably many opinions out their from other users.

IMO, both the ground and flight handling were fine in v2.0 so that combined with the new TBM throttle capability would be a great interim solution while you work on longer term changes. It's fantastic that you have brought a solid 331 simulation to XPlane. The only other example I know of is the Jetstream 32 and the Conquest II in P3D but both of those had their own issues. 

[Ch.Cole]

just to add, Fuel Flow at flight idle is above 270 per engine...

[tkyler]

And just got some hard numbers from a Moo owner.  FI torque is approx 15% on the ground and leans closer to 20% on descent, but may vary based on engine 'personalities'.

also, I met with both Philipp and Austin at Oshkosh AirVenture...and Philipp is going to put in both NTS lockout and overspeed governing for the TPE.  Its a lot easier for them to do it in their code base than for me to "hack" around their current implementation

-TK

Edited August 6, 2022 by tkyler

[sardilli]

Sounds good, looking forward to flying the next update!