Prop governing in reverse

[youretootall]

Tom, can you check this please?  I think the props should not be strictly governed to 70% in reverse, with the CLs to TAXI.  This is based on my two flights in the right seat of an MU2 IRL (and also having watched basically every MU2 cockpit video on YouTube while up with my newborn the last few weeks).  I think there is a rise in RPM when the pilot goes to the reverse range to take the props off the locks.  I also recall that moving the CLs to TAXI while still in reverse on rollout keeps the RPM up...until the point where the PLs are advanced towards ground idle.

[tkyler]

I'll agree with you this one partially,  I don't get rides in MU2s anymore .    I partially agree with you in that I'm not sure exactly the RPMs vs condition lever position in reverse region because I never really confirmed it numerically or asked my pilot buddies to do so either.   I am mostly going off of sound and "to the letter" of the documention for reinforcement....I did record sounds on one flight from engine start all the way through takeoff and there is really no noticable rise in RPM pitch when going into reverse with condition levers at taxi, only the change in timbre of reverse pitch... and this is what I based my behavior off of.  I have about 30+ right seat flights and it seemed, IIRC, that this was consistent behavior.  I did pay attention to sounds.

In addition, all MU2 docs say the condition lever "commands engine RPM",  and does not distinguish whether or not the engine is in reverse pitch or not.    So at taxi...I'd expect the engine to remain around idle speeds, even when in reverse...and the recordings I have corroborate this "with squinted ears"....BUT, the MU2 docs are pretty darn general about a lot of things so I wouldn't bet my house on the behavior.  A slight rise in RPM is logical though, as I'd expect increase fuel delivery with the prop load of reverse; however, the final variable is the fuel controller.  Not all TPEs use the same one.  Most have Woodward controllers, but some retrofitted...and I recall my buddy telling me he didn't like flying the old Woodward units for some reason I can't recall, but it did insinuate differing engine behaviors. Anyhow...

What videos / time stamps are causing you to have your conclusions?  We can assess that here as a group

-tkyler

Edited June 8, 2023 by tkyler

[youretootall]

4 hours ago, tkyler said:

What videos / time stamps are causing you to have your conclusions?  We can assess that here as a group

-tkyler

Fair enough!  To be clear, I'm not questioning your personal expertise on things MU2...just thought I'd mention my recollection since you've indicated before that some of the engine stuff is still work-in-progress. 

I see now that it's hard to prove anything because you'd need a video that clearly shows the position of the power levers, and that always seems to be out of frame.

[tkyler]

1 hour ago, youretootall said:

Fair enough!  To be clear, I'm not questioning your personal expertise on things MU2...

It would not bother me in the slightest if you did...I have zero pride...I make plenty of stupid errors.    I don't spend the kind of time operating the sims as you guys do as I always have some other area of development I have to deal with... and always welcome observations I may have missed.   Its a great part of this feedback loop and please don't hesitate to point out whatever....it makes the product better!  I couldn't do it without your inputs.

-tkyler