My Mooney is too fast.

[jaylw314]

3 hours ago, A64Pilot said:

It’s a very bad thing to do to an engine as it may I believe the term used is detune the crankshaft balance weights. 

I know that’s a possibility in a fixed pitch aircraft especially in a dive, but I thought that a constant speed props governor would help prevent that as if RPM begins to exceed the set point, the governor will add pitch to prevent an over speed. But to autorotate the prop will take pretty much a dive I thought, something most wouldn’t do.

I’ve pulled the engine back on turbines and dove steeply and initially the big prop keeps the speed low, it acts like a brake, then suddenly the governor adds pitch because the prop is auto rotating and you accelerate, but it takes a pretty steep dive to do that though.

Tjese are NOT our engines, but it explains what happens.

https://www.lycoming.com/sites/default/files/SB245D Detuning Dynamic Counterweight System.pdf

Then read 4(d) here

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-103.pdf

I think that we are fine to leave the prop at high RPM, just don’t pull the throttle off fast and or dive the airplane, rapid changes in RPM is bad.

 

I've just assumed that the prop is designed to not hit the high pitch stop at max RPM until you're past Vne, no?  Heck, I've been able to keep the RPM at 2000 in descents at 175 KIAS.  It's hard to imagine the governor couldn't keep the prop below max RPM up to Vne.

[Pete M]

On 7/10/2021 at 3:40 PM, A64Pilot said:

It’s a very bad thing to do to an engine as it may I believe the term used is detune the crankshaft balance weights. 

I know that’s a possibility in a fixed pitch aircraft especially in a dive, but I thought that a constant speed props governor would help prevent that as if RPM begins to exceed the set point, the governor will add pitch to prevent an over speed. But to autorotate the prop will take pretty much a dive I thought, something most wouldn’t do.

I’ve pulled the engine back on turbines and dove steeply and initially the big prop keeps the speed low, it acts like a brake, then suddenly the governor adds pitch because the prop is auto rotating and you accelerate, but it takes a pretty steep dive to do that though.

Tjese are NOT our engines, but it explains what happens.

https://www.lycoming.com/sites/default/files/SB245D Detuning Dynamic Counterweight System.pdf

Then read 4(d) here

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-103.pdf

I think that we are fine to leave the prop at high RPM, just don’t pull the throttle off fast and or dive the airplane, rapid changes in RPM is bad.

 

io 360 a1a's are not counterbalanced. No dive involved. Pulling throttle back to 15 or below at high rpm will get the prop driving the engine. No dive necessary. Short body e's are very slippery. J's are counterbalanced. Not sure what the limitations are. 

Pete

[Pete M]

I was in the break area with my student while you were taking to ken:) Didnt know it was you until ken told me after you left. 

Pete

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