Jean,
 I love It,
 Perhaps we can get Paul to finalize his torque system to go into your box.
 I digress a little.
 Paul,Your water manometer reminded to bring up a point that has been
 discussed before reference a torque indicator(HP gage).
 Perhaps we are missing the boat by not putting a torque gage in every
 airframe, that way every airframe becomes a test stand. We may be missing a
 lot of basic data because of the lack of a primary indicator for engine
 power and performance.  Sorry to change the subject.

 milo


 I am for that. It can be built into the motor mount.

 Paul Lamar

Paul,


I see you have put a lot of work into this motor mount  torque sensor  concept over the years now.  But isn't the torque measured in that manner only a partial force?  Load paths would vary depending upon the rear motor mount design.  Many have four motor mounts with the purpose, if I'm not mistaken, to hold the motor in the proper position and absorb torsional input without excessive engine rocking.   Airplanes engine don't respond as quickly as auto engines so they can use harder mounts.  As you well know in airplane applications we are mainly concerned with isolating unwanted harmonics from the airplane frame.

   For the torque sensor to work in the manner illustrated a single floating rear support would be needed thus  compromising the purpose of a sturdy engine mount.

For helical geared PSRU,  with its inherent  thrust component, the annular hydraulic cylinder behind the needle thrust bearing you proposed is a brilliant idea.

Incorporating a torque sensor into  the torque dampener, which does have enough twist between the engine side and PSRU side, is also possible, but takes some electronics, either a small load cell or an optical device.  Both  present challenges but the components are readily available.

Doug in Japan

The design is based on our 3 point motor mount. It won't work with
four points. Also it must be calibrated by locking the engine and
applying a load to a prop tip.

A four mount design is redundant.
We decided 12 years ago to go with the Questar Venture type
of mount. People that have flown this airplane rave about
the lack of vibration. In fact we are using the exact same rubber
bushings.

Paul Lamar