Drive train losses
 

Is there a general formula for determining losses through the drive train?

An HP500 delivers 470 HP @ 5200 to the prop through a Bravo drive, a 900SC delivers 850 HP @ 6000(?) RPM to the prop through a VI dry sump. These numbers define the efficiency of those drivetrains at the given RPM. But what happens above and below the RPM at which these numbers are measured?

I don't believe that these losses are a constant HP loss or a constant % HP loss. My guess is that these losses go up as some power of RPM.

Any mechanical engineers out there?

Hi, I was looking at BAM's site yesterday reading everything for the zillionth time but they have a 'trans dyno' which can dial in a rpm and measure on a strain guage how much HP is requuired to achieve that rpm. Now how about hooking up the input shaft of a bravo 1 or input of trans and TRS drive and measure the Hp required to spin at 2,3,4,5,6,7,8000 rpm. I think that is what you need. My computer here at work is doing great with excel. I'm wandering around and getting a feel for it and it seems to work for all my data. I'm still playing. Thanks.