Access, I'll try that out and see what happens. I can measure efficiency now, I have the current sensor. The only motors I have are a hacker 13.5, novak 13.5, and a novak 7.5. I have a sensorless tekin 468 motor and a mamba 5600kv motor too, but I can't measure rpms on them. I am gonna go around the track this wednesday and see if I can borrow a 10.5 Novak to test too. I borrowed another Novak 13.5 and I am going to compare it against mine.
I currently have a few dyno tests of the hacker 13.5 right now, but we are in the final stages of tweaking that spreadsheet, then we will post it for download in case anyone else wants to do this themselves.
I also wanted to say that the efficiency curve comes in slightly after the power curve. I have an efficiency curve for the Hacker, and it comes at around 15k rpms I believe. I'll be posting those graphs within the next few days.
I'll try to do what you ask access, and feather the throttle to keep it at a constant RPM, and yea I agree, I bet it has a good efficiency.
Here is a more recent graph I made using the newer flywheel, no efficiency yet, this was taken I believe last Thurs.
And here is a link to the data.
http://arcadechamp.net/radio/hackerlarge2.pdf