Hi Jim,
So it's the chopping rate that we see. Okay, that's high enough to easily filter out of the regulator output, and low enough not to cause any RF issues, seeing how the RX ground is going to end up riding on top of a common mode noise signal at the same frequency.
I wonder if there is any real high frequency crap as well? I can't imagine that the big electrolytic caps we see on any firm's ESCs are any use at RF. I would imagine that 2.4G is completely unaffected, but 72 Meg just might get unhappy.

E-Stunt? Let me see if I can sum it up in just a few words. It's GREAT! There are a fair number of holy-war, "don't change my event" naysayers, but it works better than even the best piped two-strokes and four-stroke setups.

1)We are running with the ESC set in helicopter RPM governor mode, and if you have the gain adjusted high enough and the RPM control loop response speed set fast enough (just a safe margin of stability, but noticeably underdamped) then ...
2)The vertical uphill RPM is only 100 RPM or so below that of level flight and,
3)vertical dive RPM is maybe 100 or so above level flight.
( for comparison, excellently set up four-strokes and piped two-strokes exhibit about 1000 RPM differences from climb to dive and the classic muffled 2-4 Stunt run shows close to 2000 RPM difference)
4) There are experimenters looking to make the system recognize where the plane is on the circle so as to compensate for the few hundred RPM variations we still see, but this is still far from ready for prime time.
5) Podium places at Worlds have been taken with electric, and this year's European Continental Championship has been won with Electric.

Now for the cross-pollination part of our discussion ... The constant RPM setup surely will work for Pattern: it will turn the throttle into an "airspeed setting lever".
The only problem is that this only works if you have enough overhead to achieve the governed RPM at the slowest speed needed while in a vertical climb.
As a data point, static current at the set RPM is about 135% of the cruise flight current at the same RPM.
I strongly suspect that the very long vertical downlines we fly, and the lack of control-line-drag will require an RPM governor that engages the regenerative brakes.

In my opinion, this approach will get close to the point where sensored motors will be needed for the frequent changes from driving to braking at high energy levels.
We already see that ESCs have issues with the transition from braking to running hard at low RPM. Sensors will fix that.

take care,
Dean P.