I am pretty hesitant to make any conclusions about something from a video with no other information.  But, I would note, this engine is running a 4-2 break, maybe faster (the audio tach gets about 9100 on the ground and around 9700 in level flight), but still 4-stroking. Given his ultimate lap times (5.55-5.6) and the trim issue, and overly-tight maneuver, led to his problem. This is probably a 4" pitch prop, so good there, but it's going to need to go around 9800-10000 on the ground to make it. That would be in a 2, but I would be concerned about that, because it is already going hard lean in the maneuvers, leaning it out further to get the necessary level flight speed is likely to put it over the top. Interestingly, it also *doesn't* seem to have a huge power difference between 4 and 2 at these low speed, which leads me to suspect that it has some extra head gaskets.

   Other than that, I wouldn't want to speculate, if the engine is modified, then all bets are off, and I would strongly suggest putting it back the way it came, then going from there. If it had been ground on, or "retimed", I can't "ungrind" it. But, offhand and with no other information, it doesn't seem that far off, and could probably be made to work to one degree or another with compression, venturi, prop, and nitro.

   This may be fine for this application, but it is definitely NOT what I suggest for the 25LA or 20FP, it needs to be 2-stroking in level flight.

    I added a comment to that video about the stooge safety practices, which are exactly the sort of thing that have led to some very gruesome and bloody accidents over the years.

     Brett

  The "engine RPM" app for iPhone, from the Apple Store. It works very well once you set the range and limits correctly, and appears to be very accurate, from comparing it to the original TNC in real life. From video, of course, I am assuming the frame rate is "real-time".

  Interestingly, it appears to work pretty well on electric models, too, presumably because of the blade noise. and the finite range knocking it down everything but the harmonics

    Brett

The Android version of Engine RPM works well also. 

Steve