Well I feel compelled to throw in my two cents worth ---- fuselage shape and CG -- I believe are at the root of the mushy elevator problem with the Bob Cat. Let me explain before everyone has a great laugh and chews me up --------

My Bob Cat is more nose heavy than most, I originally installed the "Rat Trap" and in doing so could not get a perfect dry balance on the CG points! My Bob Cat is slightly nose heavy with no fuel, 1/4 ---- 3/8 inch forward. You know I've never checked the CG with full fuel, but I can feel the CG when flying and at takeoff and for about the first 5 min of flight I am very careful through high speed high G turns, split S pull outs etc. ------- CG changes toward the end of the flight, but I never get the recommended CG configuration.

Now for my really unconventional idea :stupid: ------ the fuselage shape ----- at high speeds I believe the canopy and general up sloping shape of the front of the Cat most of it being in front of the CG also contributes to the soft elevator response. I notice it especially when really smoking through a descending to level high speed round house turn -- the higher the speed the more mushy the elevator response. It feels like something is pushing the nose out and or down, something more than a slightly nose heavy CG force and different than servo stalling. (although to my knowledge I've never flown any model aircraft that the elevator deflection was stalled because of aerodynamic pressure, even during the extra hard pulls when racing)

My reasoning is if the servo stalled OK -- so be it -- but I already had enough up elevator to continue the turns diameter, but I still was getting a strange push on the nose only to be reduced by reducing the speed. I have tried increasing the throws and that helped slightly. So the geometry of the elevator linkage, travel distance, and power of the servo will help at the margin.

Now for an observation I made that helped convince me the fuselage aerodynamics also is in this mix and has an effect, and possibly at the root of this anomaly. I tried the same high speed turn similar fuel CG configuration "inverted" inverted the mush seemed to be greatly reduced fact is I didn't notice it at all, I had plenty of elevator authority! Go out an try it and see what you think, but be careful to remember down is up and up is down

OK I'm ready to get clobbered for my thoughts on fuse shape, but I couldn't see this thread wilting on the vine yet before I got to add my 2 cents ---- Note: A straight and level high speed pass shows none of this push tendency so maybe the push feeling is some kind of airflow blanking created by the nose ------

I wished we could put the Bob Cat in a good wind tunnel with full smoke indicators so we could really see whats happing aerodynamically.

The only thing I haven't tried yet is stronger servos ----- I would guess more elevator travel and more servo strength will over come almost all of the mushy "pushing" feel at high speeds -------
Lee H. DeMary
AMA 36099

PS I don't think this anomaly is a real problem, unless you've already stuck your Bob Cat in the ground because of it - ---- the Bob Cat has so many other good characteristics --- I just live with it and love it Fact is I've ordered the King Cat ---- but I am going to setup the CG more tail heavy on the King for starters -----