Posted by Dead |
Jan 12, 2009 @ 05:47 PM | 4,291 Views
I can tell you I purchased an IPA package and still had to shim the motor a bit. I go through the same routine with every aerobatic model I fly regardless of what the manufacture (or it's rat pack) claims.
Simply adjust the CG to your style of flying. Ever so slightly nose heavy or completely neutral depending on flying style. Of course in order to correctly set the CG of the plane you have to trim out the plane the best you can first so you can roll it over. Do multiple tests both upwind and downwind. Best if no wind at all but not always possible. Once you have the plane flying completely level roll it inverted. If it neither climbs or descends it's neutral which I like for 3D. If it climbs it's tail heavy. If it dives inverted it's nose heavy. Many pilots prefer a slightly nose heavy plane so it will GRADUALLY dive inverted.
Land, move battery, fly, land, move battery, etc until you have the CG where you want it. Retrim the plane perfectly for level flight again. I like to fly directly toward and away from myself so I can see any yaw from the rudder.
Next do a secondary elevator/CG test. Climb up super high, dive straight down with NO THROTTLE. Check to see if it pull to the wheels or canopy, to the left or to the right. Left or right is a rudder issue. Canopy or wheels is wing incidence or CG issue. Adjust and go through this all again.
Next adjust OR VERIFY the thrust line of the motor. This is a two step process as you have to check the up/down and left/...Continue Reading
Posted by Dead |
Aug 04, 2008 @ 06:58 PM | 5,154 Views
Assuming the same prop and motor efficiency, and also assuming the kv's quoted for the motor are correct, then going from 950kv to 800kv will reduce RPM roughly in proportion to the kv rating.
Power change is proportional to the cube of the change in RPM, so in round figures expect to see power levels of around 60% of what you had with the 950kv motor. Thrust reduces by the square of the RPM change so should be about 70% of what you were getting previously. Pitch speed reduces directly in line with RPM so you will have 84% of you old pitch speed.
thanks.. You can use the same principal to estimate what effect changing battery cell count will make.
Power is roughly proportional to cube of the voltage, thrust to the square and pitch speed is directly proportional (assuming same motor and prop and efficiency)