FT Simple Cub and varying propeller sizes.

[Hvon11]

I have been flying the FT Cub with a 3S and stock motor Radial 2212-1050kV and 9x4.5 prop. After a few minutes on a fresh battery the flight characteristics are slow to sluggish. Don’t get me wrong, it’s a fun slow flying plane, but starts out with good zip and then peters off to a meander. I was wanting a bit more pep in my flights. I tried a 9x6 prop and man was that exciting. Too fast and difficult to handle but a good thrill even at slower speeds. Motor was noticeably hotter when checked at landing. Today I tried an 8x5 and I think this a perfect match. Good zip but not to the loss of control point, plays nice at slower speeds and goes from a slow and low approach to up up and away seamlessly and smooth. Will try a few more sizes but I Think the 8x5 is optimal.

 

[Merv]

Be careful when trying a larger props, you can burnout your motor, esc or battery.

I always do a test with a new prop size. On the ground, run the motor at full throttle for 10 seconds. The stop, check the temperature of the motor, esc & battery, by touching them. Warm is OK, but if it so hot you can hold them, that’s too hot. The prop is too big. If it passes, try a 30 second run, if it passes, then a 60 second run. If it passes 60 seconds, you will likely be OK. It always a good practice to test all the temperatures after a flight. A prop that worked when it’s 70 may be too much when it’s 95+.

 

[Hvon11]

Be careful when trying a larger props, you can burnout your motor, esc or battery.

I always do a test with a new prop size. On the ground, run the motor at full throttle for 10 seconds. The stop, check the temperature of the motor, esc & battery, by touching them. Warm is OK, but if it so hot you can hold them, that’s too hot. The prop is too big. If it passes, try a 30 second run, it it passes, then a 60 second run. If it passes 60 seconds, you will likely be OK. It always a good practice to test all the temperatures after a flight. A prop that worked when it’s 70 may be too much when it’s 95+.

Great advice. Will use the ground test procedure from now on. I even have an IR laser heat thermometer i will use.