Hi there! I'm also building a rubber powered PT-19. Yours flies great! Did you balance it according to the plans and what's up with that propeller? Is it aftermarket? It looks much larger than the prop that came with my kit and I believe our models are of the same scale. My plane climbs suddenly and then dives steeply before leveling out and I'm only winding the prop 150 turns. should I add some ballast weight, get a bigger prop or add more winds to the rubber band before flying the thing? Any tips you have would be greatly appreciated!
Trimming a rubber power model can be more of an art than a science at times, but the basic process is this: 1. Set the balance point (CG) at ~1/3 wing chord back from the leading edge of the wing (add noseweight/tailweight as needed) with the rubber motor installed. 2. With ~100 turns, test glide and add up or down elevator (a piece of tape will work as a trim tab) to get level gliding flight. 3. Add more power and adjust the thrust line as needed with shims to get a good climb. I think I'll make more videos in the future describing the flight trimming process in better detail. It makes more sense in person. Also, unfortunately we lost the PT-19 at a competition, but it had a 5" propeller and in that video is flying with probably 1700 turns.
Hi there! I'm also building a rubber powered PT-19. Yours flies great! Did you balance it according to the plans and what's up with that propeller? Is it aftermarket? It looks much larger than the prop that came with my kit and I believe our models are of the same scale. My plane climbs suddenly and then dives steeply before leveling out and I'm only winding the prop 150 turns. should I add some ballast weight, get a bigger prop or add more winds to the rubber band before flying the thing? Any tips you have would be greatly appreciated!
Trimming a rubber power model can be more of an art than a science at times, but the basic process is this:
1. Set the balance point (CG) at ~1/3 wing chord back from the leading edge of the wing (add noseweight/tailweight as needed) with the rubber motor installed.
2. With ~100 turns, test glide and add up or down elevator (a piece of tape will work as a trim tab) to get level gliding flight.
3. Add more power and adjust the thrust line as needed with shims to get a good climb.
I think I'll make more videos in the future describing the flight trimming process in better detail. It makes more sense in person.
Also, unfortunately we lost the PT-19 at a competition, but it had a 5" propeller and in that video is flying with probably 1700 turns.
What kind of motor are you using & how long is the wing from tip to tip?