How hard it is to build a RC plane without plans and starter kits? To do it in “Trust me, I’m an engineer” style. In mid June I’ve decided to give it a try and right now I can tell: it’s hard, but not that hard as one might imagine. All the problems I’ve faced were faced previously by someone else. I only had to ask right questions, read a lot, and use engineering sens to make plane work.
And well, it works. Way better than I expected it might work. Look for yourself.
It even flies. See the maiden flight video.
And now some facts about my design. My, since I did not used any plans or anything like that.
- material: 6mm Depron sheets, balsa, carbon fiber spars,
- glue: polimer wood glue, Uhu Por, packing tape,
- wingspan: 125cm,
- length: 85cm,
- wing area: 18dm^2,
- motor: Turnigy T2730 1500KV,
- ESC: Hobby King Blue Series 12A,
- battery: Turnigy 1300mAh 3S 30-40C,
- servos: 4x 9g,
- radio: Turnigy TGY-i6 with TGY-iA6 receiver,
- wing profile: KFm-2 with 8% thickness,
- propeller: HQProp 7×4.5″ or APC 7x4E,
- weight: 465g
After about 2 hours in the air I can state:
- The plane is super easy to handle. This my first RC plane, I have never piloted one before, but had no bigger problems to fly it. Maybe not withtout crashes, but still,
- Depron is cheap, but also quite fragile. It fractures easy. Both wing and fuselage need some reinforcements. Although I’ve used carbon fiber spars (1x5mm) to reinforce wings from inside, it was not enough to make it really crash resistant. Packing tape makes wonders, but you can not put it indefinitely,
- Aileron has to be big. The one I’ve designed are just too small. They take little more than 1/3 of wing. Definetly not enough. Rolls are almost impossible to do on low altitude. They take to much time and altitude,
- Turnigy T2730 1500KV motor is intresting design, but not powerful enough for a model that weights about 0.5kg. Thrust and pitch speed (of both 7×4″ and 6×4″ props, I’ve tried both) is too low for almost any acrobations. Even gaining altitude is hard. So this plane definitely need bigger power plant (Turnigy D2826-6 2200KV is on the way).
- And it was hard to choose a propeller too. 6×4.5″ was within power limits, but with so little power, each W not converted into thrust was a waste. So I decided to go with 7×4″ APC and 7×4.5″ HQProp. Both slightly above limit, so I’ve programmed radio to allow full throttle only when one switch is in exact position. That way I will not overheat the motor.
- On the other hand, I have destroyed one T2730 1500KV. It did not burned, it just stopped to work. Probably some mechanical damage to wires.
But that’s not all. I’ve so much liked working on this plane, that it will not just end with it. Oh no. Right now I’m building a replacement wing with huge ailerons, stronger build and some additional features. Plus, I have an idea for two new planes. Completely different from this one.