• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

building a RC airplane

#1
Hi, I try to build a RC airplane, its weight is about 1kg including all (I got its body done and electronics), I'm using a Cobra 2203/28 2800Kv motor with 6/4 APC propeller.
The problem is that there is no lift (just a little), the airplane just falls slowly to ground.
Here is by how I made the wings - https://www.youtube.com/watch?v=qJZoqGHAIDE

Please give me an advice about what's the problem in my design, what propeller or motor should I use?

Thank you, Dan
 

JimCR120

Got Lobstah?
Site Moderator
#2
Hello Dan.

I could venture some guesses about your problem but it might be easier if you shared a photo or let us know certain aspects of the plane. The weight at 1kg is heavier than most of mine but not the heaviest. I have an Excalibur that weighs 1kg but also has a very powerful motor and a larger prop.

If you're new to flying there is another factor that is very common. Often a new pilot with a plane that has enough thrust to go forward but not upward will take to aggressive of an angle of attack. What I mean is that normal planes (not fighters) use forward speed to generate lift over the wings, more airspeed=more lift. A new pilot though often pitches nose up too early and thus decreases airspeed, less airspeed=less lift. And the next reaction might be to pull back on the stick more but that just decreases his airspeed more.

My recommendation would be to try flying in a large enough field without obstructions that you can launch and just maintain a straight and level course. Straight is also a factor becasue banking your plane also reduces lift. Once your plane gains airspeed, gently pitch up a bit and see if that works better for you. The same for turns. Make your turns gradual.

Again a photo of your plane will likely give us more insight and if you can a video of your flight attempts would too.

As a newcomer to the forum we would also like to know more about you. Where in the world do you fly? How did you get into the hobby? Do you have family or friends in it as well.

Welcome to the forum.
—Jim
 

TeckRC

New member
#3
I think you need a bit more power for the weight of that plane! Something like the electronic Power Pack C they carry here on the store would be closer to what you need maybe.
 

rockyboy

Skill Collector
Mentor
#4
If you have the 2204 motor instead of a 2203 (I wasn't able to find any data for that one) then you're very likely under powered.

Cobra-2204-2300kv-thrust-2.jpg

With a 6x4 prop you're probably at a about a 50% thrust to weight ratio, which is about as low as a high-wing trainer style plane could be and still fly. Generally, about an 80% ratio is a better feeling for a high-wing trainer type plane, but each one is a unique snowflake too :)

It will definitely help to have some photos as well as a wingspan measurement so we could recommend a better solution for you.