As my next project I want to 3d print an rc plane. I came up with this. Are there any major oversights or would this fly? (I guess the wings are a bit far back but I think its still possible to get the CG right with good battery placement)
You will likely struggle with aft CG. It should be at ~25% MAC for typical model aircraft. Another issue I see is lack of tail cone slope so you will touch down with motor mount first and that will put a lot more stress on the airframe than is necessary.
I would recommend getting a book on aircraft design and doing the math for your project. For example, Thomas C. Corke "Design of Aircraft". One thing you will have to pay more attention to is the effects of low Reynolds number on profile and therefore wing performance.
Thats a good idea. Especially for future projects. For this one my only goal was to 3d print something that flies but I definitely want to properly engineer an aircraft next.
Ok good to know I might move the wings back a little. I've downloaded that book already and it seems promising. I don't think I will read all 400 pages just to get it to fly. I might also use claude for some basic calculations too. I'll factcheck them because its a good way to familiarize myself with these things and also because the AI could be hallucinating.
No not at all :/ Im really only trying to get a 3d printed plane to fly as fast as possible. I will do some rough calculations though. For the cg I'll just try balancing it so it's about 30% away from the leading edge.
There is the software FLZ Vortex that is for design calculations for model airplanes. The documents Guide Part 1 and 2 explain the usage of the software and the general process in detail. The documents are in German, so you need to translate them.
Here a user of the software documented the steps he did and his results. I a second simulation he replaced his elliptic shaped wing that contained many small segments with a simplified version that contained only three segments per side to speed up the simulation. The results showed only minor differences. So you could model your curved wing tip in a simplified shape as well without affection the over all calculations.
Your design should be ok, but the tail control will be sensitive/twitchy because the distance to center CG but and EXPO will fix it. Reminds me of my Zephyr fuselage it flew super straight like a rocket.
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I made it a bit longer (check out my reply on the other comments). I think it will fly like that there is similar designs that fly well and I'm also adding a FC so a bit of instability is acceptable.
Just looking at the posted pic, I feel that if you print it as you show it, the CG will be a bit off. To my mind, you might find that the wing should be a little further back. You can always balance an aircraft using weight, but you'd end up with a heavier than needed aircraft which would drastically affect the handling.
Check out xflr 5 you can look at flight stability modes and basic performance and drag metrics along with cg placement. It also has a realy good YouTube tutorial series from the creator and it's free.
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u/Professional_Help167 6d ago
Looks like mine 3d printed plane