The TORTOISE- easy bush/STOL plane

[Fluburtur]

After the disappointment that was the crash of my canadair into a tree I decided to built yet another plane (it's been like 3 months since I last built a plane, can you even imagine)

I decided to build a bush plane for slow flying and acrobatic flight, this way I can fly at the park where trees are not in the middle of a goddamn river.

I learned a few things from the canadair, the most important being that the eppler 205 got tons of lift! I could almost hover it in no wind and it likes flying inverted too so im going for a low wing loading and nice wings for good slow speed flying. I am also aiming for a high TWR for some prop hanging and knife edges.

Since I now have a 3d printer I decided to make the tail and landing gears with it!



I tried to make the tail very light, it is a simple 3d printed frame covered with clear tape. I think it is about 45g, I wanted to make it light as possible in order to avoid nose weight.


The gear isn't done yet but I used a fairly clever design, it uses 6mm BBs in a sort of ball bearing. The inside of the bearing is made in two parts that clamp down together and the outside is one simple part. This way it is the balls that hold the wheel and deal with all the loads, I need to tune my printer a it but it works fine already. I will probably make a video about that because it is a bit hard to explain.




Today I cut the body, I have enough foam to make maybe 3 of them but I want to build a flying wing too.
I don't have the electronics yet but I will probably make the wings soon and I need to finalize the landing gears design, as always I will keep you informed!

 

[Pieliker96]

Great use of a 3d printer. This makes me wish i had kept mine around...

I like the design of the tail feathers with the circles and packing tape covering.
The integrated bearing/wheel assembly is really clever.

I'm curious as to how the suspension/gear will turn out, considering this is a bush plane.

Looking forwards to this project.

 

[Fluburtur]

I will use rubber bands for the suspensions and tube insulation foam for the wheels, it will be rather soft. I need it to also be able to roll in grass so it will need fairly big wheels, I might re-design them a bit bigger actually.

A friend was telling me that using a standard triangles structure on the tail would be stronger (and probably lighter) but I have a printer and I can do weird shapes so I do weird shapes.

 

[Fluburtur]

I have made a very important discovery



Because the wings are thin enough I can get a pair out of each slab of foam.
This means that either I can bring the wingspan to 2.4 meters or make it a biplane, or do nothing.
What do you think? I think making a biplane would be very nice, wouldn't look much like a bush plane but would give incredible performances.

 

[PsyBorg]

Bi Planes are ALWAYS cool to me. I would think the larger wingspan would make it more Gliderish then Bush plane though. Maybe change the cord to make full use of that foams width and make control surfaces and flaps from foam board or balsa. that would help the STOL characteristics more I would think.

 

[Fluburtur]

I thought a bit about it and I think I won't make it a biplane. It was designed to be a high wing and it would look weird as a biplane since the wings will be long and rather thin.

This means that I need to add "proper biplane" to the list of things to build!

 

[Fluburtur]

I did some more work on the landing gears, and by that I mean that I basically re-designed everything.



The gear itself is much bigger, this way it can use 35mm tube isolation. The bearing is basically the same, it has some friction but it shouldn't be significant when the plane is rolling. The wider gear should allow use it somewhat tall grass and rough surfaces.

I will release the STL files when I release the video about that I think, I may need to tweak some stuff.

 

[earthsciteach]

Fluburtur! I love this! What does it weigh? Like 5 grams? LOL!!! I'm excited to see this thing fly!

 

[Fluburtur]

I tried to save weight on the tail but im not too worried about the rest, I prefer having weight in the design and not having to add more to balance the plane. I will post the plane of the whole gear later when im done making it.

 

[Fluburtur]

I did more work on the landing gears but they are still not done.




The leg parts are a bit challenging to print because the bearing part is upside down and angled so im not optimal so I have to find a way to make that a separate part or find out how to put supports correctly, also they fold inward a bit too much.

Shouldn't be very hard to solve at least.

 

[mrjdstewart]

:applause:

 

[Fluburtur]

The landing gear is pretty much finished




They aren't glued on yet, I will use them to balance the CG actually and I still want to correct the geometry a bit, make them a bit more separated.

Also I said I would give the files when I release the video but I lied.

Here are the files, instructions are in there too.

Print them and tell me how it goes, btw they are made to go on a plane with a 50mm wide fuselage because that's how thick mine is.

 

[Fluburtur]

Progress has been slow while I was waiting for parts, as a matter of fact im still missing a lot but I got the motor.



It's a 1400kv racerstar motor, it looks very similar to my usual cheapo orange motors so I guess they are related but this one is somehow cheaper. Anyways I only want it to work, the nose is kinda ugly right now so I might design some sort of scale cowl if it needs nose weight.

I expect the plane should be airworthy during next week so I will probably make a video the week after that.

 

[foamtest]

So this is what that tail ended up going to... and why you haven,t been too active on the discord lol

 

[Fluburtur]

Today I stopped being lazy and glued the wings together.




I haven't put the spar in yet however, also I received the servos and I hope I will get the ESC tomorrow.

Im currently printing a thing to try holding the wings on the body with screws to make it easy to store and transport, we will see how that goes.

 

[Fluburtur]

I finished the plane today and did some taxi testing and it went great!



this is the tail controls


It like to lift the tail before it even starts moving and doesn't want to tip over so that's great and it is fairly easy to control it while rolling on the ground.

I will test fly it tomorrow, I expect it should go fairly well but I will program some dual rates just in case.

 

[foamtest]

Cool, I can't wait to see how it goes! Also what's the AUW, 5 grams? lol

 

[Fluburtur]

It weights 810g, a bit more than planned actually.

I maidened today and it didn't go as well as planned, I think it was a bit tail heavy.

I broke off the nose and tail (tail was from getting it out of the tree) and the wing is pretty damaged but it is fixable.



Not sure I want to fix it however, I also want to make myself a better fpv wing and the electronics of this one would fit it just fine.

 

[PsyBorg]

Was probably tail heavy as you did not fly with the weight of the landing gear up front and probably did a CG check WITH the gear I would bet.

 

[Fluburtur]

I did check the CG, it was 1/3 back from the front of the wing as I always do (I also put my spar on the cg so it is easier to find)
Yet it was back heavy, if I flew it on the 4s it would probably be fine.

The controls were a bit funky too but that might have been because of the thrust angle and my weird tail setup.