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200% Simple Soarer

#1
I'm working on making a 200% Simple Soarer. According to my calculations, the final wingspan will be about 9.8 feet. As I'm still not an expert on foamboard airplanes, I could use a little design help.

The main problem is that the foamboard spars and foamboard fuselage, at least I think, won't stand up to the forces in flight. I'm thinking that I need to add a spar or two to the wing, and some sort of spar to the fuselage. The other problem is that the nearest flying field is about 5 miles by car from my house, so I have to be able to transport the wing in my car, which requires that it collapse into two or more pieces. The fuselage should be fine in one piece.

What's the best way to add a spar to the wings and still have them collapse into 2+ pieces?

What is the best way to sturdy up the fuselage without adding too much weight? I was thinking about using thin wall aluminum tubes to be in the wings, one in the front and one in the back, to resist wing torsion.

Any thoughts or other things to keep in mind while building this behemoth?
Thanks,
luketheduke
 

Montiey

Master Tinkerer
#2
There isn't any good "flitetest-approved" method that I'm aware of for torsion resistance, but you could use an aluminum pipe/rod, and securely anchor it to the main fuse, and the back of the tail. Then, the foam board tail would basically just be superficial and the torque would be handled by the rod. However, of course, that may give you CG issues. I think you're going to have to give it a try and see what happens
 

Hai-Lee

Old and Bold RC PILOT
#3
Spoiler alert! Currently I am working on a FB prototype which has a CF spar tube that is removable as are the 2 wings.

The wings "Key" into the side of the fuselage and have locking tongues which are secured internally using either screws or pins.

The CF tube slides into a Box spar in each wing.

If you are interested in experimenting I would gladly "Clip" the wing spar box design and post it here for you to perhaps get some inspiration from.

have fun!
 
#4
Spoiler alert! Currently I am working on a FB prototype which has a CF spar tube that is removable as are the 2 wings.

The wings "Key" into the side of the fuselage and have locking tongues which are secured internally using either screws or pins.

The CF tube slides into a Box spar in each wing.

If you are interested in experimenting I would gladly "Clip" the wing spar box design and post it here for you to perhaps get some inspiration from.

have fun!
That would be great if you could post it. I'm thinking of using small(~1/2") aluminum tubing for the wing spars and body, but now I just have to find where to get it...
Thanks,
luketheduke
 
#5
Glue two pieces of foamboard together to make a 200% quarter piece of foam. Repeat this 4 times, glue them all together, and you got your self a 200% sheet of foam. Otherwise,m try finding a sheet of foam that is 8-10mm thick and apply 3M Super-77 on it, then put a paper with the same dimensions as the foam sheet on it. Do the same on the other side.
 

Hai-Lee

Old and Bold RC PILOT
#6
Here is the spar tube plan V1. When folded up and the end closed with the fold in end pieces the CF spar is slid into the open end up to the end stops.



Between the 2 spar tubes there is a gap because of the fuselage and the profile thickness of the design plane is only 25mm.

The 2 large outside pieces are mounted vertically so that they are able to function as spars in themselves.

Hope this helps.
 

Attachments

#7
What size CF spar are you using and what shape is it? Also, where did you purchase them? Amazon and hobby king both sell CF but it seems to mostly be a fiber and carbon mix with resin, so not true CF...
 

Hai-Lee

Old and Bold RC PILOT
#8
The tube I am using is the HK type 6mm O.D. tube which is around 1Mtr long but i purchase mine here locally.

For your wing you could use similar size tubing and use the Al tube as joiner sleeves in each wing and the fuselage.

For heavy plane the central spar could be larger diameter for extra strength. 3 x 1Mtr is 10ft!

Have fun!
 
#9
I've constructed the Wong and most of the fuselage with pine dowels as spars. Current wingspan is just short of 9' 6". I'm considering using two motors for extra thrust and placing them on the wing for differential thrust. I plan on using two Eman rs2205 2600kv motors with 6045 props. Thrust benchmarks I saw online say it should be able to do 1300g per motor. I'm expecting an AUW of 2-3kg so will this be enough thrust? How far out should the motors be from the fuselage? I get that the farther out, the more turn control, but is there a tradeoff for strength, ie bending the spar versus control? Also, someone suggested to me to use the dual motors in place of ailerons. Is this possible? I've only seen it done before with replacing the rudder, but not ailerons...
Thanks,
Luketheduke
 

Hai-Lee

Old and Bold RC PILOT
#10
I know that the two motors blowing across deployed flaps can really slow down the landing speed, and give very rapid take offs.

Have fun!
 

Hai-Lee

Old and Bold RC PILOT
#12
What are your thoughts on my choice of motors from my previous post?
They seem to be adequate if not a little spirited for the job. Personally use good quality props and not cheap rubbish as I have had props throw blades at high power settings, (normally at the worst possible time:black_eyed:), in the past.

I would suggest that you consider mixing a little rudder into the throttles in the event of a motor/propeller issue.

Finally and this is only my personal preference on aircraft which I want to fly slowly and calmly I chose lower Kv motors combined with the largest SF props the plane could support. I just like the immediate "LUMP" of engine thrust available with low Kv SFs. High Kv props normally need some real airspeed to reach peak thrust.

Looking forward to your maiden flight post!

have fun!