Indestructible h quad frame $10 and 80g

[Shaunuk]

Hi guys,

So firstly, nothing's indestructible so that's a rubbish post title. But this ones quite strong, I've built loads of quads and experimented with lots of h quad designs and this one has worked out the best.

I thought I would share it as I was amazed at how cheap and easy it was to make. I was on a work phone call and picking up bits of material the desk, before the end of the call I'd made a super light carbon fibre h quad using only two materials. Cheap carbon fibre hollow square section pieces and zip ties.

I found out if you zip tie two straight pieces of rod together and then twist one 90 degrees you get- A really strong join. Do this 4 times and you have a full square. It's so ridiculously simple it's amazing.

So the tension on the zip ties tries to return the rods straight but two on each end oppose each other and keep the whole frame square (ish) and tight.

Here's the best bit, the carbon on carbon friction stops the joints moving but in the event of a crash the zip ties either slip a little or snap. Keep a few in you're pocket and you have a full build kit.

I then used two zip ties per motor and a Center plate from a 450 also zip tied together and boom.

I ended up double zip toeing the joins and mounting the motors using one each side of the motor mount and one between the two to keep them together.

It ways about 80g frame only and flys amazingly. Plus the confidence gained by not worrying so much about crashes is invaluable.

I used some 1200kvm motors and a qbrain 4in1 esc 20a. Kk 2.1 and a megapirate flashed multiwii. Huge power to weight ratio make for great flight times and on 8 inch props is will yaw round about two times per second.

It's unbeleavable. I though it would come apart in the air but it's great. Also the zip ties seem to have some sort of vibration reducing effect. Few pictures attached. The last one is after a crash from 20 meters and embedded into the field. Multiwii locked up I think. Frames fine.

Interested in people's thoughts. I've used lots of off the shelf frames but this just seems better !!

 

[Cyberdactyl]

Looks like an awesomely simple build. I like the concept of ties connecting everything.

Since all wiring is outside, you could even go the next step and epoxy dowel inside the tubes. That would pretty much double the frame's weight, probably somewhere around 80g, but increase the tube strength by 3X. Unfilled, I've found those pultruded tubes will split in a hard crash.

My only slight concern would be the motor booms vibrating outwards off their main spar members. If you placed a small piece of very thin rubber, like bicycle tube rubber at the contact point between the spar and boom before cross tying them together, it will give them a much higher non-slip connection over bare CF contact and also provide more compression. Ties relax over time a bit and the rubber would add a few thou of compression distance and insure less chance of slippage. It would also provide a token bit of vibration isolation.

Overall, wonderful idea!

 

[Shaunuk]

Great idea on the rubber. I'll put that in the next rebuild. I'm going to try a smaller version as well. Will post back any progress.. Fowl is a cool idea also - or some sort of full fill carbon fiber rods !!