This is the result of my "indestructable" quadcopter design blog.

I dont know how well it crashes it yet but after 2 test flights, it flies very well! I need to do some PID tuning as the arms are quite short. They are 450 size heli tail booms that I cut for no other reason but to make the quad smaller and see what happens. Any PID tuning recommendations for shorter arms?

 

On to the nitty gritty. All the carbon fibre is 1mm thick. It was cut with a jigsaw using a fine metal blade and it works really well. The motor mounts are made of 4mm perspex and were cut using a hole saw. The landing gear is also 4mm perspex cut with a jigsaw and bent with a mini blow torch. I never realized how strong perspex actually is till I started messing around with offcuts! its unbreakable! under huge stress it just folds but never breaks in 2.

 

The total mass without battery is 630g and with 2200mAh battery 828g. I actually have no idea if this is light or heavy for a quad?

 

Price:

2x 100mm x 300mm x 1mm carbon fibre: $10.79ea

4 x 450 heli carbon fibre tail boom: $2.40ea

Screws, nuts, bolts: $8.00 nylon screws are quite pricey!

Perspex 300mm x 300mm x 4mm sheet: $10.00

 

Total: $50.00 Not Bad =)

Views: 9725

Comment by Ellison Chan on November 11, 2011 at 3:20pm

Not too bad in weight.  Indestructible, I have my doubts, for the following reasons:

1- Your props extend past the tubes.  Better to use longer tubes, and mount the motors so that the propellers don't extend beyond the end of the tube.  That way the tube protects your motors and props against hitting obstacles.

2- You're using nylon spacers, nuts, and bolts for the centre plate.  They will snap after any kind of crash.

 

A nice clean design, aside from those points.

Comment by john seaman on November 11, 2011 at 4:48pm

Nice build, and amazing results for the budget.  I noticed your motor wiring hanging out the end of the arms, part in and part out of that key slot.  A strong hit to the end of the arm might damage the motor wires, so when I used round ALU arms I enlarged the slot a little to pull the wiring off the end and zip tied it into place.  But I also crash more often.  :-)

Comment by John Hanson on November 11, 2011 at 11:00pm

Very cool!  Does the carbon give the gps any grief?  I used the plastic screws on the original frame legs and they broke many times, but saved the arms, I went to metal screws and there was less breakage but it was much more severe damage to arms, etc.  I now have spring mounted legs working very well sofar.

 I like the weight too. Any camera mount plans?

Comment by brett binnekade on November 12, 2011 at 12:37am

Thanks for all the compliments =)

 

@Ellison chan- Main reason for using nylon nuts and bolts throughout was to create failure points. its cheap and easy to just replace nuts and bolts. The way the frame is designed also makes it possible to take out any nut or bolt without have to remove any other parts. Damage to the main parts of the frame hopefully will be kept to minimum, As John Hanson is saying too=) Perhaps If I keep the 450 tubes standard length this will help protect the props =) Thanks for the tip =)

 

@John Seaman- Yeah the wires should be all the way in the slots with a rubber stopper on the ends. Still need to go get those. thanks for the heads up though =)

 

@John Hanson- I havnt actually tried the gps yet as it will be going on top but im busy making perspex cover to protect it first. I had the same experience with my last frame with using nylon and metal bolts hence the reason I went this route. I am planning on mounting a camera also using carbon to build the mount, thats why I made the landing gear quite high =)

Comment by Ellison Chan on November 12, 2011 at 8:36am

True about the nylon hardware, but you'll find that they just need too much changing.  I used to have nylon hardware too, and that's what I found.  And when I switched to steel hardware,  and the centre plates were cracking, but I was using acrylic plates.  I solved the cracking centre plate problem by using lexan sheets. They are more flexible, and once sandwiched between the tail booms with metal bolts, it's very durable. (haven't cracked any centre plate since I started using them)

Now, I'm using aluminium tail booms, which are easy to drill, and cut cleanly with a plumbers pipe cutter, and can sustain moderate crashes with no problem.  They can also be bent back into shape, and are half the price of CF tubes.  And not CF dust all over the place.

The longer tail booms do protect props.  My quad just bounces large obstacles.  The only other addition I would make is to add cross bracing between the tail booms to prevent smaller objects from entering the prop area.  A good place for CF tail boom braces or those training gear sticks.

Comment by Jeff Cartwright on November 25, 2011 at 8:19pm

Hey I'm wondering how you made the landing gear? did you make a jig, heat it up and bend it?

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