Hi there,
my first post here :) Just want to share this build log of my first DIY quadcopter frame in carbon fiber.
Setup
- APM with GPS and Magnetometer
- 25cm Arms
- 54cm from Motor to Motor
- 18Amp HobbyWing ESC
- 750kv Motors
- 10x4.5 Props
- Turnigy nanotech 2200mha 25-50c
Extras
- HobbyKing camera with mount
- Fatshark 5.8Ghz 100mw video transmiter
Weight
- 640gr only the frame, motors and escs
- 980gr Total with the Video transmitter (not in the pictures)
Is this a good weight for this frame size and config?
About the build
I used CF 1.5mm sheet and CF tubes with 13mm diameter, to mount the motors i drilled the holes directly in the CF tube and used some plastic prop adapters to reduce vibrations. I also used some thin double side foam between the arms and top plate this way the arms will not be in direct contact with the CF plate, don't know if it helps or not. To hold the APM board the the frame i used the same double sided foam, i used 2 pieces on top of each other to give it a bit more height.
I intend to use this frame at first for some FPV, i used 8mm CF square tubes to make a camera mount, it looks pretty cool :)
I could save some grams in the wiring, but in this first step i decided to keep the wires in its original length for later changes, right now its a mess of wires between the 2 main center plates.
Some things i noticed after the build and 2 short test flights:
I thought that it was a good idea to drill the holes in the CF tubes and mount motors directly on it, actually the tubes can handle the screws even very tighten, they didn't crack, but its hard to get perfect hole alignment without proper tools. I used an aluminum profile 15x15mm, inside diameter was 13mm exactly the outer diameter of the CF tubes, i easily drilled the holes in the aluminum profile to serve as guide and inserted the CF tubes inside. It worked pretty well, but the inclination was not so good, it's hardly noticed but motors have some minimum inclination.
I'm afraid this inclination error will affect the stability, anyone has something to say about this? I'm thinking in changing the arms to aluminum square profiles or get some mounts like Heli tail booms, it would be easy to adjust inclination.
I didn't tune PID's yet, so first flights were a bit unstable, also i wonder if having the plates stacks too high can affect the stability as well.
Also the arms look nice when short close to the motors, but will be a problem if it crashes, and i'm sure it will :(
Here are some pics of the build, Cheers!
Comments
Thx for your comments guys :)
@eduardo - The motors i used are these ones: http://flyduino.net/T-Motor-MT2212-750KV_1 , i also ordered propellers and power distribution board from this store. The carbon fiber sheet and tubes are not from HobbyKing, i ordered it at www.easycomposites.co.uk The tubes are much stronger than the HK ones.
@Mike - the tubes are strong enough, only problem was to get holes perfect aligned. Yes the velcro is for the video transmitter, and i plan to add telemetry. Unfortunately i didn't had time to test it properly, i plan doing it this weekend, i'll post my results then.
@Aleksandr - I'll post how i did the holes later
@F11music.com - i don't see a problem moving escs close to the motors, in fact it would be better because they would be cooled by the props.
Thx guys, i'll post updates this evening, Cheers!
hhhmmmm... nice... :)
When drilling holes, I used a tiny bit, and then stepped up with a cutter to enlarge the hole.
I am also curious what other people do. Just figured I'd share what I am doing now, so people can suggest better ways ;)
I found that you want to pay attention to the speed... when I was using the dremel too fast or too slow, I had problems. And I had to replace the bits when they wore down. I chipped/shreaded a few items when I was not doing it correctly.
For CF, I have cut and drilled using a dremel and diamond tipped bits and cutters. I have seem people use water, but I didn't. I know it is important to use a mask, and also to vacuum the CF dust, as it is not expelled by your lungs properly, and can basically become a sort of toxin, because of how your body (does not) react property to it to reject it, as it would with other substances.
Curious about what tool you use for making holes, from my small experience, i completely broke tube when tried to drill it. Thanks for answer :).
I don't know if you will have this problem, as the arm tube walls seem thicker than some people use, but I have often heard about the arms getting crushed or split at the motor mounts in this kind of CF mounting method.
I think the most common solution used is to insert a wooden dowel section to reinforce the CF arm, just for the part under the motors. This allows the motors to be firmly attached, and lets the wood take some of the strain.
I haven't used CF tubes like this, so I do not know from experience, just from reading what others have said.
It is always nice to see custom frame builds, thank you for sharing.
Is the other velcro strip up top for the video transmitter? I didn't see where the video transmitter is located.
Have you seen any problems with the ESCs causing interference with the magnetometer or sonar, given how close underneath they are?
Are you planning on adding Xbee telemetry?
I would be curious to know if you have any inter mod or other interference with the GPS, if you place the video transmitter that close (it might knock it out entirely, maybe you just lose a few of the satellite locks when the transmitter is on? I'm going to guess that it does not interfere at all, but I am still curious.)
simple and good design.
where are your motors from ?
are you using hobbyking cf tubes ?
regards.
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