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Old Feb 03, 2011, 04:51 PM
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Making my first quad copter, maybe my DIY frame is too heavy?

After a few weeks of stalking this forum, lusting after all these amazing machines I finally decided to build a quad. I like DIY stuff so after looking at all the options I decided on a MultiWii. I ordered a lot of the parts, but they won't be here for a while, so I headed down to the home depot to see what I could put together as far as a frame.

I ended up using 3/4" square aluminum tube and a couple of corner brackets to build the frame. It's about 29" end to end (is that too big?), and I intend for this to be a stable FPV platform. I was thinking of going with 10" props, and I wanted to keep them as far apart as possible to prevent wash when descending.

The whole thing with all the bolts seems a bit heavier than I was expecting. It's about 500g - 600g, maybe 1.2-1.3 lbs. Would that be OK, or do you think I would need to come up with a different frame? Is this too wide?

I did not order the motors, escs, and props yet - that has me really confused. Any suggestions on what size motors and props to get considering I will be adding FPV + gopro + possibly a DSLR in the future?
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Old Feb 03, 2011, 09:47 PM
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Why not use a flat bit of board or plastic to join the frame. instead of using those heavy L brockets.
also 10mm square tube would be better.
some thing like this pic

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Old Feb 03, 2011, 10:24 PM
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3/4 in tube is very big, it won't benefit you at all unless you want a heavy lift quad.

I use 3/4 for my heavy lift hex and still have to spend 3 hours milling out all these hole to save 200grams of weight.


10in prop with 29inches quad is bigger than it need to be IMO. I think you can cut it down a bit to shave some weight.
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Old Feb 03, 2011, 10:32 PM
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I would also recommend not cutting one of the axis and just keeping it as one long bar, like I did here: http://www.rcgroups.com/forums/showthread.php?t=1380176
Slightly better structural strength incase of a light crash.
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Old Feb 04, 2011, 08:54 AM
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I would also recommend not cutting one of the axis and just keeping it as one long bar, like I did here: http://www.rcgroups.com/forums/showthread.php?t=1380176
Slightly better structural strength incase of a light crash.
Thanks for the replies and ideas. I wish there was a noob section, I feel silly posting questions like this when I see most of the more advanced coversations going on in this forum.

I thought of having one axis not cut AFTER I assembled it. Oh well, this is a learning experience for me, I figure I will make my mistakes on this one and then try again if it just won't fly.

I will try and trim down the arms for sure. That is a great idea to mill out the arms for weight savings, but I don't have access to a mill.. maybe I could just go crazy with the drill press and make it look like swiss cheese to save some weight? Luckily my time is worthless, so I dont mind spending a few hours whittling away at it.

Also, any suggestions on where to get the plastic board? Craft store maybe? Or some place online I could get something more specific to this task?
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Old Feb 04, 2011, 09:35 AM
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Originally Posted by bigdumbdane View Post
After a few weeks of stalking this forum, lusting after all these amazing machines I finally decided to build a quad. I like DIY stuff so after looking at all the options I decided on a MultiWii. I ordered a lot of the parts, but they won't be here for a while, so I headed down to the home depot to see what I could put together as far as a frame.

I ended up using 3/4" square aluminum tube and a couple of corner brackets to build the frame. It's about 29" end to end (is that too big?), and I intend for this to be a stable FPV platform. I was thinking of going with 10" props, and I wanted to keep them as far apart as possible to prevent wash when descending.

The whole thing with all the bolts seems a bit heavier than I was expecting. It's about 500g - 600g, maybe 1.2-1.3 lbs. Would that be OK, or do you think I would need to come up with a different frame? Is this too wide?

I did not order the motors, escs, and props yet - that has me really confused. Any suggestions on what size motors and props to get considering I will be adding FPV + gopro + possibly a DSLR in the future?
Try lighter tube... if it's the 3/4 inch stock I am thinking of it is very heavy. Go to home depot and ask for the aluminum towel rack bars. They are similar in size, CHEAPER, and very very light. Lighter than G10. Should be well under 8oz. My G10 frame is 8oz and it is quite a bit heavier than a towel rack frame. Below is my towel rack frame. Make the center plate from 1/8" aircraft plywood from the nearest hobby store, or any other thin plywood.


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Old Feb 04, 2011, 09:43 AM
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For this size of quad, lighter tube is the way to go. Also, I would not suggest to make 1 cross bar long... yes it add strength, but only to 2 arm. In a crash, if you bend one side. Then instead of having to replace one.. you have to pull the other one out and cut it down... So what's the point?
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Old Feb 04, 2011, 01:00 PM
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Multi rotors are becoming very popular. true would be great if rcgroups gives a bit more space for sectioning the multirotor area.
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Old Feb 04, 2011, 01:45 PM
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Multi rotors are becoming very popular. true would be great if rcgroups gives a bit more space for sectioning the multirotor area.
I couldn't agree more.. As a newbie this forum is an amazing resource, but hard to navigate and find specific content. Seems like one thread with 600 posts encompassing ask aspects is the current method.

I am also surprised that the arf and rtf commercial offerings are so far and few between.
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Old Feb 10, 2011, 07:54 AM
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Thanks everyone for your suggestions.

I drilled a ton of holes, now it looks like it's made from an erector set.

I also switched out to Lexan plates in the middle, which helped reduce weight... and I also added nylon bolts and washers from Lowes, also saving weight, so it's at about 380g now, without any landing gear or platform for electronics.

Using small cut sections of fuel line as washers to help isolate vibration..

Any suggestions for a good wide (cheap) landing gear that could also hold a gopro?

Of course, hobbyking released that $14 frame after I already spent $30 on my DIY frame - @#@!$!@!!
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Old Feb 10, 2011, 08:44 AM
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Originally Posted by bigdumbdane View Post
Thanks everyone for your suggestions.

I drilled a ton of holes, now it looks like it's made from an erector set.

I also switched out to Lexan plates in the middle, which helped reduce weight... and I also added nylon bolts and washers from Lowes, also saving weight, so it's at about 380g now, without any landing gear or platform for electronics.

Using small cut sections of fuel line as washers to help isolate vibration..

Any suggestions for a good wide (cheap) landing gear that could also hold a gopro?

Of course, hobbyking released that $14 frame after I already spent $30 on my DIY frame - @#@!$!@!!
ahhhhhh but your frame looks better! and....... the way you have it setup now it would be very easy to change it to a folding frame just by removing the correct four bolts when ready to transport


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Old Feb 10, 2011, 09:07 AM
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Of course, hobbyking released that $14 frame after I already spent $30 on my DIY frame - @#@!$!@!!
That $14 frame + minimum of $10 for shipping $24 ..

Also its out of stock. They have to have more made. Its lunar new year ( spring festival ) The entire country is turned off untill at least the 15th. Then the groggy wake up from the coma.Then the factory that makes them has to catch up on its backlog from the holiday.

I doubt you will see stock in them until st paddys day.

I have a frame similar to yours .. $3 towel bars from the local home center.

Connected with a custom ( + shaped , not square ) plate of 1/16 in steel , held together with pop rivets. AUW with a 2200 battery was just a hair shy over 1kg. And it flys well with 18a speed controllers and kda 20-22 motors swinging 10X4.5 SF props.

I think you are well on your way to a good first frame. Likely you will make changes and adjust for your second one ( and third .. and forth .. ) but isnt that what this hobby is all about ??

( Once it clicks that you can basically drop 4 motors onto anything and make it fly , EVERYTHING will look like a quad frame to you. Or perhaps I am just insane :-D )
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Old Feb 10, 2011, 09:33 AM
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( Once it clicks that you can basically drop 4 motors onto anything and make it fly , EVERYTHING will look like a quad frame to you. Or perhaps I am just insane :-D )
Hmmm... (looking at wife's chihuahua)...
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Old Feb 10, 2011, 09:45 AM
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Hmmm... (looking at wife's chihuahua)...
Funny you should mention that

My evil mind has been plotting ..

http://hobbyking.com/hobbyking/store...dProduct=11935

Thats a 25c 5000 .. Which , if it actually performs as rated , should be able to provide 125 amps continuous with 250 peak.. Quick back of the napkin calculations say that if I can find the right props and motors .. I should be able to lift between 10 and 15 pounds with it ..

SO ... if I can figure out a frame and get the auw around 5 pounds or so .. The local taco dog ( Jack ) who weighed in at just over 5lbs last time I checked him , will be getting a ride around the yard.


And yes I am mostly joking.. but not totally joking

/me goes off to petco.com looking for harnesses.
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Old Feb 10, 2011, 10:07 AM
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I have a fat Chihuahua - 10lbs.

It would end up being more of an aerial hawk feeding platform....
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