Aluminum arms for dji flamewheel frames

Hi everyone,

I'm a senior mechanical engineering student and I started flying multirotors early this year. I bought a DJI flamewheel 450 becuase it was very cheap and found that it was a good frame to start into multirotors. Something that I hated about it was that on every small crash that I had, the arms broke. Then I had to spend about 20 to 30 minutes replacing the plastic arms. Yes, the plastic arms a very cheap but spending that much time replacing the arm was a waste of time for me. So I thought about designing an aluminum arm that will not break or get damaged as easily as the stock arms. Having that in mind, I designed these aluminum arms. The are made using CNC machining and will have red and black anodized finish for orientation. They fit perfectly on the frame plates, they have the same thread size as the stock ones, so no modification is needed. They are 50mm longer to improve the flight stability. I added 3 holes on the motor side to have the option of adding a second motor mount for an X8 configuration.
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Luckily, I was living very close from the warehouse of ReadyMadeRC. I went there with my computer and showed my design to Tim (owner of readymaderc), and he like it, so he agreed to sell them.
Here are some pictures of the prototype arms on my quad:
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On the first flight with the arms I noticed the improvement in stability and control because of the extended length of the arms and because they are very stiff.

After about 2 months since I had the idea, they are now posted in www.readymaderc.com http://www.readymaderc.com/store/index.php?main_page=index&cPath=76_155 They'll be in stock in about 2 weeks so you can pre-order them now. I only made an small batch so they might sold out fast.

Please give me your feedback about this.

Thanks,
Michael Maymi

 

I designed the arms for the 450s because there are a lot of them out there but I can easily adjust the design to be smaller to fit the 330. It depends on the market.
As far for the center plates, I have not considered using aluminum because I think that carbon fiber will be a better option and can be cut using the same process as aluminum. A one piece carbon fiber arm will be way more expensive than the machine aluminum arm but with the plates the only difference is the material cost.

 

I know is not cheap but if you have been around in the RC hobby you'll should have seen aluminum CNC parts that are a lot smaller than the arms and they even cost a lot more. Just look for helicopter cnc aluminum parts. I worked hard to produce them at the lowest price possible in the United States and after quoting with different suppliers, I found one that made it possible. CNC parts are very expensive but the final product is great. Plastic might spring back if the stress was not enough to pass it's yield point and with my experience the yield point of nylon is very low compared to high quality aluminum.

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I used a finite element analysis software to find the weak areas of the arm, I added material on those areas and remove some where it was not necessary. I used a 20 lb force and the results where pretty good so they will support more than that before yielding. I have not measure how much force it takes to break the plastic arms but I bet you can easily break them with your hands, my aluminum ones you can't. I crashed my multirotor already, ( too bad I was not recording) and basically everything broke but the arms. It was kind of funny because I really did not wanted to crash it but there was some failure with the controller. I was impressed myself that the arms where in perfect condition considering of how hard the crash was. Give them a try, you won't be disappointed.

 

The optional coax motor mount will be only available for the aluminum arms. You might have to do a lot of modification on the plastic arms but I'm not sure if it will work.

 

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Two quick pictures of final production arms. They look sexy! :nevreness:


NOW IN STOCK! but they are selling too fast so go now and get yours before they are gone.
http://www.readymaderc.com/store/in...h_in_description=1&keyword=aimdroix&x=32&y=14

 

The picture provided on the description is under vertical stresses. Is not only about crashing, it's a good advantage that they are more stronger, but the biggest advantage is the increase in stiffness over the plastics arms. This makes your multirotor to fly more stable and you'll notice a big improvement flying on windy conditions.

 

Great :nevreness: If you have any questions write me to support@aimdroix.com.