Integrated Motor Mount. DT750, 700, XXX

by bofred | August 5, 2013 | (23) Posted in Tips

Hi all. I'm new to this forum. And I saw that many people are using the DT750, 700 motor in multicopters. I too use them (for many years) and think they are great. But the motor mounts are not.   In my first tricopter (signguy style) I made an over worked motor mount. It worked great but was hard to make.

I thought I might share my idea of mounting the motor in a multirotor now. It has many advantages. Its light, easy made, sturdily and looks nice ;)

I use a common 10x10 mm aluminium rod bought at Bauhaus (a common hardware store in Sweden). The rod measures 8X8 mm inside like the DT750 diameter.

Simply drill a 8mm hole 25mm from the outer edge in the center of the rod and a 3.2mm hole 18mm from the edge (angled 90 deg. from the 8mm hole).
Then use a small iron saw and make a ~8mm long slit from the 8mm hole towards the edge of the rod.
Fasten the motor with a ~M3x14. Remember to use loctite. See pictures:

Happy flying! 

 

CAUTION!

I found out there are two different kinds of DT750 motors. fzr1000 had motors with 9mm diameter and those wont work in this solution. So dont go buy anything before you measure the motors...

- Find this article & others like it at www.FliteTest.com -

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COMMENTS

apache64 on August 13, 2013
Great idea, it keeps the weight down and a lower profile multicopter, whilst protecting the wires too.
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RMS on August 14, 2013
Another way to do it (Signguy style) is to cut the slit to the end of the arm and just use a tie wrap instead of the bolt.
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bofred on August 15, 2013
That was a really good idea I have to test. I like simple solutions and zip ties :) The risk I can see in such way of mounting the motors is a twisting movement of the aluminium rod when making the slit all the way to the end of of the rod. And maybe not enough force when compressing the 8mm hole? Did you try it? Thanks /b
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baru on August 8, 2013
That's fantastic - so simple and effective.
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charlies on August 8, 2013
bolt through the end of arm as 'safety' to keep wood from splitting? Seems like a good idea.
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ccrawford on August 9, 2013
I think the general idea is it's a metal (aluminium) arm and that the bolt and cut together work to clamp the motor in the hole.
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sailorJohn on August 12, 2013
Thanks for the idea, I've been avoiding this style of motor due to mounting problems, don't have a 8mm drill but a 21/64 th should work.
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saitek93 on August 12, 2013
Really great idea! That would have simplified my last build tremendously. Great thinking though
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Cyberdactyl on August 8, 2013
Love it. Nifty. Well worth considering since it saves several grams of weight.
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bofred on August 11, 2013
Thank you, I'm glad you like it. Also, I forgot to mention that when the motor is mounted close to the aluminium rod the twisting torque on the rod becomes smaller. That makes the motor more "firmly mounted" and that should result in faster adjustment of the motor speed (more stable multicopter). That is why I like to mount the motor close to the rod and this is a easy way of doing it:)
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fzr1000 on August 19, 2013
Hello, this is a good idea, thanks. But with my motors (DT750), doesnt work. The DT750 diameter is 9X9 mm, the 1mm left turns the 10x10 mm aluminium week... i will try to find 15x10 aluminium.
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bofred on August 20, 2013
Thank you, you are right. There seems to be two different kinds of the motors. I recently bought some TurBORIX DAT-750s for spares and I opened one up just to measure it to be 9mm. That is bad news for me because I cant use them as spares. Did you buy yours from HobbyKing? Are they also 9mm now? (All my old HK DT750 are 8mm)
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fzr1000 on August 20, 2013
Hi, yes I bought them from hobbyking, I have six of them, all 9mm. I am going to try to find aluminium with more than 10mm in one side but maintaining 10 in other for not having to do a new frame...
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WBG on August 15, 2013
På vilken avdelning på Bauhaus hittade du aluprofilerna, och vilket varuhus var det på?
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bofred on August 15, 2013
Jag köpte mina profiler på Bauhaus i Barkarby. Vet inte vilken specifik avdelning det är men det finns en gång runt mitten av varuhuset där det finns en massa olika aluminiumprofiler och andra pinnar. Typ järnavdelningen... Det brukar finnas 1m och en längre som jag tror är 2m. De har funnits där länge och är nog standardsortiment. Jag är mästare på att krascha så jag har köpt ett antal under åren...
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WBG on August 18, 2013
Ok, tack för svaret. Får åka till varuhuset i Linköping o leta, hittade inga i deras webshop!
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fonzi on August 14, 2013
Awesome! This helped me soo much. I super glued the bolts and nuts on the standard mounts to avoid vibration. After a few crashes I could no longer use the frame. I couldn't take off the mounts, so i thought that my motors were useless. This article fixed everything! :D
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Integrated Motor Mount. DT750, 700, XXX