RCTimer DJI-style Arm Dimensions

[colorex]

Hi there, colorex here.

I'm in the planning stage of making a quadcopter frame like the TBS Discovery / OFM Seeker / Reptile500 etc.

I am going to use the RCTimer version of the DJI arms, included with this frame kit:

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=686&productname=

However I haven't ordered any arms yet, never ever seen them other than in pictures.

I need to know the hole pattern for these arms, to make plans for lasercutting plywood.

Would anyone be so kind to provide these measurements? I have found some on other threads but they are not complete.

Distances shown in attachment:

F: distance between the two bottom holes.
G: height of root of arm (inner distances between top and bottom plate.

I'd appreciate tolerances within 0.2 mm, use of calipers encouraged over rulers.

Thank you very much in advance for your time and answers.

 

[Tritium]

A=22.5mm
B=16.0mm
C=20.0mm
D=07.5mm
E=38.0mm

Hole Location on bottom of arm for attachment to bottom plate is 20mm between centers wide and in same plane through the arm as A dimension holes. 6 screws per arm / 4 top and 2 bottom.

Thurmond

 

[colorex]

A=20.5mm
B=14.0mm
C=20.0mm
D=07.5mm
E=38.0mm

A=22.5mm
B=16.0mm
C=20.0mm
D=07.5mm
E=38.0mm

Thurmond

Thank you, Tritium. Are these your own measurements?

 

[Tritium]

Andre, Yes BUT see my corrected measurements above.

Thurmond

 

[colorex]

Andre, Yes BUT see my corrected measurements above.

Thurmond

No problem. That's exactly why I asked

 

[colorex]

Andre, Yes BUT see my corrected measurements above.

Thurmond

Could you provide the height (inner distance between plates) and the distance between the bottom holes? I believe they are different from the top ones.

 

[Tritium]

Could you provide the height (inner distance between plates) and the distance between the bottom holes? I believe they are different from the top ones.

27mm. Edit changed from wrong measurement.

Thurmond

 

[colorex]

22mm.

Thurmond

Isn't it closer to 32mm?

 

[Tritium]

Isn't it closer to 32mm?

Man I am having trouble reading these calipers, 27mm between plates.
Measured it in English and converted to metric this time.

By the way I REALLY like this arm.

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=845&productname=

Same mounting measurements too.

Thurmond

 

[colorex]

Man I am having trouble reading these calipers, 27mm between plates.
Measured it in English and converted to metric this time.

By the way I REALLY like this arm.

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=845&productname=

Same mounting measurements too.

Thurmond

Hehehe, thanks!

I might get those arms if I need something longer for more stability.

 

[Tritium]

Not only longer but stronger due to design changes (not flat top or bottom).

Thurmond

 

[colorex]

Man I am having trouble reading these calipers, 27mm between plates.

Thurmond

You should get some sleep, Thurmond.

I downloaded the plans for the ov3rquad, plate offset distance is 36.9mm there...

Don't take offense, I make many repeated mistakes myself sometimes.

I'll post a diagram later, to clear things up. Thanks a lot for your help!

 

[Tritium]

You should get some sleep, Thurmond.

I downloaded the plans for the ov3rquad, plate offset distance is 36.9mm there...

Don't take offense, I make many repeated mistakes myself sometimes.

I'll post a diagram later, to clear things up. Thanks a lot for your help!

Not a lack of sleep. I am studying for my Extra Class ham license and the math is making me crazy. I haven't had to use my algebra, Trig or calculus since I was 20 and that was 34 years ago. I am remembering how much I have forgotten.

Andre you are absolutely correct. I grabbed my 800mm frame to measure the distance between plates and it is 27mm. The frame you linked IS 37mm as measured on my quad frame from RCTimer. My bad. Definitely ignore any thickness measurements till I check them again. Other dimensions should be the same though. I will remeasure and post any discrepancies tomorrow.

Thurmond

 

[KKArioKA]

didnt trusted my measurements !!

 

[colorex]

didnt trusted my measurements !!

Nopey Didn't trust the measurements from the ov3rquad, the TBS plan, or another RCGroups member either.

They are all different!

 

[colorex]

http://www.rcgroups.com/forums/showthread.php?t=1824077

 

[Tritium]

E is 31mm

The rest of my measurements in post # 2 are good at second check.
As stated in Post # 13, 37mm is the distance between upper and lower plate.

Thurmond

 

[colorex]

Thanks! Will update the drawing tomorrow.

 

[colorex]

Well :$ I haven't updated the drawing yet, but my RCTimer frame is here. I like the looks of the FG plates, the holes don't really line up but I'm not using those anyway. I'll finish up my drawing and get those laser cut plywood plates down from Quito as soon as possible.

Apart from the holes not lining up (which can be easily fixed) I like the RCTimer package a lot.

Unlike HobbyKing who ship in boxes, RCTimer shipped my stuff in a bubblewrap envelope. Items in it:

Plates

Screws

Velcro straps

Zip ties and Hex key

Arms

Quickly assembled frame, to see what it looks like

This will give me enough fun to start finishing (LOL) the plans for the plates.

 

[KKArioKA]

Looks familiar to me


RCTIMER KIT is far superior than HK KIT

rctimer have 2 bags of screws labeled, HK have just 1 bag with a fixed size and they were not enough to complete my frame. Also HK is 2.5mm and rctimer is 3mm screw.

Rctimer kit have a velcro, a battery strap, zip ties and a allen wrench; HK kit have just a velcro and no zip ties or battery strap.


Colorex i would suggest you take it easy on the assembling, the head of the screw is soft ! so is the crappy allen wrench.

looking closely to the picture, i can see that you only fitted the frame with one screw on each side ... good job !