Scratch building quad frames, and prop clearance.. - RC Groups
Shop our Airplanes Products Drone Products Sales
Thread Tools
May 04, 2012, 06:34 AM
Martin - AKA mr.sneezy
PLMS's Avatar

Scratch building quad frames, and prop clearance..

I've read hundreds of posts and many many threads on this forum so far, but I've not stumbled across posts discussing the way to size a frame for a quad yet. (yes I used 'search this forum'

Two initial questions - Is there a thread here discussing how to build a quad frame that's 'just big enough' for a certain spec motor and props ?

Then if not, can anybody tell us how much clearance you should have between the blade tips as they arc past the pod carrying the flight control board ?

I'd guess that you'd want enough so that down droughts from the blades does not blast across the pod/board and induce vibration or buffeting. I'd guess that would be bad for a baro sensor as well.
Soooo.... How much clearance seems to be enough ?

A third question while I think of it - Are all X style quad frames 'square', or do any use frame angles that make it longer front to back than the width ?

(My equipment is going to run 10x4.5" or 11x4.7" SF props BTW)

Thanks for any answers.
Sign up now
to remove ads between posts
May 04, 2012, 02:14 PM
the frame should be symmetrical as possible. foam on the FC and balanced blades also help a lot on vibrations. keeping the airflow away from the FC would be good! that would be especially for baro as it measures air pressure. most people put some foam over it to help more.

when i made my cheap CF frame, it was about 6in between each prop and about 5in from the end of the prop to the FC. But you can move them closer if you want. i think it was at least 3in between props(for smaller sport quads)? and then a props length between props for super stable. i dunno, but its so that the air being pushed by the props doesn't interfere with other props. the further the props are apart, the more stable, but slower yaw and flips.

here's mine:!.jpg
and log:
May 05, 2012, 01:11 AM
Martin - AKA mr.sneezy
PLMS's Avatar
Originally Posted by sirbow2
here's mine:!.jpg
and log:
Ah, very functional looking, my kind of style.
I noted that you have extra length on the arms past the motor clamps. Is that to 'tune' the arm length to find the stability sweet spot, or to protect the motors a bit from being hit ?
Thank for the info on the prop clearance. Sounds like 3" is a good minimum then so far.
May 05, 2012, 02:37 AM
more of a prop protector. i was going to go all the way past the end of the props, but the CF wasn't long enough/ motors not close enough, oh well.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Scratch Build advice - design, motors, props. glenneaux Electric Plane Talk 2 May 02, 2012 12:24 AM
Sold Dex mini quad frame w/ Hoverfly Sport / motors / escs / props beeker_12 Aircraft - Electric - Multirotor (FS/W) 7 Apr 14, 2012 12:42 AM
Build Log Scratch Build Quad with HK Parts Flying Penguins Multirotor Drone Talk 39 Mar 11, 2012 08:29 PM
Help! Micro quad, scratch build help? r6_cannibal Multirotor Drone Talk 2 Feb 03, 2012 01:40 PM
Build Log New CNC Joe Frame 650mm Quad Build Z06 Tony Multirotor Drone Talk 76 Feb 17, 2011 08:10 PM