Following on my Carbon H-Quad, I have now built a foam one!! (Ok, it has a bit of carbon too)

The problem with the full carbon one was weight. Yes, it was super stiff but it was around 300g heavier than my X525 frame and thus my flight times were 3+ minutes shorter, thinner carbon plate would've helped but it's fairly expensive, difficult to come by (here) and difficult to work with.

My main priority was portability, it has to fold as small as possible and I also really do prefer flying the H-frames, orientation being the major advantage but also no props in onboard video.

I had a few blocks of a hard black EPP foam and I picked one up the other day and it was really firm (no twist) AND light (100g for the whole block), suddenly... bing!... I had spare arms for the X525 so why not.

A quick drawing in CAD to check the angles and sizes and some problem-solving with mountings and construction and here it is... took about 2 hrs to make and another 2-3 to assemble. I used the carbon pivot plates cut off from the old frame and they're just cyanoed to the foam with 2 bolts right through and 2 through just the arms and plates. Flies really well with very little twist (not enough to cause the yaw problems associated with twist)!

Weight is 925g ex-battery so 78g lighter than the X525 with the same components (The carbon frame was ~1300g).

Diagonal (open): Motor to motor (open): Length (folded, max): Width (folded, max): Weight:
EPP-HFQ 690mm 490mm 435mm 160mm 925g
X525 550mm 400mm 795mm 160mm



Before attaching the motors, closed Open, no components
3 4
5 In the old box!

Views: 14562

Comment by Louis on April 12, 2013 at 9:58am
Cool dude !! Now seeing is believing. Very cool oom.
Comment by Noth666 on April 12, 2013 at 10:22am

Nice but is there a stiffener lenghtwise in the body section all the way front to back?

Also, if you want to save more weight, ditch the alu arms for square formed carbon tubes, will save ~66% of the arm weight often. Alu in most cases is 3 times as heavy, plus you could go down a size to 10mm or so. 

Comment by Morli on April 12, 2013 at 11:25am

does the youtube link shown work?  the second doesn't for me :(

Graham,  cool job.

Hobby king has similar folding H frame.

Comment by Graham Dyer on April 12, 2013 at 11:34am

@Morli, this address is slightly different for the video:

@Noth666, there are two 5mmx0.8 mm strips of carbon on the top between the two end plates, not sure if they're doing a lot as they really need to have been diagonal. There is a small bit of twist which I may try later to minimize but at the moment it's flying well!

Yes, I may well ditch those Alu arms, not easy to find 10 or 12mm square thin wall tubes here though, will have to order online somewhere.

Comment by C. Escudero on April 12, 2013 at 12:55pm


Comment by Randy on April 12, 2013 at 4:35pm

Good for Sparkfun AVC where we need to fly over water.

Comment by John Githens on April 12, 2013 at 4:43pm


Comment by Dave G on April 12, 2013 at 10:19pm

Impressive!  Well done.

Comment by Louis on April 15, 2013 at 1:35am

Ok now I believe you, it flies awesome, Now I am impressed Mr G !! 

Very well done.  

Comment by Glenn M on April 15, 2013 at 5:07pm

I need to find a big chunk of EPP by the look of it. This frame is pretty much exactly what I want to build...


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