H-Frame Folding Quad with EPP fuselage - HFFQuad

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

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

The problem with the full carbon one was actually 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, I had used 2mm carbon sheet whereas 1mm would've been adequate, but it's fairly expensive and a little difficult to come by (here).

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 visible in onboard video from a wide angle camera.

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!... why not, I had spare arms for the X525. (Note: This foam is very firm, not the soft stuff that some new 3D planes are made of.)

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. I used two end mounting plates from the X525 frame on the orange arms to ensure that the motors were equi-distant apart when in open position because the front arms' angle is more acute so the motors end up being closer together. I added the glass fiber braces later accross the top of the EPP although I suspect they are not really neccessary.

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).