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Ultimate KFm6 FPV Wing

by | Sep 25, 2019 | 0 comments

Remember this…?

This was the first KFm wing that I ever built back in 2014. It only flew a handful of times and never under FPV control, however it did fly VERY nicely.

I’m going on a bit of a tour with work in a few weeks time and I really wanted a new FPV wing to take with me. I needed something a decent size, hard wearing, and about as simple as it gets – so I decided to turn this old KFm6 design into the ULTIMATE KFm6 FPV WING!

Keep It Simple Stupid!

The design is about as simple as it gets. A single core layer of foam board outlines the whole shape and then two steps above and two below form the KFm6 airfoil.

In total I used about 1.5 sheets of 40″x32″ foam board. There are no spars, but I did include a couple of design improvements which I’ll go into in more depth below…

FPV POD

For this wing I designed and cut a custom FPV pod. I don’t want to go mega-long-range with this wing so the battery bay is sized for an 1800mah 4S Tattu LiPo.

Slots in the front portion are sized perfectly for the Foxeer camera and GoPro Session.

MOTOR MOUNT

Another custom made item for this wing. The motor mount has two 6mm thick lugs on either side that root it firmly into the wing core.

Press nuts are epoxied into the rear firewall plate so that motors can be easily removed for repair.

ROBUST CONTROLS

For once I used some decent servos! metal gear slim servos are embedded into the wing panels and finished with 3D printed covers.

Very strong pillar type control horns clamp to the ailerons and use ball links for smooth operation.

LEADING EDGE MODS

It’s hard to tell but the leading edges are more than meets the eye!

Inlaid Depron strips are sanded to shape and then a 5mm hardwood dowel forms a hard front edge. A cloth tape coating finished the wing with a smooth surface.

Finishing Off

All wiring was routed through channels cut into the middle panel. This keeps things nice and clean for finishing although it does make repairs to wiring almost impossible.

The panels were coated in packing tape before final assembly. The coloured tape is very easy to use and gives a bit more resistance to the foam board without adding much weight.

Control is via the FrSky D4R-II receiver. There is no flight controller and no OSD on this build – just a boy and his wing going back to basics.

All up with LiPo and GoPro installed the weight is 1260g, which is more than reasonable for an 1100mm wing. The Turnigy 2836/1100kv motor and 9x5 folding prop should be more than adequate for cruising around the countryside.

Incidentally, with this setup the CG is pretty much spot on at 160mm back from the nose.

Time to get Airborne!

Okay, so at the time of writing this I have yet to maiden the Ultimate Kfm6 FPV Wing.

Everything is programmed, checked and the batteries are charging though so hopefully by the time you read this I’ll have some good news.

Watch this space…