By the end of the last article I had built the wing and were getting ready to put in the gear. Witness now the epic final installment of the build and maiden flight of the FPV Wing project…
Putting in the gear
The GoPro and FatShark Attitude FP gear had been tested and laid out on the wing. There was a period of swearing as I made up extension leads for everything. If you are supposed to keep everything as far apart as possible, you’d think the cables would be a bit longer as standard!
The placement of radio gear was a lot easier. The small 6ch receiver went far out on the right wing. No long range at the moment so simple 2.4ghz gear made things nice and easy. The servos were fitted in much the same way as other foam board builds with the servo hatches taped in place.
For the power train I chose to use a 28mm Turnigy inrunner that had never been used and was lying around. Stuck for an ESC I “borrowed” a large OEM unit from a HobbyKing glider and fitted this in the center section of the wing along with the FPV power filter. For the motor mount I made up a simple ply firewall that was glued directly to the wing base.
Now all I had to do was wait for some nice weather and go out for the maiden flight.
When CG measurements go bad…
Video speaks louder than words so hear is the maiden flight footage from the GoPro:
Somehow I had managed to measure the CG incorrectly when I did my initial calculations and placed the balance point 40mm to 80mm aft of where it should have been. I’m still not entirely sure how I got it onto the ground in once piece but it was totally unscathed.
I redid the calculations using this cool online tool – http://fwcg.3dzone.dk/ and stuck a bit of lead up front. We were ready to go again…
When ESC’s go bad…
The second flight took place this weekend. I still didn’t put the goggles on until I was sure of the wing’s performance, but I did plug them in a hand them to my (nearly) 4 year old daughter. This is what she saw:
The mistake I had made was thinking I could get away with matching up an untested prop/motor/ESC combination.
To be honest it looked awesome as the flames flickered in the center section and smoke streamed from the motor like something from a movie.
The damage was actually very limited. The ESC was of course toast but apart from that a bit of melted plastic on the power filter and small patch of melted foam was about it.
The important thing is that the wing flew and flew very well. It has a huge presence in the air and tracks through the air smooth and stable.
The mistakes made were in the power train setup. I should have spent a little more time and cash putting a decent motor and ESC in – lesson learned.
So what other lessons did I learn?
I will certainly be working on a new version of this wing and there are a few things beyond power system that I will consider:
- I think the spar needs to be a little deeper. It would be nice if I could get 2 batteries up front rather than using lead to balance the wing.
- I like the idea of actually making the ailerons deeper outboard and thinner inboard. The roll response was slower than I had expected and I notice a lot of FPV wings have larger outboard ailerons for crisper controls.
Other than that I still think this one is a winner. I hope to have another version in the air soon for some proper FPV work…
In the meantime, I do have the original plans available for download. They are far from complete but it you want to give it a go you can download below:
The construction of this wing follows the FT Versa Wing fairly closely so you could always check that out for some further guidance (or just ask below).
PS – I’ve also just noticed the plan doesn’t show the spar for the center section. Just extend the lines parallel from the end of one of the spars and you should be good to go.
PPS – CG on this wing is 160mm to 200mm back from the very pointy tips of the wing panels.