The first FPV wing suffered a balance problem followed by a catastrophic on-board fire during the maiden flight. I didn’t want to trust the old airframe so I started work on version 2.0…
FPV Wing 2.0 – welcome an old favourite
The first FPV Wing design suffered a number of problems but the most glaring of these was that I made it a bit big! Whilst impressive in the air (for the short time it did fly) it was far too big to fit easily in the car.
I knew from the first FPV Wing, and other builds that the Flite Test Versa Wing is (as the name suggests) an immensely versatile design. The only problem was the lack of space in the center. The obvious solution was to take the wing panels from a FT Versa Wing and add a center section.
Bringing it all together…
The center section proved to be a bit of a pain and took a long time to come together as I had to wait over Christmas for some parts to be delivered. In the end the easiest way I found to do it was to cut the foam board, lay everything out and then glue just the bottom sheet into place. Once this was done I could hook up all the electronics before pulling the top layer over and gluing into place.
Test flight number 1…
The first day I went out things looked good. I had tested everything and the airframe was sound. I stood on the runway and hit the throttle. Much to my surprise the prop forgot to open, vibrating the motor mount clean off the back of the airframe…
Test flight number 2…
So apparently there is such a thing as a “prop-stopper” when you turn a folding prop around. Live and learn!
The damage was minimal and I rebuilt the mount quickly. I replaced the prop with a solid APC style electric prop, just to be sure. Heading back out to the field the weather was not looking good. The wind was getting up and I really should have known better…
I also didn’t have anyone with me so I was going to have to hand-launch myself and hope for the best. So… everything checked, throttle up, throw the plane… straight into the ground… bugger!
Test flight number 3…
So apparently it’s not a good idea to hand-launch pusher-engined wings that are completely untrimmed and un-flown. Live and learn!
Again, the damage was minimal so I put it all back together. This time I also removed all the FPV gear and replaced with a stand-in weighted GoPro to get the balance right.
I had learned my lesson from the last attempt but I still didn’t have a spare hand to launch the model. So I decided to bungee launch the model so I could at least get some height to start the test.
This proved to be a great idea, right up to the point at which I started the motor too soon, fouled the tow line and burnt the motor out… bugger!
Test flight number 4…
So apparently it’s not a good idea to start a pusher motor whilst the bungee is still attached. Live and learn!
It didn’t take long to get the motor swapped out and back to the field. This time it was a nice day, I was well prepared and I knew the pitfalls of previous attempts.
I was going to go with the bungee launch again as it worked right up to the point where I stuffed it up. Things looked good, model tracked straight up the line, didn’t start the motor early, hook won’t release… what… bugger!
PING!
The line finally released and we were off. A little bit of trimming and the model was flying straight and true. After that I tried some hand-launches at it proved pretty easy with the model now trimmed out – so much so I strapped on the GoPro to get some footage:
A happy ending at last!
Finally the FPV Wing project has reached a successful conclusion with the FPV Wing 2.0. Although, we’re not quite there yet… this model still hasn’t actually been flown FPV.
Well, the gear is now back in and we are ready to go so stay tuned for the footage…
View the complete article at http://red20rc.org
Nice work ! and thanks for sharing :-)
I'm also looking for adding a center section to my wing.
Could you confirm me that your are using the same foam as the one used for the 2 wings (6mm foam) ?
And how did you get this fixed to the wings? simple tape and hot glue did the job?
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The foam in the center section is exactly the same as that used for the wing panels. I just had a blue sheet spare that I bought from Officeworks here in Australia (and to be honest it isn't the greatest quality for building).
With joining it is just glue and tape. I joined the bottom skins first to make sure it was all flat. Then I put the electronics in before folding the top over and "closing the lid". I then ran over all the joints with reinforced tape. The resulting joint is absolutely solid. I don't think I have any concerns over the strength in normal flying...
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Then it's strong, even with the gopro?
I wil try to do the same, and maybe I'll add a carbon pipe if I'm adding some fpv stuff on it !
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I must say though that it does seem very strong without any other reinforcement. It is quite surprising how strong this foam is when joined with hot glue. Hopefully I'll get some more flying in over the coming week (once this rain passes) so I'll soon find out if there is a weakness!
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I have just published the plans for this Versa Wing modifications at http://red20rc.org/fpv-wing-plans/
Enjoy!
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The motor in this one is an old 2400kv 28mm outrunner that I had sitting around with a tiny 7 inch prop on it. It really screams but it does seem to perform rather well. I am also in the process of testing out a similar size wing with a KFm-6 airfoil that has a Turnigy 2836/8 1100kv motor on it. That is turning a 10x4.7 folding prop and has more than enough power for vertical performance.
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I haven't done any sums but I would think the tiny little motor and 7 inch prop probably wouldn't be enough but the Turnigy motor and big folding prop would have enough grunt.
Other than that I might be tempted to look at something like a Park 480. I had one in my UAV thingy and with a 10 inch 3-blade prop the power was awesome (and a bit too much for that model!).
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