29 January 2008

Making a V tail

I have recently finished building a "Banshee", a 60 inch slope speed foamie from Tuffplanes. I bought it because I liked it's no-nonsense look as opposed to the many semi-scale planes they had on offer. (Tuffplanes seem now to have closed as the enire website is out of stock). The plane is now finished and flies very well. It needed masses of lead in the nose to get the C of G right due to both a short nose and a fibleglass strengthened tail, so she is not made for light winds - however when the wind is strong, as it was on Sunday at Switchblade, she goes zipping around the sky, and I look forward to entering her in a speed comp.

My biggest challenge however was the V tail - I was supprised when the kit arrived that all I got was a balsa plank and rough sketch showing me how to assemble the tail. I was very worried I'd mess it up and decided to make a jig. First I did a computer printout of the 110 degrees I needed, then cut out 2 identical cardboard frames that I had to line up exactly - also ensuring the two sheets were parallel and 90 degrees from the tabletop. Once it was set I put the two cut out surfaces into the jig shamfering the bottom of each and doing an initial light epoxy glue. Once set I did a second epoxy, then put 3 layers of fibreglass (in diminishing lengths) on both sides.
The next big challenge was gluing it to the fus. I got the fus perfectly level, then cut the jig in two and put the halves either side of the tail as a former before epoxying the tail on. Again finishing the tail/fus join with 3 layers of glass.
The final challenge was the control surface connections. Again all I got was a brass pipe and a sketch... My only concern was that I wanted top hinged elevators (the kit suggested there was no need for rudder input or "ruddervaters") using book binding tape and not the central hinge on a curved elevator end they where suggesting . The problem came as the copper pipe (which is curved) would run up the joint. But in the end it worked out. Getting the brass bent at the right angle was quite a mission though. I also had to make my own "Y" pushrod for the elevator control horns which I made with 2 threaded bar onto one with epoxy and wrapped in thin metal wire.
There was not a whole lot of room to play with and I used brass connectors not the normal plastic ones. I also struggled to get decent play on the elevators - but due to the long tail the small play is fine as it turned out.
This plane is also a great dynamic soarer, and here is a link to a video of it screaming around!: http://www.tuffplanes.com/Banshee_60/Banshee_60_EV1.wmv

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