Scott Voigt's Build Logs

Balancing

With all the gear in, I strapped on the wing and tested the balance, finding it still tail heavy. The farther forward the weight is, the better leverage it has against the tail weight, so I decided not to make a lightweight balsa nose block - this cone is made of epoxy and some lead sinkers . Some 3/32" sq. framing helps give it shape.
 
I used 6-minute epoxy. I applied it to the top half of the nose first, then once that cured I did the bottom. It gets firm fast, so my technique was to work with it and form it until it starts to get sticky, and by then it holds its shape enough to let it sit and cure. If I were to go overboard and weight the nose too much, I'd sand or drill out some epoxy.

Done

My Thermic 50-X is now airworthy. After flying it I'll go back and complete the covering job; I left the nose and some small patches of the pod uncovered in case anything has to be changed. I'm not covering the rudder, boom, or wing rests because they look good plain.

As a radio control conversion, I would recommend this kit to anyone with, at very least, either a) some experience with any kind of R/C plane, or b) for the absolute beginner, access to this build log and the ability to contact Tom and Mike with questions. Either of these, in conjuntion with the directions on the plan, would be enough to go on.

A Name

I like to give my planes titles other than "the 50-X". What if the Spruce Goose was refered to as "the H-4"?

Because of the fishlike appearance, I'm calling this Cypselurus, one of the genera of flying fish. I'll have to call my Thermic 50, which also looks like a fish, Hirundichthys.

Flight

Well, it's time to put Bernoulli's principle to use. We managed to get out during a brief time of unusually still air. My usual flying field gently slopes south which makes use of the predominant wind here. The grass is now about 6 inches tall and a few small gusts of wind were coming out of the southwest.

 

This is the very first flight of the Cypselurus. Having flown mostly stocky Art Hobby planes this light little glider seemed almost buoyant. It easily flew a hundred yards while I weaved from side to side testing the controls. I gave it more rudder throw but the elevator seemed good. Nice launch!

Several times I saw it just gain a few feet of altitude out of nowhere. For a hand launch, the flight times are great.

I wondered if the wings would be overloaded with the R/C weight. They flex slightly while flying but not so much as to be a problem.

In the picture above, the grass on the other side of the trees is the dam of Clinton Lake. When the wind's from the East, it provides good slope lift. I think it will be enough to keep this plane airborne indefinitely. Assuming, that is, that we get an East wind, which we never do.

 

Ground effect
After some hand launches we tried hand towing. I should say my grandpa tried hand towing; I just piloted. We've had success with another glider which I modified to tow, although we couldn't get this one to work. The hooks I made are way to small and the line fell off every time right when I let go of the plane. I'll replace them and then I expect long flights from towing.

As for flight characteristics- although it would be a bit fragile for a first time pilot, it's easy to fly. A good pilot could easily keep this in the air with a steady supply of thermal assistance.