Speedo Mk II Slope Soarer
R Hobbies Speedo Mk II
I took a while to figure out that these carbon tubes are to put in the wing where the wing attach bolts go to prevent crush.
Wing servo covers are made of very thick abs, and look odd next to the cleanness of the rest of the glider. They do double as wing skids
should you find some level clear ground to crash on. I used the Hobby King servos here and had to shim down the aft end so they did
not push up on the upper wing covering. I attached the servos to the covers with a hot glue gun.
The JR S185 servos are small enough to fit without adjustment.
Where mine balanced for the first test flight with 39 grams of ballast. It had good pitch stability but tended to veer toward the occasional
outhouse. I added 2 grams to the left wing tip to get lateral balance. That may be because I didn't get the wing exactly centered.
I made a clay impression and cast a mold from it, then melted some split shot fishing weights for a nose weight. Don't tell my wife I used one of her
salad spoons for a ladle! Kerry commented that if I used a nylon push through elevator arm that needed no bolts arm I might need less weight.
I added the 2-56 bolts and nuts I used to my scale until I got 1 gram, which required 50 bolts and nuts, so the weight of the 3 sets I used is on
the order of .06 grams. The moment arm from the 35% CG position to the elevator bolts is twenty inches and the moment arm to the nose
weight is 10 inches, so it took .12 grams additional nose weight to balance them.
To tell the truth, I thought the machine screws and nuts would be heavier than they are.
Balance point calculations. Avaliable as a PDF.
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