The Incomparable BTC-4

Well, I did it this time.  No, I really did!  I built a plane with minimal time involved so it can crash away with no emotional involvement at all.  Really.  I don’t care.  Not in the slightest.  It’s nothing to me…

Presenting the BTC-4.  I didn’t put the absolute minimum time into it, but I put very minimal time into it.  It took an afternoon/evening to draw it out, cut the parts for two airframes, and glue one airframe together.  Then I sprayed it this morning with four light coats of flat clear LustreKote to fuel-proof it.  This is the second plane I’ve done in flat clear, and I’m really coming to like it.  It looks just like bare wood.






I built it with a 20 inch span, four inch chord.  Five to one aspect ratio should make for a good looper/figure-eighter.  Especially with the ridiculous amount of elevator I gave it.  I just used the Brodak radial mount because it was the way to finish the nose with the least time/effort invested.  Simple thread hinges (which I’m coming to like also), and a surplus Carl Goldberg bellcrank.  I’ll weigh it tomorrow to see what the final weight is, but it should come out between 6½ and 7 ounces.  I pulled out a new-in-the-bag product engine and a 3/8 ounce tank from Bernie.  Because of what I’ve read here and elsewhere, I pulled the engine apart and checked it out.  The piston ball had excessive play, so I reset it with a few light taps in the reset tool.  And, I cleaned out the metal shavings that Estes left in there.  Should be good to go now.



I balanced it at the 20% point.  On the following picture you can just see the two small marks I made at the 20% point.  


And here is my novel balance fixture.  I bought a big bag of assorted safety pins at the Dollar Store Friday.  I used the largest size for the pushrod guide, the smallest size for the tail skid, and the medium sized pin I glued to the end of the fuselage. I tried various sizes of crimp on fishing weights until I found the size that would balance the plane at 20%, then firmly crimped it on with some pliers.


I’ll try the plane with no wingtip weight for now, as when I balance it fore-aft on the prop shaft and tail, the outboard wing drops quite positively.  I’m calling this one the BTC-4R, as it’s got the radial mount.  The other wood I cut has a longer snout for a beam mounted Medallion.  That’ll be the BTC-4B when I finish putting it together.


The Carefree Mark