about carving your own propeller. If you’re going to compete in the rubber classes, it’s a skill you’ll need to have. You can find this book at
www.freeflightsupplies.co.uk. Mike has a wide range of other items of use to freeflight modelers. Many of us use button and badge DT
timers for our freeflight models. There are a lot of theories about how to rig them. Cali- fornians John Riese and Norm Furutani have some opinions on the subject. John swears by regular Stren monofilament fish- ing line in the 4- to 10-pound sizes. He uses a slice of silicone fuel line at the stabilizer end. That provides a snug fit over the stabi- lizer hook. At the timer end he runs the DT line through a piece of CyA tubing or stripped wire insulation to make a loop. All knots are square knots. John sometimes uses a drop of
CyA on the knot. Stren brand monofilament has enough “stretch” to hold things down. John says you can buy Stren in “leader” sized packs. John cautions not to make things so tight that the fuselage gets bent. Norm Furutani does things a different
way. Norm uses button thread or heavy car- pet thread. He uses a rubber band for ten- sion. He loops the DT line around a wooden peg at the aft end of the fuselage. The rub- ber band goes in the line between the peg and the timer. The peg takes a lot of the “pull” from the stab hold down bands while letting the small rubber band in the line pro- vide a lower amount of tension for the but- ton timer. Norm uses a separate limit line to control the angle of the stabilizer upon DT. Look at the photo of the engine in Brian Martin’s Kanga Kub. I’m not certain what the engine is, but it caused me to make in-
quiries about just what a “slag engine” is. Apparently most of those late 1940’s slag en- gines used aluminum pistons running in aluminum cylinders. Running similar met- als together is a recipe for excessive wear. The slag engine makers tried to solve the problem by using electrolysis to etch or cor- rode the piston surface leaving a layer of aluminum oxide on it. The piston surface was then harder than the cylinder wall, which prevented wear. Bill Schmidt of Kansas told me that if you
ran a new slag engine slow, using a 1/1 oil and gas mix until it was seasoned, the en- gine was usually good to go. He says he has a Rogers slag engine that will run with a good Ohlsson .23. However, one fast hot run on a new slag engine meant that the thin aluminum oxide coating was blown out the exhaust—and the engine was trashed.
Bill Schmidt’s Class A Skyrocket (above left) with a small McCoy ignition engine. The Skyrocket was a favorite model of your columnist, albeit powered by a diesel E.D. Bee. The Skyrocket climbs fast—comes down fast as well. Brian Martin launches a Kanga Kub (above right) designed by C.E. Bowden. It’s an ungainly slice of 1930’s modeling history—but lots of us love it. This looks
to be a slag engine of some sort in the nose of Brian’s Kanga Kub(below left). Perhaps a reader can identify the engine. Vince Burton’s Scientific Varsity (below right). At 370 square inches of wing area, it’s a bit big for the Speed 400 class, but with a brushless outrunner, it would be a fine park flyer. Harry Klarich has a short kit for the model.
FLYING MODELS
27
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68