Leaf Blower
Two for one! Build it as a fast EDF sport jet or as one of deHavilland’s early jets.
By Dick Sarpolus PHOTOGRAPHY: DICK SARPOLUS
s long as jet planes have been around, modelers have been de- veloping ways to model them. The easy way is to put a prop in the nose or on the tail, and ignore the spin- ning prop while flying the plane, but model- ers want more authenticity than that. In the ’50s, CO2 cartridges were too heavy and Jetex rocket motors weren’t too reliable. The first ducted fans with their stamped and twisted aluminum fans on OK Cub .049s didn’t produce much thrust, so the air- frames had to be stick-and-tissue to be light enough to fly.
A In the ’70s, better ducted fans came along,
but the high revving glow engines needed were again not too reliable. More recently, true small turbines arrived, and if your wal-
56
let can stand the strain, real jet modeling is now possible. But the latest electric ducted fans are here now, with lots of power, fairly low cost, and they’re easy to handle. I bought a 70mm EDF unit, by ELE, from BP Hobbies
www.bphobbies.com because it came with the motor installed, looked easy to use, and was about the right size, I guessed, for the 36–40-inch wingspan pro- file foamy warbirds I like to build. I had a profile Sabre, and I simply cut a hole in the profile fuselage above the wing and stuck the EDF unit in place, anchoring it down with some dabs of hot glue.
Wondering how the air in and out would do with that profile fuselage in front of and behind the EDF, I wasn’t expecting much. I was amazed at the thrust that EDF unit
produced! That fan unit blew out so much air that I could use it as a leaf blower! The plane flew considerably faster than it had with the conventional prop in the nose, jumping out of an easy hand launch. And on dry, short grass, it skidded across the grass, jumped off and climbed straight up! Hey, jet power is easy! Who needs landing gear. So I quickly laid out and built a twin boom non-scale jet styled airplane, called the Leaf Blower of course, to have some jet flying fun. At a 39-inch wingpan, 29-inch length, and with about 400 square inches wing area, it’s the same size as a bunch of electric profile foamies I have been having fun with. If you don’t have a way to hot wire cut foam wing cores, I’d suggest you go to The Core House
http://home.earthlink.net/~philcartier. They
JANUARY 2013
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