PHOTO: TOM HALLMAN
Scott Dobberfuhl gets his hands around the problem of launching his lovely Hoople Multiplane (above left), a 1910 design by W.P. Gary. John Regalbuto’s
still has moisture in it, that beautiful wing tip will probably shrink a bit as it fully dries, and maybe even warp. Test before you com- mit that piece to your pride and joy. Make up a test wing tip that is 10% oversized and one that is to size, and let them dry for a week or two under a weight to keep them flat. Check against the original plan, and see where you stand.
Scraping by Or... try your hand with dry bamboo. Bam-
boo skewers come in diameters of about 1⁄8 to 3⁄32 inch. These are easy to make thinner; you can draw them through a wire gauge, start- ing at the size closest to the skewer and pro- gressively working down to the desired di- ameter. If you don’t have a wire gauge, drill a series of holes of decreasing diameter in a piece of thin sheet steel. Chuck the skewer into a drill and run it through each hole in turn for the initial sizing. Then, without ro- tating the drill, draw the skewer back and forth through the hole to scrape and clean up the surface. A bit of sandpaper to finish, and violà! Custom bamboo dowels. Of course, there may be some instances where you would rather work with a piece of squared stock. In this case, try splitting some larger stock down close to the size you want. Typically bamboo is very straight- grained, and once a cut is begun in one end of a stick it’s an easy matter to split away a straight run. This rough piece can then be scraped down to the desired size with the edge of a single-edged razor blade, or fin- ished off with sandpaper.
If you are careful, you can work down a The bends
To bend dry bamboo, soak the strip or dowel in water for a half hour before apply- ing it to your heat source. Have a bowl of wa- ter handy at your work bench as well. The idea is to thoroughly heat the general area of the bend first, then firmly and patiently be- gin to force the curve into the wood by bend- ing it over the radius of your heat source. As the heat dries out the moisture—which will happen very quickly, as the iron should be hot enough to create steam—remove the bamboo from the heat and soak it in the wa- ter for a few seconds before returning it to the iron. Back and forth, back and forth, back and forth again. Try to avoid scorching the bamboo. The thicker the piece you’re bending, the more critical replenishing the moisture becomes.
I warn you now: it will seem dreadfully te- dious to create even the slightest bend with- out kinking or breaking the bamboo, which is why you will have prepared a few extra sticks if you are smart because, I guarantee you, you will move too quickly at first. You’ll be eagerly pressing forward, looking for the
PHOTO: JOHN REGALBUTO
contra-prop electric Aquila (above right) shows what can be done with bent aluminum tubing. You really have to see this rig run to appreciate it!
piece of well-split (i.e., straight grained and true) bamboo in this fashion to extremely thin dimensions; so thin and flexible in fact that you may be tempted to skip everything below and avoid steam-heating a permanent bend into it. Turn away from this tempta- tion, pilgrims! I promise you, a light but con- stant stress captured within a delicate structure will, someday, wreak havoc upon the alignment of your surfaces. Embrace the challenge.
quick reward and will feel the resistance suddenly give way, and you will see the break on the outside of the radius, and you will curse aloud and scare the dog, and you will have to remind yourself that nothing worth anything comes without something. But you will try again; and at some point, you will find that once the bamboo begins to get the idea that you desire it, please, to do your bidding—to bend to your benevolent will—it will relax ever so slightly, become incrementally more plastic and pliable, and will start to accept rather than resist your efforts.
In short, the initial stages of the bend are the hardest. When this moment of under- standing occurs between you the craftsman and your material, you will smile, and it will be good, and you will wonder at all the things life still holds in store for you—like bow-legged model airplanes.
Phew
Now that we all have mastered the zen of bending bamboo, let’s exhale and have a lit- tle show and tell. West Coaster Scott Dob- berfuhl builds a lot but rarely finishes mod- els, so any picture of him flying something is worth sharing, even if it’s a few years old. His marvelous Hoople Multiplane will prob- ably never max, but who cares? Next, John Regalbuto sent me pictures of his Polish 1910 Aquila contra-prop electric. John wrote: “Ronny Gosselin built a rubber powered version with contra props. This ver- sion features a bi-rotary engine just as in the original (The crank case rotates in one direction, the crankshaft rotates opposite). Each drives a contra prop. The entire drive system, motor, battery, flight profiler, charging plug and on/off switch are con- tained in the replica motor. Weighs a ton. With the long fuselage [it’s] very tail heavy. Front end is built up from aluminum tubing. Functioning sprung landing gear (even the tail wheel). Might do better the next time.” I had the privilege of seeing this thing do a dry run at the 2013 FAC Non Nats, and it was something else!
PHOTO: TOM HALLMAN
Vance Gilbert’s Avro warped up a little bit in the hot weather at Geneseo, resulting in some unexpected wash-in/wash-out trim settings. It can be extremely difficult to get the incidence properly set on a triplane.
FLYING MODELS
Speaking of something else, Vance Gilbert was recently photographed making concrete the philosophical concept of decon- structivism with his Avro 547. While there’s only so much that’s rounded on this aircraft, it has had a round-about history, which came to an end this year at the Non Nats. We’ll discuss that event a bit next month. Cheers!
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