Up and Around
George M. Aldrich 12822 Tarrytown, San Antonio, TX 78233
Restoring the AG-1 Duster
It is late February as I write, so the fifth edition of the Vintage Stunt Championships will be history by the time this is in print.
I have been rather frantic in efforts to restore my now-30-year-old AG-1 Duster for this ever-growing happening. While working on the model, a number of the problems with butyrate dope that occurred a couple of years ago were recalled and, to some extent, solved.
The Duster was designed and built during the winter–spring of 1963–64, and it was the first model I tried the nontautening (zero-shrink) type butyrate on. The fillets, which were liberally coated with a number of non-shrinking applications, show no signs of blistering to this day. None of the frustration experienced earlier from color, talc, and dope-filler cracking and splitting has recurred.
Just as I was about to mix a fresh jar of talc-and-dope filler, somewhere from the dark dim reaches of my mind came the memory of cornstarch. Years ago I had mixed cornstarch—instead of talcum powder—with clear dope to make a filler.
After pouring about three ounces of straight dope into a quart jar, I filled the jar with pure cornstarch. I added as much butyrate thinner as possible, screwed on the lid, and shook the jar really hard. As soon as the cornstarch was thoroughly mixed with the dope and thinner, there was room for a great deal more of the powdery starch and more thinner. This process was repeated several times as the air trapped in the cornstarch was dispersed by the thinner. I now had a thin filler that just floated off when sanded.
Rejuvenation and repairs
It's not unusual to find that such an old model is quite dry and brittle and has a lot of hangar rash—i.e., nicks, dents, and cracks. Most dope producers make a product called a rejuvenator. The Randolph people call theirs Butysolve. One thin, sprayed coat soaks through, softening and restoring—or rejuvenating—the finish.
For the dents and nicks, I poured a couple of ounces of the thin filler into a small jar, which was again filled with cornstarch and thinner until I had a much thicker mix. This did a great job of smoothing out the model to near-original condition with a minimum of sanding. The neat thing is that no curdling, cracking, or any of the other problems experienced earlier recurred.
I reiterate the value of a zero-shrink butyrate clear dope. Because the butyrate base does not adhere nearly as well as nitrate, the zero-shrink allowed normal, trouble-free finish over sharp corners without the blistering or pulling away commonly attributed to this finish base. Please, somebody, make it for us again.
Sources, books, and tools
While I normally try to keep this a noncommercial communication, a few items bear mentioning to give you immediate connections to valuable sources. Much of my mail asks for sources of items no longer carried by local hobby shops. At the end of this column I list special-interest groups that carry advertisements for the smaller cottage industries in their publications.
If your interests lie in control line or free flight, then you should belong to and support these groups. Many products overlap, so a product intended for one may apply to another.
- Do You Speak Model Airplane? — Dave Thornburg has written the neatest book with this title. If you want a real trip back through aeromodeling in America, order from Pony X Press, 5 Monticello Dr., Albuquerque, NM 87123, or check your local hobby shop. ($19.95 + $2.50 postage paid.)
- 1992 NFFS Model Power Book — edited by Keith Hoover; available from Fred Terzian, 4858 Moorpark Ave., San Jose, CA 95129. ($21.50 + $2.50 postage paid.)
I've always been a nut for good tools, and one of the most useful I have seen is now available from Tork-It, 6048 Dee Court, Stone Mountain, GA 30087. As one might guess by the company name, Tork-It is an adjustable torque wrench intended primarily for model engines. Of particular interest are the hex-drive bits for both the inch and metric sizes. No toy, this is a fine piece of equipment intended for a lifetime of use.
Engines and test notes
A few years ago Ol' Dirty Dan Rutherford produced an extremely interesting article for Model Aviation about his travels in Russia. Dan recently copied me in with some of his correspondence covering the past three or four years. I've seldom read anything more fascinating. Regardless of the Dirty Dan veneer, Mr. Rutherford exposes an inner warmth and understanding of a people that belies his rough exterior. From some of the photos, you can see the results of Dan's travels in a more than ordinary group of products.
The photo captions cover the generalities, but the little (34 grams) VA .049 is worthy of additional comment. Truly unique are the rod, wrist pin, and two-piece piston assembly. Note that the bar-stock connecting rod is connected, via a wrist pin, to a threaded collar that mates with the internal threads in the piston. This ingenious design not only is very rugged, it allows shimming between the collet and piston for two adjustments of the cylinder port timing.
Dan has a select dealer list and can be contacted at 4705 237th Place S.E., Bothell, WA 98021; Tel.: (206) 487-1735, for further details.
While on the subject of 1/2A engines, I'll share some results of an afternoon spent running some Holland Hornets in comparison with the VA .049 and some more recent offerings on the market. These tests are far from complete and will be expanded in greater detail when finished.
For now, the important comment is that the Twinn-K people are once again producing the 5R high-nitro racing button head. This design was discontinued back in the early 1980s, much to the consternation of those who had learned to use it. Several of us have tried to use our SP and SRX button head plugs in the old Holland Hornet, with poor results. The chamber shape in these units gives a compression ratio that is too high for many engines to tolerate, even with a number of shims.
To test the 5R button in the Hornet, one of the standard glow heads was bored through with a 5/16" drill bit. When this was done, it took off all but the last fin on the original glow head. Then by filing or milling a 1/2" flat on each side of this last fin, the collar that had been formed could be used to lock the 5R button in the Hornet cylinder. The result was a clear 900-rpm gain over the high-performance trumpet-shaped Holland Hornet head that has been out of production so long.
Further VA .049 tests will include fuel with more than the 25% nitro to which we limit the scarce Hornets. Three M (factory modified) Hornets were tested and even with the Glo-Bee plug, they were 2,000 rpm below the VA .049!
I'm sure the Wiley .36 photo is of more than a little interest. What is a Wiley .36? Who is Wiley? William "Willie" Wiley has been behind the scenes with some top high-performance engines for a number of years. A machinist by trade, Willie decided last September that he would design an engine using a crankcase layout. It would allow him to build not only a top combat/free-flight .36 but also .40–.45 engines in everything from a pylon rear-valve to a side- or rear-exhaust CL stunt/RC pattern engine.
I plan to work closely with him on a rear-exhaust piped stunt .45 and, along with Frank McMillan, have one flying by the time you read this. Our experiences will follow.
Foam brushes and doping technique
With so many plastic covering materials in use now, it is rare to discover someone who has not tried foam brushes for doping models. It is always frustrating to have a brush bristle come out just as you finish applying a coat. The foam brush not only eliminates this problem, but a streakless finish—not unlike one that is sprayed—becomes a reality.
I have come to prefer the cheap, one-inch-wide brush that has a wooden handle. Masking tape wrapped around the foam-to-handle juncture gives a stable unit that lasts quite a while if cleaned properly. This means blotting all the dope out of the foam with a paper towel before it has time to dry. When ready to apply another coat, just soak the foam in the thin dope mixture until it is soft again.
Where this method really shines is in the application of the first coats. Often the dope tends to run through the pores of the covering or silk-to-silk covering, leaving an unsightly blob hanging to the inside of the surface. Quickly squeeze the excess dope from the foam and, holding the surface upside down, blot the blob right back out through the material. Remember, the thinner the dope, the smoother the finish.
Events
For those who can't manage the long trip to Tucson, Arizona, in April, the second annual Eastern States Vintage CL Champs will be held September 18–19 in Tifton, Georgia. Old-Time Stunt will fly on Saturday and Classic Stunt on Sunday. Contact Tom Dixon, 3390 Woodrun Trail, Marietta, GA 30062, for details.
Publications and sources
Here are some publications that carry advertisements for hard-to-find items:
- Precision Aerobatic Model Pilots Association (PAMPA), Stunt News, 1019 Creek Trail, Anniston, AL 36206 — $15/year U.S.; $20 Canada/Mexico; $25/year other countries.
- National Free Flight Society (NFFS), 19 Frederick Dr., Newport News, VA 23601 — $15/year, age 19 and up; $7.50/year, age 18 and under.
- Model Aircraft Combat Association (MACA), M.A.C.A. News, P.O. Box 111, Jacksonville, IN 47348 — $15/year U.S.; Canada/Mexico $18/year; $25/year other countries.
- Society of Antique Modelers (SAM), SAM Speaks, 85 Bellevue Ave., Belvedere, CA 94920 — $15/year U.S.; $25/year other countries, airmail.
- F.Y.I. — Model Flight, the sourcebook for everything for flying models. Dynamic Models, 4922 Rochelle, Irvine, CA 92714-2941. $19.95 plus $1.40 postpaid.
Transcribed from original scans by AI. Minor OCR errors may remain.
