Up and Around
Photos and submissions
Preparing material for these pages has sent me searching through more than 40 years of old photos and negatives. While I will continue to use those of my own, it seems likely that many of you have a wealth of history hidden away in a drawer somewhere. If you have photos that you would like to share, please send them. Color is preferred, but black and white is fine. I will return any that you want back.
Junior FAI program
Over the years, we have heard all sorts of cures proposed for the younger set's decided lack of involvement with our continuing pleasure in modeling. In 1989, I observed one of our junior club members as he became involved with the Junior FAI program. In the early spring, 15-year-old Jim Troutman appeared to be in a state of sheer terror. By midsummer, with the able assistance of Reid Simpson, he had been transformed into the epitome of experienced, fluid motion, launching Howling Nelson .15 in his F1C model.
That he placed an excellent fourth individually, and the team placed first in world competition, was no accident. It was amazing to watch young Jim, with help from Reid and Jim's dad, Mark, start his engine and tune it, check all the multifunctions, and launch his model as though he had been doing it for years.
The Junior program is funded to send a team; help is needed. It's going to take $21,000. Anything you can afford should be sent to AMA offices, marked "Junior FAI Fund."
Engines and port timing
When commenting on port timing and Schnuerle engines in my last column, I had no idea I would receive a Moki .51 engine from the Hungarian Aero Club via its importer, Bob Davis of Davis Diesel Development fame. What makes this engine worthy of comment is its obvious "lugger" timing directed at CL stunt. Total exhaust timing is only 125°. Compare this with the 140° common to many top stunt engines of the past 40 years.
The power stroke begins at ignition (we'll call this TDC, or top of the stroke, for this discussion) and continues until the piston comes down and opens the exhaust. To find the power stroke we write:
P.S. = 180° - (E.T. ÷ 2)
Putting 140° into this equation yields a power stroke of 110°. With the Moki .51 (E.T. = 125°) this figure increases to 117.5°, or almost a 7% increase.
What really makes me call this a stunt engine, though, is its blowdown period—the difference between the exhaust and intake port timing. Blowdown is often considered optimum around 120° total. With the Moki the intake timing is 118°, giving a blowdown of only 7°.
Having put this engine in the air, I can promise you that not only will it swing a big prop, but it will swing the prop at a very steady rate. That is, it will be physically locked into running at a dependably constant speed no matter what the setting. This is the first Schnuerle‑type engine that is designed from the start to eliminate the "runaway" problems so prevalent until now. Many engines made today fall into the high‑quality bracket, and the Moki is right in there.
(Continued on page 156)
Up and Around / Aldrich
Flown his old Playboy Cabin the day before. I asked him why he had not flown his recently approved six‑foot Brooklyn Dodger. It seems he had wiped out the wing at the AMA Nationals. The clincher that really shows Sal's years of experience came next. He had a new wing all finished, but it did not fly to my mind as the dope hadn't aged long enough. I didn't ask Sal if he used nitrate or butyrate; but, as I remember, nitrate takes about 30 days to settle down, and butyrate takes up to 90 days or more. Trim a model before the dope has cured, and it's pretty certain to change on you when it does.
Many have asked where to get the T.C.P. plasticizer I've mentioned. The best source I know is Flexall from Dave Brown Products. My experience with castor oil is that it works in nitrate, but if you put it in butyrate, it's likely to turn white on you. T.C.P. is much safer. A mix of 1 oz. per quart of straight dope is a good starting point.
In 1951, I worked part‑time for a while in the old ABC Hobby Shop in Houston while going to school. I well remember the first Ringmaster kits that came into the shop. The price then was $2.95! The next six months saw a profusion of this kit, which is now in its 40th year. Many flew them in combat, sans landing gear, almost immediately. I'm sure it's the all‑time best seller as a stunt trainer.
The Ringmaster I remember best was flown by a priest at the 1957 Nationals, I believe. The father would start doing loops and gradually tighten them up until the model was maneuvered into an absolute stall. I found an old photo of his Ringmaster standing on its tail. Unusual for this kind of performance, the engine was not set up with a lot of offset, but it could be made to hang so still that someone could catch it easily!
For those of you who write and want a reply, please enclose a SASE. If this is done, I will always answer. I will accept phone calls, but please don't call if writing will suffice. I do have a business to run.
- Address: 12822 Tarrytown, San Antonio, TX 78233
- Tel.: 512/656‑2021 (fax answers after six rings)
Transcribed from original scans by AI. Minor OCR errors may remain.
