CONTROL LINE AEROBATICS
Frank McMillan, 12106 Gunter Grove, San Antonio, TX 78231
Tom DeVille and Youth Programs
Over the years I have mentioned Tom DeVille as a name from the past. In the early 1950s Tom was an exceptionally competitive modeler in the New York/New Jersey area, flying Stunt at times—even a Dynajet Stunt, which was a real achievement in those days. (One of our biggest achievements is that we both survived growing up on the streets of New York.)
Tom called recently to chat about old times and to pass on some information about his current work with youth groups in New Orleans. Tom and his wife use modeling to hold these kids' interest, keeping the children away from the epidemic that is plaguing America's youth: drugs. Tom says they have been very successful, but there is a continuing need from model-associated sources to keep going.
In the past many individuals and manufacturers have contributed, such as:
- K&B
- Smith Industries
- Great Planes
- Sig
- Du-Bro
- and many more
This is a continuing need, and we must solicit everyone's help. Tom will take anything you would like to contribute: kits, engines, balsa, paint, coverings, parts, pieces, etc. Whatever you can't use will be put to worthwhile use; anything and everything is truly welcome.
Contact: Tom DeVille 1325 Franklin Ave. New Orleans, LA 70117
(Tom would also like to hear from friends from the old days, such as George Fong.)
Vintage Stunt Championship Fund
Since the beginning of the Vintage Stunt movement, event organizers have tried to get the famous fliers from "the beginnings" to attend the big meets and swap stories with new and old fliers alike. Unless you've experienced this, you are missing a great time—it’s our history, after all.
A movement to ensure that this happens is the Vintage Stunt Championship and beyond, being aggressively promoted by Walt Pyron, a well-known flier from that era. Walt is seeking to build up a fund to sponsor these people to the contests.
Contact: Walt Pyron P.O. Box 99-0894 Redding, CA 96099-0894 Tel.: (916) 244-0140 (weekends only)
Tech Tips: Trimming the Engine for Optimum Performance
Some of my most useful flight trimming occurs after the Nationals. I'd like to pass on something well known, but with a little twist: trimming the engine for optimum performance.
For many years the work had been to ensure that your motor runs the same whether upright or inverted. Years ago we didn't worry about the Foxes; we just bolted them down and the one-inch tank height took care of the run, until the mounts compressed. In the old days only the good fliers knew much about motor trim.
Now most fliers design a convenient way to shim the tank or adjust the internal plumbing to effect a change. For this column I want to address the symptoms and effects, and how to recognize and deal with them.
(CG) with lifting stab is the mark of a model that can be reliably trimmed out with high power. With low power levels, any Old-Timer (well, almost any) can be trimmed out—we are talking competition free flight here.
Certainly the most common method of looking at engine characteristics is by timing the laps, both upright and inverted, and making an adjustment. This is generally a good starting point—there are some underlying assumptions or variables. Consistency of both the actual timing and the engine run will produce reasonable results, but if the motor run is changing and you time at different places in the flight, you may not reach proper conclusions. Also, you really need a digital stopwatch that measures to 1/100 second to capture meaningful data.
To establish and maintain a motor performance database, compare the times of several initial upright laps to the times of several inverted laps during every practice session. (As an aside: I do this every session to monitor the motor during the season because motor runs have been known to change due to the weather, and also at major contests where the altitude is significantly different from the usual flying site.)
In addition, check the progress of the run during the flight to see if the motor is progressively running harder, which indicates a possible heating problem. Note that a slight slowing near the end of the flight is more or less normal for a uniflow tank setup.
When trimming, reach the point in tank adjustment where the lap timing is very close—equal, or at worst, less than half a tenth of a second. I remember that for a long time we used to intentionally set the inverted timing a tenth faster to get outside square loops. Now we're looking for exactly equal.
The next step is subtle but can affect the overall pattern. Note the inside and outside rounds in reasonable wind and ask yourself if there is a noticeable difference in feel of the maneuvers. You're looking for one set softer than the other—usually the outside.
Many times the model will tend to accelerate on the insides and be controllable on the outside. This means you need to move the tank slightly higher in the plane until there is no discernible difference. The opposite tendency requires the opposite correction.
If you weren't "banking" on the trim before, what you're left with after the adjustment is a real feeling of "niceness"—the characteristics will be more precise in how the motor reacts to loading in maneuvers, and where it comes on and off. Once you have a model working this way, you will want to persevere on every model to really get the setting correct.
With every engine/tank/model combination there are many variables, but it is wise to keep track of numbers as a good ballpark setting so that when you work new models you can go to the nearest right value from the start. With the metal tanks I use, I measure the distance from the engine mounting plate to the top of the feed tube. This is the most convenient parameter to measure using the depth feature of a dial caliper. Yes, you can modify the distance to the feed tube by shimming the tank, but when you know what works, you have a high probability of repeated good runs.
B-Pylon and Rubber Models
For B-Pylon, the popular designs are the Zipper, the Gas Bird, the Alert—the latter probably the best—and the Playboy Junior. I will continue this next time because I want your input. I especially need your thoughts on rubber models in all classes. I know the frequent winners, but what "sleepers" do you know?
Plans Catalog: Allen Hunt
Another plans catalog is from Allen Hunt: Box 726, Dunbar, West Virginia 25064. It costs $4, which is refundable on your first order. There are over 2,400 plans listed, and many have sketches in the catalog so you can see what some of the more obscure designs look like.
One such design is the Pushover, which I created about a third of a century ago and published in MAN. It has long been out of print, and I am glad to see someone making it available.
The Pushover is an all-sheet balsa pusher for Pee Wee .020 power—no contest model, but stable and cute. I have often thought of making it for CO2 or Electric. I lost mine twice; the first time it landed 23 miles away, and the second time it didn't come back, so I don't know how far it went.
I was a very active contest flier at the time, and I made it for fun-flying in a small field—sort of like Joe Wagner's Dakota—and felt the glide was not floaty enough to worry about thermals... NOT!
If you make one, send me a photo. I got a nice photo and letter from Steve Staples, an Associate VP for the AMA, saying the Pushover design was his first successful model 30-plus building years ago.
The catalog has a lot of Scale, including Ace Whitman–Joe Ott material that you should see: very nice plans, light and practical structures. There are many other kit and magazine plans for Scale and Duration—gas, rubber, Control Line, etc. One unique feature is the inclusion of some plans in more than one scale, like a Scientific Flyer in the original 25-inch span and also in a 36-inch span. The Earl Stahl Rubber Scale models are offered enlarged and are great fliers that way. Keep on helping me out, folks.
Corrections and Apologies
It has been called to my attention that I have slighted one of our prominent junior fliers, Derek Barry, by misspelling his name and not recognizing the performance he worked so hard to achieve at the past Nationals. I extend my sincerest apologies to Derek and his father, Dale.
Transcribed from original scans by AI. Minor OCR errors may remain.
