CONTROL LINE SPEED
Glenn Lee, 819 Mandrake Drive, Batavia, IL 60510
JETS
Model jet engines—and the full-scale versions—have very little published information. Modeler Donald Laird is trying to collect data and make engineering drawings of all model pulse jets that were manufactured in the U.S. He is currently working on a Sona-Jet, built years ago in Latrobe, Pennsylvania.
Donald needs a copy of the "complete operating instructions" that were included with every engine, and he is looking for historical data concerning the M.E.W. and Minijet Motor companies. Please contact Don at 4706 Diane Dr., Ashtabula, OH 44004, or call him at (216) 998-1371 if you have any information. It will be greatly appreciated.
New developments
I read as many engineering and scientific magazines as I can find, looking for things that can be applied to model engines. One of the better idea sources is Design News. An article in the June 1996 issue described coatings of tungsten carbide–carbon developed by Balzers Tool Coating of North Tonawanda, New York. This process improves frictional and wear behavior in variable lubrication conditions, including dry running.
The coating is applied by sputtering tungsten carbide targets in a carbon plasma in a vacuum chamber; the clean, high vacuum results in an excellent metallurgical bond to the parts for high adhesive strength. The coating is laid in alternating carbide-rich and carbon-rich layers, which give good sliding behavior under high frictional stress.
This process was used to treat piston wrist pins in a racing motorcycle in Germany; the pins survived the entire racing season of approximately 3,500 km at speeds up to 280 km/hr. The soft bronze bushing normally used in the piston (which usually wears out) was eliminated, resulting in less weight and a stiffer connecting rod with a smaller end.
The process was also tested, with successful results, on tappets and injection pumps. Possible applications in model engines would be to coat wrist pins, crankpins, and crankshafts that run in non-ball-bearing housings. Since the coatings are self-lubricating, oil content in the fuel could be reduced. Four-stroke engines would probably benefit more than two-stroke engines. It is not a process to do easily in the basement, but engine manufacturers might give it a try. Air-cooled engines run pretty hot, so any treatment or coatings that might help should be investigated.
The Lewis Research Center in Cleveland, Ohio, has developed a thermal-barrier and a wear-resistant self-lubricating layer for sleeves in advanced high-temperature engines. The thermal barrier allows an engine to run at a higher temperature—improving efficiency—where oil-based lubricants can't survive.
The coating system uses a layer of zirconia for the thermal barrier, coated with silicon carbide, silver, and a calcium fluoride/barium fluoride eutectic. Silicon carbide is a hard, wear-resistant matrix; silver provides low friction; and the fluorides provide lubricity. If air-quality laws become more restrictive and oily exhausts must be eliminated, such designs may become acceptable.
A Loss
Don Jehlik called to tell me that speed flier Bob Lauderdale passed away in the fall of 1996. Don and I flew with Bob for many years and we had many memorable flights. I met Bob in the 1950s, and I was at Glenview Naval Station in 1958 when he set a world record of 172 mph in the 10cc displacement class (I think I cranked the starter and Don set the needle).
Bob was on the U.S. Speed Team several times, and he competed in Kiev, Russia, and Budapest, Hungary. He set several more world records with the guys who flew with him in Huntsville, Alabama, in the 1960s.
All of Bob's airplanes featured elliptical-shaped wings and stabilizers, with dihedral in the stabilizer, and they were painted bright yellow. Different models included Dizzy Boy, Dizzy Bee, and Dizzy Bug; some of them were kitted (I don't remember who did it). His airplanes were beautiful, and the insides were finished as well as the outsides.
Bob could get more speed out of a plain engine (without special machined parts or modifications) than anyone I knew. He won many National Aeromodeling Championships (Nats) trophies. Afterward he married a woman who thought model airplanes were toys, and he hadn't flown since.
Plans for his world-record Dizzy Boy, renamed the All American by Popular Mechanics, were published in the July 1959 issue. The write-up and construction techniques are still up-to-date, and speed aircraft are still built the same way. I use his elliptical shapes for some of my airplanes.
Proto
As I write this in February, cold and snow are forecast! Bob Whitney has been test-flying in Florida; California fliers have been having contests; and the Texas guys will soon be flying. Maybe I should move south.
I hope some of you are building Chris Sackett's beautiful Blondie .21 Proto that was published in the April Model Aviation. I hope to see many Blondies at the Nats.
Several modelers have written to let me know that they are building Protos, so it should be a good year. There will be trouble flying Class A, .21 Sport Speed, and .21 Proto on the same day; it's going to be similar to the old days at the Nats when you put your name in and waited for your turn!
Profile Proto
Years ago, participation in the 1/2A events dropped so low that they were eliminated, but 1/2A Profile Proto for Juniors and Seniors was wisely saved as an entry-level Speed event. Open-class competitors complained that they wanted to fly 1/2A Profile Proto too, so the event was opened to all fliers.
Larry King (Arkadelphia, Arkansas) wanted to know how to build a Profile Proto. Since he can build a Mouse (he and his daughter fly Mouse Races), he would surely be able. I told him to read the rules first so he would have enough wing area, a canopy, external controls, wheels, etc. Key rules and minimums include:
- Minimum wingspan: 14 inches (12 inches for a biplane)
- Minimum wing area: 45 square inches
- Minimum fuselage length: 12 inches
- Canopy: must be clear (it can be thin; this is a profile)
- Landing gear: two wheels at least 7/8 inch in diameter and separated
- No exhaust extensions
- Exposed two-line control system
- Models must be of profile design with an exposed tank
- No fuel restrictions (you can run high nitro)
More Junior and Senior Speed fliers are needed; 1/2A Profile Proto is one of the easiest events in which to get started, and the same model can be flown in other Speed events. Help your kids or grandkids build a model, and come to the Nats this summer!
Carbon Fiber
Quite a few Speed fliers like to build models with thin aluminum-sheet wings, but building the crutch and wing spar is a problem. Bob Whitney made a mold and produced a full-span crutch/spar assembly using carbon fiber and epoxy, with provision for a round bellcrank. The assembly is strong and lightweight. I'll try to get a good photo of it for a future column.
Florida Area Speed Team (FAST)
Bob Whitney has been trying to get some Speed flying going in southern Florida, so he made a FAST T-shirt for himself. A bunch of people there are interested in Speed, and I wish they would organize a club and put on a midwinter Speed contest. It would be a good excuse to get away from cold weather!
Please write and let me know if you have any suggestions or questions.
Transcribed from original scans by AI. Minor OCR errors may remain.
