CONTROL LINE SPEED
Glenn Lee, 819 Mandrake Drive, Batavia IL 60510
This column is titled "Speed," and I've assumed that meant any and all kinds of fast models, not only control line. There are quite a few events that utilize the high-revving, high-performance model engines one way or another. I throw in anything that I think you readers might be interested in. Sometimes I hear about it from fliers, and most comments are very helpful.
Crankcase castings
For instance, Denny Hitson (Kalamazoo, MI) was interested in my photo of the various unfinished crankcase castings I'm working on and wondered where he could get some. Such things are hard to find, but there are some available. I bought the TWA cases about 30 years ago, but picked up the others recently from various people.
Ron Bernhardt of Australia sells some Yellow Jacket–type castings that take Dooling .61 internal parts, but the Dooling bypass is not cast in. It takes a very special machine tool to cut that bypass, so you either have to build such a mechanism or just fake it and grind the bypass out by hand.
Most crankcases presently are made by the investment, or lost-wax, process:
- You make a wax pattern, surround it with investment plaster, cook the wax out, then inject molten aluminum alloy into the cavity under pressure.
- Casting while the mold is hot retards shrinkage and improves the quality of the part.
- It's expensive and time-consuming, but it gives you a semifinished case with all bypasses cast in and minimizes finish machining.
- The die that makes the wax pattern is complicated and expensive, so you don't make it unless you want a lot of pieces.
Sandcasting is a lot cheaper, but the parts are much rougher and more unfinished.
Photos and column notes
Denny also wondered why the photos with that column didn't match the text. Good photos are hard to come by, and I don't always have ones that match what I'm writing about. Sometimes I'll do things like that just to see if I get any response — and sometimes it works.
Electric Speed
Did you know there are Electric Speed classes? I had heard about it but never paid much attention and never bothered to look in the rule book. William Stewart (Thousand Oaks, CA) wrote and sent some pictures of his and Howard Doering's Speed models.
- Howard's Class A model holds the present record at 90.42 mph.
- Bill's Class B held the record for a while at 106.97 mph.
Classes are differentiated by the number of batteries used: Class A is limited to a maximum of seven Ni-Cd cells, and Class B can have up to 30. The models are flown on two .018 lines 60 feet long, are timed for seven laps, and use 8x8 props. Complete rules are printed in the Electric section of the AMA Competition Regulations.
I haven't seen anyone fly Electric Speed in this part of the country yet, but maybe we should take such events a little more seriously to encourage more competition in our highly populated areas. The elimination of the noise factor would make Speed flying more acceptable to people, and schoolyards and parking lots might be more available for control line flying.
Rubber-powered Free Flight Speed
A few years ago there was another Speed event held at the Nats — Rubber-Powered Free Flight Speed. Models had to be powered by rubber bands, had to ROG (rise off ground), and were timed over a distance of 200 feet. This event has been flown for many years; it started not long after the modeling craze began in the early 1930s.
I have been visiting with a gentleman who has been flying it since then, and he still holds the record of something like 53 mph. Walking into his house is like walking into a modeling museum, with twin-pusher models hanging on the walls, airmotor-powered models sitting around, and photos of old flying events and race cars all over. He has many famous old free flight models, such as one that flew at the 1912 "Nats," powered by a 1910 Gamages engine.
He still has full-scale airplanes such as a Cannonball Heath racer, a few engines from World War I airplanes, and owns an Indy race car called the Tuffinelli 270, powered by an Offenhauser engine. On his basement wall hangs a huge propeller from the Brock-Moraine monoplane that won the first race from London to Paris and back in 1914!
Tether cars and anecdotes
Peter Larson (Aurora, ME) wrote after he saw the photos of the tether race cars in the July issue. He was a race car fan back in the '40s and ran the prototype rear-wheel-drive cars powered by Super Cyclone engines. His last car was powered by a McCoy engine. He was present at the Trenton, New Jersey, track the day the 100 mph barrier was broken (104 mph with a Dooling-powered streamliner). The owner of the car wasn't there; he was a B-29 pilot, couldn't get off duty, but flew over the track at the time it was setting the record!
Tether cars can still be proxy-operated; the owner doesn't have to be present at a race. Willing volunteers can usually be found, and many times the proxy-run cars will go faster than when the owners are there. Peter handled a car at a meet in Kearny, NJ for Rochester, Jack Benny's chauffeur. Rochester's car was a beautiful Proto, finished inside and out complete with a driver. Peter also designed a centrifugal clutch that protected rear-end gears from stripping when the engine backfired during starting.
Pioneer Museum — Minden, Nebraska
There is an interesting Pioneer Museum in Minden, Nebraska that has transportation items ranging from hand-powered push cars to the first jet-powered airplane built in this country. They have wagons, cars, bicycles, several old airplanes — just about anything you can think of — and even some model engines.
There are a bunch of full-scale airplane engines, including several rotaries and classics such as:
- Gnome Mono-Soupape (circa 1913)
- OX-5 from a WW I Jenny
- Pratt & Whitney Wasp (1938)
- Other period engines
One single-cylinder engine sitting there was labeled as being designed and built by Glenn Curtiss for his hill-climb motorcycle in 1905. This was before he became a noted aeroplane builder. The engine was built in Hammondsport, NY, and used in a Mercury racing motorcycle that set a record. It would turn more than 7,000 rpm — a fantastic speed for that period — and featured an offset crankshaft, where the bore of the cylinder does not lie on the centerline of the crankshaft. Theoretically, if the cylinder is a little to the side, the downward force on the crank is increased.
This offset has been used in several model airplane engines, but we always called it the DeSaxe offset. If Curtiss used it first, why is it called DeSaxe? Did DeSaxe patent it? There are engine designers who argue the merit of such an offset and even argue as to which side of the crankshaft it should go. It is my opinion that the offset doesn't do much for power, but it does alter the timing and could change the operating characteristics of the engine. Anyway, Curtiss went into airplanes in 1909, and the 1905 engine impressed a guy named Waterman so much that he designed the first outboard boat motor using it for power.
Transcribed from original scans by AI. Minor OCR errors may remain.
