CONTROL LINE SPEED
Glenn Lee, 819 Mandrake Drive, Batavia, IL 60510
I'm writing this column just before I leave for the Nats, so everything is rush, rush, rush! Most of my airplanes are ready, and I've been filing and sanding props, mostly fiberglass ones. I wear a dust-filter mask and long rubber gloves when I work with fiberglass—I just hate those itchy little glass fibers sticking in my fingers.
There are several items I'd like to cover in this column, so here goes.
The Quest
It's difficult for a flier to fly Speed all by himself. As a result, there have been many Speed teams down through the years, including:
- Clem Beasley and Kim
- The ZOOM Speed Team
- Harris and Shelton
- Graham and Booher
- Nash and Pardue
- Stegens and Dodge
- Telford and Violett
- Lauerman and Delaney
- Theobald and Wisniewski
- Roselle and Frye
- Bussell and Jett
- Anaston and Morton
- Hustad and Roy
The list sounds like a Speed Hall of Fame, doesn't it?
In the late '60s, the team of Bartley and Garner (from High Point, NC) were tough competitors; they won contests and set records all over the country. John Bartley's son, Danny, also won in Junior and Senior. He was a great, good-looking kid, and an accomplished Speed flier.
Tragically, Danny lost his life in an auto accident in the early '70s. Bernie Stadiem and other Speed fliers from the area donated some money and had a beautiful silver trophy made as a memorial to Danny. The Danny Bartley Memorial Trophy was to be awarded to the Control Line Champion at every Nats. Points were accumulated in every control line event and were calculated the same way that points for the National Champion were compiled.
Each winner would have his name (and the year) engraved on a small plaque on the trophy, and would keep it until the next Nats.
I had some good-running equipment then, and I was Control Line Champion in 1972 and 1974; Terry Herron won in 1973, Mike Langlois in 1975, and Brent Bussell in 1976.
About that time AMA decided that it was too much work to collect the data and compute the points to select a National Champion for the National Championships. There was no Nats Champion, no Control Line Champion, and we lost track of the Danny Bartley Trophy.
I don't know if anyone got the trophy after Brent—wouldn't it be great to find it and reactivate the award? I'd like to keep the memory of Danny alive, and with today's computer coverage it would be simple to arrive at a winner. Let's think about it—and let's look for that trophy!
Lore
Like most experienced contestants, those of us who have been flying Speed for many years have picked up vital tricks, techniques, procedures, and items that make our equipment much more reliable and/or faster. For those beginners who have yet to learn such things—we should pass this knowledge on to make their lives a little easier and their flying more successful.
Needle Valves
If you use a surgical-tubing bladder tank (with its resultant high pressure), the size of the hole where the tapered needle meters the fuel should be no larger than about .046" diameter. If it's bigger than that, the needle setting will be critical; the area of opening changes drastically as you adjust the needle. However, if you use a metal tank and crankcase pressure, you might need a larger hole since there is less pressure.
I had this problem with my K&B .65; it wouldn't run rich enough until I drilled out the needle seat fitting to .055" diameter. You can have another problem with a metal tank—the hole in the crankcase-pressure fitting may be too big. If you get surging, try reducing the pressure-fitting hole size: soft-solder a piece of music wire into the hole, then pull it out just as the solder sets up. Try .014" wire to start. I've used wires as small as .012" and they worked OK, but a slightly larger wire will probably work as well.
Fuel Injection
Another trick that can give any engine a steadier run is to make sure the fuel is injected out near the center of the carburetor intake opening—not dribbled out of a slot or hole near the wall. Air tends to stick to surfaces—you want to get the fuel outlet away from this boundary layer so it can be atomized properly. Try to get the fuel outlet at least 1/8" from the wall.
Fuzzy Props
Propeller tips always tend to get scuffed up during landings. On an engine turning more than 20,000 rpm the tips are moving several hundred miles per hour! The slightest amount of fuzz or scuzz on the tip can really load your engine down and cut your speed. Instant (cyanoacrylate) glue is good to help repair tips of fiberglass props—you can file and sand them properly before using them again. (Make sure to balance the prop again, too.)
Bolts
Don’t mount your Speed engine with hard, heat-treated socket-head screws. They’re strong, but the vibration from a high-revving engine will soon pop the heads off—the screws are too hard and don’t have a very good fatigue life. Mount engines with soft-steel or brass screws—they’ll shear off in a crash and help prevent engine damage.
Control Line: Speed
Another New .21 Engine
I just test-ran a Thunder Tiger #9565 Pro .21 M-R engine. It is a marine engine, so I got one without the water-cooled head, throttle carburetor, and flywheel. I had to use some of my own parts, including a head clamp, collet and prop driver, and remote needle-valve assembly. It is labeled as an ABC engine on the box, but it's really an ABN. The piston fit seemed a little loose, but it was probably necessary with the nickel-plated sleeve.
My degree wheel indicated that the boost port was open for 114°, the bypass ports were open for 124°, and the exhaust port was open for 160°. The front-intake rotary valve opened at 40° after bottom dead center (ABDC) and closed at 52° after top dead center (ATDC). These numbers sounded pretty conservative for a speed engine, but I decided to test-run it before I tried any modifications. To my surprise, after a few minutes of running at a slightly rich setting, it turned a 6 x 5.5 Kelly prop at nearly 27,000 rpm!
Afterwards I disassembled the engine and ground the opening in the crank so it opened about 30° ABDC and closed at 67° ATDC. With the same prop the engine now turned exactly the same rpm—just under 27,000. I've always had the opinion that timing is really not too critical; this experience reinforces that idea somewhat.
I may raise the boost port to match the bypass ports, but I'll leave the exhaust port alone to conserve power for full six-inch-diameter props. We need quite a bit of prop to haul those large props around. The Thunder Tiger importers were considering a control-line version of this engine, so we may have another source for reasonably priced .21 Sport Speed engines.
K&B
If you ever need parts for your K&B engines and find that it's impossible to get them from your hobby dealer, order them from the factory. If you do, call Tina in Customer Service; she knows what's going on there.
Muncie
If you're ever near Muncie and AMA Headquarters, make sure you stop in to see the museum—it's really neat!
Transcribed from original scans by AI. Minor OCR errors may remain.
