CONTROL LINE RACING
By Dave McDonald
Dave McDonald, Box 384, Daleville IN 47334; E-mail: [email protected]
Mouse II
As I write this column the roar of racing engines from Daytona, Florida, indicates that spring is almost here, and with that comes another flying season. I recently attended the annual Tangerine contest in Titusville, Florida. Some of the events flown were Mouse II, Quickie Rat, and Fox Racing.
In Mouse II the usual starting problems plagued most competitors, resulting in poor race times, but the airspeed even on the longer wire was extremely impressive for some pilots. Bob Whitney had prepared two first-class airplanes—one for himself and one for his pilot Dave Hallas. Bob's entry suffered this year, but Dave's was definitely the class of the field with Cyclon power.
Dave's model was consistently about 96 mph in traffic during the race. The 100 mph mark is not out of the question, and I would expect to see some airplanes running that speed at the Nationals. What makes this even more impressive is the 10% nitromethane fuel being used.
Brian Silversmith came from New Jersey to race and provided not only an unforgettable airplane but an unforgettable set of incidents. Although his model looked conventional, it had an aluminum brake attached to the landing gear: an upside-down "T" with the wheel bolted to the rear of the horizontal piece and the front acting as a brake during pit stops. By nosing the airplane over on landing, the aluminum piece would drag the ground and stop the airplane.
This is an old concept that needs better design. I do not recommend the horizontal approach: if a pit crew member misjudged a catch even slightly, an aluminum plate could be sticking into a hand or other body part. It could also become a line-snagger on landing; the forward‑protruding piece might catch the lines and cause a catastrophic accident. Safety is vital at all contests, and participants must be alert at all times.
A second memorable event occurred during the two-minute warm-up and could have easily resulted in injury or at least a lost airplane. A pit crew lapse in communication and circle awareness led to the person responsible for holding the airplane letting it go while the starter was engaged. Fortunately, Dave Wallick had the handle and prevented a serious incident. The people involved were shaken and humbled by their lack of awareness. Safety is everyone's responsibility—always be aware of what is going on around you in the circle.
Brian went on to win with a time of 5:51—an extremely good time for this contest. Gabe Manfredi finished second, and Ralph Aaberg was third.
Quickie Rat
In Quickie Rat I flew Wayne Trivin’s entry, which was one of the fastest airplanes at the meet. With a one-flip start and a one-flip pit, Wayne posted a 3:01 in the first of his heat races. That’s a good time in this event; with a little luck through traffic it could have been under three minutes.
All of the airplanes are closely matched in this event, so it usually comes down to who can outpit the other person. In this case Ralph Aaberg and Byron Bednar turned in good heat times to secure their spots in the final with Wayne. The final was less than stellar: Wayne didn’t get his airplane to start and finished third. Ralph claimed first place and Byron took second.
If you are looking to escape the winter, I highly recommend planning to attend this event next year; the weather is usually nice. There are many things to see and do around this area of Florida—plan on making a week or so of the trip:
- Visit Daytona Speedway
- Spend time at Walt Disney World
- Tour Cape Kennedy
- Play one of the many golf courses in the area
Engine testing and modifications
Testing of new Quickie Rat engines and ideas became a reality recently. I stopped by John McCollum’s on a business trip and we tested some engines in his indoor test room, which is equipped with a tachometer stand, an adjustable-height fuel-delivery system, and exhaust removal.
Over the winter I gathered parts—many spare pistons and liners for approximately nine Quickie Rat engines—and documented all of the engines: timing numbers, head clearances, rod types, and the vintage of the crankshafts.
Using the K&B 4011-series engines, I observed two basic types of cranks:
- Older type: black counterweight and pressed-in crank pin. It is softer and slightly smaller in inside diameter (ID).
- Newer type: crank pin machined as part of the crank. It is harder and has a slightly larger ID.
Both cranks can be bored out using a carbide drill and mill. The question is how far one can go without reliability problems. I have bored some cranks out to .385 and have not encountered reliability issues. With a .315 venturi as the maximum, my focus is not simply making the crank bigger but making every moving part lighter—the crank is the first step.
Other modifications I have tried:
- Removing material from the inside of pistons. This may be more work than it's worth, but it fits the goal of reducing reciprocating weight.
- Removing the center from a conventional connecting rod to lighten it, improve cooling, and reduce obstruction around the crank hole. This idea came from UK F2C practice. The modified rod saved noticeable weight and produced a measurable performance increase; so far it shows no abnormal wear or fatigue.
- Examining rod types: K&B made many variations over the years (some with bushings, some without). There is debate over round rods versus conventional rods. Unless you plan to modify a stock rod, I suggest using a round rod. Do not use a rod that lacks bushings at both ends.
- Removing material under the venturi area: K&B 4011-series front ends have a square opening under the venturi. I made a fixture and removed some of that square area to allow a better fuel-delivery system while retaining the case holes for the needle valve. When done properly, you can remove the entire front surface area and still maintain the sides that control crank timing.
- Recutting heads to experiment with head clearance—this requires shims to set the desired clearance range.
- Other work in progress: removing material from sleeves, thinning webs in exhaust and transfer openings, and changing engine timing to evaluate effects on power, range, and torque.
As testing continues, we will see which modifications are beneficial as a package and which are not.
Carbon landing gear
Steve Wilk has introduced a new carbon landing gear for Scale Racers. These are copies of the Glenn Lee landing gear and weigh roughly half as much as titanium gear. Initial testing is ongoing; Steve is making two variations depending on the material and the amount of tow or cloth used. My initial reaction is positive—I prefer the type with cloth on the exterior of the gear. Using a test stand is one thing; I look forward to seeing how these perform in race conditions as the weather improves.
For more information or to order carbon landing gear, contact: Steve Wilk 3257 Welcome Ave. N. Crystal, MN 55422 E-mail: [email protected]
As always, your comments are solicited and appreciated. MA
Transcribed from original scans by AI. Minor OCR errors may remain.
