Control Line: Aerobatics
Wynn Paul
FAI Notes
With the outstanding success of our precision aerobatics team in England last summer, it is up to the stunt fliers around the United States to get charged up for another tryout next summer. Most likely, present World Champion Bob Hunt will go over to defend his title, which allows three others to compete as team representatives. That means that, in all probability, we will pick three fliers at the next Labor Day tryouts.
Sites already mentioned for the tryouts are Cincinnati and Dayton, Ohio. Cincinnati has a large number of ready workers and two excellent circles at Lunken Airport. Also, just across the street, the airport management has agreed to furnish approximately eight circles for practice all week long. The circles are on a runway ramp that is little used during the week. On Saturday the extra circles will be reduced to two or three. I have a letter from the airport manager stating that the circles will be available for the FAI tryouts on Labor Day weekend.
Dayton has one of the finest layouts for a contest in the nation: three excellent circles (although one of them has a speed fence around it), and a motel just 100 yards away. Unfortunately, help to run a contest is at a minimum — at least this has been the case the past couple of years at their local contest. Perhaps with the importance of an FAI event again (trials have been successfully run there several times), some of the workers will come out of hiding. Jim Fasimpaur served as assistant E.D. at the ’76 Nats, judged at the ’75 FAI tryouts, and knows what is needed for a good contest — but needs some help!
Any other site representatives who wish to be considered for the FAI stunt tryouts should contact PAMPA president Keith Trostle at:
- 10900 Phillips Drive
- Upper Marlboro, MD 20780
Maybe the FAI speed people should drop by the stunt tryouts to learn how to make an official flight.
Aero-Challenge — Post Mortem
Bill Allen of DeKalb, Illinois, knocks himself out each year to set up his two-day extravaganza with lots of control-line events and great awards. This past contest had 137 contestants and generated $1,297.75 for the Jerry Lewis Labor Day Telethon. Stunt, for instance, had 33 entrants in four classes and included some top national qualifiers.
Unfortunately, not everyone shares our enthusiasm for model airplanes and associated activities. Bill sadly received a discouraging letter from the Wurlitzer Company, the site of the 1978 contest. According to the facilities manager, they are concerned over protecting their investment in landscaping and underground sprinkler systems; they also felt that the children present were not under proper control (some fool was actually playing in their fountain!). “Therefore, I regret Wurlitzer cannot offer you their facilities for future model meets,” signed R. G. Myrland, Facilities Manager.
How narrow-minded; such a wholesome activity for the people involved, plus spectators and, added to this, the donation raised for the Telethon. Is Wurlitzer’s margin of profit so slim that they can’t support civic activities such as this? Let’s hope that Bill Allen can find another site for his Aero-Challenge.
Swept-Forward Trailing Edge
This idea has been used by Bill Werwage on several of his planes recently and also has been tried by Al Rabe, Bob Gialdini and Don Shultz. Bob Hunt said recently that he, too, is going to cut a foam wing to try this idea for next year. The claim for this method is that with the swept-forward trailing edge the plane will not yaw. According to the experts, air spilling off the conventional trailing edge when the flap is deflected helps to create yaw.
Hunt cites the example of grasping a 12-inch ruler in the middle and drawing it through a pan of water: the ruler will yaw back and forth. However, a piece of wood cut and glued at the center to represent a swept-forward trailing edge does not exhibit the same tendencies.
It is obvious that with the swept-forward trailing edge the deflected flap does not meet the airflow flat across the entire surface but, rather, the air is channeled or spilled off the ends. Werwage had a trailing-edge sweep of some 2.25 inches. Bob is trying two configurations:
- 1.5 inches
- 2 inches
Forties Coming on Strong
The switch to the .40-size engine is becoming a roar rather than a trickle. The HP-40 and the Max 40 FSR are getting the majority of stunters. Talking with Bill Werwage recently, he said that he has been experimenting with the HP, both the Max .40 and .45, as well as the ST-46 all during 1978. His new plane will be built to accommodate all four engines.
How is this accomplished? Bill’s resident machinist has carved out some odd-sized front covers for the crankshaft so that the extensions all end up at the same place for the spinner.
Recently, Bill tried a novelty. He put the front half case and crankshaft of an HP-40 onto a Max 40 FSR. The result was a very nice 8 oz. engine; however, it didn't run too well. Bill attributes the loss in performance to the smaller porting in the HP crankshaft. He feels that the almost double port in the Max crank gets more fuel/air mixture to the chamber, which in turn gives more power. Bill stated that he really likes the “guts” that the Max .45 has but it is just too rough to suit him for stunt. He likes the combustion chamber design of the .45, but still the engine has rough spots that don't please him.
Those who have been running the HP-40 with success all seem to have to adjust the timing of the sleeve. It seems that about .015 in. drop of the liner will make the HP run better for stunt. Popular venturis for the HP are in the .290 to .296 range.
The writer has had some limited experience with the Max 40 FSR and it does appear to be a very good engine. Tank height is a problem. Werwage suggests that the tank be 1/8 in. or more off the beams for a better run. I experienced wind-up in the consecutive maneuvers but have not yet been able to try adjusting the tank height. One thing for certain: the Max can be flown right out of the box. It looks like a good engine; certainly it can be about the same as an average or better-than-average ST-46 without any reworking. And you can use the .015-size lines, which is an advantage.
Contact
For information on stunt or PAMPA, write:
- Wynn Paul
- 1640 Maywick Drive
- Lexington, KY 40504
Transcribed from original scans by AI. Minor OCR errors may remain.
