CL Aerobatics
Frank McMillan, 12106 Gunter Grv., San Antonio TX 78231
One of the wonderful things in Precision Aerobatics during the past 10–15 years has been the sharing of information. Sure, there's been an explosion of technology, but it's the people who have offered themselves and their knowledge for the advancement of the event.
Many years ago, the famous Garden State Circle Burners club started an annual symposium, which it held each winter. From building techniques to flying, the club covered a spectrum of topics.
Last year, the Dallas Model Airplane Association started an equivalent Southwest Regional, and had an excellent turnout. Again this year, the Dallas club hosted its annual Stunt forum. Tom Niebuhr was the organizer, serving as he did for the Garden State Circle Burners. With the help of all participants, Tom put on a varied forum that covered a spectrum of interesting subjects.
Before getting to the technical side of the presentation, we had the usual club, regional, and national activities.
Announcements
- AMA District VIII Vice President Sandy Frank reminded us of the Southwest Aeromodeling Conference on May 19–20. PAMPA (Precision Aerobatics Model Pilots Association) and the Dallas Model Airplane Association will host a booth.
- Contact Sandy at 105 N. Brazos St., Weatherford TX 76086-3207; Tel.: (817) 599-7131; E-mail: [email protected].
Technical presentations
Bill Lee, several times a member of US international teams, kicked off the technical presentations with a discussion of propellers and Stunt—or as he titled it, "Of Bumble Bees and Precision Aerobatics."
Bill brought to this discussion a strong background on propellers; he has made his own for the FAI (Fédération Aéronautique Internationale) team races, and has made several carbon/epoxy propellers suited to the larger piped engines. The latter are excellent—extremely light and worth trying.
Bill talked about using the Prather pitch gauge, the available standard, and its practical use. He also supported his paper with empirical observations related to Abbott and von Doenhoff's book, The Theory of Wing Sections.
One of Bill's conclusions was that the propellers we use now seem more efficient in terms of advancing the model versus the theoretical pitch. In all, it was a very interesting presentation.
The next presentation was by Bob Gieseke and Mike Scott, on the plastic tanks they use and how to set them up for Stunt.
There are advantages to using converted radio-control tanks, such as consistency and ease of setup. These tanks can be made to run well, as Bob and others—including Bob Hunt and Bill Werwage—have demonstrated throughout the years. Of course, the model must be set up to accept the much-deeper shape of the Sullivan 6- to 8-ounce tanks.
Mike and Bob discussed how to set up the internal tank venting and the fixed aircraft-side vents. They demonstrated the ease of setup and the good results that show plastic tanks are a viable alternative to the standard metal tanks.
Bob Gieseke followed up with how he covers his superlight models with Japanese tissue.
His approach to finishing is to cover the entire model with 0.2-ounce carbon veil, then cut out the open bays of the wing. These are covered with Japanese tissue, and the entire airplane is finished normally.
Bob is very specific about the type of tissue he uses—even the yellow color works best. He discussed procedures in detail, such as how he controls the amount of paint by spraying techniques.
- Several light, dry coats are sprayed to seal the surface, then the succeeding coats will remain on the surface rather than penetrating, which prevents a thicker, heavier finish. That philosophy is applicable to all our finishing.
Bill Wilson's painting presentation also garnered a great deal of attention. He is a professional auto painter and is reading up on the newest materials and techniques.
Bill had many examples of how he uses airbrushed shading and other materials. He gave a lengthy survey of the new multipart "Poly" paints and how they are used. In particular, he talked about how quickly he could apply a utility finish.
- As with any multipart paint, you have to be very cautious in its use. Follow the safety precautions.
From the latest to the sublime, Don Hutchinson showed his Yates Dragon with an original Orwick .29 on ignition. He surveyed the latest in ignition systems and how to operate the Old Timers. Call it the "Romance of the Early Days"; it's fun and available to all.
New products and methods
There was some interesting news on the new-products side.
John Lowry announced that he is entering the supplier business; he is buying out the Bob Bearden line of Bear products, and he is going to produce his own line of glow plugs. John is also looking at producing several kits, such as the well-known Tom Farmer profile Forerunner and the Bob Gieseke Bear.
Good luck to John; we look forward to seeing his new products.
Host Tom Niebuhr followed with an excellent look at the now-famous lost-foam method of construction. This method features accuracy in developing the ribs, the molded leading edge, and the panel layout.
Tom has used the lost-foam method to build several different types of wings and has been very pleased. The purpose of the presentation was to show the practical side of how these wings are constructed and the procedures that ensure accurate, light wings.
It's been a long time since we have been treated to some Al Rabe "fire."
Throughout the morning, Al demonstrated molded shell developments, and he molded a set of Bearcat shells. Al showed how he wraps the shells and how he sands them on the molds.
Part of the discussion focused on the development of the molds and the techniques involved in ensuring accuracy and reference points. Al also discussed how the fuselage is constructed once the shells are completed.
The shells are halves in the Bearcat. The interior structure is added to one half, then the other half is fitted.
Al casually pointed out that you have to be careful about alignment with the semicelsales, and that they are a challenge. Bill Werwage calls them "3/4 airplanes," because it takes that much effort.
It's good to see Al back and involved.
The Dallas Stunt forum continues to grow in technical presentations and in participants. Thanks to Tom Niebuhr and the Dallas Model Airplane Association for this informative day. Hopefully they will keep the forum going.
Transcribed from original scans by AI. Minor OCR errors may remain.
