Control Line Scale - 2006/10
Karl Georg Krafft’s Boeing Model 100 and Pond Racer
Bill Boss [[email protected]]
I always welcome overseas mail, and I have the opportunity once again to write about and show the work of Karl Georg Krafft of Hagen, Germany. In the past several years we have seen some of his great work in the form of his Curtiss Gulfhawk, Curtiss Goshawk, and Northrop Gamma. This month we will take a look at his Boeing Model 100.
According to the Complete Encyclopedia of World Aircraft, the Model 100 was the company designation of four airplanes, similar to the F4B-1, that were built as commercial and export aircraft. The variants include:
- Model 100A: a single special two-seat aircraft built originally for Howard Hughes.
- Model 100E: two aircraft, equivalent to the US Army’s P-12E and supplied to Thailand.
- Model 100F: a single aircraft, equivalent to the US Army’s P-12F, built as an engine test bed for Pratt & Whitney.
Karl Georg’s airplane was built to 1/6.3 scale, producing a model with a wingspan of 55 inches and a weight of 9 pounds. The airplane’s color and markings represent a civil sport version of the F4B fighter that was used at air shows.
Karl Georg notes that the full-scale aircraft was flown by Frank Tallman and Kermit Weeks, both great stunt pilots. Frank Tallman did stunt flying in motion pictures such as The Blue Max, The Great Waldo Pepper, Catch-22, and Capricorn One. Kermit Weeks won the United States Aerobatic Championships twice and won several invitational masters championships in different worldwide competitions. One of Weeks’s greatest accomplishments was the establishment of the Weeks Air Museum facility in Polk City, Florida, which is approximately 20 miles southwest of Walt Disney World.
The museum features a main attraction called "Fantasy of Flight," which allows the public to see part of the world’s largest private collection of vintage aircraft. It also features many exhibits that tell the story of the early days of aviation.
Karl Georg’s scratch-built Model 100 has several true-to-scale construction features. The wings are covered with Solartex and have simulated rib tape and stitching. He built the tail assembly in the usual manner with balsa and then covered it with a fine corrugated material to replicate the prototype’s corrugated tail surfaces. He made the flying wires from flat steel with cut-down clevises silver-soldered to the ends.
Power for the model is an O.S. .91 four-stroke engine, controlled with a two-line (coated) system and a four-function electronic system available from ex-world champion Vladimir Kusy. Another feature is the model’s onboard glow system that is used for starting the aircraft and keeping the glow plug hot during low-rpm runs. The onboard system consists of two 1100 mAh cells and is controlled in conjunction with the throttle servo. The system allows the engine to be started without the use of an external battery and provides a safety margin since you don’t have to reach into the area of the spinning propeller to disconnect a glow-plug lead.
Pond Racer (Profile Semiscale Model)
Another of Karl Georg’s models I’m featuring this month is a profile Pond Racer he flies in semiscale class events. These categories have a maximum limit for static points, and a great deal of emphasis is placed on the competitors’ flying ability. Because static points are noncritical for scoring, the semiscale events draw many more competitors.
Burt Rutan developed the Pond Racer, an Unlimited-class airplane, for Bob Pond, who was trying to introduce new technology at the Reno Air Races. It was hoped that success at Reno with the new technology would help to preserve many of the World War II warbirds and engines that are destroyed each year.
The racer was built in the US in 1990 and was equipped with two Electromotive-Nissan VG-30 3-liter GTP engines. The engines were designed to run on methanol and develop 1,000 horsepower. The airplane had a wingspan of 25 feet, 5 inches, and a length of 20 feet. However, the engines didn't live up to expectations and developed only roughly 600 horsepower. The aircraft appeared at the Reno Races from 1991 to 1993, where it qualified at 400 mph. It was destroyed in a landing crash on September 14, 1993, which killed pilot Rick Brickert.
Karl Georg's Pond Racer is built to 1/6 scale, giving it an approximately 6-foot wingspan. Power is provided by two O.S. .20 engines that are controlled with a three-line system.
The model's balsa wing has a symmetrical airfoil and was built using sparless construction in a foam cradle. The fuselage and booms are built-up structures rather than solid. For convenience when transporting the model, the outer wing sections were made removable using two sizes of carbon-fiber tubes.
Karl Georg says the model, with its swept-forward wing, looks great in the air and is a pleasure to fly. The Pond Racer is a great example of how an out-of-the-ordinary prototype can turn into a fine scale project. What subject can you find that would make a unique CL Scale model? If you find one, I would like to hear from you so I can tell our readers about it.
Publications and Resources
Since I have written about vintage and unusual aircraft, I want to let you know that a good source for such aircraft information is World War I Aeroplanes, Inc., 15 Crescent Rd., Poughkeepsie, NY 12601. The company produces two publications dealing with early aircraft:
- WW I Aero: The Journal of the Early Aeroplane (1900–1919)
- Skyways: The Journal of the Airplane (1920–1940)
Both publications contain a variety of information about early aircraft, including technical drawings, three-views, historical research, cockpit views, information about paint and color, old engines, and some scale modeling material.
I have been receiving the Skyways journal for several years and have found it to be fine reading as well as a great source of information for the scale modeler. The cost of each journal is a minimum contribution of $42, and anything exceeding the minimum amount is tax-deductible. For further information about the publications, write to the address above or visit www.warjournal.org or www.skywaysjournal.org.
2004 Scale World Championships CD
The 2004 Scale World Championships was held at the Air Force Academy in Deblin, Poland. US C.L. Scale team member Dale Campbell has produced a CD covering the event.
The disc contains more than 300 photos including competing models and modelers from other nations. It also includes several video segments showing some of the Polish landmarks, the local people, and championship officials.
Dale said he will provide a copy of the CD to anyone who is interested in getting a glimpse of what a world competition is like. The cost is $5 to cover packaging and postage. You can write to Dale at 126 Wise Rd., Vale, NC 28168.
Contact and Submissions
Please send ideas, notice of upcoming events, contest reports, workshop "how-to" hints, and especially photos of CL Scale activity to me at the e-mail address at the head of this column. You can also send US mail to:
77-06 269th St. New Hyde Park, NY 11040
Remember that your photos must be 35mm prints or submitted on CD if from a digital camera. MA
Transcribed from original scans by AI. Minor OCR errors may remain.
