Pong Dragon Radial Engine.

[DesertFox4]

Step back in time. The genesis of the bump cowl.

Kitfox_Test_283 Pong Dragon Radial engine..jpg

[mscotter]

So what's the history? Whatever happened to that engine?

[beeryboats]

Very cool. Four cylinder??
Nope, now I see five...

[avidflyer]

Radials are always an uneven number of cylinders as far as I know. Wonder why this engine didn't work out? Jim Chuk

[HighWing]

Jim,
Your thinking was exactly where I was when I saw the pic. I went out and counted my bumps - 6 actualy 12. My guess was when the engine dropped out of consideration, the cowl was modified for aesthetics.

[avidflyer]

I really don't know why Kitfox stuck with the big round cowl. Most of my flying has been in Avid Flyers, and there is so much more room to see over the cowl with them. After I started to fly the Kitfox 1 this summer, I got to look around the cowl instead of over it...(sort of) I've always been more of a function over fashion type of guy. To each his own of course, but I have an Avid MK IV cowl that will go on the Kitfox 4 if/when I finish it. It looks a bit like the Kitfox smooth cowl from the side. JImChuk

[Dusty]

Thanks for posting the image,I have looked on the internet many times and have never seen an actual photo.
The 12 bump cowl always had me wondering
The story behind this engine is rather interesting.
Any more images?

[Av8r3400]

I'd like to learn more about the Dragon, too.

Stop being such a tease, Steve!

[DesertFox4]

Saw one years ago hanging in Murle Williams shop. Cute little devil.

Was it availability, reliability or lack of power the reason for it's demise as the foundation power plant for the early Kitfox?

[dholly]

I had some time to search:

The Pong "Dragon" designed by Alex Pong made its debut at OSH 1984. The "Dragon" was a six-cylinder, four-stroke engine that was very light and compact due to the ”two row three" configuration of it cylinders. Alex claimed 35 hp from 1400cc displacement at a weight of 44 pounds and a diameter of only 15 inches. He also talked about how larger versions would have the same advantages of size and weight over more "conventional" air-cooled engines. For example he claimed that he could duplicate the installed performance of a 450hp Pratt and Whitney with an engine that was only 27 inches in diameter and weighed about 335 pounds.

More info:

The Pong Dragon prototype was a beautifully machined engine which unfortunately was really no better than a fancy paperweight. I don't recall whether the failure was due to an initially poor design or whether it was due to the fabricator (who has a pretty bad reputation a mile long) who somehow wheedled his way into a partnership. Later, the fabricator at the time somehow managed to get the engine project under his control but like many things he was involved in, it too eventually went kaput.

Last I heard the idea and prototypes were purchased and the project was resurrected about the late eighties or so. The idea went from the really pretty machined design to a rather ungainly looking thing that tried to use VW cylinders, but it too died a pretty quick death.

The biggest problem with the Dragon was it was a 6 cylinder radial design. Radial engines will not work well with an even number of cylinders, as it causes much torsional vibration. I worked with a Dragon engine adaptation for the Avid and soon gave up on the idea. Another problem with all radial engines is their large frontal area. The drag caused by the design, regardless of what make of plane it is on, makes them less efficient than a same displacement horizontal boxer style engine with a aerodynamically shaped cowl.

By Don Downie
COUPEVILLE, Washington

- Wanted: a good home for the Sadler radial engine. This unique 65-hp, six-cylinder radial is in the market for a change of leadership. Bill Gewald, who developed the engine from Sadler's design, has turned 75 and together with his wife Betty feels it is about time for younger, more energetic people to take charge.

Back in 1985, Bill Sadler and Bill Gewald began searching for a reliable four-stroke engine for ultralights and homebuilts. Sadler had developed the Sadler Vampire, a twin-tailed ultralight that was eventually produced for government reconnaissance drones and modified as a ground support fighter. He went on to design Formula 1 race cars and was an instructor at Massachusetts Institute of Technology.

Sadler teamed with the Gewalds to form the engine development company. Prior to that, the Gewalds operated two oil exploration air charter companies in Southeast Asia-one in North Borneo and the other in Singapore.

Betty took flying lessons in Manila and Bill, a mechanical engineer, was taught to fly by his charter pilots in the company Cessnas, Lockheeds and C-47s.

Sadler and the Gewalds began a worldwide search for an existing reliable four-stroke engine and found nothing to their liking. So they decided to invent and build one on their own.

End result was the Sadler 6-cylinder radial engine with a four-cycle, dual electronic ignition with direct drive unit. Made with up-to-date materials and using modern computer numerically designed machinery, the engine has redundancy (12 spark plugs), low rpm, minimum vibration, low fuel consumption and low noise levels.

Patent No. 5,l50,670, was issued in 1992 and a total of 43 proof-of-concept engines were built, but none were offered for sale. According to Betty the company could not support the units with spare parts. However, the engine was installed in an Avid Model C where it produced a cruise speed of 85 mph, a 1,250 fpm rate of climb at gross weight, and a service ceiling above 12,500 feet. The engine, including electric starter and alternator, weighed 121.4 pounds and the all-up weight including engine mount, exhaust manifold and propeller was 162 lbs.

The engine package being offered to investors includes drawings, CAD programs, patterns, jigs and fixtures and many parts for the 65-hp R1765U engine. In addition, preliminary engineering and feasibility studies have been completed for 85-hp and 110-hp versions. Mrs. Gewald stated that only crankshafts and cylinder heads are needed to produce completed 65-hp engines.

"We have never been able to raise enough money to go into full production, but we have all the drawings on autocad. We also have over $17,000 worth of patterns for all the proprietary parts," she said. "It is a reliable, smooth, compact engine with low RPM (red-line is 3000 rpm) that runs beautifully on automotive fuel and sounds like a radial.

We want to sell to someone with the financial resources to treat the engine with the TLC it deserves. We will accept the bulk of any payment based on sales royalties and will personally help all we can in production and sales."

The company now has one engine running on a stand at the Arlington Airport north of Seattle that is available for demonstration the homebuilders with scaled-down replicas of the Golden Era of biplanes: Wacos, TravelAirs, Stearmans, Rearwins, and others originally produced with radial engines. The sound alone would bring pilots and bystanders alike out of the airport cafes and ready-rooms just to listen.

So, if there is someone or a group out there wanting the challenge of producing a well-researched, out-of-the-ordinary engine design with the time-consuming R&D and basic tooling already complete, contact the Gewalds at Sadler Radial Engines, Inc, 603 NE 9th St., PO Box 953, Coupeville, WA 98239-0953.[/quote]