A 1/6 Scale Kinner
Radial Engine by Ralph Waser

Ralph Waser, who usually builds multiple wooden models for his grandchildren every Christmas, built this single radial engine from scratch. It runs. He brought it to lunch today (11/1/11), and I brought my light tent and Panasonic DMC FX35 digital camera.

Ralph tells me he spent a minimum of 1000 hours building the engine, and possibly 1500 hours or more.

The full scale original was a Five Cylinder Radial by Kinner. It was available at the outset of World War II and used ubiquitously in many trainers, one being the Ryan ST.

Here are some specs describing Ralph's 1/6 scale Kinner:

  • Bore = .687"
  • Stroke = .827"
  • Bore = .270"
  • Displacement, each cylinder = .370 cu. in.
  • Total Displacement = 1.853 cu. in.

Above is some information gleaned from paperwork Ralph loaned me. Below is some information emailed to me by Ralph's daughter, Judy Nobles:

Ralph Waser's 5-Cylinder Radial Engine

Built: Feb. 1, 1997-Aug. 1998
Work Hours: est. 1000-1500 hrs.
Machines Used: Bench Mill and Lathe
Model Scale: 1/6

History: It was Bob Johannes' idea to reproduce this 5 cylinder radial engine from plans found in "Strictly I. C." (Internal Combustion) Bob was a retired McDonald Douglas engineer but an inexperienced machinist. He came to Ralph for his Toolmaker experience and said that if Ralph would mentor him through the process and help him build his own engine, Bob would buy a machine shop in which to do the project. Once Ralph determined that the plans were very good he agreed, and the two of them set out to each build identical engines.

Comments: Once built, both engines ran well. Ralph noted that the bottom cylinders run cold if the engine rpm is too low, cold enough that it can be touched, unlike the upper cylinders. This problem was common in the original 5-cylinder engines as well. Ralph thought the problem might be solved if a wire was run to keep the glow plug lit.

"If I was a few years younger," Ralph commented. "I'd like to build a horizontally opposed engine."

For high resolution (avg. 1.5 MB, 10" x 10") versions of the above image -- and five others -- click on the numerals below:

(suitable for printing 8 x 10)

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Another pretty good web page by Grant MacLaren