Japanese Engine Research
at the
Smithsonian National Air and Space Museum
Page 1

Japanese Aircraft Engines - The Book (research in progress)

Japanese engine researcher Robert Mawhinney, of the Smithsonian National Air and Space Museum, has kindly provided a collection of "working" images he uses in his research. Regarding the images, Rob says, "These are not all the greatest photos. They are used to avoid climbing the racks at Garber, pencil/paper in hand, to translate data plates and take notes on details. They also help save time by not moving engines here and there. They are a good peek into the Japanese engine collection at NASM though, for that alone they are worth it."

We could not agree more!

Nakajima J1N1-S Gekko

One of my current projects fits into the Japanese engine work nicely. I'm part of a three-man crew disassembling NASM's Nakajima J1N1-S Gekko (Code name: "Irving”). The Gekko was restored at NASM some years ago but has never been on public display.
Some time this summer we will move and reassemble it at the Udar-Hazy center. This is a good chance to have a look at the complete installation of a power plant.

The engines are Nakajima Sakae Model 21's.
It is interesting to note the differences between the two engines. The right engine's nose case has "Sakae" cast into it in Katakana. Katakana is a phonetic way of “spelling out” Japanese words. The left engine has a “data tag” that uses the Kanji symbol for Sakae and states the model number. The quality of the casting on the right engine nose case is not as good as that of the left engine. Other differences are; No carb data plate on the right engine, rocker box oil sumps are not the same and many other minor details.

The carburetors are Nakajima two-venturi Model 100 "Ko" units on both engines.
Of note in the close up of the carb from the rear are the two large hoses running to it. These are engine oil lines feeding hot oil through the carb for anti-icing protection.

Right Engine (Nakajima)