Updated: 26-Jun-2019
Irwin Aircraft Co. built small 4-cylinder radial engines in two planes. Like two crossed boxers, one behind the other.
“Meteormotor”
-The Meteormotor is from 1922. It gave 20-25 hp at 1,900 rpm. and had a displacement of 79 cu. in.
-The 79 Aka is from 1926. It had the same displacement of 79 cu. in. and it gave the same 20 hp of power.
-Irwin was initially and from 1919 in Sacramento, CA. Later in 1928 it moved to Corning, CA, and eventually, in 1930, it was located in Watsonville, CA.
“Irwin prototype”
-We provide a simple drawing of the engine that appears photographed in the main text. It is the Model 72 from 1926. Some three years later the Irwin model 79 came out.
“Irwin 72 Model”
-We can see that between the engine supports and the wooden bench there is no type of elastic suspension, so the vibrations and gestures of the engine would be transmitted to the structure of the aircraft.
-And we were already entering the 1930's.
From Appendix 6: We come back with the small Irwin engine (Meteormotor) mounted on a biplane (also Irwin).
“Irwin engine with 20 hp”
-It is a four-cylinder, cross-shape engine.
-At the Smithsonian's engine warehouse there is an Irwin on a shelf, half-hidden and in the dark, but good looking.
“The Irwin engine at the NASM”
From Appendix 9: From this North American brand we localized a four-cylinder cross-engine. Now we can see that there are two boxer engines that are mounted one behind the other, and crossed at 90°.
“Four-cylinder Irwin”
-This detail is difficult to observe in the examples shown in the main text.
"Another view of the crossed boxers"
-Photos provided by Czech contributor Mr. Evzen V. from his blog <aircraftengine.cz>.
-Below we show a close-up photo of the specification-plate for the same engine.
“Irwin engine plate”
-It reads: Irwin logo / Irwin aeronautical engine no 129 / Model Number 79 / Normal RPM 1730 / Rated HP 20 / Cu. in. displacement 79
From Appendix 12: An Irwin engine held by a young lady in a promotional photo.
“Irwin with two crossed boxers” (PiP-Flu)
-Photo extracted from the German "Flugsport" magazine.
Engines of IRWIN
Model: 72 cu. in., 4 cyl. en X
Arquitecture: 4-cylinder X-engine
Cooling:
Total Displacement: 72 cu. in.
Bore / Stroke:
Power:
Weight:
"Irwin Model-72 engine"
Model: 79 cu. in., 4 cyl. en X
Arquitecture: 4-cylinder X-engine
Cooling:
Total Displacement: 79 cu. in.
Bore / Stroke:
Power: 20 HP @ 1900 rpm
Weight:
"Irwin Meteormotor"