Japanese Engine Research, Page 3


Hitachi "Hatsukaze Model 11"

License Built Hirth 504, which powered both Army and Navy Basic trainers (Allied code name "Cypress"). This is believed to be a Navy engine and this is reflected in the serial number prefix of "11". (First two digits of Navy serial numbers are model numbers)


Translation of Data Plate:
Hatsukaze 11 Model Hitachi Serial Number
Next lines are cam timing, Intake open and close, then Exhaust open and close followed by lash.
Then ignition timing, next line is firing order, then design fuel; in this case 70 octane aviation gasoline.


Another Hatsukaze -- but with a twist

The data plate reads as a Hatsukaze 11. (Serial # 125), but the nose case is different. Hatsukaze engines are direct drive engines; this one has a modified nose case. This appears to be a "step-up" gear rather than a reduction gear, it is believed to be the "recip" engine side of the Campini-type jet (TSU 11) that powered a version of Ohka.


Of interest, the nose case has a unique "cast in" designation. It reads; Hatsukaze Toku ("Toku" translates as "special") Model 13, with the Hitachi logo and a serial number of 1362 (stamped in). I have yet to find any record of the number for TSU 11 engines produced, but 62+ suggests a larger number of units than previously considered. However, it is possible that nose cases were produced and stamped with serial numbers before Hatsukaze 11 engines were modified (at a Navy arsenal) to become Model 13 Toku engines (then TSU 11's). The one way trip planned for the engine/air frame assembly did not require logging of TBO. A close inspection of NASM's Ohka will shed some light on this ... or muddy the waters further. It is all part of the fun of Japanese engines. (This engine is on the top level of the rack system -- tough to get to, photo and inspect. Getting Ohka and this engine inspected are on the list of things to do.)


Ohka 22

Tsu 11 (pronounced like "Sue" with a "T" in front of it)
Caproini Campini Style Jet
Static thrust - 180kg
Weight - 200kg
Recip RPM - 3,000
Fan RPM - 9,000
Smaller warhead and Tsu 11 powerplant gave a range of approximately 82 miles (versus approximately 23 miles for the rocket powered version)


Of note in the photographs:
The view up the jet pipe shows the four "combustion chambers" arranged around the center bullet. They are more like flame holders and help shield the injectors from the combustion heat. Also note the small scoop at the 5 o'clock position. This is the carburetor air supply, taking advantage of the high pressure air from the fan.

In the overhead shots the step-up gear box can be seen the tucked in between the fan inlet ducts. The fuel line and ignition wiring can also be seen passing over the inlet ducts.


Hitachi Amakaze 31 (Also known as Tempu 31)

The Amakaze is a small (17.9 l) workhorse radial engine designed in the late 1920s that stayed in production through the end of the war. Starting out as a no-frills 300 hp engine (Amakaze 11) with no accessory options, it was continually developed and up-rated through out its life. The Amakaze/Tempu powered several small trainers, float planes and utility aircraft for the Army and Navy.
This is a Navy spec Amakaze Model 31. The 30 series engines were introduced into service in 1944. The Amakaze name and model number is cast into the nose case, along with the Hitachi company logo. The serial number block is stamped with the number 31522.


There are a couple interesting things to note in these photos. The views of the accessory case and the prop governor oil line show the “adapted” installation of a constant speed prop system. This was a new feature for the 30 series engines. The 20 series was equipped with a two-speed prop and this can be seen in NASM catalog number A19731553000.

Note also, the stamped in reference to “Lorna”, the Allied code name for the Kyushu Q1W Navy Patrol Aircraft. This marking was done by U.S. personnel, but it is not clear where and when it was done. There are references made to four Lorna aircraft being prepared for shipping or shipped to the U.S.A. at wars end. What we don't know is, is this the engine from one of those or a “spare” marked and shipped to support these aircraft. The stamped number 3012 does not relate to any FE number I have found, it could be an aircraft serial number, but that is speculation at this point.