| L88 | |
|---|---|
| Type | 4-stroke petrol V-12 watercooled aircraft engine |
| National origin | Germany |
| Manufacturer | Junkers Motorenbau GmbH (Jumo) |
| First run | 1930-1 |
| Developed from | Junkers L8 |
The Junkers L88 was Junkers' first geared V-12 engine, appearing c.1930 and based on a pair of 6-cylinder L8s. In 1932 a supercharger was added. It was used in the world's second working pressurised aircraft, the Junkers Ju 49 and, for a while, in the large G 38 airliner and its Japanese built military version.
In 1929 Junkers developed their successful Junkers L5 6-cylinder inline 4-stroke aircraft engine into the L8 by increasing its rotational speed and gearing down the output shaft. Just as the L55 V-12 was made by combining two L5s, the L88 combined two L8s into a 60° V-12. This had the same bore, stroke, camshaft operated twin pairs of valves per cylinder, watercooling etc. as the L5, like the L55 driving a common crankshaft in a revised crankcase. An exhaust driven supercharger was added after a year to maintain power at high altitude and this version was named the L88a.[1]: 266
Only a few L88 and L88a engines were built. The Ju 49 high altitude research aircraft initially (1932) flew with the L88 and later (1934) with the supercharged L88a.[1]: 95 The two G38s used a variety of engines including both the L88 and the L88a.[1]: 266 The heavy bomber variant of the G 38, built in Japan as the Mitsubishi Ki-20 was initially powered by L88as. These were replaced, as on the G 38s, by Jumo 204 diesel engines.[1]: 88
Data from Kay (2004) pp.266