Hirth HM 512
The Hirth HM 512 is a German aircraft engine developed in the 1930s by Hirth Motoren GmbH based in Stuttgart-Zuffenhausen .
development
The HM 512 appeared in 1937/1938 as the last and most powerful motor of the 500 series HM 504 , HM 506 and HM 508 developed by Hellmuth Hirth . The structure of this series of drives was largely identical and u. a. characterized by the use of unit cylinders of the same displacement and a split crankshaft with Hirth teeth , which made it possible to use the same and to exchange individual components in and between the individual models. Two versions of the engine were produced: The A version was equipped with a bottom loader and a fully independent Sum carburetor , the B version received a height loader and two Pallas carburettors with manual single lever operation . The HM 512 was in direct competition with the similarly constructed As 410 A from Argus . In contrast to this, it had a lower weight with approximately the same performance near the ground, but its performance parameters fell 10% below those of the counter-design from 3000 m. When Hellmuth Hirth died in 1938, his company was taken over by Ernst Heinkel AG , which geared production exclusively to four-cylinder engines and took all other Hirth models out of the range. As a result of all this, the HM 512 was unable to prevail against the As 410 and only a few examples were built.
construction
HM 512 is a air-cooled twelve-cylinder - four cycle - V-type engine with suspended in two rows of six at an angle of 60 ° to each other cylinders , planetary gear , and, depending on the design, soil or height loader . The engine has fresh oil lubrication for the crankshaft bearings and the cylinders as well as splash oil lubrication for the remaining components, which are ensured by a double gear pump and two return pumps. The crankshaft is split and put together by means of a Hirth coupling; it runs in six roller bearings and one radial bearing . The cast motor housing consists of tempered electron . The ignition is carried out by a Bosch twin igniter with automatic ignition timing adjustment and an oil pressure servo unit. Each cylinder is provided with two spark plugs and two valves and has a head made of heat-resistant light metal alloy.
use
Technical specifications
| Parameter | Data (Hirth HM 512 A) | Data (Hirth HM 512 B) |
|---|---|---|
| length | 1.51 m | |
| width | 0.66 m | |
| height | 0.83 m | |
| drilling | 105 mm | |
| Hub | 115 mm | |
| Cylinder displacement | 1 l | |
| Total displacement | 11.94 l | |
| compression | 6.0 | |
| Reduction (gear) | 1.5: 1 | |
| Reduction ratio (charger) | 1: 3.8 | 1: 9.3 |
| Short power (1 min) on the ground |
400 hp (294 kW) at 3110 rpm | 450 hp (331 kW) at 3100 rpm |
| Best short-term performance | 360 hp (265 kW) at 3000 rpm on the ground |
390 hp (287 kW) at 3000 rpm in 2300 m |
| Continuous output | 300 hp (221 kW) at 2810 rpm on the ground |
332 hp (244 kW) at 2810 rpm in 3000 m |
| Best continuous output (30 min) | 330 hp (243 kW) at 2910 rpm on the ground |
360 hp (265 kW) at 2910 rpm in 2700 m |
| Dry weight | 270 kg without equipment | 275 kg without equipment |
| Power to weight ratio | 0.68 kg / hp | k. A. |
| Displacement | 33.3 hp / l | k. A. |
| Fuel consumption | 64.5 kg / h | 83.0 kg / h |
| Lubricant consumption | 0.9 kg / h at 300 hp | 1.0 kg / h at 332 hp |
| Octane number | 87 | |
literature
- Werner von Langsdorff : Handbook of aviation . Born in 1939. 2nd, unchanged edition. J. F. Lehmann, Munich 1937, p. 528/529 and 560 .
- Kyrill von Gersdorff, Kurt Grasmann: aircraft engines and jet engines . In: German aviation . Bernard & Graefe, Munich 1981, ISBN 3-7637-5272-2 , pp. 127 ff .