Praga D
The Praga D is an aircraft engine made by the Czechoslovak manufacturer Praga in 1938. It is a performance-enhanced further development of the Praga B 2 from 1936. Although it was created before the Second World War , it was only widely used after the end of the reconstruction of the country's aviation industry. It was used primarily in sport aircraft . However, there was also a version for helicopters, the Praga DH .
construction
The Praga D is an air-cooled four cylinder - four cycle - boxer engine with pairs of opposed cylinders . The cylinders are made of steel and are each equipped with two valves. The heads are bolted together in each pair and made of aluminum. The four- cranked crankshaft runs in three roller bearings and one ball bearing , the camshaft in bearings made of bronze. The crankcase is made of light metal and also serves as an oil container. The DR version is also equipped with a reduction gear with internal teeth and a streamlined crankcase.
Use (selection)
Technical specifications
| Parameter | Praga D | Praga DR |
|---|---|---|
| Gear reduction | no | 1.33: 1 |
| height | 0.58 m | 0.4 m |
| diameter | 0.81 m | |
| drilling | 95.0 mm | |
| Hub | 100.0 mm | |
| diameter | 1260 mm | |
| Displacement | 2.84 l | |
| compression | 5.72 | 6.7 |
| Best rated power close to the ground |
60 hp (44 kW) at 2410 rpm | 78 hp (57 kW) at 2880 rpm |
| Best full performance close to the ground |
79 hp (58 kW) at 2610 rpm | 90 hp (66 kW) at 3000 rpm |
| Dry weight | 65 kg | 74 kg |
| Power to weight ratio | 0.82 kg / hp | k. A. |
| Displacement | 27.8 hp / l | k. A. |
| Fuel consumption | 14.7 kg / h | 18.7 kg / h |
| Lubricant consumption | 0.5 kg / h at 60 hp | 0.7 kg / h at 78 hp |
| Octane number | k. A. | 84 |
literature
- Werner von Langsdorff : Handbook of aviation . Born in 1939. 2nd, unchanged edition. J. F. Lehmann, Munich 1937, p. 531 .