Rolls-Royce Condor
The Rolls-Royce Condor was an aircraft engine from the British manufacturer Rolls-Royce , which appeared for the first time in 1920. It was a water-cooled twelve-cylinder V-engine with standing cylinder banks inclined at an angle of 60 ° to each other. Its basic design corresponded to the Rolls-Royce Eagle , but had a larger displacement. It was used in Blackburn Iris , R100 and prototypes of the Avro 549 , among others .
Condor Mk.I
The development of the engine began at the end of 1917 with the aim of creating a drive for the planned British long-range bombers. The first test engine ran on the test bench in August 1918. However , it was too late for use in World War I and it was not until 1920 that it went into production as the Condor Mk.I with 600 hp . The engine's gas exchange was controlled by an overhead camshaft driven by a vertical shaft and four hanging, radially arranged valves per cylinder. The cylinders were grouped into groups of three, but each cylinder had its own cooling jacket. There were no removable cylinder heads. The ignition system consisted of two Watfort magnets, each supplying six cylinders. The mixture was in two Claudel-Hobson - double carburetors prepared, which were manufactured by Rolls-Royce itself. The planetary gear had a reduction ratio of either i = 1.5 or i = 1.8. The engine was prepared for starting with an electric starter right from the start and was only supplied with a left-handed propeller. A total of 72 pieces had been produced by 1921.
The next series, Mk.IA (sometimes referred to as Mk.II ) had a different carburetor layout , with the carburetors now placed to the right and left of the crankcase. The mixture reached the inside of the cylinder rows through an intake line surrounded by a water jacket, which was passed between the groups of three, from where it was distributed to the cylinders via corresponding lines. With slightly increased compression, this engine achieved 650 hp at 1900 min −1 . Another change in this version, of which a total of 34 pieces were built, is the reduction ratio of the propeller drive changed to i = 1.806.
Condor Mk. III
As the engine was considered too heavy, a prototype with extensive design changes was made in 1924. Instead of the planetary gear, a lighter and shorter spur gear with a reduction of i = 2.095 was used. The twin carburettors in 1924, which were improved in terms of mixture adaptation and which were considerably more economical in partial load operation than the original version, were arranged in front of and behind the cylinder banks, the individual cylinders of which were now arranged at the same distance on the crankcase. The crank drive was also changed and fork and inner connecting rods were now used instead of the main and secondary connecting rods. In addition, it was possible to mount a synchronizing gear for a barrel weapon firing through the propeller circle. The crankcase was stiffened for series production. The engine went into production with an output of 670 hp. 196 pieces had been produced by 1927. In the Mk.IV version, 13 of which were built, the reduction gear was omitted entirely and the output could be increased to 750 hp.
For Mk.III and Mk.IV there was a conversion kit for the bearings, which improved the long-term load capacity. Converted engines were then given the designation Mk.IIIA or Mk.IVA. The Mk.IIIB version also got a new crankshaft, a new crankcase and enlarged main bearings.
Technical execution Mk.III
The engine's gas exchange was controlled by an overhead camshaft driven by vertical shafts and four hanging and radially arranged valves per cylinder. For this purpose, there were three cams for each cylinder on the sixfold bearing and case-hardened camshaft, which actuated the valves via a special rocker arm arrangement. The middle cam opened the two intake valves, while the two outer cams each actuated an exhaust valve. The cylinders were attached to the crankcase with short bolts. Each cylinder, which formed a unit with the cylinder head, had its own cooling jacket made of stamped and welded sheet metal. The crankshaft made of forged nickel-chromium steel had six crank webs and was supported seven times in layered bearings made of phosphor bronze with a white metal frame. The pistons were made of aluminum and had four piston rings, three of which were above the piston pin and one below. The top and bottom rings were wiper rings, the middle two compression rings. Forged and then heat-treated fork and inner connecting rods made of nickel steel were used, which had an H-profile. The connecting rod bearing was made of white metal, while the piston pin bearing was made of phosphor bronze. Both bearings were connected to the oil circuit and were supplied with pressure oil.
The crankcase, which was split lengthways at the level of the crankshaft, was made of aluminum, and stud bolts connected the two halves. While the upper half carried the cylinders, the water pump, the pressure oil pump and two oil return pumps were attached to the lower half. The oil pressure was 93 lbs / sq (0.64 MPa). Both return pumps were protected from foreign bodies by a coarse filter, and there was also a fine filter that was easily accessible for cleaning on the outside of the engine.
Two Watfort magnets were installed as the ignition system, each of which supplied a spark plug for the twelve cylinders and had automatic ignition timing adjustment. The mixture was prepared in two Claudel-Hobson twin carburettors, which Rolls-Royce manufactured itself. The fuel was delivered by a four-piston pump, although pure gravity operation was also possible.
The reduction gear for the propeller consisted of a single pair of spur gears. The driving gear was decoupled from the crankshaft by interposing a multi-toothed shaft. Both gears ran in ball bearings and were mounted in an aluminum housing in which an interrupter gear for controlling on-board weapons could be accommodated. The propeller shaft was made of a chrome-nickel steel alloy.
Special designs
The MK.V version was equipped with a two-stage turbocharger for the first time in 1925, but only a test sample was made because the Air Ministry prohibited further work. There were test runs, but no flight attempts.
The last version was the Mk.CI diesel version with 480 hp, developed at the suggestion of the Air Ministry and presented in 1932. In the autumn of 1932, a 50-hour acceptance test was successfully carried out with one of the two engines built, while a flight test was carried out with the second in a Hawker Horsley . The conversion was carried out by the Royal Aircraft Establishment with the support of Rolls-Royce.
Applications
- Blackburn Iris
- R100
- Avro 549 (prototypes)
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Technical specifications
| Data | |||
|---|---|---|---|
| Mk.I | Mk.III | CI | |
| Bore mm | 139.7 | 139.7 | 139.7 |
| Stroke mm | 190.5 | 190.5 | 190.5 |
| Displacement l | 34.5 | 34.5 | 34.5 |
| horsepower | 600 | 670 | 480 |
| at min −1 | 1800 | 2000 | 1900 |
| compression | 5.1: 1 | 6.5: 1 | 12.5: 1 |
| Length mm | 1750 | 1760 | 1886 |
| Width (mm | 1120 | 1044 | |
| Height mm | 1129 | 1097 | 1155 |
| Weight kg | 728 | 619 | 682 |
swell
- Flight , July 27, 1939.
- Flight , November 17, 1932.
- Flight , August 7, 1924.
- Flight , December 19, 1918.
- Alec SC Lumsden: British Piston Aero Engines and their Aircraft. Airlife, Shrewsbury 1994, ISBN 1-85310-294-6 .