Guiberson A-1020

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A Guiberson A-1020

The Guiberson A-1020 was an American air-cooled diesel aircraft engine . These were a Neunzylinder- radial engine , which according to the four-stroke - diesel principle worked. Although it was developed as an aircraft engine, it was also used as a tank engine.

history

Since the 1930s, the Guiberson Diesel Engine Company in Dallas worked on the development of air-cooled diesel radial engines. Under the direction of the young Austrian engineer Fred Thahald, the smaller but also nine-cylinder predecessor models A-980 and A-918 were created. These only had a single valve per cylinder and the exhaust gas was flushed through air scoops using the dynamic pressure of the propeller wind. From the further development of these engines, the slightly larger A-1020 was created, which received conventional cylinder heads with two valves each. The engine received its type certification in April 1940 and was approved by the Buda Engine Co. in Harvey , Illinois , made. However, because of the war, there was a need for tank and boat engines in this performance class at that time, so the T-1020 (T for tank ) was developed from the A-1020 and adapted for use in land vehicles, e.g. B. by a cooling fan.

construction

The Guiberson was a single-row nine-cylinder radial engine. The crank mechanism consisted of a main / secondary connecting rod linkage. The ribbed cylinder liners were made of forged steel, the pistons and cylinder heads were made of aluminum alloy. The liners were screwed into the cylinder heads and shrunk. In contrast to the usual structure of single-row radial engines, the cam drum and the pushrods of the valve train were attached to the rear of the engine. The cam drum had four cam lobes on each of the two tracks for the inlet and outlet valves and ran in the opposite direction at one eighth of the crankshaft speed.

Another control track with four elevations was screwed to the cam drum, which actuated the nine individual plunger pumps for fuel injection, which were attached concentrically to the rear crankcase . The individual pump elements were supplied with diesel oil through holes in the housing. Between the cam track of the injection ring and the push rod to the pump piston, rocker arms were arranged, which had a roller for the cam track at one end and were mounted on a control ring rotatable around the housing at the other end. By turning this ring when operating the gas lever, the rocker arm and thus the wedge-shaped inclined control surfaces of the rocker arm, which transmitted the cam lift to the pump pushrod, were moved on the circumference of the injection cam track. As a result, depending on the position of the sliding wedge, both the injection quantity (via the variable pump stroke) and the injection time for all nine pump elements were set.

Steel lines of exactly the same length led from the radially arranged injection pumps to the injection nozzles , which were screwed into the rear of the cylinder heads. These were three-hole nozzles of a closed design that produced a fan-shaped injection jet. The engine had no pre-chambers , but worked on the principle of direct injection .

The engine had neither a propeller gear nor a supercharger , it was operated as a purely naturally aspirated engine . Due to the lower speed level of the diesel principle, the former was not necessary; Due to the high excess of air of the diesel principle, the power loss with increasing flight altitude was within a range that did not yet require charging (during test flights an flight altitude of 18,300 feet = approx. 5,600 m was reached).

Technical specifications

  • Cylinder: 9
  • Gas exchange: 2 valves, OHV valve control
  • Cylinder bore: 130.18 mm (5⅛ ″)
  • Stroke: 139.70 mm (5½ ″)
  • Displacement: 1021 cubic inches, equivalent to approx. 16.7 l
  • Continuous power: 325 hp at 2150 rpm
  • Compression ratio: 15: 1

use

Comparable engines

Web links

Individual evidence

  1. ↑ Chapter 1 - Development of the Diesel Aircraft Engine, page 4 f., Article at the Aircraft Engine Historical Society , PDF file, in English, accessed on December 2, 2017
  2. ↑ Guiberson T-1020 Diesel Engine at the New England Air Museum , accessed May 20, 2015