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A New Boost Control

A New Boost Control AIRCRAF T ENGINEERING September , 1936 Th e Eclipse Automatic Supercharger Regulator for Wrigh t Cyclone Engines shown at A and Β in the accompanying N the operation of modern supercharged diagram ; A is evacuated. To offset the aircraft engines close control must be kept accompanying loss in internal atmospheric over the intake manifold boost or super­ pressure, a compression spring is provided in charger pressure to prevent exceeding the this bellows. In the opposite bellows, which is allowable output. connected with the intake manifold, is located I n some cases, in order to provide higher an adjustable tension spring to give a definite power for take-off, the normal sea level manifold amoun t of tension on the evacuated bedows. pressure of supercharged engines may be This spring is attached to diaphragm C in the exceeded for a short time, bu t soon after the manner shown. aeroplane has left the ground the engine must Through adjustment of the tension of this b e throttled back to the specified limits. It is spring, the unit may be made to regulate to also necessary to maintain manifold pressure higher or lower absolute manifold pressures within specified limits at cruising speeds in within a range of 25 to 40 in. of mercury order to realize longer engine life and economy. absolute. The absolute pressure reference in Heretofore, the manifold pressure has been this device is the evacuated bellows. As both controlled by manual operation ,of the throttle, bellows have the same area, changes in which has been provided with a stop at the atmospheric pressure within the housing do throttl e setting a t which th e maximum manifold not affect the accuracy of the regulator. pressure was developed at take-off. At cruising The operation of the regulator is compara­ speeds, manual operation of the throttle also accordance with the desired conditions, through tively simple. At the take-off the pilot sets has been necessary and frequent reference to an engine-oil actuated servo-piston, controlled th e selector lever at the " Take-Off " position th e manifold pressure indicator and the through two bellows by the intake manifold and shoves the throttle full open. Suppose, for pressure. The change-over from one position tachometer was required. example, as is normally the case, the manifold to the other is made by a simple movement Particularly during the take-off run, this pressure at full throttle on the ground is above of a selector lever by the pilot. The oil- method of regulation, worked a hardship on the th e limit set for which th e regulator is adjusted. operated servo-piston moves the throttle to already busy pilot. The Eclipse Aviation The tension spring B1 is unable to offset maintain the desired pressure without any Corporation have developed an automatic two- th e pressure communicated through Ρ to the movement of the pilot's throttle control owing position supercharger pressure regulator, for bellows B, with the result that bellows Β t o the action of the linkage shown in the use with the Wright Cyclone engine, in which expands to the left, carrying the diaphragm C diagram. (Fig. 1.) th e manifold pressure is limited to th e allowable with it. The diaphragm in turn pushes the boost at take-off and in cruising, regardless of oil valve V to the left and admits the engine Details of Operation. changes in engine speed or altitude, by auto­ oil under pressure from G through H into the matic regulation of the throttle. The weight The two bellows, similar to those used in servo-piston cylinder D, forcing the servo piston of the regulator complete is only 3½ lb. modern motor-cars to prevent the circulation t o the right and tending to close the throttle of the coolant through the radiator until the t o which its shaft is linked. As soon as the The two-position regulator automatically throttl e is closed sufficiently to provide the proper temperature has been reached, comprise maintains the maximum boost at take-off and proper manifold pressure, the drop in pressure th e heart of the device. These bellows are limits the boost at cruising or rated power in is communicated to bellows Β which contracts t o its normal position and permits the oil valve to return to the neutral position shown in the sketch. Any oil in chamber F behind the servo piston, displaced by the piston in moving towards the right to close the throttle, drains down through J to b e returned to the crankcase through the oil drain Κ provided at the bottom of the housing. If the manifold pressure is below normal for th e conditions, the opposite action occurs. Bellows Β contracts, moving the diaphragm C to the right and pulling the oil valve in the same direction. This opens channel J and permits the oil to enter the chamber F, moving th e servo piston to the left and opening the throttle . Oil displaced in chamber D drains through Η and I through the housing and back t o the crankcase. By closing the throttle beyond the point where the servo-piston Ε reaches its inward stop S, the regulator is rendered ineffective and throttle control becomes normal, permitting th e pilot to operate at supercharger pressures below the regulated pressures. The supercharger regulator may be adjusted b y the makers to maintain pressures between 25 and 40 in. of mercury absolute. Th e regulator is designed to bolt directly to th e rear cover of the Cyclone engine, which ha s been modified to include openings in the flange for manifold air pressure, oil pressure and oil drain, thereby eliminating the need for external oil and air pressure lines. The crankcase vent for the oil tank has been removed from the cover and incorporated in th e housing of the regulator. (Fig. 2). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

A New Boost Control

Aircraft Engineering and Aerospace Technology , Volume 8 (9): 1 – Sep 1, 1936

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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0002-2667
DOI
10.1108/eb030094
Publisher site
See Article on Publisher Site

Abstract

AIRCRAF T ENGINEERING September , 1936 Th e Eclipse Automatic Supercharger Regulator for Wrigh t Cyclone Engines shown at A and Β in the accompanying N the operation of modern supercharged diagram ; A is evacuated. To offset the aircraft engines close control must be kept accompanying loss in internal atmospheric over the intake manifold boost or super­ pressure, a compression spring is provided in charger pressure to prevent exceeding the this bellows. In the opposite bellows, which is allowable output. connected with the intake manifold, is located I n some cases, in order to provide higher an adjustable tension spring to give a definite power for take-off, the normal sea level manifold amoun t of tension on the evacuated bedows. pressure of supercharged engines may be This spring is attached to diaphragm C in the exceeded for a short time, bu t soon after the manner shown. aeroplane has left the ground the engine must Through adjustment of the tension of this b e throttled back to the specified limits. It is spring, the unit may be made to regulate to also necessary to maintain manifold pressure higher or lower absolute manifold pressures within specified limits at cruising speeds in within a range of 25 to 40 in. of mercury order to realize longer engine life and economy. absolute. The absolute pressure reference in Heretofore, the manifold pressure has been this device is the evacuated bellows. As both controlled by manual operation ,of the throttle, bellows have the same area, changes in which has been provided with a stop at the atmospheric pressure within the housing do throttl e setting a t which th e maximum manifold not affect the accuracy of the regulator. pressure was developed at take-off. At cruising The operation of the regulator is compara­ speeds, manual operation of the throttle also accordance with the desired conditions, through tively simple. At the take-off the pilot sets has been necessary and frequent reference to an engine-oil actuated servo-piston, controlled th e selector lever at the " Take-Off " position th e manifold pressure indicator and the through two bellows by the intake manifold and shoves the throttle full open. Suppose, for pressure. The change-over from one position tachometer was required. example, as is normally the case, the manifold to the other is made by a simple movement Particularly during the take-off run, this pressure at full throttle on the ground is above of a selector lever by the pilot. The oil- method of regulation, worked a hardship on the th e limit set for which th e regulator is adjusted. operated servo-piston moves the throttle to already busy pilot. The Eclipse Aviation The tension spring B1 is unable to offset maintain the desired pressure without any Corporation have developed an automatic two- th e pressure communicated through Ρ to the movement of the pilot's throttle control owing position supercharger pressure regulator, for bellows B, with the result that bellows Β t o the action of the linkage shown in the use with the Wright Cyclone engine, in which expands to the left, carrying the diaphragm C diagram. (Fig. 1.) th e manifold pressure is limited to th e allowable with it. The diaphragm in turn pushes the boost at take-off and in cruising, regardless of oil valve V to the left and admits the engine Details of Operation. changes in engine speed or altitude, by auto­ oil under pressure from G through H into the matic regulation of the throttle. The weight The two bellows, similar to those used in servo-piston cylinder D, forcing the servo piston of the regulator complete is only 3½ lb. modern motor-cars to prevent the circulation t o the right and tending to close the throttle of the coolant through the radiator until the t o which its shaft is linked. As soon as the The two-position regulator automatically throttl e is closed sufficiently to provide the proper temperature has been reached, comprise maintains the maximum boost at take-off and proper manifold pressure, the drop in pressure th e heart of the device. These bellows are limits the boost at cruising or rated power in is communicated to bellows Β which contracts t o its normal position and permits the oil valve to return to the neutral position shown in the sketch. Any oil in chamber F behind the servo piston, displaced by the piston in moving towards the right to close the throttle, drains down through J to b e returned to the crankcase through the oil drain Κ provided at the bottom of the housing. If the manifold pressure is below normal for th e conditions, the opposite action occurs. Bellows Β contracts, moving the diaphragm C to the right and pulling the oil valve in the same direction. This opens channel J and permits the oil to enter the chamber F, moving th e servo piston to the left and opening the throttle . Oil displaced in chamber D drains through Η and I through the housing and back t o the crankcase. By closing the throttle beyond the point where the servo-piston Ε reaches its inward stop S, the regulator is rendered ineffective and throttle control becomes normal, permitting th e pilot to operate at supercharger pressures below the regulated pressures. The supercharger regulator may be adjusted b y the makers to maintain pressures between 25 and 40 in. of mercury absolute. Th e regulator is designed to bolt directly to th e rear cover of the Cyclone engine, which ha s been modified to include openings in the flange for manifold air pressure, oil pressure and oil drain, thereby eliminating the need for external oil and air pressure lines. The crankcase vent for the oil tank has been removed from the cover and incorporated in th e housing of the regulator. (Fig. 2).

Journal

Aircraft Engineering and Aerospace TechnologyEmerald Publishing

Published: Sep 1, 1936

There are no references for this article.