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Aviation History
1956
1956 - 1329.PDF
"Flight" photographs The advantages claimed for the Sperry powered flying control (left) were displayed on an adjacent information panel; roll auto-stabilization of the model aircraft in the Hobson exhibit could be sampled by operating the control column and an auto-stabilizer activating switch. SHOWGROUND . . . Servodyne-powered flying controls, whichhave been developed to a high degree of reliability. One such control, which isused on the Comet 2 and 3 with con- siderable success, is of the tandem type,weighs 30^ lb and now has a proposed overhaul life of 2,000 hr. In order thatthe mechanical as well as the hydraulic input can be duplicated, the controlintended for the Comet 4 will have a side-by-side duplication arrangement. One advantage of electrical signalling ofthe pilot's stick movements to the powered-control valve is that distortion ofthe structure caused by reaction from the powered control, or distortion of thefuselage under aerodynamic loading, will not affect the position of the mechanicallinkage and feed unwanted angle to the control surface. With the mechanicalsystems in present use, some re-arrange- ment of the input linkage may be neces-sary. Special provision of this nature has been made in the powered controlexhibited by Short Bros, and Harland, Ltd., which incorporates a banana-shapedlink, and is obviously for a specific appli- cation. The spool-type valve which isused is completely immersed in hydraulic fluid and is operated through a bell crankand rotary shaft in order to reduce seal friction. This control has been designedfor manual reversion, a pressure-loaded plunger operating the "manual-in" clutchif the pressure supply fails. An example of the modern powered-flying-control thought is shown by the Sperry Gyroscope Co., Ltd., whose newcontrol may be used as a mechanically signalled plain powered control, or, whenautopilot integration is desired, signalled electrically from the stick through aSelsyn transmitter. By making both flying control and gyro mechanisms, Sperry areafforded the opportunity of matchinc response when automatic control is usedand reversion to mechanical signalling can be made through a clutch should theelectrics or instrumentation fail. Pro- vision is made on the control for aduplicated hydraulic supply with a change-over valve, but other forms ofduplication can be provided. PROTECTIVE CLOTHING THE whole question of protective clothingfor aircrew in case of cabin pressuriza- tion failure is evidently reaching a head. For some time now both American andBritish companies have been working to develop garments along various lines, andtwo trends were in evidence in the static display—partial pressure and full pressureequipment. Both G.Q., Ltd., and Franken- stein and Sons, Ltd., have made theAmerican type of partial pressure suit, and G.Q. also developed a successfulhelmet of their own to go with it. Now G.Q. have shown the Type C clothpartial pressure helmet and the Type D which includes a protective plasticshell and gives better visibility, greater comfort and the hole to allow the man tofeed himself which now appears to be a standard requirement. Frankensteinshowed another approach to this type of clothing. It is based on a Mk 1 pressurejerkin, covering the torso and thighs which will, on selection of emergency oxygenflow, inflate with oxygen and provide com- pensated pressure breathing and mechani-cal constriction of the body. Tied in with this jerkin is the anti-g suit Mk 4, whichis set to inflate at the same time as the jerkin, so constricting the legs also. Thepressure jerkin is equipped with an in- tegral Mae West and Sarah rescue beaconhousing, and is intended to be worn as an outside garment. The dummy thusapparelled was surmounted by a partial pressure helmet made by Baxter, Wood-house and Taylor, Ltd. M.L. Aviation, Ltd., showed three pres-sure helmets, each of them incorporating a plastic protective shell for the forwardand top part of the head. Two of these were of the IIP partial pressure type—theearly and developed models. Their vizors were mounted on booms and could besnapped shut by an electric solenoid operated by a pressure capsule, so thathelmet pressurization occurred automatic- ally after cabin pressure failure. The newertype had a slightly larger and thicker vizor and both featured red circular trap-doorsfor feeding and (in less pleasant circum- stances) vomiting. The red colour was toindicate that for all normal situations the trap-door should be locked shut. On thelater helmet there was no separate inter- comm lead "pigtail," and the oxygen tubeconnector appeared to contain electrical contacts which suggested that the inter-comm lead was integral with the oxygen tube. The early version of this helmet wasworn this year by W/C. Beamont during very high altitude test flights, togetherwith the pressure jerkin exhibited by A dummy wearing Frankenstein's pressure jerkin and anti-g suit and the Baxter, Wood- house and Taylor,Ltd.,partial-pressure helmet. Frankenstein. He apparently reported thatit was most comfortable. Ranged above the two 1 IP helmets was the Type F2 fullpressure helmet, externally similar to the IIP in appearance, but using a differentpressurization principle; it was somewhat larger than the others and bore a cordtackle attached to the flying suit to hold it down on the head when pressurized. Full pressure suits are more difficult toproduce than the partial pressure type be- cause, relying on actual pressurizaticnwith air, they present mobility problems. The garment consists basically of a seriesof large tubes enclosing the body and limbs. Though they freely bend to accom-modate a sitting pilot when not pressur- ized, they have an annoying tendency tostraighten inexorably and spreadeagle the hapless pilot when inflated. Franken-stein's own particular solution to this problem was seated in an ejection seat ontheir stand, but no details of it were being given. The goldfish bowl-type dome overthe dummy's head was, in this case, a lash-up for exhibition purposes. Siebe Gorman and Co., Ltd., admittedparticipation in the full pressure suit field with a large photograph of a developedversion of the full pressure suit which was shown at the Farnborough Jubilee lastyear. This relies for mobility on linked
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