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Aviation History
1943
1943 - 1954.PDF
146 FLIGHT AUGUST 5TH, 1943 Topics of the Day In Support of Standardisation "Indicator" Returns to a Time-honoured Subject ; The Need for Similarity in Certain Controls : Must it Always be a Case of Every Designer for Himself 1 : Convenience versus Expediency A DMITTEDLY I've talked about the need for control /-% standardisation at least once before, but, at the risk •*• -^ of being' boringly repetitive, I want to offer some more comments and arguments. The point is, I feel, a very important one, and quite a few expensive, if "safe," accidents could1 have been prevented if anyone of influence had taken the matter up long ago. The basic trouble is that the different manufacturers and designers carry on very largely in their own sweet way, and are rarely much influenced by other people's ideas or arrangements. Furthermore, test teams—or, at least, tjfte senior and more important members of the test teaarlB— remain unchanged year by year and have their own fixed ideas, bred of familiarity, of what constitutes an ideal lay- out. I know very well that if these teams moved regularly from factory to factory the troubles would be cleared up in a month, since a test pilot's opinions carry more real weight than those, of anybody inside or outside a factory. Otherwise, any move must obviously come from the top and take the form almost of an order, or a .basic feature in all specifications. s With -aircraft and ancillary design or layout in sa£h a | necessarily fluid state, it would be impossible to lay down ' hard-and-fast rules about the disposition of the different; controls. So much depends on convenience of installation. \ But certain broad ideals might be aimed at, and shapes, at least, might remain constant. For instance, though I have a personal preference for an undercarriage selector lever which can be reached easily by the throttle hand (so that one's right hand can remain continuously on the control column during the difficult period of initial climb), I am by no means adamant about it, and there are certain advantages, particularly with high- , efficiency twins, in having the selector on the right side so that the hand can be kept on or near the throttles. Engines do stop and throttles occasionally vibrate back and cause a swing in one direction" or the other. But I can see no reason at all why the lever shouldn't always be the same shape, have the same relative movement and, most important of all, have the same kind of safety device. Standard Knobs Even if no other control is considered, I think that the undercarriage selector should be standardised just as soon ' as possible. All selectors should be the same length, relative to surrounding objects, should be the same colour, should have the same shape (this is important, because one normally feels for the little beast), and should have exactly the same kind of locking and/or safety device. All of us, at one time or another, have fought for a matter of twenty vital seconds with a strange kind of safety catch which couldn't be made to work and which, of course, couldn't be tested and tried before actually becoming airborne." Some of them in volve the most intricate work with the fingers; once, in the old days, I met one which couldn't be moved at all, and I had to land, find another example of the same type on trestles, and practise with the darn thing until I found out how to release thg^catch and operate the lever with one hand and one hsKfiTonly. While on the subject of hydraulics, I'm not at all clear why certain aircraft types still suffer from that old-fashioned device, the "power bolt" or master hydraulic control. It has certain technical advantages, of course, but it seems to me to be an anachronism in 1943 and merely adds to the mental and physical labours^pffhe unfortunate pilot. The flap lever is not important, but it should have a very dis- tinctive shape so that it will not be confused -with the undercarriage lever, and be near, but not too near, the latter, I see no reason, either, why flap and undercarriage indi- cators should be as various as peacetime spring models, and in" such totally different relative positions. The former vary from invisible mechanical pips, which move up a thing like a slide-rule, to little clock faces showing* a highly in- accurate series of degrees or percentages. Undercarriage indicator design varies from a series of lights to a collection of shutters, rather like... the old-fashioned household bell indicators. Even the lights~xlon't necessarily indicate thej same things. Some of them sj^ow nothing whatever when* the undercarriage is properly h<5me, and others glare un- '•'• •••••• - - the a*st oithe flight; some can be son. Every one of the iething or other to recom- each manufacturer for favourite system; but surely mly that they shall all be this better of worse? devil blinkingly at you fo switoJafed off and oth ingenious id it, and nobod dng to his well- "soAebody can fci sal Brake Lever ept e basic differences between American and BritfchvWea's'of brake operation, here, at least, we are in a vefj? nearly perfect''position. Two or three aircraft of an obsolescent or pjWtially obsolescent nature have ordinary car-type brake levers which, when negotiating difficult corners, involve* the pilot in hysterical contortions between the'th-Fottles'and the lever, but the "control-column thumb- lever is pretty well universal over here and, with one or. two exceptions, the pedal-type brakes, with their dashboaj4 locking device, are universal in America. Each has its points and nobody minds good basic differences of this kind—except the unfortunate pilots who are expected to fly each more or less alternately. Throttles and airscrew controls needn't be together, but they should be near to one another and move in the same direction. Here, too, undue similarity in feel should be avoided as far as possible. In some American types the pilot has almost to read the notices before he dares to move any lever in the quadrant in case he takes a handful of airscrews when throttling bak, or a handful of carburettor heaters when he intends to reduce the revolutions or put the automatic pilot into action. The most- ckeadful errors in cockpit layout design are those of arranging the throttJes so that either the small pilot cannot open them fully or he catches his knuckles on assorted items as he opens up ; and those of placing the pitch controls in such a position that the pilot has to lean forward and downward when he is reducing revolutions after take-off. 1 know of two types in which the pilot actually loses sight of the ground and sky ahead during this operation. Once I very nearly wrote myself off in a strange type through this cause ; I had to lean right down to reach the c.s. controls, and had not been told that this particular machine became progressively nose-heavy as the under- carriage went up. When I'd finished the job of bringing back a "runaway" engine (the c.s. control stop had been incorrectly adjusted) I found that the machine had been losing height at the same trim setting and we were about to charge into a row of elm trees. In brief, one should be able to carry out every one of the operations which are done immediately after take-off with- out excessive movement and without taking one's eyes off
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