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Aviation History
1961
1961 - 1019.PDF
FLIGHT, 27 July 1961 119 The Business Aircraft Contest KIDLINGTON, Oxford, is the base chosen for this year's International Businessand Touring Aircraft Competition, organized by the Royal Aero Club and theBusiness Aircraft Users' Association, which is to be held tomorrow and Saturday, July 28 and 29. The contest comprises a distance event on formula (see map) on the firstday, followed by tests at Kidlington on the second day. The overall winner will receive the Royal Aero Club Diamond Jubilee Trophy, and thewinners of the three classes into which the aircraft are grouped will be awarded respectively the Osram Cup, McAlpine Cup and Beagle Cup. Class 1 contains single-engined single-or two-seaters up to 2,2041b gross weight; Class 2 is for single-engined machines with more than two seats or exceeding 2,2041b but not exceeding 12,5001b; and Class 3 embracesmulti-engined types up to 12,5001b. In the distance event aircraft in the first two classes are permitted to refuel at one orboth of two specified turning points, while Class 3 machines are required to complete the course without refuelling. The second-day tests will be devoted to short take-off, shortlanding, and judging of aircraft on the basis of comfort and convenience, general condition and flight operating equipment fitted, and baggage capacity. The following article, a competitor's guide to the competition, has been written by oneof the pilots who is participating. CONTEST PROSPECTS IT might be said of this year's business and touring competitionthat it sets out to measure the success of a compromise. Every aeroplane design is a balance between this factor and that factorand, by examining most of the attributes with which, to a greater or lesser extent, the designer imbues his brain-child, the competitionshould discover this year which is the very best business aeroplane. It is not simply a question of which is the most expensive aircraftin its class, although undoubtedly first cost and equipment cost figure in the equation. Nor is the competition purely one of flyingskill, although pilot ability, too, will inevitably influence the end result. The aircraft that wins will be fast, economical, and with agood short-field performance, but it will also be comfortable, beautiful, and practical for day-to-day operation. Of course, in setting all these desiderata, the Royal Aero Cluband the Business Aircraft Users' Association have themselves been faced with some of the problems that face the aircraft designer.How much weight should be given to good performance? How much to navigational equipment ? How important is it that, whenall the tanks are full, there is space and payload available for a full complement of passengers ? How many marks should be awardedfor baggage capacity? What value should be placed on range? So in some ways, in the second competition of this type, the rulesand markings are just as much open to questions about the best choice having been made, as are the wide variety of types that arecompeting for the accolade of Best Business Aircraft. Readers may recall that, in spite of this being the second contestof its kind, the competition last year really proved nothing at all, except what was already self-evident—that if the weather restrictsthe competition to landings and take-offs, it is the modern, high- lift-device aeroplane that is going to win. By force of circumstances, the big question last year left un-answered was: Which aeroplane represents the best balance between the conflicting requirements of good short-field ability, good pay-load capacity, speed, and economy? And having determined all this, which business aeroplane then best fulfils all the car-likefunctions of utility, comfort, equipment, visibility and quietness? More importance is being attached this year, in the contestat Kidlington, to the touring side of the balance sheet. Much the Short take-off tests, introduced at last year's Business and Touring Aircraft Competition at Shoreham, will again be featured in this year's contest. Here a Piaggio P. 166 clears the I Oft barrier at Shoreham "Flight" photograph same formula for determining efficiency is being used as in 1960.It takes into account achieved air miles per gallon, block speed and payload, but this year the course distance is much greater,about 620 miles instead of 380. This heat of the competition carries a maximum of 1,500 marks. Starting at Kidlington the crews will fly north-east to Seethingin Norfolk, west via the Airedale kennels at Rearsby to Shobdon, near Leominster, south-east to another Beagle centre at Shoreham,via Beachy Head to Short's light-aircraft base at Rochester, across the river to Panshanger and—after nearly six hours in the air forsome—perhaps a bit wearily home to Oxford. Results will be judged on the formula:— Marks = Course distance x total fuel used Course distanceelapsed time 10 Where the factor N = Ng^eats (1601b + lb baggage per seat) 1 oO or number of seats, whichever is the smaller.Some of the factors affecting the award of points under this formula were discussed prior to the contest last year (Flight, May 20,1960), and all that it is proposed to review of this aspect here is a brief reminder that it is possible to plot, for an aircraft where agood manual is available, curves of air miles per gallon x true airspeed against, say, percentage power for a series of altitudes.The basis of this plot is curves of altitude against TAS, and altitude against range at various powers. By equating altitudes it is thenpossible to determine the height at which air miles per gallon (range divided by full tankage) x block speed (TAS used as anapproximation) reaches its maximum. This is the cruising condition we are looking for. Unfortunately, such comprehensive information is not oftenprovided, though its usefulness is undeniable. (It can be revealed now that the graphs printed a year ago were constructed from themanual for the Mooney Mk 20A, a dark horse which, had it entered and had the full contest been held, could have done well.) Now supposing that a good manual is not available, probablythe best that can be done is some practical flying to determine empirically fuel consumptions at various power settings andaltitudes. In any case such a technique could well be adopted by entrants whose aircraft demand high cruising altitudes, and whoare anxious to determine the best climb and descent techniques to achieve highest block speed and minimum air miles per gallon.It is extraordinary how little information on cruise-climb and cruise- descent techniques is given in most owners' handbooks. Best offare probably the owners of Beeches and Cessnas with fuel-injection engines. The fuel pressure instrument—that inevitable if unsatis-factory adjunct to non-automatic fuel injection—is really a flow- meter, and with the fuel-pressure computer all the usual sumscan be worked out in reverse to arrive at just the right power settings to achieve a known flow of fuel. Since this circular slide-rule computer also makes an allowance for temperature, a bit of intelligent pre-flight planning should pay handsome dividends. Unfortunately, it is also generally true that most of the businessaircraft types equipped with fuel-injection engines require to operate at considerable heights to achieve their best performance. A10,000ft cruising height is simply not practical when there are seven
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