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Aviation History
1937
1937 - 0105.PDF
JANUARY 14, 1937. FLIGHT. 4r Private Flying ECONOMICAL TRANSPORT for TWO Flying the Porterfield "70" : A Tandem-seater Cabin Monoplane Which Cruises at 100 m.p.h. on 70 h.p. The general layout of the Forterfield "70" and the pilot's range of view are adequately shown in this Flight photograph of the machine flying near Croydon. DESPITE the increasing popularity of side-by-side seating lor both luxurv touring and training, the tandem arrangement still has a very great deal to recommend it. Apart altogether from the desirability of complete control freedom, the lone pilot can be provided with a " both sides " view which is very pleasant and useful near a crowded aerodrome or when flying in bad weather. In the American Porterfield monoplane, the agency for which, in Western Europe, has recently been acquired by Sumy Flying Services, the seats are arranged in tandem and, more important, the machine may be flown solo from either —suggesting that, as a stepping stone from a standard trainer to a cabin machine, it might lie very useful. The view from the front seat the only one I tried) is fair to good, though, until one has spent several hours in a particular machine, judg ment on this point is somewhat premature. During a turn a high wing comes down to cover that part of the earth which, especially during an approach to land, the pilot most ardently desires to see; in the Porterneld it is possible to put one's head, so to speak inside the deeply curved screen and to see what would otherwise be cut off. Essential View With such an expanse of deep window in a high-wing mono plane the view of the ground in level flight is everything that one would expect In cruising attitude the top of the engine cowling lies decently below the level of the horizon and only while taxying dots the nose impede vision—a fault to which a " smgle-engined machines are prone. The left-hand windows may be opened for ventilation or for landing in rain. . =0 much for the view question, which I consider to be most important when dealing with a machine designed primarily or tin amateur pilot. The second most important concerns Maintenance costs. Welded steel tube fuselages are not verv ^onimon in this country, but, short of making a landing which n°ATfr cJac*c a c',up'e of longerons in a wooden machine, it fon ] t0 See What Could S° wrong- The win§ is of straight- thel ZQoden construction, with steel bracing struts, and heli 1 u' radial has a successful six years' reputation the"'1 The c°ntrol cables can be readily inspected and "re machine has an air ol rugged simplicity tlv 'ng machine the Porterfield, stiffness in the control operation itself, and the ailerons are certainly effective right down to the stall. In any case, the machine is virtually without vice and sits about the sky at all speeds as if hung from a cord. Let everything go in a tight turn and it yaws its way back to level; hold the stick right back and the machine merely wallows momentarily before dropping its nose and repeating the process. A steep sideslip can be held, using full rudder, without an increase in speed, though a crab sideslip provides the most effective method of losing height. The landing process, with a somewhat heavy elevator movement, should be almost foolproof. The only control criticism worth mentioning concerns the position of the trimming lever, which is arranged on the left side behind the front seat so that it can be used by either occupant. Its somewhat awkward placing would be of small account if it did not, in addition, require an excessive number of turns—though the machine, even when flown from the front, can be held up comfortably in the glide without altera tion of trim. The heel brake pedals, which are duplicated, are easily used with accuracy after a little practice. Since neither the A.S.I, nor the altimeter were working properly at the time of the trial, no first-hand performance figures can be given, but the take-off run given in the table is certainly not optimistic. I flew the Porterfield both solo and otherwise, and in a moderate breeze the machine was comfortably air-borne in rather less than a hundred yards, provided that it was pulled off the ground. The price includes all the "usual instruments, including a compass, and navigation lights and battery can be fitted for £10 if ordered with the machine. Accommodation for luggage is provided in a locker at the rear of the cabin. H. A. T. As »s sti!! heavy . though small and light, typically American, with a light rudder and somewhat "'•rons. Much of this apparent heaviness is caused by THE PORTERFIELD "70" 70 h.p. Five-cylinder Le Blond Weight loaded Weight empty Maximum speed Cruising speed I-anding speed Range Rate of climb (full load) Take-off run (full load) landing run Price Distributors Surrey Flying Services, Ltd., Croydon, Surrev. ... 1,310 1b. 8001b. ... 115 m.p.h. ... 100 m.p.h. 40 m.p.h. ... 350 miles. ... 600ft./min. .. 130 vards ... 130 vards .~ £635' Airport of London,
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