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Aviation History
1949
1949 - 1953.PDF
FLIGHT, i December 1949 •719 SCANDIA PROGRESS First Production Model Flies : Performance ImprovedT HE first of a series of ten production-type Saab Scandiassoon to be delivered to A.B. Aerotranspon (the Swedish section of the Scandinavian Airlines System) is reportedto have been successfully test-flown, for a period of 30 minutes, on November 12th. This marks another stage in the careerof what promises to be a popular medium-sized airliner. The test pilot. Captain A. Helgstrand, reported improvedtake-off characteristics, due to the increased angle of attack made possible by the extension of the nosewheel leg. Reduc-tion in rudder-pedal forces under asymmetric power condi- tions has resulted from the fitting of a spring tab to therudder. The decrease in aerodynamic balance has led to an improvement in the self-centring of the control andelimination of the sluggishness which was encountered with the rudder of the prototype. This has also had the effectof improving directional stability. The introduction of a spring tab on the elevator has con-siderably improved longitudinal stability at low speeds, thus conferring more pleasant landing characteristics. The testpilot, in concluding his report, said that his general impres- sion was that, from the pilot's point of view, the 90A-2 meetsthe greatest expectations one might have for this type of aircraft. Compared with the prototype Saab-90 Scandia (now makinga' two-month tour of South America, having created consider- able interest on its demonstration tour of the United States),the Saab 90A-2, as it is designated, is fitted with the more powerful Pratt and Whitney R-2180 engines of 1,800 h.p.each (with water injection), in place of the original R-2000S installed in the prototype. The R-2180, which incorporates experience gained by the American manufacturers duringWorld War II, is generally considered to be an outstanding engine from "the point of view of economy and ease of main-tenance A great improvement is now claimed in the overall per-formance of the Scandia, and the cruising speed is said to have increased from 215 to 250 m.p.h. Hamilton StandardHydromatic four-blade reversible-pitch airscrews are now fitted. Other improvements—incorporated with the object ofattaining still better economy in operation—are said to have increased the all-up take-off weight by 4,190 1b, thereby pro-viding a considerable increase in payload. In anticipation of possible future production under licence inthe United States, Saab has also published details of two further versions of the Scandia, designed to cater specifically for theneeds of American operators. Designated 90A-3 and 90B-3 re- spectively, they are primarily distinguished by their increasedcapacity, namely, 30-38 passengers instead of 24-32 in the 90A-2. The increase has been gained by redesigning the fore and aftsections of the passenger compartment. In accordance with U.S. standards for an aircraft of this size,the number of crew carried has been reduced from three to two (pilot and co-pilot-radio operator). It is intended to equip the 90B-3 with a pressurized cabin.This will necessitate redesigning the fuselage, which will then present a more circular cross-section than that of the non-pres-surized version. Notwithstanding the slightly increased take-off weight of these latest models, no impairment of flight characteris-tics is anticipated, and it is expected that the same cruising speed as that of the 90A-2 will be maintained. ^-: r-::^: O.U.A.S. ANNUAL DINNER ;. • 7 HELD this year at the Forum restaurant, Oxford, theannual dinner of the University Air Squadron was attended, as usual, by eminent members of the colleges andServices. The commanding officer, W/C. C. N. Foxley Norrisi D.S.O.,M.A., in his speech to welcome the guests, broke the news that the Chipmunk was "only just round the corner" andthat the Oxford Squadron would be the first unit to have its Tiger Moths replaced. Referring to the War Minister asthe cuckoo, and the Territorials as the cuckoo's egg, W/C. Foxley Norris expressed alarm at the prospect of the Squadronbeing ousted from its town H.Q. nest at Manor Road. The matter, he said, was being taken up by Lord Halifax, theChancellor of the University and Field-Marsha' Sir William Slim, the C.I.G.S. The CO. then went on to plead with members of theSquadron to join the R.Aux.A.F. on going down from the University. It was of little use, he observed, to go fromthe O.U.A.S. to the Reserve and continue to fly ab initio types of aircraft. The gap between O.U.A.S. training andAuxiliary standard he assessed at approximately 30 hours on Harvards. The president of St. John's college, Mr. A. L. Poole, M.A.,replied on behalf of the guests, congratulating the Squadron on its imminent re-equipment; he compared its present air-craft with the vehicles seen in the "Old Crocks' Run" and, expressing regret at the possible loss of town headquarters,looked forward to the time when members would be picked up and taken to their new airfield at Kidlington by helicopter. Air Chief Marshal Sir Guy Garrod, G.B.E., K.C.B., M.C..D.F.C., LL.D., proposing the toast of the Squadron, gave an enthusiastic panegyric on the virtues and joys of flying,and Mr. P. F. H. Emery, Oriel, in replying, revived the pre- war O.U.A.S. tradition of paying tribute to an outstandingfigure in the aeronautical sphere; he named Geoffrey de Havilland. AUTOMATIC AMBASSADOR '"PHE excellent flight characteristics of the Airspeed AmbassadorJ- (referred to in Flight's "In the Air" on October 20th) and proof of the capacity of the Smith S.E.P.i electric auto-matic pilot with which it is equipped, were fully demonstrated recently when Mr. George Errington, chief test pilot ofAirspeed, Ltd., made a successful take-off and landing using only the automatic pilot controHer. This controller, it willbe remembered, is, in effect, a miniature "stick" for fore-and- aft control, surmounted by a knob for turn adjustment. No B y difficulties were experienced, although the aircraft was flyingat its maximum all-up-weight. Two points of interest arise from the demonstration, oneinvolving yaw correction on take-off—when large rudder dis- placements may be required—and the other concerning the finalstages of the full-incidence landing procedure. One of the principles governing the S.E.P.i automatic pilot lies in theapplication of aileron to initiate banked turns, co-ordination being achieved by subsequent application of the rudder control.During take-off, yaw corrections are normally required without bank but the automatic pilot naturally applies bank withvery small corrections. To obviate this difficulty it would be a simple matter to switch off the rudder control and applyyaw corrections on the pedals during the initial take-off run. However, on the occasion of this demonstration, all three axesof control were left in the automatic position and the accuracy of the corrections made clearly showed the wide range, oicontrol provided by the Smith autopilot for all conditions of flight. During landing no advantage was taken of the fact that theAmbassador is fitted with a tricycle undercarriage, the auto- matic controller being successfully used to provide a full tail-down landing incidence and to hold the nosewheel off the ground after the actual touch down. A further point of interestwas that the reduction of engine revolutions after touch-down (and consequently of electrical power supply) coincided with themoment when backward pressure on the control column would normally have been eased to permit nosewheel contact as speedfell off; thus the automatic pilot completed the landing perfectly (even if quite incidentally at the end of its mission—no auto-pilot yet being educated enough to taxi an aircraft back to the tarmac or use a fourth control—the nosewheel tiller. MERGER REDUNDANCIES FOLLOWING the recent merger of B.O.A.C. and B.S.A.A.,the Aeronautical Engineers' Association states that it has learned that B.O.A.C. has decided to dismiss as redundant 58per cent of the aircraft inspection staff formerly employed by B.S.A.A., together with an unspecified number of otherworkers. The Association is said to be protesting to the Minister of Civil Aviation. B.O.A.C.'s comment on the matter is as follows:-— " In theprocess of merging B.O.A.C. and B.S.A.A. and the concentra- tion of operations at London Airport there has been a generalreview of engineering staff which has involved reductions in most categories. Discussions with the trade unions on thismatter have taken place and they are fully aware of the position."
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