Flight, September 1938

UNITWIN in ACTION

   FROM time to time during the past year we have given details of the developments of the Unitwin engine installation, which, in its initial form, consists of two Menasco engines of 260 h.p., each of which is mounted side by side and drive a single airscrew through a controllable gearing and clutch arrangement.
   This idea has distinct possibilities since drag is considerably reduced, the failure of one engine does not involve the other in more than its natural additional work, and the whole arrangement, in normal operation, permits proper synchronisation and consequent efficiency.
   Tests were carried out in a modified Altair, and now the Vega Airplane Company, a subsidiary of the Lockheed Corporation, has announced some details of the first machine to the designed round this new type of power unit. This machine will be known as the Vega, and will be an all-metal low-wing monoplane carrying five to six persons. The power unit will, of course, have a single constant-speed airscrew, which will enable the maximum efficiency to be obtained where one or both engines are providing the power. Another interesting feature of the machine is a retractable tricycle gear. In its retracted position all three wheels will still be available for emergency landings.
   The fuselage will consist of two main sections, the forward being constructed of steel tube, from which is mounted the aluminium alloy cabin shell, while the rear section will be a semi-monocoque of aluminium alloy. The two main panels of the wing are bolted directly to the fuselage structure so that there will be no centre section. Needless to say, split-type flaps are to be fitted.
   No estimated performance figures are given in detail, but it is suggested that the machine will have a top speed in excess of 200 m.p.h. and will have a non-stop cruising range of 1,000 miles. The estimated gross weight is 5..400 lb. Production is now under way and the first machine is expected to be completed during next January.