A number of Douglas Aircraft engineers have joined together to develop a light helicopter in their spare time. If financing can be completed, they will probably launch out under the name Lift Systems Inc. Mr Martin Jensen is vice-president and treasurer of the organisation, which is developing his co-axial rotor configurations; he designed the Bendix Helicopter Model K which first flew in 1944, and the two-seat Jensen Helicopter Model 21, flown in 1948.
Lift Systems' prototype craft, designated LS-3, made its first flight two years ago. A two-seater powered by a 160 hp Lycoming O-320, it has a tubular steel airframe skinned with glass fibre with a honeycomb core. The all-metal rotor blades have rolled-steel leading edges and stainless steel skin. Controls are simplified: there is no cyclic-pitch control of the blades. Inherent stability is derived from the dynamics of the co-axial arrangement and mechanisms developed by Lift Systems. The machine is expected to reach 2,000hr between overhauls and the fail-safe design of critical parts (drive gears, shafts, rotors and lift structure) has been allied to low stress-levels. The transmission is used solely to transmit power to the rotors and elimination of internal fasteners is intended to make it jam-proof. The use of a clutch and splines ensures a positive drive.
The LS-3 is strictly a test-bed to prove the basic design. Production aircraft would have three seats and be powered by a 180 hp Lycoming. A four-seat turbine powered design is envisaged, and so is an armed military proposal. The LS-3 rotor diameter is 27ft, and the fuselage is 14ft long.
"Flight International", March 6, 1967