Here is an article from
Flight International (7 March 1974) which contained all three pics that Triton posted further up
here:
Garrett's flying jeep
Garrett's Stamp (Small Tactical Aerial Mobility Platform), which made its first, tethered, flight on December 21 last year, is the latest in a long series of American attempts to devise a practicable minimum-size vehicle—a flying jeep in fact.
Built under a $500,000 contract from the United States Marine Corps, the Stamp is a vectored-thrust Vtol feasibility demonstrator comprising the forward fuselage of a Hughes OH-6A helicopter with rotor system, engine and tailboom removed, and a 474 s.h.p. Garrett TSE231 turboshaft engine substituted. This powerplant drives a 6,000 r.p.m. ducted fan, specially built for the application by
Garrett, which generates the thrust needed for lift, motion in the horizontal plane, control and trim.
The project began in December 1972 when the USMC negotiated the contract and supplied the company with the helicopter; Garrett identified itself with this high-risk venture by providing the engine. A similar contract was awarded to Williams Research for its Wasp (Williams Aerial Systems Platform), see Flight for February 21, page 251. The design was undertaken by a floating establishment of up to a dozen Garrett engineers under the technical direction of the Naval Weapons Centre at China Lake, Calif.
The drawings on this page show how the jet-lift system works. The fan is located at the rear of the vehicle and sucks in air from an aft-facing intake. The flow is mixed with the hot turbine exhaust, which increases thrust and cuts down infrared emission (an important military consideration, says Garrett), and is divided into two streams which pass either side of the fuselage by means of twin-branched ducts.
Four sets of fixed cascades, two in each branch of the duct, direct the flow vertically downwards to sustain the vehicle in flight. Forward and reverse thrust for translational flight is obtained by rotating two more sets of cascades, one in each duct, to divert the flow in the appropriate direction. Pitch and roll attitude changes are accomplished by moving simple diverter plates in the airflow via the pilots' controls.
Garrett told Flight recently that, despite the limited flying time so far —a mere 3min—it had verified the vehicle in a qualitative manner. The very tight budget called for heavy reliance on intuitive design and there are little electronics or other sophistry. Despite this limitation the vehicle is described as "manageable"; yaw control is said to be good, though pitch control is only marginal, and it is skittish in roll.
It is not clear whether the company will go forward to the next stage, the construction of a more realistic prototype based on theoretical and windtunnel investigation. This vehicle would have a maximum speed and altitude of 75 m.p.h. and 5,000ft respectively,
a range of 30 miles and an endurance of 30min.
The Stamp feasibility demonstrator weighs 6701b and measures 8ft long by 6ft wide and 6ft high. Air enters the engine through the bellmouth intake at the rear of the fuselage and is exhausted through the rectangular ducts on each side. No ejection seats are fitted for the two-man crew, though crew safety in a fully engineered prototype will be a matter of some priority. The drawing on the left shows the airflow through the engines, while the diagrams, below, illustrate how the thrust is diverted to provide attitude control and horizontal movement by means of deflector plates and variable-angle cascades mounted in the ducts