PIASECKI 59H 'AirGeep II'

Military designation: VZ-8-P(B)

Engines: 2 x 530 hp Turbomeca Artouste IIC turboshaft engines

First flight: 15 February 1962 (pilot: S.A. "Tommy" Atkins)

Piasecki wanted to build a bigger and better 'AirGeep', and the Army Transportation Research Command obliged them by issuing a contract for what Piasecki called the Model 59H 'AirGeep II' and what the Army called the VZ-8P(B), which made its first flight in the summer of 1962. The 'AirGeep II' was similar to the Model 59K 'AirGeep', except that the aircraft was "bent" in the middle so that the rotors were tilted fore and aft, reducing drag in forward flight.

The 'AirGeep II' used twin 530 horsepower (some sources give an unlikely 400 hp only) Turbomeca Artouste IIC turboshaft engines (turbines), once again linked so that if one failed the other would drive both rotors. This also enabled a larger payload. One engine could also be linked to the landing wheels to drive the machine on the ground. The increased power allowed a maximum take-off weight of 2.2 tonnes (4,800 pounds). The pilot and observer had "zero-zero" ejection seats, allowing safe escape if the machine was on the ground and standing still, and there were two seats for additional passengers.

Compactness in width, length and height gave the 'AirGeep II' a mobility that no other VTOL system possessed. It could operate with ease along roadways, from ship deck, or in other confined areas. The Airgeep's rotors were loaded heavier than helicopter rotors and not capable of autorotation. Thus multiple engines and zero speed-zero height ejection parachutes were used for safety. The canted fuselage allowed placement of the rear duct at a smaller in-flow turn angle than the forward duct in forward flight. This reduced the momentum drag caused by the sharp turn of airflow through the horizontal ducts. The higher power and high fuel consumption of early turbines stimulated the idea of powering the landing gear to extend range when not hindered by surface obstacles. A hydrostatic pump drive from one turbine and two hydrostatic motors mounted on the main wheel axles enabled the vehicle to move on the ground at 35 mph with substantially reduced fuel consumption.

The 'Airgeep II' could fire weapons while remaining obscured behind an obstruction. Only the weapon and sight need be visible above the line of defilade. The helicopter must rise above the line of defilade in order to launch its weapons mounted below the rotor plane, revealing the large rotor disk, and thus eliminating surprise and providing a much greater target area. The 'Airgeep II'’s ability to fly under trees, overhanging obstructions, under bridges, and even inside buildings, enabled the 'Airgeep II' to operate within the nap-of-the-earth and thus maintain its invisibility. The ducts of the 'AirGeep II', when in the hovering position, shielded the propellers and thus their flickering could not be seen visually or by radar, maintaining "stealth" in the battlefield. Unfortunately, cutbacks in military research funding shelved this promising development, as well as other projected versions.

Population: 1 [58-5511]

Specs:
Length 24.5 ft.
Width 10 ft.
Height 5.8 ft.
Rotor prop diameter: 8.4 ft.
Empty weight: 2,611 lb.
Normal gross weight: 3,670 lb.

Crew/passengers: 2