- The Army Signal Corps established requirements for the rocket that met its meteorological payload needs.
A study of the proposed sounding rocket, requested by the Ordnance Department was completed by Stewart and Frank Malina.
Project ORDCIT resulted in development of the Private A and Corporal missiles.
- The first missile to be tested used a solid propellant rocket engine that could be quickly provided, as proposed by Tsien and
Frank Malina in 1943. It was called Private A, with the intention to name subsequent
missiles in hierarchical order of army ranks. The JPL missile series ended in 1954 with
the sergeant, a solid-propellant, surface-to-surface missile with an inertial guidance system.
- The Private A (also designated the XF 10S1000-A) was designed to provide experimental data on the effect of sustained
rocket thrust on a missile stabilized with fixed fins and on the use of the booster rockets for missile launching.
It had a length of 92 in., a maximum diameter of 10.25 in. and four tail fins extending 12 in. from the
body. The gross weight was 500-550 1b. The solid-propellant motor, manufactured by the Aerojct Engineering Corp. (now Acrojet General
Corp.) delivered a thrust of 1,000 lb. for about 30 sec. The specific impulse of the asphalt-base castable propellant GALCIT
61C was 186 sec.
- The Private's launcher was a 36-ft long rectangular steel boom of the truss type, with four guide rails inside the truss.
It was mounted on a steel base and both the lateral and vertical angles could be varied. The missile was boosted by four modified
Ordnance Department aircraft armament rockets in a cluster. The four rockets delivered a thrust of 22,000 lb for 0.18 scc. They
completed their burning and disconnected from the missile before it left the launcher.
- Firing tests were made in the Mojave Desemeach Springs, Camp Irwin, near Barstow, Califomia, between December 1-16, 1944.
24 rounds were fired in all. The Private A booster rockets and missile rockets reportedly performed "satisfactorly." The
average range for the fully charged rockets was 18,000 yards; the maximum range was 20,000 yards (11.3 miles).
The missile reached an estimated peak height of 14,500 ft. and an estimated maximum speed of 1,300 ft/scc. Trajectory analyses were
carried out by W.Z. Chien and C.C. Lin. The firing tests were completely successful, meeting all of the objectives specified for
the program. The Private A became the precursor of composite propellant rocket engine missiles as the Sergeant, Polaris, Minuteman, and Poseidon
and of anti-missile missiles.
- The Private F:
Tsien and F. Malina also proposed the addition of wings to a missile having the characteristics of the Private A, estimating
that the range would be increased by about 50 percent with a reduced payload. We pointed out that the problems of stability
and control of such an unguided missile were very complicated. The winged Private A was designated Private F (also the XF
10Sl000-B), and used the same Acrojet solid propellant engine. The missile was provided with fixed wings, having a span of
5 ft, stubby wings of 3 ft span were placed at the forward end for trimming the aerodynamic forces and, at the rear, horizontal
stabilizers and a vertical fin. The same Private A booster rockets were used. A new launchers was constructed with two rails, in
order to clear the wing and tail surfaces.
- Test firings of the Private F rocket were carried out at Hueco Range, Fort Bliss, Texas between April 1 and April 13, 1945.
The tests began on April Fool's Day and tumed out to be quite appropriate to the occasion.
A total of 17 rounds were fired, including two dummies to test operations of the launcher and boosters.
All of the Private F rounds, though successfully launched, went into a tail spin after a short
flight. A striking corkscrew smoke trail was drawn in the sky by the rocket jet. Engineers concluded after
a postmortem that better performance might have been obtained if the missile had been constructed with greater precision and if the
lifting surfaces had been more readily adjustable. In earlier times, after the war, when the use of funds is more carefully scrutinized,
programs such as the Private F would have begun only after more theoretical studies of such a complex devices had
been made. and more care would have been taken in its construction.
- 01 April 1945 Private F rockets tested.