C-41

SISPRE experimental rockets

Following the IAF congress in Amsterdam in 1958, a program of sounding rockets was born in Italy, under the form of a collaboration between the DGAM (Direzione Generali Armi e Munitioni) of the Aeronautica Militare and the SISPRE (Societa Italiana Sviluppo Propulsione a Reazione), a subsidiary of Fiat and Finmeccanica. This program was directed by the Lt-Col. G. Metallo of the DGAM and the engineer A. Angeloni of the SISPRE.
The first of these rockets was the C-41 assembled from "60 pounds" military surplus solid motors. The first stage was a cluster of four motors with communicating combustion chambers and the second was a single motor of same type. After a series of static firing to validate the technique of cluster with communicating chambers, the rocket, weighing 75 kg, was tested in flight from the PerdasdeFogu rocket range. The aim of these tests was to study the problems dealing with rocket takeoff and stage separation, to collect information on wind effects and to experiment the efficiency of different luminous devices to visualize the trajectory. The six launches (of which three with dummy second stage), occurred in July-August 1960, proved satisfactory.

Thus ended the first phase of the DGAM sounding rocket program. Next phases were incorporated in the Comitato di Ricerche Spaziali of the CNR (Consiglio Nazionale Ricerca) program. This Committee was funded with money coming for half part from the Comitato Razzi e Missili of the Ministry of Defense and for other half part from the CNR. The CNR established a collaboration with NASA that was to culminate some years later with the San Marco project. Development of rockets made in Italy was not a priority for it.

BPD Meteorological rocket

After the development and successful firings of the C.41, the Sezione Ricerche Scientifiche of the DGAM directed by Lt-Col. Metallo, proposed the study and the manufacture of a low cost meteorological rocket, capable of carrying a 2 kg payload to approximately 100 km of altitude. Negotiations with SISPRE on a two-stage C.7-Mighty Mouse rocket having failed, the DGAM came into contact with the BPD (Bombrini-Parodi -Delfino) company. The meteorological rocket was conceived from two BPD motors already available : a 30 kg motor, 160 mm in diameter (M2P30, polybutadien, ISP = 220 seconds) and a small 5 kg motor, 70 mm in diameter. This rocket, called 160-70, had to weigh 45 kg, to be 2.44 m high and to be capable of reaching 70 km altitude. Five were launched in 1961 and ten in 1963. The 160 mm motor, topped with an inert "dart", could carry a payload composed of radar tracked shafts at 50-80 km altitude to determine the speed of winds.

SISPRE multi-stage geophysical rocket

SISPRE undertook the study of another kind of rocket for geophysical researches according to an original idea of Lt-Col. Metallo. The vehicle would be composed of a first group of 7 motors, a second group of 4 motors and an upper motor topped by the payload, that is to say 12 BPD M2P30 motors. It had to function as a 5-stage rocket constituted in the following way:
- 1st stage: 4 motors of the first group with communicating chambers,
- 2nd stage: 3 motors of the first group with communicating chambers,
- 3rd stage: 3 motors of the second group with communicating chambers,
- 4th stage: 1 motor of the second group,
- 5th stage: last motor.
Calculations shown that this vehicle could have take a 20 kg payload to an altitude higher than 200 km with total weight at the takeoff lower than 400 kg. As an intermediate phase, the project planned the development of a 3-stage rocket comprising a group of 4 motors as first stage, a group of 2 motors as second stage and an unique motor as third stage. This rocket, called C-43, was tested in flight in a version with two active stage (4 + 2 engine M2P30), then the program was cancelled.