TANK REQUIREMENTS IN LIBYAN FIGHTING

Crews of the American made medium tanks, now designated as "General Grants" are asking for as much 75 mm ammunition as it is possible to carry. Seeking a total operational capacity of from 80 to 90 rounds, they are prepared to forego 37 mm and Browning ammunition and also to remove the front hull guns and mounting.

A plan has been worked out by the Middle East Engineers which will permit the following ammunition load:

75 mm 81 rounds 37 mm 80 rounds .303 in 5000 rounds .450 in 700 rounds

Military Engineering has been cabled for stowage diagrams and details of the scheme referred to.

The British are considering the development of command tanks. These would be standard tanks suitably modified to carry two radio sets, the armament being replaced by dummy equipment. Vehicles of this nature are being considered for use as observation posts, for Royal Horse Artillery (completely motorized) and field artillery units in Armoured Divisions.

(G-2 COMMENT: The Germans have command tanks. The British feel the need of them, not only as command tanks but also as O.Ps for artillery supporting tank units.

The basic principle for artillery O.Ps is that the O.P. should be in the same type of vehicle used by the supported unit. Therefore an armored car is more suitable for artillery supporting an Infantry Division. The American Scout Car has been used with success.)

No decision has yet been taken on the requirements for command tanks. A description of the "British Crusader" tank modifications is promised in the next technical report and drawings are being sent separately by air mail. It is stated that the "General Grant" has not yet been investigated in this regard.

Removal of the auxiliary turret on the "Crusader" tank has been approved and this is being accomplished. The opening in the hull is being blanked off and the space used for stowage.

The frequency of failure of the 8,500 pound springs in the suspension of the American medium tank (General Grant) is becoming very high. Various theories have been put forth to account for this, but none is entirely satisfactory. The main reason appears to be that the springs are not suited to the demands made upon them.

Three cases of failure of the big end bearing of the master connecting rod have occurred. No explanation can be found for the fractures. It is interesting to note, however, that a case of sudden fall in oil pressure occurred in an engine while on the test bed. Investigation showed an air lock in the oil suction line and it was necessary to prime the line before the pump would deliver any oil. Users should be warned that the system must be most carefully checked for leaks and that the failure to get oil pressure on starting is probably due to an air lock in the suction line.

A weakness in design which has been brought out as a result of the investigation into fires is the considerable area which present designs of fuel tanks offer to hostile fire. In future designs consideration should be given to keeping fuel tanks as low and unexposed as possible.

(G-2 COMMENT: The proper protection of ammunition should also be considered.)

The P.8 compasses have proved to be quite indispensable to tanks, but they are not yet sufficiently accurate to allow them to be used as a sole method of navigation. Apart from leakage of fluid and breakages of the glass of the grid ring, no defects have occurred in the same compass equipment. It is suggested that the supply of a metal cover to fit over the compass would save damage. P.8 compasses are now being issued with a brass cover which meets the point raised.

The engine oil tank on Crusaders is in two parts, interconnected by a small pipe. It has been reported by units that it takes a driver up to one hour to fill it with oil, and that the flow between the tanks is so slow that an impatient man is apt to assume that both tanks are full when only the one into which the filler passes is really full. A modification is being introduced by which an additional connecting pipe 2" diameter will be run between the tops of the tanks.

(G-2 COMMENT: The oil system is also a source of much difficulty.)

During the recent fighting there were two cases of British Valentine tank drivers being killed and collapsing over the gear lever. The remainder of the crew were unable to remove the driver to get at the gear lever on the clutch and were unable to stop the vehicle. A similar incident occurred in a British Matilda tank during General Wavell's advance, although in this case it should have been possible to disengage the clutches with the hand wheels provided. It is considered that all Armoured Force vehicles should be fitted with a means for stopping the engine from the fighting chamber.

A "dead man's switch" is fitted to most gasoline driven tanks. The question of providing the British Covenanter and the American tanks with this switch is being considered.

(M/A Report, London, No. 47672.)