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보/고/서

ATIS INTERROGATION REPORT NO. 3541　23 February 1951

FIELD REPORT (ADVATIS Sp Rpt 026)　12 February 1951

PW was very cooperative, intelligent and observant. Reliability - good.

(1) PW received no training on computer.

(2) 9 men were required to operate computer.

(3) Computer cannot be used alone for finding range.

(4) There was no director where PW was, but a field phone was seen. Directions were relayed by phone to this computer unit.

(5) Test problems were used to check whether or not the computer was functioning correctly.

(6) Did not know if the director was used during battery practice.

(7) Did not know if radar was used during battery test firing. There was no radar in PW area.

(8) Electric wire ran from computer to a wet cell battery from which four wires ran to four different guns.

(9) Description: 5 x 4 x 5 mounted on two pneumatic tires and two steel stands. Computer constructed of metal. Bench for operators mounted around the middle of the unit.

(10) Dials: Three non-luminous dials on side of computer. Dials had white face with black numerals and needle.

(11) Alignment Rod: A metal rod, 6” high painted blue was mounted on the rear right top corner of this computer unit.

(12) Purpose: This rod was used by the AA gun operators to align their guns with the computer unit.

(13) Receiving and Altitude Reading: The computer unit received the altitude reading from a three man range finder unit situated few feet from the computer unit.

(14) Range Finder: (Revolving type mounted on a rod) The range finder was 5’ long, manned by three men who determined the altitude of the aircraft.

(15) Remarks: Direction of approaching aircraft was related to this unit by phone from director located at a place unknown to PW. Source of electrical power was a wet cell battery. The battery was charged at an unknown place. One battery lasts approximately one month. His unit did not carry extra batteries.

(1) Guns in PW battery were Russian M1939 85mm AA guns mounted on four wheels.

(2) The guns were made in 1942.

(3) Recoil mechanism was operated by oil, and gas produced by firing of shell.

(4) Ammunition was not marked.

(5) Velocity of ammunition was 800m/sec.

(6) There were four guns to a battery.

(7) There were six men to a gun.

(8) The duties of these 6 men were:

No 1 man - Sighter

No 2 man - Gunner

No 3 man - Fuse Setter

No 4 man - Gun Elevator

No 5 man - Ammo Carrier

No 6 man - Ammo Carrier

(9) The guns were towed by trucks.

(10) The battery required 2 minutes to get into position and be ready to fire if the guns were already in position, otherwise it required 10 minutes or more to set up the guns, get into position and be ready to fire.

(11) This gun fired 12 rounds per minute.

(12) Time fuze was used.

(13) When the gun was in a 45° position, the maximum range was 15,000m. Effective range was 10,000m. If it was in a 85° position its maximum was 10,000m; effective range 8,000m.

(14) These guns could be used against ground targets, direct as well as indirect, as long as the target was 200m or more away. These guns also could be used against tanks and had shells for this purpose.

(15) Bursting radius was 100m.

(16) Operation: An electrically operated dial for altitude reading was attached to the guns. The dial had two needles, one run by electricity and one manually.

The electrically run needle was operated from the computer unit, while the manual needle was operated by gun elevator (#4 man).

As the computer unit receives the altitude reading from the range finder, a button is pressed making electrically operated needle on the guns point to the specific numerals indicating altitude. Then the #4 man elevates the gun until the manually operated needle is aligned with the electric needle. Then the desired angle for the specific altitude is obtained.

(17) Mechanical defects experienced by PW on the 85mm Gun.

PW being #4 man frequently had trouble with the elevator handle. Other trouble on gun was the shell ejector. Many times, the ejector did not eject the empty shells. Shells were often defective. The rim of shell could not be grasped by the ejector, because it was too large.

For the Commanding Officer: