AAA Ground Recognition Signals

The following comments from the commander of the U.S. 5th Armored Division on the proper use of ground recognition signals were published in “Antiaircraft Artillery Notes,” No. 5, November 22, 1944.

Subject: Use of Ground Recognition Signals
Source: AA Section, Headquarters Twelfth Army Group

The following extract is taken from AAA Situation Report No. 98, First US Army:

*    *    *    *

“a. The following is quoted from a letter received at this headquarters from the Commanding General, 5th Armored Division:

“‘1. At approximately 1630, 2 November 1944, nine to twelve P-38s approached the CP of the 47th Armored Field Artillery Battalion located in a group of buildings about fifty (50) yards south of paved highway one mile southeast of ROETGEN (K-919273). After circling the CP twice, the three lead planes broke out of the circle and flew off in the direction of ROETGEN. The next three planes made a diving attack of the CP, dropping six bombs. ******* The 440th AAA thereupon fired six recognition flares, at which the remaining planes pulled out of dive without dropping bombs and dipped their wings and left the area.*******

“‘3 ******* AA did not fire on planes, other than recognition flares.’

“b. The AAA complied strictly with standing instructions, by firing flares and withholding fire of their weapons. The friendly A/C, recognizing the signal and the lack of fire from the ground, immediately ceased the attack. This exemplifies the manner in which such incidents must be handled.”

 

M19 Twin 40-mm Gun Motor Carriage

Diagram of the M19 Twin 40-mm Gun Motor Carriage, from Technical Manual TM 9-1729A, U.S. War Department, 1944.

M19 Twin 40-mm Gun Motor Carriage

 

Fire Control

Fire control notes from the September 1944 issue of C.I.C. (Combat Information Center) published by the U.S. Office of the Chief of Naval Operations.

Fire control notes and comments

fire control notes and comments...

Excerpts from ship reports with comments by the Bureau of Ordnance.

ON THE RADAR MARK 12

There is no comparison between the Mark 12 and the Mark 4 equipment in the ability to pick up targets at long range. Destroyers of the MAHAN and BUCHANAN types have been picked up consistently and easily in the 25,000 to 30,000 yard range band, in complete darkness, on CIC designation. “The maximum range on a DD recorded to date is 30,000 yards. Larger targets have not been tracked to extreme ranges.

A series 60 sled with radar screen was tracked easily to 20,000 yards. Aircraft are easily tracked to 55,000 yards. A drone was picked up at 36,000 yards over land. Approaching aircraft of combat types are easily detected at 40,000 yards.

The improved performance of the Mark 12 radar over the Mark 4 radar is due to the difference in transmitted peak power, the Mark 12 power being four times that of the Mark 4. This factor alone should increase range performance on targets above the horizon by about 40 per cent. The higher frequency also improves antenna gain.

ON TARGET WITH SEARCH RADAR HELP

A considerable amount of drill at picking up planes from search radar designation has been carried out, with extremely encouraging results. The average time to get the director on a low-flying plane at a range of 10 miles is about 25 seconds. That time includes training the director at least 90 degrees.

During a very recent drone firing one director picked up the drone over land at 35,000 yards. The plane had immediately faded on the SK radar, but the Mark 12 got the target, and a good Baker run was eventually fired.

The Mark to true bearing indicator now installed in Mark 37 directors is very helpful in picking up targets from CIC designation.

The pip-matching indication, superimposed oil the long range sweep on the train and elevation scopes was particularly designed to improve target acquisition. This presentation gives the pointer and trainer a complete view of all targets in the radar beam, and enables them to start getting on target before the target pip is notched. When notched, a change to “spot” or “meter” indication for more accurate tracking can be made.

DIRECTORS ON SEARCH RADAR PHONE CIRCUITS

During the night of 21 February 1944, while under plane attack off Saipan, the forward Mark 34 director, equipped with a Mark 8 radar, was able to pick up and track low-flying planes at will. Contacts were made as far out as 14,000 yards, generally between 6,000-8,000 yards, tracked as close as 1,900 yards, and then as far out as 25,000 yards (opening). Naturally, getting “on” was the most difficult problem due to the delay in surface and air search ranges and bearings reaching the directors from the radars through CIC. This lag was greatly reduced by the directors cutting in on the search radar phone circuits.

The ease with which the director crew tracked these low-flying planes offers serious possibilities worth investigating, of using the generated ranges resulting from such tracking in assisting the 40mm and 20mm gun batteries in opening fire.

NURSING MACHINE GUN BATTERIES ON LOW-FLYING AIRCRAFT

Single low-flying planes of both twin and single engine type, can be tracked from 15,000 yards on into the ship. The relative bearing and range obtained from the main battery directors is used to get the machine gun battery “on” low-flying night torpedo planes. The Mark 8 radar in some measure fills the need for information on enemy planes when they close within 6,000 to 8,000 yards, data not obtainable from the SK.

In one instance fire was opened at 1,900 yards using this information when it is believed the target would not normally have been seen until the range closed to 1,000 yards.

 

537th AAA AW Bn in Action

Report on a small-unit action by Battery D, 537th AAA AW Bn from “Antiaircraft Artillery Notes,” HQ ETO, No. 3, November 1944:

Subject: Gallantry in Action.
Source: Antiaircraft Section, Headquarters Twelfth Army Group.

a. Another outstanding example of individual gallantry, again from Battery D, 537th AAA AW Bn, has come to our attention.

b. On 10 August 1944, the crew of Gun #4, First Platoon, which was emplaced about 7 miles north of Le Mans, France, were excitedly told by two French civilians that several Germans were hiding in a nearby wood. Two details were organized to round up the Germans. One of the details, consisting of T/5 Albert T. Cascio with two other members of the crew, started out across open fields in the direction of the woods. The other detail took a circular course to approach the woods from the flank.

c. As T/5 Cascio and his detail were crossing one of the fields and were about 100 yards from a heavily wooded hedgerow, without warning a volley of small arms fire came from the hedgerow, forcing the detail to drop quickly to the ground for protection. Without regard for his personal safety, T/5 Cascio rose to a kneeling position and fired a burst of thirty rounds from his sub-machine gun into the hedgerow. Upon completion of the burst, and although he could see an enemy machine gun pointing through the hedgerow, Cascio remained in a kneeling position and demanded that the enemy surrender or be shot. Immediately thirty Germans began to filter through the hedgerow. One of the enemy still held his machine pistol. T/5 Cascio motioned for him to drop the weapon, but instead the German brought it up in a menacing fashion; whereupon, Cascio fired another burst, killing the holder of the machine pistol and wounding four others who were coming through the hedge. This treatment seemed to have an immediate reaction on other Germans still in the hedgerow, as they now began to pour through the hedge, this time with their hands up. The final count showed four (4) officers and sixty-two (62) enlisted men captured.

d. During this whole incident, T/5 Cascio’s two assistants were protecting his flanks. The other detail arrived just as all resistance ceased and took over the prisoners, while T/5 Cascio and his assistants went into the hedgerow to search for any of the enemy who had not surrendered. None were found.

e. A considerable number of enemy hand grenades, ammunition, rifles, pistols, machine pistols and four (4) light machine guns were found in the hedgerow. It is believed that had not T/5 Cascio displayed such boldness, initiative and outright courage in ordering the enemy to surrender that he and his fellow soldiers would have been wiped out and convoys would have been subjected to serious attacks and delay.

f. T/5 Cascio was awarded the Silver Star for the above achievement, and was afforded the additional honor of having it pinned on by General George C. Marshall during a recent 90th Division ceremony.

 

40mm Twin Mount and Crew

40mm twin mount and operating crew, from: Naval Ordnance and Gunnery, NAVPERS 16116, Bureau of Naval Personnel, Training Division, May 1944.

40mm twin mount and operating crew.

40mm twin mount and operating crew.

 

Dragon 1:72 88mm Flak 37

New 1/72nd-scale 88mm Flak 37 announcement from Dragon Models: #60634: 88mm FlaK 37, Eastern Front 1942-43.

88mm FlaK 37 Eastern Front 1942-1943 Dragon Armor
 

Cavalry Reconnaissance Antiaircraft Weapons

Antiaircraft security while moving: from Cavalry Field Manual FM 2-30: Cavalry Mechanized Reconnaissance Squadron, U.S. War Department, March 1943.

SECURITY — While Moving. Antiaircraft weapons in all elements of the squadron are alerted for antiaircraft fire at all times. Whenever overhead cover is available, units will attempt to escape detection by concealment. When observed and attacked by hostile aircraft, all possible small-arms fire should be brought to bear on the attackers. If aerial threat develops during operations in open country, the best security is effected by dispersion of vehicles, off the road, if possible, or by extending the column to increase the distance between vehicles. Columns with a distance of from 200 to 300 yards between vehicles present an unremunerative target because they force airplanes to attack each vehicle separately.

Jeep Antiaircraft Machine Gun -- Wrong

(1) Wrong

Jeep Antiaircraft Machine Gun -- Right

(2) Right

FIGURE 10.–Antiaircraft weapons are alerted for antiaircraft fire at all times.

 

90-mm Antiaircraft Gun Emplacement

90mm Antiaircraft Gun M1 Emplacement

Gun battery emplacements. Camouflage omitted. (FM 5-15: Field Fortifications, U.S. War Department, February 1944.)


 

Japanese Aerial-Burst Bombs

Further intelligence reports on Japanese aerial-bombs used against Allied bombers:

JAPANESE AERIAL-BURST BOMBS

This article briefly outlines information received from the South Pacific regarding Japanese aerial-burst incendiary bombs.

At the present time two types of Japanese bombs are known which are designed to give aerial bursts. These bombs correspond with descriptions by pilots of bombs dropped on flights of our planes.

32 KILOGRAM BOMB

The 32-kilogram (70-pound) Model 99 high-explosive incendiary bomb appears to be the most commonly used type. This bomb is equipped with an impact nose fuse and a mechanical time tail fuse. The body of the bomb contains 198 incendiary pellets of steel filled with phosphorus and the tail contains 3J pounds of high explosive. On explosion the incendiary pellets shoot downwards in the form of a cone with an estimated danger radius of 50 to 75 yards. In addition to the incendiary effect of these pellets the bomb case supplies a fragmentation effect though probably not extending beyond 75 yards.

The bomb has angled tail fins which cause it to spin in the air.

250 KILOGRAM BOMB

The 250-kilogram (550-pound) high-explosive incendiary bomb is Type 2, Mark 3, Model 1. It is equipped with an impact nose fuse and mechanical time tail fuse. The bomb contains 73 pounds of high explosive and 756 incendiary fragments. On explosion fragments are sprayed conically downwards with great force to a range of 200 yards. Due to its angled tail fins this bomb also spins in the air.

TIME FUSE

The aerial-burst fuses used by the Japanese are all mechanical time fuses. Settings cannot be made in the airplane. The fuses do not arm until the bomb spins at the rate of 1,000 revolutions a minute. To attain this rate of spin the 250-kilogram bomb requires a drop of 3,000 feet and, therefore, must be released at this altitude or higher to insure a burst. The 32-kilogram bomb requires a similar drop. They may be set, however, to drop much greater distances before bursting.

BOMB CLUSTERS

Captured documents indicate that bomb clusters may be used against aircraft in flight. One type contains 76 bombs each weighing two-thirds of a pound while another variety contains 40 two-pound bombs. These bombs detonate on impact and are of the hollow charge variety.

For additional intelligence reports on German and Japanese use of aerial bombs against Allied bombers, see:

 

Japanese Model 88 75-mm AA Gun

Description of the WWII Japanese Model 88 (1928) 75-mm Antiaircraft Gun from Japanese Field Artillery, Special Series No. 25, Military Intelligence Division, U.S. War Department, Washington, D.C., October 15, 1944.

Model 88 (1928) 75-mm AA Gun.

Model 88 (1928) 75-mm AA gun is the standard Japanese mobile antiaircraft artillery weapon. It has been encountered more generally in U.S. campaigns against the Japanese than any other artillery weapon. It has a high velocity which makes it suitable for use against ground targets, especially armor. It has been used both in defense of airfields against ground attack and in a dual-purpose role as an antiaircraft and coast-defense gun. For antitank purposes it has the advantage of all-round traverse and the disadvantage of limited mobility. It thus can be quite effective when fired from ambush against tanks, but it cannot shoot and run.

Continue reading Japanese Model 88 75-mm AA Gun