|
|
By Lone_Sentry_Admin, on November 27th, 2011%
“Lessons Learned” by U.S. Eighth Air Force fighters against German flak taken from Light, Intense, and Accurate: U.S. Eighth A.F. Strategic Fighters Versus German Flak in the ETO, Headquarters, 65th Fighter Wing, August 1945. The booklet was the work of Lt. Col. San Souci and Capt. William D. Thurston, assisted by Lt. Col. R. F. Kennedy, Wing A-2.
CHAPTER XI: LESSONS LEARNED
In fighting back at light flak, Enemy No. 1 of our fighters in the Eighth Air Force, we all learned a great deal. Operating as we did in East Anglia in England, a tight little area crowded to capacity with strategic air units, we were ideally situated to analyze, discuss and record what we learned over a considerable period of time. Our military communications net was perhaps the finest that ever existed in any combat zone, and the exchange of information among units left little to be desired.
Some of the lessons that grew out of this particular situation are worth setting down in a list, followed in Chapter XII by recommendations based on our experience:
1. Specialization in Fighters is a Myth. Anyone using fighters in a strategic air force might just as well make up his mind in the beginning that before it’s over his pilots will come up against every type of defense the enemy has. It was an error in the early days in the ETO to assume that high-level escort fighters would not be bothered by light flak. Ultimately we had to prepare to meet it, and we should have started sooner than we did.
2. Photo Interpretation is Reliable in Locating Flak. Our own experience as we went along, and investigations on the ground in Germany after the war, both proved that the flak defenses pin-pointed by photo reconnaissance were over 90% correct.
3. Reconnaissance Must be Continuous. It is obvious that frequent photos of every area reached by the strategic air force are absolutely essential in order to keep abreast of the fluid flak situation.
Continue reading Flak: Lessons Learned
By Lone_Sentry_Admin, on January 15th, 2011%
Description of 20 mm guns and mounts deployed on U.S. naval vessels, on merchantmen, and at many shore stations in WWII from Naval Ordnance and Gunnery, NAVPERS 16116, Bureau of Naval Personnel, Training Division, May 1944.
20 MM. GUN AND MOUNTS
7C1. General. The 20 mm. gun assembly, shown in figure 7C1, is an AA machine gun mounted on a pedestal-type. free-swinging mount. The mount is so arranged that the trunnion height can be adjusted for the convenience of the gunner when the gun is used at different angles of fire. The elevation limits are 5° depression and 87° elevation. There are no limits in train.
The gun is designed for automatic firing only and, like other automatic guns, it uses some of the force developed by the explosion of the propellant charge to eject the empty case, cock the gun, reload, and fire the next round. It embodies, however, certain features of gun design which are not found in other automatic and semi-automatic guns. The most important of these are:
1. The gun barrel dues not recoil.
2. The breechblock is never locked against the breech and is actually in motion at the moment the gun is fired.
3. There is no counterrecoil brake, the force of counterrecoil being checked by the explosion of the following round of ammunition.
The 20 mm. fires fixed ammunition which is fed into the gun from a magazine having a capacity of 60 rounds. The cyclic rate is about 450 rounds per minute. When the normal time required to change magazines is considered, the rate will vary between 250 and 320 rounds per minute depending upon the skill of the gun crew. The projectile used is a high-capacity type and is fitted with an impact-type nose fuze. Usually every other projectile or every third projectile in the magazine carries a tracer.
The 20 mm. gun is being used extensively on all classes of naval vessels, on merchantmen, and at many shore stations. It has been designed for and is particularly effective against aircraft targets at ranges up to about 2,000 yards. For this purpose it has almost entirely replaced the caliber .50 machine gun, principally because the heavier 20 mm. projectile with its high-explosive charge causes much more damage than the non-explosive caliber .50 projectile. The gun may also be used against lightly-armored targets.
7C2. Mounts. There are several kinds of pedestal-type, free-swinging mounts in use. The major difference between these mounts is in the method of adjusting the trunnion height. The mechanical mount shown in figure 7C1 is the one which is most widely employed at the present time.
 Figure 7C1. 20 mm. gun assembly; mechanical mount. The fixed pedestal is bolted to the deck. The pedestal head, through which the column rises, is so mounted that it can be rotated around the top of the pedestal and locked in any desired position by means of the clamping lever. The column-raising handwheel, mounted on the pedestal head, is used to raise and lower the column. By this means the trunnions can be raised about 15 inches to better position the gun for the gunner when firing at elevated targets.
The trunnion bracket and pivot is free to rotate around the top of the column on ball bearings, and there are no limits to this training motion. This part supports the shield, the cradle spiral spring, and the cradle. The gun is carried in two grooved slides in the cradle, and is held in place by a bolt. The cradle spiral spring, mounted around the left trunnion, as one end attached to the trunnion and the other to the spring case. This spring functions to counterbalance the weight of the gun.
From the above description it is evident that the gunner, strapped to the aft end of the gun, can swing the gun to any position within elevation limits, and that the trunnion height can be adjusted for his convenience and comfort. As the gun is moved in train, the column-raising handwheel can also be moved into position for easier operation.
Two other mounts which are used to a limited extent are shown in figure 7C2. The fixed mount, so called because it does not have an adjustable trunnion height, has a higher pedestal than the mechanical mount. The gunner is provided with a circular stepped platform around the mount to enable him to utilize the full range of elevation and depression available. The elevation limits are the same as for the mechanical mount and there is no limit in train.
 Figure 7C2. 20 mm. gun assemblies; fixed and hydraulic mounts. The hydraulic mount has a foot-operated hydraulic mechanism to raise and lower the column. The three equally spaced pedals around the pedestal are connected to the hydraulic pump and control valves within the pedestal. Any one of these pedals can be pumped to raise the column or fully depressed when the column is to be lowered. The column can be raised 24 inches, and the gun elevation limits are 15° depression and 90° elevation. There are no limits in train.
…
7C13. Ammunition. The 20 mm. gun uses fixed ammunition which is designed to give an I.V. of 2,725 f.s., and a maximum horizontal range of about 5,000 yards. The following projectiles are used: (1) high-explosive bursting charge with tracer, (2) high-explosive bursting charge without tracer, (3) blind loaded with tracer, (4) blind loaded and plugged, and (5) incendiary. The high-explosive bursting charge is either tetryl or a high explosive known as pentolite. The tracer charge is effective for about 3¾ seconds duration. It occupies about one-half of the projectile cavity, and hence projectiles with tracers carry approximately one-half as much bursting charge as those without tracers.
The projectiles are equipped with a simple impact-type nose fuze. On impact a closing disk is displaced into the fuze body and an air column within is instantaneously compressed and forced through an inner disk, thus heating the air column. The heated air ignites a small pellet of lead azide which in turn sets off pressed tetryl in a detonator, exploding the burster charge. The 20 mm. projectiles do not have the self-destructive arrangement found in 40 mm. ammunition.
7C14. Magazine. A sectional view of the magazine is shown in figure 7C15. The spring is hand wound from the outside and its tension is indicated on the indicator block. The cartridge feeder, driven by the spring, exerts a pressure on the innermost round and tends to force the cartridges around the spiral guides and out of the magazine mouthpiece. The lips of the magazine mouthpiece are partly closed so that a round can pass through only by being pushed out longitudinally at right angles to the direction of the pressure from within. A gap is cut in the forward end of the mouthpiece to allow the rounds to slide in or out. The magazine has a capacity of 60 rounds; a new-type magazine holds 100 rounds.
 FIGURE 7C15. 20 mm. magazine. 7C15. Gun sights. Tn the past, fire control of the 20 mm. gun has been primarily by means of tracers, ring sights having been used to get on the target. However, the present tendency is to rely upon the Mark 14 sight, supplemented by spotter’s observations of tracers. At present, then, available sights for this weapon include the following:
1. The Mark 14 sight, a gyroscopic sight mechanism which automatically computes the lead angle necessary for different speeds and motions of the target. The gunner sights on the target through a small window through which luminous crosslines are projected. The crosslines are kept on the target, and, as the gun swings following the target’s movement, the crosslines are offset to give the proper lead angle for the gun.
2. The older cartwheel sight, or peep and ring sight, consists of a rear peep and a forward circular grid, with concentric rings to indicate the amount of lead necessary for different target speeds. This sight enables the gunner to get on the target before opening fire; thereafter, tracer control normally is used. Several types of ring sights have been developed.
7C16. Gun crew. The gun crew for the 20 mm. mechanical mount consists of at least three men (four if the Mark 14 sight is used):
1. The gunner, who is strapped to the shoulder rests on the after end of the gun elevates, trains and fires the gun.
2. The trunnion operator, who raises and lowers the column on which the gun is mounted.
3. The loader, who places loaded magazines on the gun and unships them when they are empty.
4. The range setter, who observes the effects of fire and changes range setting on the Mark 14 sight.
The gun crew may also include ammunition passers, who hand loaded magazines to the loader and take the empty magazines after they are removed from the gun. The number of ammunition passers used depends upon the location of the ready boxes.
 Figure 7C16. 20 mm. gun and operating crew. The gun is entirely free-swinging, and thus can be elevated or trained merely by the movement of the gunner’s body. The trunnion operator stands to the left of the gun, faces the gunner, and keeps his back to the shield on the mount. He moves his handwheel around the pedestal of the mount as the gunner swings the gun in train. He watches the gunner’s knees and adjusts the gun height so as to keep the gunner’s knees slightly bent during firing. The loader stands to the right of the gun and, operating the magazine catch lever, removes the spent magazine and replaces it with a filled one. A gun and operating crew is shown in figure 7C16.
…
7C19. General data.
| Caliber | 20 mm. (.79 inch) | | Length of barrel (calibers) | 72 (approximately) | | Limits on elevation (mechanical mount) | 5° depression and 87° elevation | | Arc of train | unlimited | | Firing rate (assuming continuous ammunition supply) | 450 rounds per minute | | Firing rate (considering time to change magazines) | 250-320 rounds per minute | | Magazine capacity (rounds) | 60 (100) | | Muzzle velocity (f.s.) | 2,725 | | Maximum range (36° elevation) | approximately 5,000 yards | | Commence firing range (with Mark 14 sight): | | | High elevation | 1,000 yards | | Horizontal | 2,000 yards | | Weights: | | | Gun | 141 pounds | | Mount (mechanical) | 1,578 pounds | | Magazine—loaded | 63 pounds | | Magazine—unloaded | 31 pounds | | Round of ammunition | approximately 0.5 pound |
By Lone_Sentry_Admin, on December 10th, 2010%
 The website Army Book of Memories tells the story of the 143rd AAA Gun Battalion during WWII from training through the fighting in the Ardennes Offensive and on to V-E Day. The website also includes photographs and a copy of the rare 143rd AAA’s unit history booklet which was published in 1945 after the end of the war.
By Lone_Sentry_Admin, on December 10th, 2010%
A report on the activities of antiaircraft gun battalions in the antitank role during the Battle of the Bulge reproduced from “Antiaircraft Artillery Notes,” HQ ETO, No. 15, January 1945:
Subject: Employment of AAA in Anti-tank Role
Source: AA Section, Headquarters Twelfth Army Group
During the recent German Ardennes offensive the 110th and 143rd AAA Gun Battalions, and Battery D, 639th AAA AW Battalion, were placed in anti-tank support of the 30th Infantry Division, in the Malmedy-Stavelot-Stoumont sector. The Division has submitted a report of the activities of these units, and made recommendations for future employment of AAA in an anti-tank role, (See ETOUSA AAA Notes No. 14 for a detailed account of the activities of the 143rd AAA Gun Bn during this action.)
Report of 30th Infantry Division
a. The above listed units were attached to the Division at 210030A December 1944. Prior to daylight of the 21st, liaison was established with the Division by the 11th AAA Group, and by each of the attached units. Upon the arrival of these representatives they were given maps of the area and were fully informed of the tactical situation. A map reconnaissance was made, and officers from the supporting tank destroyer battalion accompanied the antiaircraft officers on their ground reconnaissance, and assisted in the actual placing of their guns in firing positions.
Continue reading Employment of AAA in Anti-tank Role
By Lone_Sentry_Admin, on October 28th, 2010%
 German Light Flak Car Carrying Two Triple-20-mm Gun Mounts, Each Sheltered Behind Concrete Walls 3 Feet Thick. Source: Light, Intense and Accurate: U.S. Eighth A.F. Strategic Fighters Versus German Flak in the ETO, 1943-1945
By Lone_Sentry_Admin, on October 20th, 2010%
Instructions for digging defensive positions for AA halftracks from “Antiaircraft Artillery Notes,” HQ ETO, No. 8, December 1944:
Digging in Half-Tracks
Source: AA Section, Headquarters Twelfth Army Group
The principle of digging in equipment is one which all AAA combat units understand and practice. Some units have learned from experience that the deeper one is dug in, consistent with the field of fire to perform the assigned mission, the better protection the crew and equipment are afforded against artillery and mortar fire. As an example of the policy that it pays to dig in deep, Figure 1 shows the plan practiced by the 554th AAA AW Bn (M). Approximately eight hours is required to prepare the emplacement, including sandbagging. This battalion, commanded by Lt Colonel L. V. Linderer, has seen continuous action since arriving on the continent 18 June, being attached to XIX Corps until 5 November when it was attached to the 29th Inf. Div. During this period the battalion has been subjected to mortar and artillery fire on numerous occasions, and to date has suffered no fatal personnel casualties due to this fire.
Notes: (a) Minimum thickness of revetment. (b) The depth of emplacement and heighth or sandbags will depend entirely on the terrain. (c) Log or plank for track to rest on. (d) Floor of emplacement slopes to the center and front to sump hole where water will drain and can be bailed out.
By Lone_Sentry_Admin, on October 10th, 2010%
Report on a single lucky 40mm shot from “Antiaircraft Artillery Notes,” HQ ETO, No. 15, January 1945:
Subject: More Economical Shooting
Source: AA Section, Headquarters Twelfth Army Group
The 445th AAA AW Bn (M) claims to have at least tied the world’s record for low ammunition expenditure when one of its gun crews shot down an FW 190 on 1 January with one round of 40mm. The plane came over a heavily wooded area at high speed. Because of the limited field of fire, the gun section was able to fire only one round of 40mm ammunition. The shell hit the fuselage behind the cockpit. Fire broke out immediately, and the plane turned off course, out of control. Front line observers saw the plane crash a few seconds later.
By Lone_Sentry_Admin, on October 9th, 2010%
“A new shape in our neighborhood… and a new face” from “Antiaircraft Artillery Notes,” HQ ETO, No. 14, January 1945:
The aircraft are the P-61 Black Widow night fighter and the A-26 Invader attack bomber.
By Lone_Sentry_Admin, on September 27th, 2010%
Diagram of snow camouflage for 90mm antiaircraft gun battery, from “Antiaircraft Artillery Notes,” No. 9, December 1944:
By Lone_Sentry_Admin, on September 27th, 2010%
German V-1s were fired in attacks against the strategic port of Antwerp after the Allied capture of the V-1 launch facilities used to attack England. Antwerp was hit by over 2,000 V-1s from October 1944 to March 1945. Numerous Allied antiaircraft units were deployed around Antwerp to defend against the V-1 attacks. The following report describing the rules for V-1 claims by antiaircraft units was published in “Antiaircraft Artillery Notes,” No. 8, December 1944.
SUBJECT: Rules for Confirming Claims of Pilotless Aircraft Shot Down.
SOURCE: Headquarters, Antwerp “X” Command, Operations Memorandum #25.
Operations Memo #25, Hq Antwerp “X” Command, 2 December 44, is quoted:
1. In order that all concerned may be apprised of the conditions under which claims for PAC (Diver) shot down are allowed at this Headquarters, the following rules governing the procedure of the Claims Board established by Operations Memo No 13, this Headquarters, are hereby published:
a. The claim is initiated by unit commander who must cite the basis for the claim.
(1) To substantiate a Cat A claim the statement will be made that a PAC while engaged by AA exploded in mid-air.
(2) To substantiate a Cat 3 claim the statement will be made that a PAC fell as a result of damage sustained from AA fire as manifested in one or more of the following:
(a) Deflection in course.
(b) Definite and abnormal change or cessation in motor sound.
(c) Appearance of fragments of PAC in air.
(d) Definite and abnormal increase in flame area around target. b. Each claim must be reviewed by commanders in the chain of command. When received at the Statistical Office, the claims board tentatively allows or disallows claim. This does not require a meeting of the entire board but may be done by any one member of the board. 2. All concerned are reminded that the records being compiled, of PAC shot down, are an important military and historical record which will be given the most careful study by higher authority and it is therefore incumbent on everyone in the chain of command to insure that all claims registered are founded on substantial fact. It is considered to be a serious dereliction of duty to enter, or allow, claims which are not so founded.
3. In forwarding claims the commanders concerned will insure that the basis of the claim is fully stated, in order that the claims board may have sufficient data on which to proceed. Prior to 1500 daily, the entire claims board will meet for confirmation of rejection of all claims which have previously been allowed tentatively. After this has been done, credit will be allocated to specific batteries for the PAC shot down.
4. In order to avoid duplication of reports, it is desired to obtain individual battery credits, or PAC Kills, from the daily Statistical Report. To avoid confusion between units “engaging” and units actually “claiming” PAC, Groups and Brigades are directed to plainly indicate on report forms the difference between the two categories.
|
|
The Haunted Tank Showcase Vol. 1
The Haunted Tank Showcase Vol. 2
Recent Comments