Artillery Against Siegfried Line Pillboxes

The following combat report by the 258th Field Artillery Battalion described the effect of short-range 155-mm artillery fire against the pillboxes of the Siegfried Line.

HEADQUARTERS, 258TH FIELD ARTILLERY BATTALION

APO 230, U.S. Army
5 October 1944

SUBJECT: Destruction of concrete pillboxes by short range fire from M12, 155mm Gun, SP.
TO: Commanding General, XIX Corps, APO 270, U.S. Army

1. Between 26 September 1944 and 2 October 1944 this battalion was assigned to the mission of methodical destruction of all pillboxes which could be located on the front or immediate flanks of the impending attack on the Siegfried Line by the 30th Division.

2. During this period intensive aerial and ground reconnaissance, in conjunction with aerial photo study, revealed 49 pillboxes as potential observable targets.

3. Of this number 43 were attacked by short range M12 fire, 1 by direct fire and 2 by 3″ guns of Co A, 823d TD Bn. M12 adjusted using fuze delay, switching to T105 fuze on obtaining the first target shot. The TD company commander fired using one gun, direct laying, firing both HE with fuze CB, and armor piercing shot. Evidence of penetration was obtained on all 46 targets above. For details of each mission, see accompanying annex.

4. Firing was terminated only on evidence that a penetration has been obtained. It has not yet been possible to verify by close-up examination of the targets whether penetration was accomplished in every instance.

Continue reading Artillery Against Siegfried Line Pillboxes

Japanese Rockets and Launchers

The following U.S. intelligence report on Japanese spin-stabilized rockets and launchers was published in Enemy on Luzon: An Intelligence Summary:

ARMY 20-CM SPIN STABILIZED ROCKET AND TYPE 4 LAUNCHER:

Several of these projectiles, the first Army rockets recovered, and the Type 4 launcher, were used against our troops in the Manila area and east of Manila. The date of manufacture, late 1944, emphasized the trend toward increased use of rockets by the enemy.

In general appearance the launcher was similar to a large trench mortar. It incorporated traversing mechanism in the bipod and employed standard mortar fire-control devices. The tube, 20.3-cm inside diameter and 75 and 5/8 inches long, was open at both ends and contained a hinged opening for insertion of the rocket. It was fired with a 25-foot lanyard attached to a pull igniter.

Japanese WWII Army 20-cm SS Rocket and Type 4 Launcher

Army 20-cm SS Rocket and Type 4 Launcher

The explosive head was a thin-walled tube containing nose fuze, booster and filling of cast TNT. The motor threaded onto the explosive head and was equipped with six nozzles canted 25 degrees. The propellant was ballistite ignited by a black powder charge located just forward of the igniter, which screwed into the motor base plate. Projectile and motor had a combined weight of approximately 185 pounds.

Japanese WW2 Army 20-cm SS Rocket and Type 4 Launcher (Firing)

Army 20-cm SS Rocket and Type 4 Launcher (Firing)

The rocket was stable in flight, exploded high order, and had an approximate range of 3,200 yards at 800 mils.

Continue reading Japanese Rockets and Launchers

German Large Caliber Artillery

Table of German heavy artillery in World War II from Catalog of Enemy Ordnance, U.S. Office of Chief of Ordnance, 1945.


Gun*Type of Carriage and TraverseWeight of Equip­ment (lb.)Length of Barrel in CalibersPROJECTILERemarks
Max. Range (yds.)Muzzle Vel. (ft./sec.)Type**Weight (lbs.)
15 cm K. in Mrs. Laf.  4526,0002,730H.E. (15 cm K. gr. 18)94.6Probably used on platform for coast defense
15 cm K. 18 (149 mm)Mod. Box Trail 12°28,4595527,0402,840H.E. (15 cm K. gr. 18)94.6 
15 cm K. 39 (149 mm)Split Trail 60°27,28055.427,0402,840H.E. (15 cm K. gr. 18)94.6Probably mfd. by Krupp
17 cm K. in Mrs. Laf. 18Mod. Box Trail 16°38,5005032,3703,035H.E.B.C. (17 cm K. gr. 38 Hb.)138Krupp, Essen
21 cm Mrs. 18Mod. Box Trail 16°36,7003118,3001,854H.E. (21 cm gr. 18)249Krupp, Essen
21 cm K. 38Field 360°78,0005037,2002,870H.E. (21 cm K. gr. 38)265360° on platform. Krupp, Essen
21 cm K. 39Field 360°74,8004532,8002,620H.E. (21 cm gr. 40)278Skoda design
21 cm K. 39/40
21 cm K. 39/41
       Both reported to be very similar to 21 cm K. 39
21 cm K. 42   37,0002,820  Muzzle brake fitted
24 cm H. 39Field 360°59,4002819,7001,970H.E. (24 cm gr. 39)365Skoda design similar to 21 cm K. 39
24 cm H. 39/40       Later version of 24 cm H. 39
24 cm K. 3 (238 mm)119,00046
(55?)
41,0003,248H.E. (24 cm gr. 35)331 
24 cm K. 18 (238 mm)Field 6°118,8005540,5003,180 332Fires splined projectile, Rheinmetal Borsig
28 cm H.L./12Static 360°111,0001211,4001,150H.E. (28 cm Spr. gr. L./3.5 m. Bdz.)770Uses DeBange Type obturator. Obsolete except for coastal defense
28 cm Kst. H.Static 360°81,5001212,5001,243H.E. (28 cm Sprgr. L./3.5 m. Bdz.)770Similar to 28 cm. H.L./12. Fires same projectile
35.5 cm M. 1Field165,000 21,9001,870Anticoncrete (35.5 cm gr. Be.)825 
42 cm Gamma Mrs.Static 45°308,0001615,5001,485Anticoncrete (s. Gr. Be.)2,249
2,253
Similar to last war equipment
61.5 cm Mrs. 264,000815,3001,380Anticoncrete (gaschosse L./4.1 für Karl gerät)4,400Reported to have an auxiliary 54 cm barrel
15 cm K. (E)Rly. 360°167,0004025,2002,800H.E. (15 cm K. gr. 18)94.6Naval design. Krupp. Same projectile as 15 cm K. 18
17 cm K. (E)Rly. 360°176,0004029,2002,870H.E.B.C. (17 cm Sprgr. L./4.7 Kz. m. Hb.)138Naval design. Krupp
20 cm K. (E) (203 mm)Rly. Turntable 360°189,5005540,0003,030H.E.B.C. (20.3 cm Sprgr. L./4.7 m. Hb.)247Naval design. Also known as 20 cm S. K. C./34
21 cm K. 12 (E)Rly.744,000196131,0005,330H.E.B.C. (21 cm gr. 35 m. Hb.)236Splined projectile. Differences are not known
21 cm K. 12V (E)Rly.       
21 cm K. 12N (E)Rly.      Believed to involve an alteration of the rifling
24 cm Th. Br. K (E) (238 mm)Rly. 1°207,0003522,2002,210H.E.B.C. (24 cm Sprgr. L./4.5 Bdz. u Kz. m. Hb. ung)328Sister piece to “Theodor Kanone”
24 cm Th. K. (E) (238 mm)Rly.209,00040
(48?)
29,0002,660H.E.B.C. (24 cm Sprgr. L./4.2 m. Bdz. u Kz. m. Hb.)330“Theodor Kanone” Naval design
28 cm Ks. Br. K. (E)Rly.262,0004032,3002,690H.E.B.C. (28 cm Sprgr. L./4.1 Kz. m. Hb.)529Naval design. Carriages are believed to be very similar
28 cm lg. Br. K. (E)Rly.271,0004540,5002,820H.E.B.C. (28 cm Sprgr. L./4.4 m. Bdz. u Kz. m. Hb.)626Naval design. Carriages are believed to be very similar
28 cm s. Br. K. (E)Rly.286,0005040,5002,880H.E.B.C. (28 cm Sprgr. L./4.4 m. Bdz. u Kz. m. Hb.)626Naval design. Carriages are believed to be very similar
28 cm Br. N. K. (E)Rly.330,000 50,2003,260H.E.B.C. (28 cm Gr. 39 m. Hb.)496Probably splined projectile
28 cm K. 5 (E)Rly. 1° Turntable 360°480,0007663,0003,670H.E.B.C. (28 cm Gr. 35)550Weight does not include turntable. Fires splined projectile. Also reported to fire a rocket assisted shell (28 cm R. Gr. L/4.7) with range of 53 miles.
28 cm K. 5/1 (E)     H.E.B.C. (28 cm Gr. 42) Differences from 28 cm K5 are unknown
28 cm K. 5/2 (E)     H.E.B.C. (28 cm Gr. 42) Differences from 28 cm K. 5 are unknown
38 cm Siegfried K. (E)Rly. Turntable 360° 55
(52?)
61,0003,450H.E.B.C. (38 cm Sprgr. L./4.5) (Si)1,096Naval design. Also fires a 1,764 lb. shell with maximum range of 46,000 yds.
40 cm K. (E) (406 mm)Rly.710,0005049,0003,450
2,790
H.E. (40 cm gr. 40)1,320
2,100
Naval design—Adolf. K.
80 cm Gustav Geschütz 2,750,0003551,500  16,700 

* Almost all the data given have not been verified by tests performed by any Allied government and information from sources available varies considerably in reliability and degree of confirmation.
** Of the several types of projectiles fired by each weapon, only one believed to give maximum range is listed.

21 cm Mrs. 18:
21 cm Mrs. mit Mrs. Laf. 18: Heavy Howitzer

20 cm K. (E) (203 mm):
20 cm K. (E): Railway Gun

 

The Artillery Jeep Plane

From “Combat Lessons” No. 4 comes this tribute to the U.S. artillery spotter planes in World War II:

The Artillery “Jeep Plane” Colonel Russell P. Reeder, Infantry Regimental Commander, Normandy.

“When our division commander asked us what we wanted our reply was ‘Keep those artillery jeep planes in the air.’

“These planes were the most effective means of stopping German artillery fire on our troops. We would be taking a real pasting from their artillery until one of these planes would show up skittering across the sky. Immediately the German artillery would stop firing. After one or two incautious enemy batteries had continued to fire and disclosed their position to the air observer, with ‘sudden death’ results, the others learned that discretion is the better part of valor.

Artillery Jeep Plane

“Even their mortars respected the eagle eye of the jeep plane and would suspend fire rather than risk detection of their positions.”

COMMENT: This disinclination of German artillery to fire under the threat of disclosing their positions to air observers has also been reported from both Sicily and Italy.

 

128th Armored Field Artillery Photos

6th Armored Division Patch128th Armored Field Artillery Battalion   John Glascock has uploaded over 300 black-and-white and color WWII photos of the 128th Armored Field Artillery Battalion, 6th Armored Division:

Noteworthy color photographs include Red Cross Clubmobile “Atlanta”, Piper Cub, Jeep Repairs, and USO Entertainment.


 

Artillery Lessons from Normandy

Artillery lessons from Normandy published by the U.S. Eighth Army in the “Artillery Information Bulletin,” October 1944.

LESSONS FROM OTHER THEATRES

a. OPERATIONS IN NORMANDY (Comments of various commanders to AGF Observer).

Be prepared to send out more LNO’s and FO’s than the T/O provides. Your LNO’s should be fine officers or you will find them valueless. His job is of primary importance and you will find that the training system of placing a weak officer on the LNO job will hurt you very much when you enter combat.

In wire laying there is no formality about senior units laying to junior. We usually lay to each other simultaneously by different routes. Lateral lines are put in whenever possible and they are most helpful and comforting when the going gets rough.

A 155 How battalion must be able to displace just as rapidly as a light battalion. We frequently displace twice a day. The battalion commander’s main job is position area reconnaissance. In a fast moving situation you must reconnoiter right up behind the infantry — otherwise the position you select will be too far to the rear when you receive the order to displace. Take your BC’s with you when you go forward if it is at all possible. You won’t be able to make a reconnaissance and then send back for the BC’s and make a trip through the area with them. You can’t wait until a displacement is expected and then go forward on reconnaissance. I was caught flat-footed in that respect once and will never let it happen again.

We usually chock our registration by firing one gun from each battery at the base point.

In a rapidly moving situation if you dig your pieces in too thoroughly you won’t be able to make the wide shifts required. My 155 How battalion is firing on a 1600 mil sector right now. Of course the men have slit trenches dug — you never have to urge them in that respect.

Our 155 guns could be a great help to the infantry if they would allow us to fire closer to their front lines, particularly against organized strong points where they are well dug in. Some divisions are better than others in this respect, usually after you have gained their confidence. A few days ago I was forward on reconnaissance and ran across some men of the 82 A/B Division who were hold up by some determined Germans in a thick walled masonry farm house. They had some cannon and some automatic weapons. I hit the base of the house on the first round at 11,500 (a K transfer on a fine map) and as I left I gave them a carton of C rations I had in my C&R. Naturally we are “in” with those people.

In this 155 gun battalion we compute our ranges and deflection from coordinates as the long fan is not accurate.

Although the maps are perfect we don’t use them as a firing chart but read the coordinates of the target and plot them on a grid sheet which we fire from. The errors caused by pasting the maps together and by shrinkage can be eliminated by this procedure. (105 Bn.)

Higher commanders have a tendency to restrict, us too much when they assign us a position area goose-egg. (155G – also 8″ How.) Considerable leeway must be given us. Routes into the position are a major consideration. (Remainder of this paragraph applies only to a 155G battalion.) The trees in these hedgerows give us a very tough minimum range problem. The smallest I have ever had is 10,000 yards. We carry 400 pounds of TNT per battery to blow our way into hedgerows. (Note: Contrary to definition the normal hedgerow is an earthen wall about 3 to 5 feet high and about 3 to 5 feet wide. On each side of the wall a sizable ditch exists from which the earth has been excavated to construct the wall. Dense hedges and tall trees grow out of many of these walls). We frequently had to get help from engineer bulldozers to break through the walls.

I think that we have a tendency to overshoot. We have invariably been able to neutralize single German guns with from four to twelve rounds and yet I have seen division concentrations placed on one machine pistol and also on movement in a hedgerow.

It is dangerous for FO’s to climb trees as our own troops will fire at them. Likewise it is almost suicide to fire a captured machine pistol. All questions are asked later.

You have heard the old story about being two or three deep in each position. It is an absolute necessity. Don’t let your key personnel travel around together. The executive, the S-3 and I always travel separately.

The only difficulties we have had with our 155 guns have been shortage of gas chock pads, scored obturator spindle plugs, and short firing pins which the ordnance lengthened 1/16th of an inch for us. Our camouflage nets are 48×60, and they should be at least 60×60. We fire with the net over the tube and when we are not firing we cover the gun completely and keep the tube horizontal.

Your AA machine gun operators must be thoroughly trained to fire only at planes which are making a specific and personal attack on your position. Frequently the German fighters will fly low at dusk apparently waiting for our troops to disclose a position by their tracers. One of our batteries was strafed and bombed thoroughly by both fighters and bombers. It was the only 155 gun battery ashore and the Germans were apparently aware of its general location because they methodically strafed and bombed all the hedgerows in the immediate vicinity of the battery. Then one of our machine guns opened up disclosing our exact position and the battery took a thorough going over. We were well dug in and fortunately only two men were wounded.

Don’t let your men go off on sniper hunts. There is a tendency for reconnaissance parties to do this.

Each battery in this 155 gun battalion has its own fire direction center which can handle the whole battalion, if necessary. When we displace by battery, I take two batteries and the FDC forward with me and send the executive, to the rear battery where all missions are handled by the battery FDC. The executive then brings the battery forward.

Maintaining your wire is a major problem. Wire personnel are fully aware of their difficulties but there is a general lack of appreciation of their difficulties by other troops. I have seen as many as 25 lines knocked out by a bulldozer carelessly operated. In such cases the linemen who discover the break repair all the lines. I believe that the senior commanders should take positive steps to make all personnel wire conscious. Obviously it is better to lay across country than beside the roads, but due to the nature of this hedgerow terrain and the rapidity of movement it has not been possible to do this.

Our main use of the W130 wire has been to pull booby traps.

The engineers trained us in the use of minesweepers. We sweep the initial route into the position, then sweep the gun locations, and then sweep the entire area. (Comment: There were a few casualties from mines in the VII corps artillery, but in general mine warfare did not develop to the extent expected. The threat of mines was sufficient to require all the necessary precautions and battalions were able to take care of themselves in this respect.)

In my opinion the most surprising tactical feature of the fight has been the manner in which heavy artillery displaces and occupies position during daylight. (Comment: Such displacements ceased after the fall of Cherbourg.)

The observation battalion has registered our 8 inch hows by sound four or five times. I would consider only one of those missions successful.

On a displacement when the entire battalion moves forward together (as was usually the case), you must be certain that your communications are in and that you have registered by a single gun taken forward with the reconnaissance personnel. We always attempt to have the set-up complete so that when the last gun drops its trail we can open fire with the entire battalion. It is pointless for the cannoneers to work like the devil preparing for action and then not be able to fire because the FDC is not ready, poor communication, etc.

When you are being annoyed by single roving guns, you must take them under fire quickly with very accurate data or you will never catch them. I feel that much of our CB fire has been wasted because the gun has displaced to another position by the time our fire arrives.

When we fire concentrations close to our own troops the Germans invariably shell our troops causing them to tell us to cease firing as our rounds are falling short. We found the best solution to this problem was to send an officer to examine the shell craters with the infantry and prove to them that it was a German shell. When once convinced the infantry has confidence in you.

A higher percentage of WP ammunition should be available. Time fire effectively neutralizes the Germans but WP will drive them right out of their fox holes.

It is difficult, if not impossible, to have one infantry unit pass through another and pick up the FO’s and the LNO’s on the way through. New FO’s and LNO’s have to be attached to the unit before it passes through.

The antiaircraft artillery automatic weapon battalion attached to the division has been most cooperative and helpful. Since their batteries are spread out with ours, their battalion headquarters is not too busy and they have provided us with personnel to help with the CP chores such as guards, KP’s, messengers, etc. We have, therefore, been able to augment the wire crews somewhat by the personnel released.

The use of the corps artillery battalion FO’s has been the subject of considerable discussion. When we are moving forward rapidly it is necessary to place the no fire line of the corps artillery pretty well in front of the infantry. As a consequence, the corps FO’s can see no targets to attack. Their presence in the front lines serves no useful purpose and yet they are up front risking their necks. Some corps battalions have ceased sending out FO’s unless there is a high OP available from which they can see in advance of the no fire line. (A rare occurrence in the Cherbourg terrain.) This problem should be well thought out by senior commanders. Some units feel that no corps FO’s are necessary and that the division artillery FO’s can adjust both their own and the corps battalion as dictated by the nature of the target. If this were the case, a no fire line would be unnecessary (except for air observers not intimately familiar with the front line situation).

The green and white bag powder situation necessitates constant shifting of powder between batteries. You have to keep a good NCO in each battery keeping track of the powder situation.

Don’t let your men discard their T/E small arms in favor of a type more to their liking as it complicates the ammunition supply.

A high burst base in the position area is most helpful, it being SOP for our battalion to put one in when the position area survey is put in. Forward OP’s are so poor it is not possible to use a short base up front.

We alternate FO’s about every two days. This hedgerow fighting is quite a strain on them and if you don’t give them a rest they become ineffective. We have found it necessary to use the 284 radio for the FO’s frequently. On occasions he uses a 609 relay to the 284.

Don’t let your staff officers heckle lower units. In most cases when you think things are going wrong investigation will disclose that everything is well in hand and people are going about their business in a normal, effective, Fort Sill manner.

You have to prod your observers to render intelligent reports. We receive frequent reports, more or less rumors on many occasions, and have a tough time tracking down the source. It is very annoying to hear a rumor that some air observer of some unit thought he saw a railway gun and then have to spend a couple of hours trying to track down the source. In the meantime higher commanders start calling you for the dope. Such incidents can upset a smooth running CP quite easily. This is particularly true when vague reports are made concerning enemy armor.

Close Liaison should be maintained between G-3, (for Air), the air support party, and the artillery. Frequently artillery can easily handle a mission for which fighter bombers have been requested. On a big air show you have to work up a counter-flak shoot to support the air.

When a battalion CO of a new unit reports for instructions, take time out to orient him on names of towns and the code names of units entirely now to him. Men you know the situation thoroughly it is easy to forget that he doesn’t and you will find that unless you give him time to digest it, he will take off on his mission in a very confused state of mind.

 

M40 and M43 Gun Motor Carriage

The 155-mm Gun Motor Carriage M40 and 8 in. Howitzer Motor Carriage M43 were self-propelled artillery vehicles based on major components of the medium tank M4A1 with the Continental engine and HVSS suspension. The M40 Gun Motor Carriage was designed to replace the earlier M12 Gun Motor Carriage. Prototypes of the M40 were tested in WWII, but the M40 and M43 were not widely deployed until after WWII.

The following data on the M40 and M43 is taken from Technical Manual TM 9-1747.

155-mm Gun Motor Carriage M40 and 8 in. Howitzer Motor Carriage M43

DESCRIPTION:

a. The 155-mm gun motor carriage M40 and the 8-inch howitzer motor carriage M43 are identical, the model designation depending entirely upon the weapon mounted in the vehicle. When designated as gun motor carriage M40, the vehicle carries the 155-mm gun, M1 or M1A1. When designated as gun motor carriage M43, the 8-inch howitzer, M1 or M2, is used. The weapons are mounted in the rear compartment and point forward when in traveling position.

M43 Howitzer Motor Carriage

Figure 1. 8-inch howitzer motor carriage M43, three-quarter rear view.

b. This carriage is improved version of the 155-mm gun motor carriage M12, based on major components of the medium tank M4A1. The motor carriage is of the armored, full-track laying type having horizontal volute spring suspension. The hull is divided into three compartments. The drivers’ compartment is at the front, the engine compartment in the middle, and the fighting compartment at the rear. Universal-type ammunition racks for the 155-mm gun or 8-inch howitzer ammunition are installed in each vehicle. Seats are provided for a crew of eight men.

M40 Gun Motor Carriage

Figure 2. 155-mm gun motor carriage M40, three-quarter left rear firing position.

c. The M40 or M43 vehicle is powered by a 485-horsepower, 9-cylinder, radial gasoline engine, Ordnance Model No. R974-C4 (Continental) mounted in the center of the vehicle.

d. The vehicles are equipped with radio for intervehicle, and telephone for intravehicle communication.

M43 Gun Motor Carriage

Figure 3. 8-inch howitzer motor carriage M43, three-quarter left front traveling position.

e. The hull is constructed of armor plate and is divided into the fighting compartment at the rear, engine compartment in the center, and the driver’s compartment at the front. The compartments a separated by bulkheads. With the exception of several removable sections, the sided, roof and floor are welded together to form a single box-like unit. The removable sections are provided to permit access to the interior of the hull for inspection, machinery replacement and personnel. The removable parts of the hull are: spade assembly which hold the carriage against the kickback when the gun is fired; tailgate and loading ramp assembly; spotlight; drivers’ seats; oil cooler shutter assemblies; cupola hatch assemblies; spade winch and cable; exhaust and tail pipes; shell racks; and towing hooks and pintle assemblies.

155-mm Gun Motor Carriage M40

Figure 4. 155-mm gun motor carriage M40, three-quarter right front view.

f. The vehicle is propelled forward and backward by two individually driven tracks. The drive sprockets at the front end of the vehicle pull the tracks from the rear and lay them down in front of the advancing road wheels. The track and suspension system consists of the tracks, which the vehicle travels on; the suspension and road wheels, which carry the load of the vehicle and travel on the tracks; the track rear idler, which is the turning point for the track and is the adjustment point for taking up slack in the track; and the support rollers, which support the upper half of the track.

DATA (M40 and M43):

GENERAL
     Purpose         Gun carriage
     Type Full-track laying
     Crew 8 men
     Fighting weight:
          M40 83,000 lb.
          M43 83,000 lb.
     Length:
          M40 357 in.
          M43 289 in.
     Width, over-all 124 in.
     Height, overall 129 3/4 in.
     Ground clearance 19 1/4 in.
ENGINE
     Manufacturer Continental
     Model R975–C4
     Type Single-row, static-radial, air-cooled
SUSPENSION
     Type Horizontal volute
     Track shoe width 18 3/4 in.
     Track pitch 6 in.
     Ground contact area of both tracks 7,544 sq. in.
     Number of blacks per track 87
     Weight of track 4,042 lb.
     Ground pressure (psi) 10.2
POWER TRAIN (1-PIECE DIFFERENTIAL)
     Manufacturer Iowa Transmission

 

Trajectory and Its Elements

Definition of elements of trajectory from FM 4-10: Coast Artillery Gunnery, War Department Field Manual, May 1944.

Elements of Trajectory

Elements of Trajectory

6. GENERAL. The trajectory is the path of the projectile from the muzzle of the gun to the first point of impact. The phrase, elements of the trajectory, is applied to the various features of the trajectory. (See figure.) The elements most frequently referred to are defined in the following paragraphs.

7. INTRINSIC ELEMENTS.

a. Trajectory. The curve described by the center of gravity of the projectile in flight.

b. Ascending branch. That portion of the trajectory described by the projectile while rising.

c. Descending branch. That portion of the trajectory described by the projectile while falling.

d. Origin. The center of the muzzle of the piece at the instant of departure.

e. Summit. The highest point on the trajectory.

f. Level point. The point on the descending branch of the trajectory at the same altitude as the origin.

g. Base of the trajectory. The straight line between the origin and the level point.

h. Maximum ordinate. Difference in altitude between the origin and the summit.

8. INITIAL ELEMENTS.

a. Line of elevation. The prolongation of the axis of the bore when the piece is set.

b. Line of departure. The prolongation of the axis of the bore as the projectile leaves the muzzle of the gun. It is tangent to the trajectory at its origin.

c. Line of site. The straight line between the origin of the trajectory and the target.

d. Plane of fire. The vertical plane containing the line of elevation.

e. Plane of departure. The vertical plane containing the line of departure.

f. Angle of elevation or elevation. The angle between the line of site and the line of elevation.

g. Angle of departure. The angle between the line of site and the line of departure.

h. Angle of site (ε). The angle between the line of site and the base of the trajectory.

i. Quadrant angle of elevation (φ) or quadrant elevation. The angle between the horizontal and the line of elevation.

j. Quadrant angle of departure (φ’). The angle between the horizontal and the line of departure.

k. Lateral jump. The horizontal angle between the plane of fire and the plane of departure.

l. Vertical jump. The difference between the angle of elevation and the angle of departure. It is positive if the angle of departure is greater than the angle of elevation.

9. TERMINAL ELEMENTS.

a. Point of impact. The point where the projectile first strikes an object.

b. Line of fall. The line tangent to the trajectory at the level point.

c. Angle of fall (ω). The angle between the line of fall and the base of the trajectory.

10. OTHER ELEMENTS.

a. Muzzle velocity (MV or V). Muzzle velocity or initial velocity is the velocity with which the projectile is assumed to leave the muzzle of the gun. It is the velocity of the projectile, measured at a distance from the muzzle, corrected for the theoretical loss in velocity during the travel from the origin of the trajectory to the point of measurement, considering that during that travel the projectile has been acted upon only by air resistance and gravity.

b. Remaining velocity. The remaining velocity at any point of the trajectory is the actual velocity
at that point.

c. Terminal velocity (Vω). The remaining velocity at the level point.

d. Time of flight (t). The elapsed time from the instant the projectile leaves the muzzle to the instant of impact or to the instant of burst.

e. Range. The horizontal distance between two points, such as from the gun or directing point
of a battery to the target.

f. Drift. The divergence of a projectile, due to its rotation and the resistance of air, from the
plane of departure. It is usually expressed in angular units.


 

Grille Self-Propelled Artillery

The Grille (“Cricket”) was a German self-propelled, heavy artillery vehicle armed with the 15 cm sIG 33 infantry gun in a fixed superstructure. The official German designation was 15 cm schweres Infanteriegeschütz 33 (Sf) auf Panzerkampfwagen 38(t) (Sd.Kfz. 138/1).

Grille Self-Propelled Heavy Artillery WW2

A Grille nicknamed "Fire Devil" in a firing position in Italy. The crew has chosen a position next to a haystack and heavily camouflaged the vehicle with foliage. (Bundesarchiv Bild 101I-716-0010-26, Dreyer, CC-BY-SA-3.0-de)

Grille 150-mm Self-Propelled Gun WW2

Another view of Grille "Fire Devil" in camouflaged firing position. (Bundesarchiv Bild 101I-716-0010-27, Dreyer, CC-BY-SA-3.0-de)

Grille SP Gun Artillery 150-mm Italian Front

Camouflaged Grille advances along a dusty road on the Italian Front. Note the large quantity of supplies carried on the rear. (Bundesarchiv Bild 101I-479-2194-28, Brünning, CC-BY-SA-3.0-de)


 

Japanese 150 mm Gun Type 89

U.S. military intelligence report on the Japanese 150mm Type 89 (1929) Gun from Japanese Artillery Weapons, CINCPAC-CINCPOA, Bulletin 152-45, July 1945.

150 MM GUN TYPE 89 (1929)

The Japanese Type 89, 15 cm gun is comparable to the old U.S. M1918 in many respects, but it has a shorter range and is less efficient than similar caliber guns of other nations. Types 45 and 90, 15 cm guns have also been reported.

WW2 Japanese 150 mm Gun Type 89

The Type 89 has a variable hydro-pneumatic recoil system and an interrupted thread breech block; the latter has a mushroom head and stepped-up buttress type screws. Two carriages have been recovered. The only apparent difference is in the two equilibrators. One has spring type and the other hydrospring type. The trail is the split box type with detachable trail spades. The traversing handwheel and scale are located on the left side of the carriage; the scale is graduated up to 350 mils in ten mil increments. The elevation scale, range drum, and sight are on the right side of the carriage; the range scale is graduated up to 42 degrees.

An 8 ton prime mover is used to tow the piece. For traveling, the gun is broken down in two loads, tube and carriage.

Characteristics

Caliber        149.1 mm (5.87 in.)
Weight (firing position) 22,830 lbs.
Length (firing position) 26 ft. 4 in.
Length of bore 18 ft. 10 in.
Muzzle velocity 2,870 ft/sec.
Maximum range 21,800 yds.
Elevation 42 degrees
Depression 5 degrees
Traverse 350 mils R & L
Rate of fire 2 rds/min.
Ammunition HE, APHE, Long pointed HE, Shrap., Illumi.