Technical Manual, War Department, June 29, 1943

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CHAPTER 2

GERMAN 88-MM ANTIAIRCRAFT GUN AND MOUNT

Section IV

OPERATION

Paragraph To place the weapon in firing position ...................................................... 21 To traverse ............................................................................................. 22 To elevate ............................................................................................. 23 To operate the breech mechanism .......................................................... 24 Points to be observed before firing ........................................................ 25 Points to be observed during firing ......................................................... 26 To load .................................................................................................... 27 To fire ...................................................................................................... 28 To recock ............................................................................................... 29 To unload ............................................................................................... 30 To place the weapon in traveling position ................................................. 31

21. TO PLACE THE WEAPON IN FIRING POSITION.

a. The piece may be fired from the wheels but must be emplaced for high angle fire. To fire from the wheels:

(1) Unlimber the prime mover from the drawbar.

(2) Set the hand brakes on the rear bogie.

(3) Engage the elevating gear clutch by pulling the clutch lever to its downward position (fig. 37).

Figure 37 — Engaging Elevation Gear Clutch

(4) Release the muzzle rest (fig. 38) by:

(a) Unscrewing the muzzle rest lock so that the chain may be swung over the barrel.

(b) Elevating the gun slightly so that the muzzle rest may be pushed forward and down onto the bottom carriage.

Figure 38 — Releasing Muzzle Rest

(5) Level the top carriage by cross-leveling handwheels, using the level indicator for reference (fig. 39).

Figure 39 — Leveling Top Carriage

(6) Unfold the rammer guard (fig. 40) to the operating position (fig. 41).

Figure 40 — Unfolding Rammer Guard

(7) Cock the rammer assembly by rotating the rammer crank handle in a counterclockwise direction (fig. 41).

Figure 41 — Cocking Automatic Rammer

b. To Emplace the Mount.

(1) Unlimber the prime mover from the drawbar.

NOTE: The operation of disconnecting both bogies is identical.

(2) Operate the winch until the chain takes all the weight from the locking jaws (fig. 42).

Figure 42 — Unlocking Front Bogie from Bottom Carriage

(3) While one man steadies the winch, disengage one locking jaw at a time by raising handle (figs. 42 and 43). Repeat for the other locking jaw on the bogie.

Figure 43 — Rear Bogie Locking Jaws

(4) Simultaneously with the above, lower the side outriggers by performing the following steps. NOTE: The instruction plate (fig. 44) on the left outrigger reads "VOR AUSLOSEN DER STUTZEN SEITENHOLM DURCH 2 MANN FESTHALTEN," which translated means, "Before releasing the side outrigger supports, steady (the outriggers) by 2 men."

(a) Releasing the locking bar plunger (fig. 44).

(b) Removing the safety chains (fig. 44).

(c) Swinging the outriggers down.

(d) Locking the outriggers in place by rotating the locking pins (fig. 45).

Figure 44 — Releasing Locking Bar Plunger and Removing Safety Chain

Figure 45 — Locking Outriggers in Place

(5) When the mount is completely lowered, unhook the bogie chains (fig. 46).

Figure 46 — Mount Lowered to Ground

(6) Disengage the hooks securing the bogies to the mount (figs. 47 and 48). NOTE: Unhook the front bogie first.

Figure 47 — Front Bogie Hook Disengaged

Figure 48 — Rear Bogie Hooks Engaged

(7) Remove the bogies, connect them together with the transporter bar, and wheel them away as a complete trailer unit.

(8) Engage the elevating gear clutch by pulling the clutch lever to its downward position (fig. 37).

(9) Release the muzzle rest (fig. 38) by:

(a) Unscrewing the muzzle rest lock so that the chain may be swung over the barrel.

(b) Elevating the gun slightly so that the muzzle rest may be pushed forward and down onto the bottom carriage.

(10) Support the bottom carriage and side outriggers with the leveling jacks (fig. 49).

Figure 49 — Supporting Mount and Outriggers on Leveling Jacks

(11) Secure the mount in position by driving the stakes through the bottom carriage and outriggers as shown in figure 50.

Figure 50 — Staking Mount and Outriggers

(12) Level the top carriage by the cross-leveling handwheels, using the level indicator for reference (fig. 39).

(13) Unfold the rammer guard (fig. 40) to the operating position (fig. 41).

(14) Cock the rammer assembly by rotating the rammer crank handle in a counterclockwise direction (fig. 41).

22. TO TRAVERSE.

a. The traversing handwheel is located on the right side of the carriage (fig. 10). Rotate the handwheel clockwise for right traverse and counterclockwise for left traverse, either in high or low speed.

(1) TO TRAVERSE IN LOW SPEED. Trip the gear selector lever (fig. 31) toward the mount so that the lever will engage one of the four notches on the inner collar on the traversing handwheel shaft.

(2) TO TRAVERSE IN HIGH SPEED. Trip the gear selector lever away from the mount so that the lever will engage one of the four notches on the outer collar on the traversing handwheel shaft.

23. TO ELEVATE.

a. The elevating handwheel is located on the right side of the carriage (fig. 10). Rotate the handwheel clockwise for elevation and counterclockwise for depression, either in high or low speed.

(1) TO ELEVATE IN HIGH SPEED. Trip the gear selector lever away from the mount so that the lever will engage one of the four notches on the outer collar on the elevating handwheel shaft.

(2) TO ELEVATE IN LOW SPEED. Trip the gear selector lever toward the mount so that the lever will engage one of the four notches on the inner collar on the elevating handwheel shaft.

24. TO OPERATE THE BREECH MECHANISM.

a. To Open.

(1) Normally, in action, the breech is opened, percussion mechanism cocked, and cartridge case extracted during counterrecoil of the gun.

(2) To open the breech manually before inserting the initial round of ammunition, grasp the breech actuating lever and squeeze the trigger to release the retaining catch (fig. 51). Rotate the breech actuating lever clockwise as far as it will go.

Figure 51 — Firing the Gun Manually

(3) Opening the breech manually may be performed either during the engaged or disengaged position of the "SEMIAUTOMATIC-HAND" ("SEMIAUTOMATIK-HAND") catch. With the catch engaged, a strong pull to rotate the breech actuating lever is necessary. To engage the catch, pull down on the catch plunger and raise the catch in front to engage the breech actuating mechanism (fig. 51). The catch is disengaged when it is pressed down in front (fig. 52).

Figure 52 — Disengaging "SEMIAUTOMATIC-HAND" Catch

b. To Close.

(1) Normally, in action, the breech is closed by the cartridge base tripping the extractors, thereby releasing the breechblock, which closes due to the force of the spring in the breech actuating mechanism.

(2) After the firing period, it is necessary to close the breech. This is accomplished by rotating the extractor actuating lever in a clockwise direction (fig. 51) or operating the loading tray interlock without a round in the tray.

25. POINTS TO BE OBSERVED BEFORE FIRING.

a. Lubrication. All points should be thoroughly lubricated as prescribed (par. 33). The recoil, recuperator, and rammer cylinders should be filled to proper oil levels (pars. 37, 38, and 39). The recuperator and rammer cylinders should be charged to proper gas pressure (pars. 37 and 39).

26. POINTS TO BE OBSERVED DURING FIRING.

a. If the gun fails to fire, the following safety precautions must be observed:

(1) Stand clear of the path of recoil.

(2) Keep the gun at firing elevation. Do not depress the piece.

(3) Keep the gun directed in traverse either on the target or on a safe place in the field of fire.

(4) The breech will not be opened until at least 10 minutes after the last unsuccessful attempt to fire the piece.

27. TO LOAD.

a. Place the shell on the loading tray and swing the tray in line with the axis of the bore of the gun. At this point the loading tray interlock is released and the expanding gas forces the rammer cylinder back along the piston; thus the rammer arm is rapidly withdrawn, seating the round (fig. 53). Swing the empty loading tray back to its original outboard or loading position.

b. When firing at angles above 45 degrees, set the buffer valve to "QUICK" ("SCHNELL") (fig. 35) by turning the valve clockwise. At angles below 45 degrees, the valve is set to "NORMAL" ("NORMAL") by rotating the valve counterclockwise.

28. TO FIRE.

a. With the loading tray interlock set at "AUTOMATIC" ("AUTOMATIK") (fig. 53), the gun will fire as soon as the loading tray clears the path of recoil and is returned by hand to its outboard or firing position.

Figure 53 — Shell Partially Rammed

b. With the loading tray interlock set at "HAND" ("HAND"), the gun must be fired by performing either one of the following steps:

(1) Raising the firing lever on the left side of the cradle (fig. 53).

(2) Pulling the auxiliary trigger on the right side of the cradle (fig. 51).

29. TO RECOCK.

a. In case of a misfire, it will be necessary to recock the percussion mechanism by rotating the cocking lever in a counterclockwise direction as far as the word "WEIDERSPANNEN," which means "RECOCK." Then return the cocking lever to its original position at "FIRE" ("FEUER") (fig. 51). Fire the gun as described in paragraph 28 again; and if the gun again misfires, wait 10 minutes and then unload as described in paragraph 30.

30. TO UNLOAD.

a. Open the breech. If the extractor does not eject the shell, grasp the shoulder on the cartridge base and withdraw it from the breech recess. Then reload the gun.

31. TO PLACE THE WEAPON IN TRAVELING POSITION.

a. To place the weapon in traveling position after having been fired from the wheels:

(1) Release the pressure on the rammer by operating the loading tray interlock without a round in the tray. The rammer guard may now be folded back.

(2) Swing the muzzle rest up to vertical position and secure the gun to it.

(3) Disengage the elevating gear clutch.

(4) Release the hand brakes.

(5) Connect the prime mover to the drawbar.

b. To place the weapon in traveling position after having been fired from emplacement:

(1) Release the pressure on the rammer by operating the loading tray interlock without a round in the tray. The rammer guard may now be folded back.

(2) Withdraw the stakes and secure them in their places on the outriggers.

(3) Swing the muzzle rest up to vertical position and secure the gun to it.

(4) Disengage the elevating gear clutch.

(5) Remove the transporter bar from between the bogies.

(6) Secure the bogies to the mount by engaging the hooks provided for the purpose.

(7) Connect the bogie chains to the bottom carriage.

(8) Place the side outriggers in traveling position by:

(a) Unlocking the outriggers by rotating the locking pins.

(b) Swinging the outriggers up against the mount.

(c) Engaging the locking bar plungers.

(d) Securing the safety chains.

(9) Operate the winch to raise the bottom carriage high enough to engage the locking jaws.

(10) Lower the bottom carriage until its weight settles in the locking jaws.

NOTE: Use steps (9) and (10) with the front bogie first.

(11) Connect the prime mover to the drawbar.