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Replacing M4 Tank Final-Drive Assemblies

Instructions for replacing the final-drive assembly on the M4 Sherman tank, from Army Motors, Vol. 6, No. 2, Maintenance Division, Office, Chief of Ordnance, May 1945.

Replacing M4 Tank Final-Drive Assemblies

Time was when M4 medium tanks with damaged power trains had to run home to mother for mending–like little apple-filchers with buckshot in their final drive assemblies. Now, when your M4-series job (or related gun or howitzer motor carriage) has something more like dribble where the drive should be, you don’t have to pack it off to some 4th-echelon tank hospital for a slow cure. Instead, you can put in a whole new controlled differential and transmission final-drive assembly right there in the field, according to TB ORD 275.

Four of these assemblies, complete with everything but whistles, have at last been made authorized items of issue for lower echelon installation. They are:

—  1-piece differential housing, single-anchor-brake type, Ord. Part No. A5700061, Official Stock No. G104-5700061.

—  1-piece differential housing, double-anchor-brake type, Ord. Part No. A5700062, Official Stock No. G104-5700062 (Fig. 1).

—  3-piece differential housing, single-anchor-brake type, Ord. Part A5700060, Official Stock No. G104-5700060 (Fig. 2).

—  3-piece differential housing, double-anchor-brake type, Ord. Part No. A57000196, Official Stock No. G104-57000196.

They’ll be assembled at your favorite base shop or Ordnance supply depot from parts and housings already in stock or made available through cannibalization. No important difference between any of them, and they’re all yours for the asking.

Final Drive Assembly

All you have to do is install ’em and send back the has-beens. But remember that the whole system will break down if you don’t send back complete assemblies. Only the final-reduction sub-assemblies (A294625) should be removed from a damaged unit before its sent to the rear for reconditioning.

Continue reading Replacing M4 Tank Final-Drive Assemblies

M26 Armored Tractor

Diagrams of the M26 armored tractor from TM 9-767: 40-Ton Tank Transporter Truck-Trailer M25, War Department Technical Manual, U.S. War Department, February 1944. The M25 Tank Transporter, nicknamed the “Dragon Wagon,” was a heavy tank transporter and tank recovery vehicle used in World War II. The M25 was composed of the M26 6×6 armored tractor and M15 40-ton trailer.

m26-tractor-truck-dragon-wagon-front-view

m26-tractor-truck-dragon-wagon-rear-view

 

P-47 Pilot Equipment

Typical U.S. pilot’s personal equipment from Pilot Training Manual for the Thunderbolt P-47N, Headquarters, AAF Manual 51-127-4, Army Air Forces, Washington, D.C., September 1945.

Personal Equipment

On all flights, wear:
1. Helmet
2. Goggles
3. Gloves
4. Life vest
5. Parachute
6. Oxygen mask
7. First aid and emergency kit
8. One-man life raft (when flying over water)
9. Knife

The mask is worn on all flights to accustom you to it and to protect your face in case of fire. You wear gloves as a fire protection and to prevent skinned knuckles, which are inevitable without gloves. Use your goggles when needed. Do not wear commercial polaroid glasses. Use only government issue. The knife is carried to puncture your dinghy should it accidentally be inflated. It must be worn where it can be reached easily, preferably on the calf of your leg.

p47-pilot-personal-equipment

 

M39 .50 Cal. Pedestal Mount

Illustration of the M39 pedestal mount for the .50 caliber machine gun. (Source: TM 9-230: Machine Gun Mounts for Boats, War Department Technical Manual, October 1943.)

Figure 1—Cal. .50, Machine Gun, Pedestal Mount M39, with Aircraft Machine Gun

Figure 1—Cal. .50, Machine Gun, Pedestal Mount M39, with Aircraft Machine Gun

 

Cause and Effect

A cartoon shows the results of trying to circumvent the censor: from “Don’t Shoot the Censor,” Bureau of Naval Personnel Information Bulletin, February 1944.

Cause and Effect

CAUSE AND EFFECT: Sailor drops letter into local mail-box (A) in foreign port. Letter slides down tube into room (B) and is thoroughly read by Nazi agent, who then slips it through slot into trouble-distilling apparatus (C). Burning letter boils witch’s brew (D), causing thermometer (E) to rise rapidly. Janitor (F) starts down basement stairs to fix furmace, stepping on teeter-totter (G) and catapulting projectile into loading chute (H) of gun (I), which is swung into position by secret range finder (J). Gun is fired and eliminates letter writer (K). Next of kin will now hear about him after all.

 

M15 40-ton Trailer

Illustrations of the M15 40-ton trailer from TM 9-767: 40-Ton Tank Transporter Truck-Trailer M25, War Department Technical Manual, U.S. War Department, February 1944. The M25 Tank Transporter, nicknamed the “Dragon Wagon,” was a heavy tank transporter and tank recovery vehicle used in World War II that was based on the M26 6×6 armored tractor and the M15 40-ton trailer.

m15-trailer-front-view-dragon-wagon

m15-trailer-rear-view-dragon-wagon

 

Head Control for Hull Machine Gun

Unique head control for the hull machine gun in the Panzer III. (Source: Preliminary Report No. 5, Pz Kw III, School of Tank Technology, September 1942.)

 

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.

 

January Figure Releases from Alpine Miniatures

Alpine Waffen SS Figures January 2013

New January 2013 figure releases from Alpine Miniatures:

• 35151: 1/35 WSS Grenadier
Sculpted by Taesung Harmms / Boxart Painted by Man-Jin Kim
• 35152: 1/35 WSS Grenadier NCO
Sculpted by Taesung Harmms / Boxart Painted by Man-Jin Kim
• 35153: 1/35 WSS Grenadier Set (2 Figures)
Sculpture by Taesung Harmms / Boxart by Man-Jin Kim

 

Two Traffic Pattern Rules

Flying Airport Traffic Pattern

There are two general roles to follow in every case, regardless of the traffic pattern. Never forgot them:

1. Keep the pattern in close enough to the field and at sufficient altitude so you can bring your airplane in safely even with the power off, if necessary.

2. In preparing to peel off, don’t come barreling in at excessive speed. The greater the speed, the longer it takes you to slow down. After you are cleared for peeloff by the tower, slow down to 200-225 IAS before actually peeling off.

Source: Pilot Training Manual for the P-51 Mustang, AAF Manual 51-127-5, Headquarters Army Air Forces, Washington, D.C., August 1945.