B-26 Marauder weapons thread

[Greg Boeser]

Like the North American B-25 Mitchell, the Martin B-26 Marauder also experienced a series of weapons upgrades and modifications during its development and production. The early production B-26 "straight" saw much development and even more field improvisation. The original specification called for four .30 caliber machine guns one each in nose, tail, ventral and dorsal positions, each with 600 rounds. However, defensive requirements were increased when the Army demanded that the dorsal position be upgraded to a fully powered turret mounting twin .50 caliber machine guns, with 400 rpg. Martin responded with the Martin 250 CE deck turret.

In addition, the .30 caliber gun in the tail position was upgraded to a .50 caliber weapon.

I like this picture because it refutes the common myth that the 22nd Bomb Group removed the rear canopy as a field modification. As this photo shows, the rear canopy was a two piece fairing that separated and slid down the sides of the tail cone to permit the use of the rear gun. In the closed position the gun barrel protruded from a hole between the two halves.

More to follow...

 

[Greg Boeser]

Stock B-26 with no guns fitted, 1941. This is a straight B-26. The B-26A was virtually identical, but the US insignia was smaller and placed behind the waist window. The Pilots Operating Instructions for the straight B-26 and the B-26A lists the armament as one .30 caliber MG in the nose, with 600 rounds, one ventral .30 caliber MG with 600 rounds, two .50 caliber MGs in dorsal turret with 200 rpg, and 200 rpg overload, one .50 caliber MG in tail with 200 rounds. The forward bomb bay would hold 20 x 100 lb. GP bombs, 8 x 300 lb. GP bombs, 6 x 500 lb. GP bombs, 4 x 1000 lb. GP bombs, or 2 x 2000 lb. GP bombs or 2 x 1600 lb. AP bombs. The rear bay could hold 10 x 100 lb. GP bombs, 6 x 300 lb. GP bombs, or 2 x 500 lb. GP bombs. In the straight B-26, a single steel, jettisonable, auxiliary fuel tank of 250 US gallons could be mounted in the left hand side of the bay in place of bombs.The A model was plumbed to accept an additional 250 US gallon tank in the right hand side of the forward bomb bay. Late in 1941, a conversion kit was produced to permit slinging a Mk 13 torpedo beneath the fuselage, attached to the keel of the fuselage between the forward bomb bay doors. This would be a standard feature on future models.
Although the manuals for the B-26, B-26A and B-26B make no mention of waist guns, modifications were made to mount .30 caliber waist guns on these aircraft by welding a socket to the lower lip of the waist windows. These provided some defensive coverage of the lower rear sides of the aircraft where the top turret couldn't depress.

Inside of waist position of Fantasy of Flight B-26 #40-1464. Note sockets for waist guns at side windows, and ventral gun in front of camera hatch. Ammo storage racks above and to rear of windows.

 

[tomo pauk]

Thank, you, Greg. Will be looking forward to see more, especially about less known/used things that go boom

 

[Capt. Vick]

Wow! Three guns in that one little area. Talk about a porcupine!

 

[Greg Boeser]

In 1941-42, Marauders typically carried a crew of seven. Pilot, co-pilot, bombardier (in nose), navigator (behind pilots), engineer (who manned the tail gun), air gunner (in turret), and radioman (who manned the waist/ventral guns).

 

[MIflyer]

Interesting thing is that the B-26's used in Europe had packet guns fitted, two on each side of the lower nose. But it seems unlikely that they used them very much. Strafing seems to have been done only very rarely. They did medium bombing from medium altitudes almost exclusively.

I have read only two accounts of B-26's using those packet guns. A B-26 pilot said he was in formation one day when a BF-109 made a pass at them. I guess he could not stand it, dove out of formation, got on the 109's tail and blew him out of the air. He pulled back up into the formation and was told over the radio, "Good shooting!"

The other account was described in the book "Flying the B-26 Over Europe" written by a navigator. On one mission and one mission only they were told to drop their bombs and then go down to strafe. The bombadier was estatic at the news; he was finally going to get to use that .50 cal sticking out of the nose! Whoopeee! After they dropped the bombs on that mission the bombadier detached the Norden bombsight, turned around and handed it to the navigator, grabbed that .50 cal and had a ball, finally getting to shoot that big machine gun.

By the way, the navigator had a position just behind the pilots but after takeoff he had the co-pilot push his own seat back so he could descend into the nose, where he spent the rest of the mission arguing with the bombadier (also a trained navigator) about where they really were. There were no seats provided for either of them in the nose.

 

[Greg Boeser]

The first 201 B-26s were to be allocated to the 22nd BG, 38th BG and 42nd BG, plus one additional recon squadron.
Each bomb group comprised 3 bombardment squadrons of 13 aircraft, a headquarters flight of 5 aircraft and an attached recon squadron of 13 aircraft. By Pearl Harbor, due to production delays and modifications, only the 22nd BG was fully equipped, while the 38th and 42nd were just beginning to receive theirs. The 22nd and 42nd were immediately ordered to the West Coast for patrol duties, while the 38th went to the East Coast. Not long after, the 77th Bomb Squadron was detached from the 42nd and transferred to Alaska to augment the 28th Composite group.

Not all of them made it. Five out of thirteen crashing enroute.

Soon more Marauders were transferred north, so that by June 1 the 77th had 17 B-26s on strength and the 73rd Bomb Squadron was re-equipped with 17 Marauders as well. These aircraft as well as many crews were stripped from the 42nd BG, which began to re-equip with B-25s and would finally deploy to the Pacific in early 1943. The Alaska based Marauders trained in torpedo attack and low level bombing, a necessity in the Aleutians, where fog and low ceilings were the norm.

 

[varsity07840]

Like the North American B-25 Mitchell, the Martin B-26 Marauder also experienced a series of weapons upgrades and modifications during its development and production. The early production B-26 "straight" saw much development and even more field improvisation. The original specification called for four .30 caliber machine guns one each in nose, tail, ventral and dorsal positions, each with 600 rounds. However, defensive requirements were increased when the Army demanded that the dorsal position be upgraded to a fully powered turret mounting twin .50 caliber machine guns, with 400 rpg. Martin responded with the Martin 250 CE deck turret.View attachment 352378
In addition, the .30 caliber gun in the tail position was upgraded to a .50 caliber weapon.
View attachment 352379
I like this picture because it refutes the common myth that the 22nd Bomb Group removed the rear canopy as a field modification. As this photo shows, the rear canopy was a two piece fairing that separated and slid down the sides of the tail cone to permit the use of the rear gun. In the closed position the gun barrel protruded from a hole between the two halves.

More to follow...

That doesn't prove that the 22nd didn't remove them. They did several other armament mods. Added nose gun sockets
and .50 cal. waist guns.

 

[varsity07840]

Wow! Three guys in that one little area. Talk about a porcupine!

One guy handled all three guns.

 

[Greg Boeser]

Here's a diagram of the layout of defensive guns on an early Marauder. Note that the tail gun is depicted mounted on a tripod. Not a ball mount as in the nose.

 

[Greg Boeser]

The 22nd BG Began deploying overseas in February 1942. The aircraft were disassembled and shipped to Hawaii, where they were reassembled and flown by island hopping to Australia. By early April enough had arrived in Australia for combat operations to begin. The first mission was flown when on 5 April, 1942, nine B-26s staged from Townsville up to Port Moresby, and after overnighting launched the first attack by US medium bombers against the Japanese bastion at Rabaul. Over the next two months 16 missions would be launched against Rabaul. Other missions were launched against Japanese positions on the north coast of New Guinea. These bases were defended by the crack Japanese Tainan Kokutai, which operated Zeroes and A5Ms. The A5Ms proved unable to catch the Marauders, but the Zeroes could, just barely. The speed of the Marauder and its heavy armament compared to the obsolete aircraft the Tainan had faced in the Philippines and Dutch Indies was quite a surprise. The Japanese found that a tail chase was a bad option against even a small formation of Marauders. On the other hand the small capacity ammo boxes provided for the Marauder's rear gun were soon recognized as inadequate. Crews scrounged larger ammo boxes from wrecked B-17s. Also the .30 caliber guns at the waist and ventral positions were also found to be unsatisfactory. Due to the low position of the waist window, gunners could only fire down without lying on their bellies, and visibility was poor. The ventral gun was also rarely needed as an approach from low rear was nearly impossible for an attacker. This coupled with the standard tactic of diving toward sea level to egress a target meant that the gun could be deleted, increasing freedom of movement for the gunner. Sgt. Pat Norton of the 19th BS, 22nd BG is generally recognized as the brainchild for the 22nd BG's adaptation of the waist position to increase visibility and mount .50 caliber guns in the waist windows.

Enlarged waist window, with scanning windows above.

This modification would be applied to virtually all 22nd BG aircraft during the second half of 1942.
Stateside B-26Bs began receiving similar modifications following a USAAF directive issued in July.
.50 caliber waist guns became factory standard for the final 141 aircraft of the B-26B-4 production run

 

[Greg Boeser]

While the 22nd was tangling with the Japanese in the Southwest Pacific, and the 28th Composite were freezing their butts off in Alaska, two more squadrons of B-26s were committed to the fray. The 69th and 70th Bomb Squadrons of the 38th BG were hastily testing and re-equipping with the first B-26Bs off the production lines in May 1942. The major change on the early B-26B was a redesigned tail section that incorporated a fully enclosed and armored tail gunner position with a pair of .50 caliber MGs. Standard ammo load was 1000-1500 rpg. After the single .50 with 30 rd ammo boxes of the earlier models, this was serious overkill.

Internally, provisions were made for two additional auxiliary fuel tanks of 250 US gallons each in the rear bomb bay.
Both squadrons then flew their planes from California to Hawaii, a distance of some 2250 miles. The first planes of the 69th arrived in time to take part in the defense of Midway, two aircraft joining with a pair of B-26s of the 408th BS for the first ever torpedo attack by Marauders. Afterwards, CPT Collins of the 69th wrote a memorandum highlighting the deficiencies of the armament of the B-26B.
He recommended upgrading the waist and nose guns to .50 caliber, and the addition of four .50 caliber MGs in the wings. He also found the tail gun ammo to be excessive. Shortly thereafter, the 69th was deployed to New Caledonia and the 70th moved to Fiji.
In New Caledonia, CPT Collins and the armament officer went to work modifying the noses of all their B-26s with fixed .50s and a large mantlet a mounting flexible .50.

69th BS shortly after arrival in New Caledonia on alert

69th BS B-26B after modification

 

[Old Wizard]

 

[MiTasol]

The first 201 B-26s were to be allocated to the 22nd BG, 38th BG and 42nd BG, plus one additional recon squadron.
Not all of them made it. Five out of thirteen crashing enroute.
View attachment 352754

This aircraft was one of three that crashed in a valley near the Smith River airport when the airport was in white-out conditions.
The other two landed gear up and suffered less damage though one broke its back.
On one the landing was so smooth that not even the bomb bay window was broken
All three were recovered in 1971 by a team from Yesterdays Air Force led by Al Reddick and shipped from Fort Nelson BC to Chino CA.
Other members of the team were Jim Maloney, Steve Hinton, the Mozalla brothers, Monty Armstrong and two others whose names I cannot remember.
The remains were built into two aircraft at Chino with the nose from the broken backed machine used on this aircraft.

 

[MiTasol]

The same aircraft in 1972, at Chino, after nose change.
There was a lot of ballast in the nose to keep the nosewheel on the ground

 

[Greg Boeser]

Yes. The finished product is now at Kermit Weeks Fantasy of Flight Museum in Florida.

https://www.fantasyofflight.com

 

[MiTasol]

Yes. The finished product is now at Kermit Weeks Fantasy of Flight Museum in Florida.

https://www.fantasyofflight.com

Thanks Greg

Great news

I will check it out
Mi

 

[Greg Boeser]

The most common field modification applied to the nose armament of Pacific based B-26s was the addition of additional sockets for .30 caliber machine guns in the sides of the Plexiglas nose cone. This was nearly universal in the 22nd BG and the 70th Bomb Squadron.

Many had the flexible centerline .30 caliber machine gun upgraded to .50 caliber. However, photographic evidence demonstrates that this was not as common as sometimes claimed. The mounting of three flexible machine guns in the cramped nose compartment proved to make the space overcrowded for the bombardier, and the side guns were rarely mounted.

Here's a shot of a 70th BS B-26B at Guadalcanal, early 1943

 

[Greg Boeser]

The 70th Bomb Squadron was the only Pacific based B-26 squadron to receive package guns, the first aircraft was modified in October, 1942, and enough kits were provided to equip the whole squadron. The squadron found that the rear mounts were weak and after a couple of instances of the guns breaking loose and shooting up the nose of the aircraft, they were removed. A notable achievement was 70th Bomb Squadron flight leader, Captain John F. Sharp, in a duel with an H6K of the 851st Kokutai, using a pair of package guns in conjunction with assistance of the other gunners on board managed to severely damage the enemy flying boat which crashed shortly thereafter. J.K. Havener in Martin B-26 Marauder, has a few good shots of Sharp's plane showing its package guns and upgraded nose guns.
After the 69th and 70th Bomb Squadrons converted to B-25s, the remaining B-26Bs were transferred to the 22nd BG, but did not see further combat.
Photo above is 70th BS #41-17575 Sundown in mid '43 just prior to transfer to 22nd BG.

 

[Greg Boeser]

In Alaska, the problem of forward firepower was dealt with in a different way. At least one, and possibly more, had the bombardier's position removed and a pair of .50 caliber machine guns and a pair of 20mm cannon were installed through the nose cone. The additional weapons were scavenged from wrecked P-38s or P-39s. This conversion is believed to have taken place after the 73rd Bomb Squadron moved to Adak, in the fall of 1942.

Captain John Pletcher, 73rd Bomb Squadron, 28th Composite Group, flew this plane (or one like it) while leading an attack against the 4000 ton Japanese transport Cheribon Maru, on 26 November, 1942, sinking the vessel in Holtz Bay, Attu