Martin Baltimore; the RAF’s Skinny American

August 23, 2023

The United States was, quite famously, a major supplier of medium bombers to their Allies during the Second World War. Aircraft like the Douglas A-20 Havoc (also known as the “Boston”), the B-25 Mitchell and the B-26 Marauder were built in such vast numbers that they not only served as mainstays of the USAAF, but also for most of the Allied air forces.

Indeed, for the British, with their factories absolutely at the limit of what they could produce, it essentially became policy that aircraft production focus on heavy bombers and fighters, with medium bombers basically being sourced from the American lend-lease program.

But while the afore-mentioned types are generally remembered because of their service with American units, practically forgotten is one aircraft that saw huge amounts of combat use but isn’t so well recalled because that service was in the hands of other countries.

The Martin Baltimore.

And what is surprising is that this aircraft would be built in greater numbers by Martin than any of their other bombers except the B-26.

The roots of the Baltimore go back to the aircraft building boom that American manufacturers enjoyed at the start of the war. France ordered from Martin several hundred of their Model 167’s, which would also serve with British forces as the Maryland when France fell.

But despite its eventual successes, the Model 167 was initially thought to be a comparatively limited design even before it got a chance to get into action, a factor that led to it being turned down for service by the United States Army Air Corps in 1939. However, Martin was convinced they had a good basic concept and so began to develop an improved version, the Model 187, for future potential orders from European nations.

In fact, the whole project originated from requirements set by the British. The French had paid for a major expansion in Martin’s factory in Maryland to boost production and speed delivery to the French Air Force of the comparatively large numbers of Model 167s that they started placing orders for in January 1939. But when Britain and France started conducting close cooperation on coordinating their orders of American aircraft, the British expressed concerns that the front-line life of the -167 would be short lived and as a result didn’t initially want to purchase any for their own use.

Instead, they proposed that an improved model be created, the -187. This took elements from the -167 such as the wings and cabin layout, but expanded the whole thing, giving it a longer but much deeper fuselage so as to carry bigger bombs, more powerful Wright R-2600 radial engines that generated over 1,600 hp to improve performance and eventually powered gun turrets. This all allowed the new aircraft to be broadly comparable to the new North American B-25 and Douglas A-20 which became the mainstays of the United States medium bomber squadrons in the first years of the war.

Though the -187 didn’t even exist yet, the new specification seems to have appealed to the Anglo-French purchasing commission and they placed orders for four hundred of the new bombers, assumably split between the two nations. However, the collapse of France the following month meant that the order was taken over wholesale by the British along with all the other French orders. They subsequently renamed the aircraft as the Baltimore, a nod to the location of the Martin factory, or at least the nearest major city to it.

You would think that, based as it was on an existing and perfectly competent design, that the Baltimore’s development would be fairly straight forward. But Martin, despite the expansion of their facilities, got bogged down with the mass of work that began to pile up on them as more and more aircraft of different types began to be ordered in quantity by the United States in addition to their foreign orders. The timescale got pushed further and further back and that almost killed the Baltimore before it flew.

In November 1940 the British, inspecting the Martin factory to check on progress of their outstanding orders, including the Baltimore’s, caught sight of the new B-26 prototype and made it plain that they really, really wanted to have that aircraft instead. This actually got some approval from US officials, who thought it made sense for Martin to cut down on their portfolio to help with their commitment issues.

But Martin were now deeply committed to building the Baltimore and successfully argued that it was too late to stop development without substantial wastage of already made parts and tooling for the contract.

Despite this, it would still be many months before the Baltimore would finally take to the air, with first flight occurring in June 1941. The delays meant that the aircraft wouldn’t start to get into British and Commonwealth service until early 1942.

As the British had a policy of sending foreign designs to overseas stations the initial idea was that many of the Baltimore’s would go to Singapore and the Far East, but the Japanese entry into the war and loss of the British colonies and territories in the Pacific meant that instead they were largely sent to North Africa and the Mediterranean.

Here they would equip many squadrons of the Royal Air Force, the Royal Australian Air Force and the South African Air Force, entering service just in time for Rommel’s spring offensive which saw the Baltimore’s thrown headlong into the fight to stem the Afrika Korps drive into Egypt.

Where they were found to have some issues and suffered heavily. The first fifty, designated as the Baltimore I were lightly armed, retaining the previous Maryland bombers layout of four rifle-calibre machine guns in the wings and with a defensive armament limited to single Browning machine guns in both dorsal and ventral position. They also had the unusual expedient of having four rearward firing machine guns which apparently were to serve the purpose of scaring pursuing enemy fighters off.

The armament was slightly improved in the second model, the -II, which fitted the dorsal position with twin machine guns and of which one hundred were built.

But the first combat missions proved problematic when the guns proved liable to freezing up, leading to a number of losses to German fighters. This led to the survivors rapidly having their dorsal armament changed to, depending on the source, either British license-built Browning .303’s or Vickers K guns.

In fact, the British had already stipulated a significant improvement in the Baltimore’s defensive armament even before they took first delivery and the final 250 of the initial order, designated as the Baltimore III, were fitted with a hydraulically powered Boulton Paul turret fitted with four .303 Browning machine guns.

This no doubt helped, but truth be told most of the losses suffered in those early operations were both due to the tempo and in the way the Baltimore’s operated; at very low-level in ground attack missions often on important logistics points or troop concentrations. In other words, targets that were well protected.

In fact it was the same old lesson on the vulnerability of operating bombers at low level in the face of comprehensive anti-aircraft fire and without adequate fighter cover; the same risk factors that had inflicted heavy casualties on Fairey Battle’s in 1940 and on Bristol Blenheim’s in 1941 were now shown to still be true with Baltimore’s in 1942 and would again be shown by the bruising treatment later B-26’s would get operating in this fashion in late 1942/early ‘43.

But the Baltimore’s, despite their initial problems, were generally popular. The narrow fuselage meant that movement for the four-man crew around the aircraft was largely impossible and made for cramped missions, a feature carried over from the Maryland. Indeed, it was if anything somewhat overpowered for its size and weight and had a tendency to ground loop violently if the pilot did not advance the throttles in complete harmony on take-off.

But there was no denying that the Baltimore was vastly superior to the principal British type it replaced, the Bristol Blenheim.

In July and August of 1942 tactics were changed by the Desert Air Force so that the Baltimore’s flew at higher altitudes to be beyond the range of light flak units as well with fighter bomber escorts. In fact, this led to a new methodology where a group of eighteen Baltimore’s would carpet bomb the target while their bomb carrying escorts would swoop down and perform precision attacks while the anti-aircraft gunners were still in their dug outs and not manning their guns.

*bombing

Though this all meant that losses were reduced somewhat, the Baltimore’s were heavily committed by this point and as the British were ready to launch their riposte to the Axis advance with the Second Battle of El Alamein in late October the Baltimore’s were one of the Imperial force’s principal bomber types in the pre-attack softening up raids.

The fighting was ferocious. To quote from one report by No.55 Squadron, Royal Air Force, which attacked a petrol depot at El Daba in Egypt with twelve Baltimore’s at an altitude of 9,000 feet on 6 October.

“Three of the twelve aircraft were shot down and all the others were holed repeatedly by intense and accurate flak. One of the crippled Baltimore’s crash landed on an enemy mine field and all the crew were killed.

“The second crew bailed out but one parachute failed to open. The third crew (except the pilot) also bailed out and became prisoners of war. The pilot, on only his third mission, found it impossible to open his escape hatch because of flak damage, so he attempted to glide back to our lines.

“He didn’t quite make it, crash landing about 1,000 yards short in no mans land under heavy enemy fire. He was rescued eventually by two South African armoured cars under cover of a smoke screen.

“The remaining nine aircraft, all damaged, got back to base, one having to belly land because of damage to the undercarriage. Our aircraft had twenty-eight flak holes…”

This level of action was fairly typical for Baltimore crews not just at that time, but throughout the aircraft’s career.

With the passing of the Lend-Lease Act in 1941 the next batches of Baltimore’s built meant that the aircraft were technically owned by the United States, and so the type received the USAAF designation of A-30 for legal purposes. These were composed of 575 Baltimore IIIA’s and -IV’s, which had a number of equipment differences but the most notable one was the switching of the dorsal turret once again for a Martin electrically-driven low-profile turret that housed two Browning 0.5-calibre heavy machine guns.

The final order was for an additional six hundred Baltimore V’s which switched out the wing guns for Browning 0.50-cals and fitted more powerful Wright engines that produced 1,700hp each. Additionally, it seems that the different operating methods led to the opinion that the ventral guns were largely irrelevant and so they don’t seem to have fitted and the crew reduced to three.

The increasing numbers of Baltimore’s available, as well as additional supplies of aircraft like the Douglas Boston, B-25 and Martin B-26 meant that other nations squadrons received them. On top of the ten RAF, three SAAF and two RAAF squadrons that operated the type, it was used by one Greek, one Free-French, and two Italian Co-Belligerent Air Force squadrons, with another 70 or so supplied to Turkey as part of efforts to sway them to join the Allies and where they served until 1950.

But their service with Imperial units was far from over, and Baltimore’s continued to operate on attack missions throughout the rest of the war, despite the increasing numbers of more modern and capable aircraft becoming available. After North Africa they fought in Italy and over Yugoslavia, assisting Tito’s partisan forces, as well as pounding German forces in Crete.

Some were sent to the Fleet Air Arm, where they operated with some success, being credited with sinking eight U-Boats. Indeed, consideration was given to building a specialist maritime patrol and attack variant, the Baltimore VI, but this was cancelled.

The end of the war largely meant the end of the Baltimore. With copious numbers of both later American and British designs available, the type was very much redundant. A squadron continued to operate the type in Kenya on mapping and pest control duties until 1948, and in fact the Baltimore’s saw a tiny amount of use with the US Navy in 1946 when a single example was used to test airflow on diving aircraft, which saw that particular Baltimore achieve a rather worrying speed of Mach 0.82.

But even these examples were soon sent to the scrapyard, and of the 1,575 Baltimore’s built, not a  single example was retained.

Considering their extensive combat records, and the losses they took fighting some of the fiercest campaigns the Western Allies undertook, is a real shame. A real battler, respected by its crews and in the very thick of it from 1942 until 1945, the Baltimore truly is a classic forgotten aircraft.

Sources/Related:

https://www.jstor.org/stable/26279342

https://boxartden.com/reference/gallery/index.php/Aircraft-Profiles/USA/WWII/Martin-Maryland-Baltimore-Variants/Martin-Maryland-and-Baltimore-232-_Page_15-960

https://en.wikipedia.org/wiki/Martin_Baltimore

https://web.archive.org/web/20070920041158/http://www.marylandaviationmuseum.org/history/martin_aircraft/16_baltimore.html

https://www.mdairmuseum.org/martin-and-community

https://www.historynet.com/forgotten-bomber-martin-30-baltimore/

http://www.historyofwar.org/articles/weapons_martin_baltimore_combat.html

https://web.archive.org/web/20071020035022/http://fleetairarmarchive.net/Aircraft/Baltimore.html

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