Author Topic: Martin B-33B Marianas  (Read 1041 times)

Offline apophenia

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Martin B-33B Marianas
« on: November 02, 2020, 10:02:41 AM »
In the late Autumn of 1944, USAAF planners turned their attention to alternative bombers for the Pacific Theater of Operations. The B-17G had been key to the bombing campaign of Germany but now dated. The B-24 was in fairly widespread use in the PTO ... but mainly because the Liberator had been seen as less successful over Europe than the B-17. Both bombers had been eclipsed by the Boeing B-29 and Consolidated B-32 then entering service in the Pacific. A need was perceived for another bomber type - more advanced than the B-17 or B-24 but more economical than the larger B-29 and B-32. Compared with those 'hemispheric defense bombers', emphasis would be on range over bomb load. The new aircraft type was intended to augment the B-29 and B-32, not to compete directly with those larger bombers.

Through the war years, Martin had studied multiple replacements for (or growth developments of) its B-26 Marauder bomber. Weight was a key issue for the earliest studies - the pressurized M-182 (XB-27) and high-altitude M-189 (XB-33). This led to a second XB-33 - the M-190 'Super Marauder' 4-engined bomber. Two examples of the latter were actually ordered in 1942 along with a contract for 400 x production model B-33s. However, that order was eventually cancelled. Follow-on developments slipped because Martin had proved incapable of quickly solving problems encountered with the B-26 Marauder in USAAF service.

The cancellation of the M-190/XB-33 order led to Martin's revised and lightened M-190A project put forward as a replacement. Around the same time, a rival project was put forward by Ford - this design meant to replace B-24N production at Willow Run, MI. The Ford project could be best described as a 'skinny' B-24N powered by four Wright R-2600 radials. Other than nacelles, the wing, main undercarriage, and tailplane would remain unchanged. Aiming at the Pacific Theater, Ford's proposal already emphasized range over bomb load. The Ford concept was also much more compact than Martin's M-190A design.

To counter the Ford offer, Martin proposed a scaled-down M-190B mostly comprised of in-production components. A stretched B-26 fuselage was mated to a revised M-162/PBM Mariner flying boat tailplane and wing. The latter was relieved of its gulled inboard section but its span and wing area were to remain the same - 118 feet and 1,408 sq ft (versus 134 feet and 1,500 sq ft for the original M-190). [1] Nacelles would be all new to accommodate four P&W R-2800 radials in standard B-26 cowlings. In performance, the resulting M-209B [2] design was not all that dissimilar to Ford's XB-24N derivative. However, USAAF planners were divided in their appreciation of the two types.

A smaller bomber type was seen as especially useful for future action in the Southwest Pacific Area (SWPA) and over the Chinese mainland, freeing up B-29s for attacks on the Japanese Home Islands. But the smaller bomber was also a lower priority type. As such, it was decided to combine the efforts of the two design teams which would now cooperate with each other rather than compete. The objective was the rapid production of a tertiary bomber type which would combine the fuselage of the Martin M-190B concept with the wings and tail from the Ford project. To that, it was suggested, the preferred Wright R-2600 engines - which were then in less high demand than the P&W R-2800 - should be housed in standard B-25 Mitchell cowlings. Thereby, a new, quite capable bomber could be created almost entirely from in-production components.

From 'Super Marauder' to Martin XB-33B Marianas

As a development aircraft, Ford's XB-24N-FO (44-48753 c/n 3608) was re-engined with R-2600-29 radials. Test flying showed a livelier performance but also revealed a need for more fin area. However, by then, the new bomber - now dubbed Martin B-33B Marianas - had already been ordered into production at Ford's Willow Run plant. [2] The prototype XB-33B first flew with the same, short fin as the XB-24N. Nose and tail gun positions were to be identical to the Marauder but dorsal and ventral turrets were remotely-operated from a forward fuselage gunner's position. [3] Under the forward fuselage was a semi-retractable H2X 'Mickey' blind-bombing radar antenna.

Early flight trials revealed a number of stability and balance issues. 'Hunting' was cured by extending the top of the fin (as had been done for the USN's PB2Y-1). However, the USAAF had also changed its armament preference. To avoid extra training for crews transiting from Europe to the PTO, it was decided to revert to familiar manned powered turrets. Accordingly, the remotely-operated turrets were replaced with an A-14 (Martin 250CE1) dorsal turret and a Sperry ball turret. [4] Balance was unaffected by the turret changes but eliminating the fuselage side sighting stations helped to shift the XB-33's c/g forward. Other armament options were considered but these would be applied to production aircraft.

(To be continued ...)

_______________________________

[1] In contrast with a span of 71 feet and wing area of 659 sq ft for the twin-engined B-26C Marauder.

[2] The original Martin M-209 project had been for a 4-engined bomber even larger than the original M-190. Despite heavy involvement by the Ford Motor Company, the Glenn L. Martin Company was made the project's lead contractor. For unknown reasons, Martin decided to reuse the M-209 corporate type designation rather than assign a new number.

[3] Often described as 'B-29' turrets, the XB-33B's remote armament actually came from the Douglas A-26 - using the General Electric 2CFR21B3 central station fire control system for the GE Model 2CGD50URC1 upper and 2CGD50LRC1 lower gun turrets.

[4] The turret actually installed was a semi-retractable Sperry A-13 made by the Briggs Mfg. Co.
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Offline finsrin

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Re: Martin B-33B Marianas
« Reply #1 on: November 02, 2020, 11:42:00 AM »
Briefing and profiles are excellent.   Am liking B-33B.  8)

Offline Old Wombat

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Re: Martin B-33B Marianas
« Reply #2 on: November 02, 2020, 09:27:22 PM »
Super-Marauder looks good! :smiley:
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Re: Martin B-33B Marianas
« Reply #3 on: November 03, 2020, 02:05:06 AM »
A smaller bomber type was seen as especially useful for future action in the Southwest Pacific Area (SWPA) and over the Chinese mainland

Hmmm...in Chinese markings perhaps...? ;)
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Offline buzzbomb

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Re: Martin B-33B Marianas
« Reply #4 on: November 03, 2020, 07:26:06 AM »
You have me convinced that this is not a whiffer.

Great story and profile

Offline Kelmola

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Re: Martin B-33B Marianas
« Reply #5 on: November 03, 2020, 06:48:11 PM »
So building the XB-33B in plastic form one would require:
2 x B-26 (the other for the extended fuselage unless suitable plastic tubing is available)
2 x B-25 (engines & nacelles)
1 x Privateer (wings, fin)
1 x regular B-24 (retractable ball turrret) or 1 x A-26 (remote turrets; additionally buying a B-29 just for the observation blisters might not be the most sensible option)
;)

Offline jcf

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Re: Martin B-33B Marianas
« Reply #6 on: November 04, 2020, 02:02:26 AM »
The difficulty with stretching a B-26 in plastic is that it doesn't have a constant cross-section
at any point, there's no area that's a parallel-sided tube. Using two B-26 kits wouldn't get
you there, you would need to introduce a new parallel body section. The best place for this
would be a new extended centre section.
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Offline apophenia

  • Patterns? What patterns?
Re: Martin B-33B Marianas
« Reply #7 on: November 04, 2020, 08:59:40 AM »
Thanks folks!

Kemola: For the production model B-33B (see next post), no B-24 or A-26 needed!  In lieu of the B-25 kits, you can get corrected late-model Mitchell cowlings (Quickboost in 1/72 or, for Greg, DMold in 1/48). Not sure about props ... I was thinking about 4-bladers (as per mid-production PBMs).

Jon: My 'stretch' would be just that - an entirely new fuselage centre assembly (to allow for different wing attachment). At a guess, the 'cut' would be mid-way though the original B-26 centre fuselage. I was assuming that would be a near perfect circular section ... oops  :-[
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Offline apophenia

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Re: Martin B-33B Marianas
« Reply #8 on: November 04, 2020, 09:03:06 AM »
From 'Super Marauder' to Martin XB-33B Marianas

The production model B-33B-FO-1 Marianas reflected more focus on combat roles. Exact armament options remained in flux. To address on-going c/g issues, the prototype's Sperry ball turret was abandoned. The Martin A-14 dorsal turret was moved forward to improve balance - which, in turn dictated a re-arrangement of the crew compartment behind the cockpit. To better accommodate the fittings of the turret, the radio operator's position was turned sideways. The navigation positions was removed to the rear fuselage - an astro dome being placed directly in front of the fin extension for the navigator's use. Aircraft were delivered from the Ford factory at Willow Run, MI, with all ventral turret fittings removed and the ball turret opening plated over.

While being fitted out for overseas service, many B-33B-FO-1s received a distinct, low-profile belly position.  This hand-held gun mount was based upon a 5th Air Force 'mod' for Liberators. Twin .50-cals were housed in a shallow plexiglass 'dish', rotating 360° around a central support post. While this 5th AF innovation had nowhere near the original ball turrets range of action, it was light, easy to maintain, and quite simple to install. Although not universal, the '5th AF' belly mount became a fairly common modifications for B-33B-FO-1s.

Top An Australian B-33B-FO-1 Marianas of the RAAF's No.201 Flight - an electronic intelligence unit. Adapted for its Antepodian specialist role by No. 1 Aircraft Performance Unit, [1] this aircraft is festooned with antennae of various kinds. The '5th AF' belly mount can be seen as well as a H2X 'Mickey' blind-bombing radar antenna under the nose. [2] No.201 Flight had formed on Liberators but these were quickly traded for the Marianas (special duties No. 200 Flight was likewise re-equipped).

This particular aircraft - originally a TB-33B - served briefly with No 7 Operational Training Unit at Tocumwal, NSW, before being transferred to No.1 ADU for conversion. Markings are essentially the same as the Flight's previous Liberators. A white recognition panel covers the uppermost fin and rudder although the significance of the black 'X' is unknown. NX+B has been dubbed 'Meddlesome Maggie', a name inherited from Liberator NX+R. Note the serial, A76-413. The Marianas received a new RAAF type code ('76') but serial numbers continued from the Liberator sequence - the last B-24M being 72-405, the first B-33B becoming 76-406.

Pattern Finally Settled ... But Perhaps Too Late?

The B-33B-FO-2 could be considered the definitive Marianas - it was certainly the last down the Ford production line. Engines changed from Wright R-2600-29As to R-2600-35s but power remained the same. The belly gun opening was eliminated altogether - being replaced by Marauder-style rear fuselage gun hatches. The main undercarriage was also strengthened. Otherwise, the final production model B-33B-FO-2 was essentially similar to the original B-33B-FO-1 Marianas.

Along with the twists and turns on B-33B armament choices, the USAAF's crewing concept also shifted. It was originally intended that the Marianas would be manned by ETO B-24 crew members with insufficient 'points' to qualify for a return stateside and demobilization. However, it was decided to redirect B-24 crews to the China-Burma-India Theater where Liberators were still widely used. The B-33Bs would, instead, be manned by former B-26 Marauder medium bomber crews. [3] Pilots were familiarized with 4-engine operation on B-24s before going on for brief type conversion on the handful of TB-33B-FO-1 trainer conversions.

Bottom 'A Bumpy Ride' - a B-33B-FO-2 Marianas of the USAAF's 427th Bomb Squadron, 303d Bomb Group, while based at San Marcelino Airfield on Luzon in the liberated Philippines. Joining Fifth Air Force squadrons, the 427th BS aircraft were used as part of Operation Pastel Three. Encouraging Japanese belief in a fictitious Allied landing on China's mainland was the chief goal of this deception campaign. To that end, aerial operations were centred on the Chusan-Shanghai area, consisting of leafleting, 'supply drops' (to non-existent agents), and bombing runs. [4]

From Philippines bases, these Chusan-Shanghai missions of 2,400 miles or so averaged just under ten hours duration - very tiring for the aircrews but well within the range capabilities of the B-33Bs. Returning from such a mission on 24 Feb 1946, 'A Bumpy Ride' was caught by Japanese flak over Formosa. She went down south of Ishigakijima but the crew were rescued by a US submarine, the USS Trumpetfish (SS-425) on its first operational cruise.

__________________________________________

[1] No.1 Aircraft Depot's Special Duties and Performance Flight until December 1943, No.1 ADU evolved into the Aircraft Research and Development Unit (ARDU) after the war ended.

[2] Generally, the B-33B-FO-1 was 'fitted for but not equipped with' the H2X radar. The RAAF specifically requested No.201 Flight's Marianas receive the 'Mickey' sets.

[3] Most surviving USAAF B-26 Marauder were being converted to AT-23 trainer/target tug status or passed on to allies as bombers or patrol aircraft.

[4] Aircraft assigned to leafleting or 'supply drops' missions still carried a minimal bomb load. This was for targets of opportunity - including any Japanese shipping found in the South China Sea or Formosan waters.
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Offline apophenia

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Re: Martin B-33B Marianas
« Reply #9 on: November 06, 2020, 09:12:45 AM »
Hmmm...in Chinese markings perhaps...? ;)


I like it! But I decided to do it postwar ... so I posted it here:

http://beyondthesprues.com/Forum/index.php?topic=351.msg178643#msg178643
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Offline apophenia

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Re: Martin B-33B Marianas
« Reply #10 on: November 09, 2020, 05:20:18 AM »
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Offline jcf

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Re: Martin B-33B Marianas
« Reply #11 on: November 09, 2020, 01:55:47 PM »
Quote
Jon: My 'stretch' would be just that - an entirely new fuselage centre assembly (to allow for different wing attachment). At a guess, the 'cut' would be mid-way though the original B-26 centre fuselage. I was assuming that would be a near perfect circular section ... oops

Right in the centre and to the aft bomb-bay are more or less 'circular' but not the same diameter.  ;)

The attached drawing was published in Air Trails in 1941 and is still considered, for the most part,
to be more accurate than later drawings. I scanned it from an original issue of the magazine, which
was an oversize pulp, so I had to scan in parts reassemble and compensate for the aged paper.
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Sense doesn’t come into it. People are
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Offline apophenia

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Re: Martin B-33B Marianas
« Reply #12 on: November 10, 2020, 12:01:11 PM »
Cheers Jon! And all the work that went into the scanning and reassembly is mucho appreciated  :smiley:

Great drawing with plenty of section-y goodness   :D
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Offline elmayerle

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Re: Martin B-33B Marianas
« Reply #13 on: November 10, 2020, 01:00:10 PM »
That's superb work, Jon.  I should know, in the past I've had the "pleasure" of cleaning up scanned in drawings for my employer of that time.

It looks like a less tapered section from section 5 aft, extending farther aft before reaching section 6 would be a start to stretching the fuselage. 

Offline apophenia

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Re: Martin B-33B Marianas
« Reply #14 on: November 11, 2020, 10:49:17 AM »
That makes good sense Evan. My original concept would change the fuselage shape enough to dictate new bomb doors. Your less tapered section being further aft means the original doors can be retained (as the new forward bomb bay doors). The B-33B's rear bomb bay doors would need to be all new anyway. Nice  :smiley:
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Offline elmayerle

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Re: Martin B-33B Marianas
« Reply #15 on: November 11, 2020, 11:16:40 AM »
Glad you like the idea.  Will you need to stretch the fuselage ahead of the wing?  That looks to be a bit more challenging.

Offline jcf

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Re: Martin B-33B Marianas
« Reply #16 on: November 11, 2020, 12:07:50 PM »
The P-35 to AP-7/EP-1/P-35A stretch is easily one of the cleanest stretches of a tapering
cylindrical fuselage that was ever done, possibly the cleanest. That might be something
to look at as a 'stylistic' guide.
 ;)
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Offline jcf

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Re: Martin B-33B Marianas
« Reply #17 on: November 11, 2020, 12:10:47 PM »
Quote
Cheers Jon! And all the work that went into the scanning and reassembly is mucho appreciated
De nada.  :smiley:

Quote
That's superb work, Jon.

Thanks Evan.  :smiley:
“Conspiracy theory’s got to be simple.
Sense doesn’t come into it. People are
more scared of how complicated shit
actually is than they ever are about
whatever’s supposed to be behind the
conspiracy.”
-The Peripheral, William Gibson 2014

Offline Artoor_K

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Re: Martin B-33B Marianas
« Reply #18 on: November 14, 2020, 07:14:39 PM »
Awesome work! I'd love to make a model of it :)
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Re: Martin B-33B Marianas
« Reply #19 on: November 15, 2020, 02:48:16 AM »
Your starting point:

All hail the God of Frustration!!!

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Offline apophenia

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Re: Martin B-33B Marianas
« Reply #20 on: November 17, 2020, 07:55:03 AM »
Your starting point:

Cool! It'd be tempting to stuff some barbettes into those outer nacelles  ;)
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Offline jcf

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Re: Martin B-33B Marianas
« Reply #21 on: November 17, 2020, 12:54:05 PM »
Your starting point:

Cool! It'd be tempting to stuff some barbettes into those outer nacelles  ;)

Nah, manned positions pushed on Martin because all of the remote gun systems were earmarked
for the B-29 and B-35.
 ;)
“Conspiracy theory’s got to be simple.
Sense doesn’t come into it. People are
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whatever’s supposed to be behind the
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-The Peripheral, William Gibson 2014

Offline elmayerle

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Re: Martin B-33B Marianas
« Reply #22 on: November 17, 2020, 01:34:43 PM »
Well, you could always go with manned gun stations on the outboard nacelles, something similar to what the TB-7/Pe-8 used.

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Re: Martin B-33B Marianas
« Reply #23 on: November 18, 2020, 02:06:42 AM »
Indeed:

All hail the God of Frustration!!!

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But you can make the Bastard work for it.