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Martin 203 Tokyo Express

Antonio

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I've just found this design on Minidocavia #25. It's a study from 1943. The brief description from the book says:

into the studies for a new heavy bomber to be deployed against Japan, Martin developed that four engined design

Anybody known if existed a formal USAAC RFP for that "new heavy bomber to be deployed against Japan". It was to be a B-29 replacement?
 

Skybolt

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More a back-up... the intended engines were Allison V-3420s and the date is 1943, when the B-29 was on the brink of the abyss due to engine fires. The other back-ups for the B-29 (B-32) had R-3350 too, so there was need for something different, and quickly, even not particularly advanced. And since La Riviere doesn't own the exclusive rights of those images, behold the Tokio Express. Image property of and courtesy of the Glenn Martin Aviation Museum via Stan Piet.
 

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Antonio

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Thanks a lot for your comprehensive answer and pic. I knew nothing about that heavy bomber to date and it is an interesting story. When I found it in the book this morning, I was surprised because the date was 1943 but looked outdated compared with the B-29. It doesn't look like a B-29 replacement because it was a backup for the futuristic Superfortress.

BTW the pic you posted is the same included in the Minidocavia book.
 

robunos

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It looks like the Marauder's daddy! :D

cheers,
Robin.
 

Skybolt

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mmm, if a Marauder ascendancy there is, it is from he Supermarauder (XB-30) with a dfferent tail and mated to a Davis wing.
 

frank

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The so-called Super Marauder was the XB-33A, IIRC, which had little, if anything in common with the B-26. The Tokyo Express, however, definitely looks related to the B-26. The XB-30 was a Lockheed Connie bomber. My first thoughts were that it looked like an enlarged & elongated B-26 with a B-24 wing & parts of a Privateer tail. Any info on the dimensions?


Skybolt said:
mmm, if a Marauder ascendancy there is, it is from he Supermarauder (XB-30) with a dfferent tail and mated to a Davis wing.
 

Antonio

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Model 203 data:

Span: 51,80 m

Mass loaded: 79 380 Kg
 

Apophenia

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Skybolt said:
mmm, if a Marauder ascendancy there is, it is from he Supermarauder (XB-30) with a dfferent tail and mated to a Davis wing.

Sky,

Rubin Fleet secured exclusive rights to the Davis laminar flow airfoil for Consolidated. So, I suspect that the Model 203 wing has only a superficial resemblance to the B-24. The B-32 shows that the Davis wing was scaleable (span: 41.2m) but the M-203 span was a lot greater at 51.80 m (B-24: 33.52m).

Martin's 'neighbouring' M-202 (2-0-2 Martinliner) had a high aspect ratio wing (10.0 compared with the B-24's 11.55). And the M-202 used an 'in-house' GLM-W 16 airfoil. Going out on a limb, is it not probable that the M-203 used an even higher aspect ratio version of that same wing -- ie: GLM-W 16 in place of the M-179 (B-26) NACA 0017-64/0010-64 section or M-189/M-190 (B-33) NACA 65-222/65-415?

All speculation, of course... unless someone know the actual airfoil section proposed for the M-203.
 

frank

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Another bit of confusion. IIRC, again, the XB-33 was a large twin engined design, somewhat like a land-based bomber version of the PBM. The XB-33A was the larger 4 engined design called the Super Marauder.


Skybolt said:
Sorry, I meant XB-33... memory lapse.
 

Skybolt

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Ah, the A ! You sure ? Every original company drawing I have of the Martin Model 190 sports a B-33 Air Corps designation, fo example see attached. Every Model 190 variation was 4-engined. The Model 189 (many variations, one a frequently published canard version) and 191 (conventional) were two-engined medium bombers. According to Stan Piet, the Model 189 did evolve in the 190, but I don't have documents stating that the Model 189 was the sole and only B-33 sans suffixe for the Air Corps. In the small production table on page 123 of "Martin Aircraft 1909-1989" the Model 189 is designated XB-33, but the Model 190 sports XB-33 and B-33 too, sans A. The same book refers in the text (not in the official drawing) to the SuperMarauder as XB-33A, don't know on which basis. So, it is probably misgiving trying to differentiate the two aircrafts with an A suffix. Simply the B-33 designation was carried over during the evolution of a model in the other. Or so is the thing from the sources I have.
Apo, unfortunately, the Martin Museum documentation on Model 203 is all in that art, even the weight, engines and span are scribbled on the back of the photo. Only a NARA search could provide some more info.
 

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frank

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I'm only sure of what I read in Lloyd Jones' book "US Bombers". I'm pretty sure I have the order correct, the XB-33 was the twin, the XB-33A was the 4 engine design. I think that's the only place I've ever seen it, so, thats all that I'm sure of, is where I read it. I don't recall ever hearing that Jones' info was incorrect about many of the aircraft he's written about, but I certainly wouldn't swear that he's never wrong, either.



Skybolt said:
Ah, the A ! You sure ? Every original company drawing I have of the Martin Model 190 sports a B-33 Air Corps designation, fo example see attached. Every Model 190 variation was 4-engined. The Model 189 (many variations, one a frequently published canard version) and 191 (conventional) were two-engined medium bombers. According to Stan Piet, the Model 189 did evolve in the 190, but I don't have documents stating that the Model 189 was the sole and only B-33 sans suffixe for the Air Corps. In the small production table on page 123 of "Martin Aircraft 1909-1989" the Model 189 is designated XB-33, but the Model 190 sports XB-33 and B-33 too, sans A. The same book refers in the text (not in the official drawing) to the SuperMarauder as XB-33A, don't know on which basis. So, it is probably misgiving trying to differentiate the two aircrafts with an A suffix. Simply the B-33 designation was carried over during the evolution of a model in the other. Or so is the thing from the sources I have.
Apo, unfortunately, the Martin Museum documentation on Model 203 is all in that art, even the weight, engines and span are scribbled on the back of the photo. Only a NARA search could provide some more info.
 

frank

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I found this at www.anigrand.com. I remembered he had recentlt released a kit of the XB-33A. Don't know where he got his info, but it or part of it may be from Jones' book, as a photo he has is one of the models in Jones' book.

"In 1939, the USAAC issued a requirement for a new medium bomber which could operate at high-altitude to avoid attack from ground fire. Preliminary designs were submitted by Martin and North American. The Martin XB-33 was redesigned from the B-26 Marauder, and North American XB-28 was based from the B-25 Mitchell. In 1940, both designs were awarded prototype contracts. The full-scale development of the XB-33 was begun in late 1940, and as it progressed, the Martin engineers found that a two-engine aircraft would not be capable of achieving the performance required in the Army specification. It was decided to radically alter the original design by adding two more engines. The entire project was scaled up to the approximate size of the Boeing B-29. The Army was sufficiently impressed with the new design; the two prototypes were redesignated XB-33A and an order for 400 production B-33A Super Marauders was placed. In 1944, Martin was awarded a contract to assemble B-29s which were urgently needed to enter Pacific theater. As B-29s had top priority to use the inventory, the entire B-33A order was cancelled before the prototypes were completed."




frank said:
I'm only sure of what I read in Lloyd Jones' book "US Bombers". I'm pretty sure I have the order correct, the XB-33 was the twin, the XB-33A was the 4 engine design. I think that's the only place I've ever seen it, so, thats all that I'm sure of, is where I read it. I don't recall ever hearing that Jones' info was incorrect about many of the aircraft he's written about, but I certainly wouldn't swear that he's never wrong, either.



Skybolt said:
Ah, the A ! You sure ? Every original company drawing I have of the Martin Model 190 sports a B-33 Air Corps designation, fo example see attached. Every Model 190 variation was 4-engined. The Model 189 (many variations, one a frequently published canard version) and 191 (conventional) were two-engined medium bombers. According to Stan Piet, the Model 189 did evolve in the 190, but I don't have documents stating that the Model 189 was the sole and only B-33 sans suffixe for the Air Corps. In the small production table on page 123 of "Martin Aircraft 1909-1989" the Model 189 is designated XB-33, but the Model 190 sports XB-33 and B-33 too, sans A. The same book refers in the text (not in the official drawing) to the SuperMarauder as XB-33A, don't know on which basis. So, it is probably misgiving trying to differentiate the two aircrafts with an A suffix. Simply the B-33 designation was carried over during the evolution of a model in the other. Or so is the thing from the sources I have.
Apo, unfortunately, the Martin Museum documentation on Model 203 is all in that art, even the weight, engines and span are scribbled on the back of the photo. Only a NARA search could provide some more info.
 

Stargazer2006

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Surprisingly, the more or less "official" model listing provided by the Glenn Martin museum lists model 203 as a "175,000 lb four engine transport". Was it meant as an armed transport, then, or were there two separate studies on the same airframe? Hard to say.
 

Jos Heyman

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I believe the MArtin 203 designation was also used for a four engined version of the Martin 202 transport. So, unrelated to the bomber project.
 

Skybolt

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The list on the Martin Museum site has some notoriuos typos, and the Martin Aircaft book one as some other notorious typos...
 

Stargazer2006

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The XB-33 was not the Model 203, it was the Model 189. There were two very different configurations proposed. There was also the XB-33A (Model 190) which was different again. I don't think these really belong in this topic.
 

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There is an article with 3-view & a photo of a model of both the XB-33 & the XB-33A in Lloyd Jones "US Bombers".
 

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