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Martin 313 Submaster (XP7M-1): Open Ocean ASW Seaplane

Stargazer2006

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As stated in the companion thread on the Grumman G-132 design, "The 1955 CNO OR AS-040502 required an ASW flying boat with the ability to alight in the open sea, up to sea state 5, in order to operate a sophisticated dunking sonar, AN/ASQ6." This resulted in the "Open Ocean Seaplane" request for proposals, dated May 21, 1956 (U.S. Navy Type Specification TS-143).

Besides the Grumman G-132 and the Convair Model 24, there was also a proposal from Convair, the Model 24, and one from Martin, the Model 313 Submaster (unofficially refered to as the P7M). This was an open ocean sonar seaplane developed from the earlier Model 290 (P5M-3) proposal, an armed boundary layer control (BLC) reconnaissance version of the Marlin. The Submaster was a four-engined high-wing flying boat type, and also had a BLC system, but this was powered by two J85 turbines, buried in outboard nacelles on the wings (some sources claim there was only one, located above the hull).

The "XP7M-1" was built only in mockup form in 1956, at Martin's own expense, but despite the company's efforts, BuAer announced Convair's XP6Y-1 as the winning entry on February 1, 1957 (at least until the whole "Open Ocean" thing was abandoned and Lockheed's land-based P3V-1 Orion was procured to fill a similar role). As aptly stated in E. R. Johnson's American flying boats and amphibious aircraft: an illustrated history, "Although Martin still had the P5M-2 in production and the P6M-1 in pre-production at the time, the P7M would be the last in a long line of Martin flying boat designs."


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Attachments also taken from American flying boats and amphibious aircraft: an illustrated history
 

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Pioneer

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Wow gents
Great find!!
I've been looking for this elusive project for years ;D
Where do I find pics/drawings of the Grumman G-132?
Thanks

Regards
Pioneer
 

LowObservable

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Was there any linkage between this project and the ShinMaywa PS/US family?
 

Stargazer2006

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LowObservable said:
Was there any linkage between this project and the ShinMaywa PS/US family?

That would be interesting to know. I've always figured the Shin Meiwa design drew heavily on the Marlin.
 

Abraham Gubler

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Shin Meiwa obviously adopted the BLC wing concept of the OR AS-040502 ASW flying boats but had a very different, low aspect ratio wing to the Martin entry. They used a Grumman Albatross as a donar wing box and upper fuselage for the aero (and hydro) dynamic test bed for their PS-X aircraft.

As an aside my grandfather was with RAAF maritime squadrons in WWII, Hudsons at Laha at the start and Black Cats at the end, and he always said the Shin Meiwa (aka Kawanishi) H8K was the best maritime patrol aircraft of the war.

There is an indepth history of the program at the Shin Meiwa webpage.

http://www.shinmaywa.co.jp/english/guide/us2_history.htm
 

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frank

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http://www.secretprojects.co.uk/forum/index.php/topic,4465.0/highlight,grumman+g+132.html

Pioneer said:
Wow gents
Great find!!
I've been looking for this elusive project for years ;D
Where do I find pics/drawings of the Grumman G-132?
Thanks

Regards
Pioneer
 

Silencer1

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Hi!

Thank you for good info on Submaster!

Perhaps Martin Model 270 experimental flying boat (based onn P5M) was a kind of it's predecessor - in hull design, at least.

Unfortunately , I couldn't find any image of this flying boat on the Internet...
Just the sketch of it's 15:1 lenght ratio hull (from aerade.cranfield.ac.uk/ara/arc/rm/3285.pdf)
and some story here: http://www.marylandaviationmuseum.org/history/martin_aircraft/25_p6m.html

I hope, someone could add or correct this mention of "Model 270"

Cheers!
 

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Stargazer2006

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Here is a picture and small text on the Martin 270.

I have more in an old Airpower issue on the Mariner, but I'll have to go and dig it in my vaults... ::)
 

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Orionblamblam

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Jarred loose some dusty old memories. I have scanned in pieces both a good three-view and an excellent inboard profile of the Martin 313. I'll need to piece 'em together. If I haven't come back with something by the end of the weekend or so, someone poke me with a stick.
 

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Pioneer

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frank said:
http://www.secretprojects.co.uk/forum/index.php/topic,4465.0/highlight,grumman+g+132.html

Pioneer said:
Wow gents
Great find!!
I've been looking for this elusive project for years ;D
Where do I find pics/drawings of the Grumman G-132?
Thanks

Regards
Pioneer

Thank you Frank!
You are a gentleman!!
Very interesting Grumman design, I had not seen before. All the competitors and their designs are falling into place now!!

Regards
Pioneer
 

Orionblamblam

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Here's the three-view. A higher rez (+ B&W) version can be found here: http://up-ship.com/blog/?p=10216
 

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Pioneer

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Found this small 3-view pic of the Grumman G-132 drawn by Lloyd S. Jones
Am I allowed to post this?

Regards
Pioneer
 

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