Martin Model 316: XB-68 Tactical Bomber

Skybolt

Skybolt

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As you all know, in the unbuilt projects research business, squeezing stone sometimes gives intriguing info... Looking last night to the Martin projects list at the end of Narkiewicz/Thompson (publisher) book, I suddenly realized that the XB-68 bomber bore the 302A project number, BUT the preceding one, project 302, is described as a Long-Range Interceptor USAF... Now, the A suffix seems to indicate a derivative, so it woukld seems that the XB-68 was originally an interceptor (looking at the desgn it makes a lot of sense). Anyone has more info on this? Also, in the same list, projects 308, 314, 344 are all listed as Long-Range Interceptors. There is even a 319, described intriguingly as TAC interceptor/bomber... Definitively there was a Martin Aircraft line in the LRI saga, besides the Northrop and North American ones. Help is needed, expecially from someone with easy access to the Martin Museum in Maryland...
 
I don't have the Narkiewicz/Thompson book at hand right now, but you must take care not to confuse Martin project numbers with USAF ones. The 302A label for the XB-68 was the USAF's "Weapon System" (WS) code for the project, and if I read your posting correctly, the other numbers you mention are Martin model numbers. The "A" in WS-302A doesn't indicate a derivative.

That said, it's of course still possible that there was an interceptor design related to the XB-68 ;).
 
Touchè Andreas! A little more research would have make clear to me that XbB-68 Martins model number was 316... By the way, on the Glenn Martin Museum site is available for download a complete (more complete than the book one...) list of Martin projects. The link is http://www.marylandaviationmuseum.org/pdf/Models.pdf .

Anyway, what we have to make of the LRI-related model numbers? Anyone volounteering info? Where is the always suprising Orionblablam??? ;) BTW, the updated projects list says that nos. 308 and 314 were alternate proposals to no.302. There is a lot of misteries and gold waiting of being mined in Martin Aircraft history... What about the halìf dozen unknown SAC and TAC bomber proposals?? :eek:
 
Skybolt said:
BTW, the updated projects list says that nos. 308 and 314 were alternate proposals to no.302. There is a lot of misteries and gold waiting of being mined in Martin Aircraft history... What about the halìf dozen unknown SAC and TAC bomber proposals?? :eek:
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Good luck with your research! Anyway, when you are looking for info on Model 327 (fighter bomber, Air Force), ignore the "WS-107A" label - that was the ICBM program ;).
 
Ok, fellows, I'll try and write the guys at the Glenn Martin Museum and ask for info, if any, on the Martin Aircraft LRI-X contenders... Wish me luck.
 
Skybolt said:
Wish me luck.
Click to expand...

You'll need it. Not that the guys at the museum, such as Stan piet, aren;t really great guys who love to help out with such things... but because the Martin archive is virtually non-existant compared to what it should ahve been. Most of the documentation got trashed years ago, only scraps remain.

But who knows, you might luck out.
 
So what was behind the other Martin B-68 design (the three engined delta wing version documented in the Lloyd S. Jones book "US Bombers")? Alternate configuration or different design team?
 
Well, Sentinel, that's one of the most asked questions in secret projects small community...
My guess is that it was a rather different project, maybe even one of the unknown LRI competition Martin's unknown submission. See first post in thread...
 
Browsing in the NACA technical report found a tunnel test of the Martin B-68. What's interesting is the alternate swept-wing configuration. Anyone has more info (I doubt, apart from Stan Piet and Co.)?
 

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To thicken the plot:
Ray Wagner's "American Combat Planes" 2nd ed says
Martin's XB-68 was ordered Sept 1956 as a two-place tactical bomber, two P&W 27500lb J75 mounted on each side of the long (109') fuselage. ... it had a high T tail and rotary bomb doorbut the 53 ft wings were straight and short like those of an F-104.
Jones US Bombers has the 3-jet delta
 
Skybolt said:
Browsing in the NACA technical report found a tunnel test of the Martin B-68. What's interesting is the alternate swept-wing configuration. Anyone has more info (I doubt, apart from Stan Piet and Co.)?
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Why did the two wing tunnel models omit the t-tail?
 
Why did the two wing tunnel models omit the t-tail?
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They may have been just testing the wing aerodynamics and wanted the fuselage to make sure the interference drag/effects were included in the measurements. They may have also been studying the wing interface with the fuselage.
 
Actually they didn't. The tail assembly has a different detailed drawing.
Attached.

The report is: "Investigation of the aerodynamic characteristics of a model of a supersonic bomber configuration with a swept and an unswept wing at Mach numbers from 1.79 to 2.67" NACA RM L58C27, dated July 21st 1958 and classified as confidential
 

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Browsing in the NASA early reports, I found this. The report says it a tactical bomber designed to cruise at subsonic speed and dash over the target at a speed up to Mach 3. No indication on the builder but the first of the two configuration has a distinctly Martin look (T-tail) and all-in-all looks like a stretched B-68 (Martin Model 316) with a negative dyhedral wing and ramp intakes a-la Vigilante. I have never seen anything like this. It seems rather late, 1959-60. The report is NASA TM X-279 from 1960. Could be the tender to some tactical bomber competition prior to GOR-183, when the going went low-altitude. My guess is this could be Model 350 (TAC bomber in the Stan Piet list) or less likely Model 319 (tactical bomber interceptor). Any help?
 

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Really no hints? Not even a snippet? A little snippet? ??? :'(
 
My dear skybolt,

I think it was Martin Model-319,because Model-350 was for SAC
strategic air command and not for TAC.
 
I found this on globalsecurity. org

http://www.globalsecurity.org/wmd/systems/b-68.htm

Other info is scarce.
Can anyone provide more info?
 
Info on the XB-68 is objectively scarce. Until the USAF Museum (and Scott on APR) published the Standard Aircraft Configuration data, people thought it had a different shape altogether. Some info here: http://www.secretprojects.co.uk/forum/index.php/topic,1420.msg11780.html#msg11780

It was a TAC bomber intended to succeed the B-66, which was an interim solution. It was canceled and supplanted by the SOR-183 in the conventional and short-range nuclear role and by missiles (MMRBM) in the mid-range nuclear tactical role. It was a NATO theatre aircraft. Probably there was some version intended for the long-range interceptor role, but only Stan Piet knows... :D
 
... and SOR-183 led to F-111...

This mean that the B-68 was a kind of"missing link" between B-66 and F-111...
 
Thanks guys.
Strange that my attempt to search this site failed, given the fact that info was allready there ???
 
Probably you wrote B-68, it was always referenced as XB-68... ;)
 
Seems to be some other source of fail, because search engine software use parts of the word the same like the whole word. It means that when you type B-68, it will find also XB-68. The same like when you type iffic, it will find every phrase identiffication, difficult, etc. Other situation is when you use "" or * or - or +, but its another story.
 
http://www.secretprojects.co.uk/forum/index.php?action=search2 ;)
 
To possibly explain the lack of success:

If you search for "XB68" you won't find "B-68" or "XB-68" because you are specifically searching for the 4 letters XB68 with no spaces, hyphens etc. If you search for "XB-68" you won't find "B-68" or XB68" for the same reason. You need to revise your search strings.

For example;
1) search for "XB 68". This will find any posts with both "XB" and "68" in somewhere.
2) search for "Martin 68".
 
overscan said:
To possibly explain the lack of success:

If you search for "XB68" you won't find "B-68" or "XB-68" because you are specifically searching for the 4 letters XB68 with no spaces, hyphens etc. If you search for "XB-68" you won't find "B-68" or XB68" for the same reason. You need to revise your search strings.

For example;
1) search for "XB 68". This will find any posts with both "XB" and "68" in somewhere.
2) search for "Martin 68".
Click to expand...

Many thanks Overscan, will do.
 
So does anyone know where Lloyd Jones got the version powered by three J79s that he depicts in his book? Is it another Martin design or is it a pure fantasy creation?
 
As I already said http://www.secretprojects.co.uk/forum/index.php/topic,479.msg11035.html#msg11035, that's one of the great mysteries of "secret projects"... ;D
See: http://www.secretprojects.co.uk/forum/index.php/topic,620.msg7235.html#msg7235

It could be: an alternate configuration from Martin for the same RFP: unlikely, there were alternates, but changes were in the wings AFAIK, and it looks more a fighter than a bomber; or, submission from another company to the same RFP: possible, but more questions than answers; or, submission from Martin to another more or less contemporary RFP: possible, my bet is for the LRI; "neutral" concept form some USAF laboratory: less probable. So, only Stan Piet knowns...
 
As the text in LLoyd S.Jones mentions about the delta:

The accompanying illustrations are stictly provisional and
based on artists configurations and other limited data
that had been released concerning the XB-68.

publication of 1962.

There was also a drawing in a Flying Review of the time
showing the 3-engined delta.
Maybe several configurations were at the Martin drawing
boards for Weapon System 302-A...
 
According to E.R. Johnson "The post- WWII USAF bombers that never flew" AAHS Journal Winter 2004, the delta-wing three-engined was the original proposal. Then in 1956 Martin conceived the XB-68 with two engines and the straight wing. Problem is that the source is the same as Lark's, i.e. Lloyd Jones... . So we are to square one. I'll have to write to Stan Piet....
 
Probable XB-68 wind tunnel model:

http://www.flightglobal.com/PDFArchive/View/1956/1956%20-%201828.html
 
The tail is distinctively Martin's, but the model refer to a still different configuration.
 
Skybolt said:
The tail is distinctively Martin's, but the model refer to a still different configuration.
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It's a seaplane bomber (Convair, I believe). Look at the drawing collection here:
http://www.up-ship.com/Book/bomproj.htm

It's the configuration at the bottom of the seaplane collection.
 
Yes, and so are explained the forward mounted engine nacelles (they swivel upward when floating).
 

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