AMSA Program & B-1 Bomber projects

[circle-5]

A low rez version of this was posted before, but here's a higher rez. A higher-rez-yet version is at my blog:
http://up-ship.com/blog/?p=11430

Also attached is a blowup of the "subsonic" model. And it actually does seem to say "subsonic." A few possible explanations:
1: Circle-5 actually has this model, which was mislabeled
2: NAA made a number of mis-labeled models
3: This was actually meant to be subsonic
1& 2 look less likely now, but #3 just seems silly.

The final AMSA development (the B-1B) has an impressive VG wing design, yet its mission is typically subsonic, with only marginal supersonic capability. I don't feel these characteristics need to be mutually exclusive, although the Subsonic AMPSS is indeed a bit much.

I only know of one example each of the models featured here, but if others appear with the same subsonic stand, then we'll definitely know it's subsonic. Even if initially mis-labeled, such models would have never made it into NAA PR and historical photographs without correction.

Attached is a rarely seen rear view of the big NAA AMPSS VG model, showing its unusual engine arrangement and gullwing appearance.

(Model photo © by Chad Slattery)

 

[Orionblamblam]

The final AMSA development (the B-1B) has an impressive VG wing design, yet its mission is typically subsonic, with only marginal supersonic capability.

Yes, but the B-1*A* was designed to go balls-out. The design the B-1B inheirited was a fast mover that had been governed down by stealth requirements.

I don't feel these characteristics need to be mutually exclusive, although the Subsonic AMPSS is indeed a bit much.

The extreme sweepback is only useful for multi-Mach speeds. So the best I can figure for this being a "subsonic" design was that it was intended to sneak in subsonically, then fold up and dash over the target, then wander on out again. otherwise the design really doesn't seem to make sense.

 

[Sundog]

The extreme sweepback is only useful for multi-Mach speeds. So the best I can figure for this being a "subsonic" design was that it was intended to sneak in subsonically, then fold up and dash over the target, then wander on out again. otherwise the design really doesn't seem to make sense.

What about for high speed NOE flight? Ride quality would definitely be a consideration for the crew and sensor systems. Granted, wing loading remains the same, but the load distribution changes, since the area is now down the fuselage, instead of laterally where I think it would be more sensitive to gust loading. Although, I haven't seen much with regard to differing wing configurations and their stability repsonses to gust loading, etc., this could be a reason for VG of a subsonic aircraft. It was obviously a serious consideration for the program, gust response, as witnessed by the load alleviating canards on the B-1.

 

[Orionblamblam]

I can't show the original (sorry), but I can show "tracings" of Boeing AMSA/B-1 concept art. I hope to improve this drawing at some point, but here's a quick sketch.

 

[circle-5]

Some AMSA concept art from North American Aviation, in high resolution. Ridiculously-high resolution files available upon request.

[scanned from original NAA large-format transparencies]

 

[Stargazer]

What a treat!! ;D

Thank you so much, and please do it again whenever you feel like it!

 

[uk 75]

Orionblamblam

The Boeing design looks very interesting... Waiting for more with many thanks..

Anything on AMSA is very rare as according to Tony Buttler most of the records
in US firms were just junked.

Maybe Ebay will yield some more models...

UK 75

 

[Orionblamblam]

This particualr AMSA concept was derived from Boeing SST studies. I'm hoping to get a higher resolution version of the artwork this was based on.

 

[overscan (PaulMM)]

General Dynamics AMSA pencil sketch (via Mark Nankivil)

 

[hesham]

Hi,


http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19800002822_1980002822.pdf

 

[Jemiba]

Had a short look at this report. I think, the XB-70 is just chosen as an example for
tests of a wide range of Mach numbers, so isn't really related to the AMSA program.

 

[overscan (PaulMM)]

This design is interesting. Dated 15 January 1970.

When was AMSA given the B-1 designation?

(Higher res copy at link above)

 

[overscan (PaulMM)]

A whole pile more AMSA drawings posted on http://www.codeonemagazine.com/article.html?item_id=114

 

[Overkiller]

A whole pile more AMSA drawings posted on http://www.codeonemagazine.com/article.html?item_id=114

Wonderful!

At the moment everyday is like Christmas, with everything that is being posted up on the Code One site!

A big thank you

Duncan

 

[hesham]

A whole pile more AMSA drawings posted on http://www.codeonemagazine.com/article.html?item_id=114

Amazing projects my dear Paul.

 

[Grey Havoc]

Here's a DTIC link to TECHNICAL DOCUMENTARY REPORT NO. ASD-TDR-62-426 from June 1962, regarding the Subsonic Low Altitude Bomber (SLAB).

ASD TDR 62-426
In Technological Force Structure Plan (TFSP) Task 9, interest was generated in strategic
aircraft which could attain extremely long strike ranges with penetrations performed
at very low altitude. The probability of penetration into enemy territory can be
increased significantly by low altitude flight. Consequently, a Subsonic Low Altitude
Bomber has been designed to satisfy a requirement for 12,500 nautical miles of range at
altitude with 12,500 pounds of payload. A sea level dash range of 2,500 nautical miles
was also required with a trade-off of not more than 2.5 miles of range at altitude for each
mile of sea level range. The specified minimum speed was Mach number 0.6. (S)

 

[hesham]

From Steve Pace book,


the North American/Rockwell D481-33.

 

[Jemiba]

The North American AMSA design from 1968:
(from Dennis R.Jenkins "B-1 Lancer")

 

[Grey Havoc]

A 1989 Air War College paper on the then limitations of, and possible options for, conventional weapons regarding the B-1B in the ETO: http://www.dtic.mil/dtic/tr/fulltext/u2/a220571.pdf

 

[overscan (PaulMM)]

Collected General Dynamics AMSA / B-1 studies from http://www.codeonemagazine.com/article.html?item_id=114

 

[hesham]

Amazing drawings my dear Paul.

 

[Stargazer]

Absolutely splendid! Thanks for sharing.

 

[OM]

Absolutely splendid! Thanks for sharing.

...Agreed. Excellent find, sir!

 

[Triton]

Yep, I saw those a while ago. I didn't want to steal the thunder of CodeOne and so I didn't post them.

 

[overscan (PaulMM)]

I posted their existence in this topic some time ago, but noone seemed to notice.

I recommend everyone check out www.codeonemagazine.com it has lots of PDF back issues with some cool articles as well as interesting online content.

 

[F-14D]

A 1989 Air War College paper on the then limitations of, and possible options for, conventional weapons regarding the B-1B in the ETO: http://www.dtic.mil/dtic/tr/fulltext/u2/a220571.pdf

Interesting paper, especially when you consider that use of conventional weapons was a major mission of the B-1A.

 

[Grey Havoc]

A 1989 Air War College paper on the then limitations of, and possible options for, conventional weapons regarding the B-1B in the ETO: http://www.dtic.mil/dtic/tr/fulltext/u2/a220571.pdf

Interesting paper, especially when you consider that use of conventional weapons was a major mission of the B-1A.

They made some ill-advised compromises with the B-1B design, in the interest of keeping costs down as well as optimising it for the low-level (nuclear) penetration role, which of course quickly backfired.

 

[F-14D]

A 1989 Air War College paper on the then limitations of, and possible options for, conventional weapons regarding the B-1B in the ETO: http://www.dtic.mil/dtic/tr/fulltext/u2/a220571.pdf

Interesting paper, especially when you consider that use of conventional weapons was a major mission of the B-1A.

They made some ill-advised compromises with the B-1B design, in the interest of keeping costs down as well as optimising it for the low-level (nuclear) penetration role, which of course quickly backfired.

They were certainly trying to reduce costs as well as make it more "stealthy" and pure nuke, but the A was also real good at low level flight

 

[aim9xray]

What were the ill-advised design compromises in the A-to-B evolution?

 

[gtg947h]

What were the ill-advised design compromises in the A-to-B evolution?

One of the more well-known ones was going from variable supersonic inlets to fixed ones with vanes to block the fan faces from radar. It reduced frontal RCS at the expense of a significant reduction in top speed at high altitude.

 

[Grey Havoc]

They were certainly trying to reduce costs as well as make it more "stealthy" and pure nuke, but the A was also real good at low level flight

Indeed. They should have stuck with the B-1A, though hindsight can be 20/20.

What were the ill-advised design compromises in the A-to-B evolution?

One of the more well-known ones was going from variable supersonic inlets to fixed ones with vanes to block the fan faces from radar. It reduced frontal RCS at the expense of a significant reduction in top speed at high altitude.

Another was the drastic reduction of the amount of titanium in the airframe.

 

[sferrin]

What were the ill-advised design compromises in the A-to-B evolution?

One of the more well-known ones was going from variable supersonic inlets to fixed ones with vanes to block the fan faces from radar. It reduced frontal RCS at the expense of a significant reduction in top speed at high altitude.

When they did the trade study they determined that the lower RCS made it more survivable despite the reduction in speed. So hardly "ill-advised".

 

[F-14D]

What were the ill-advised design compromises in the A-to-B evolution?

One of the more well-known ones was going from variable supersonic inlets to fixed ones with vanes to block the fan faces from radar. It reduced frontal RCS at the expense of a significant reduction in top speed at high altitude.

When they did the trade study they determined that the lower RCS made it more survivable despite the reduction in speed. So hardly "ill-advised".

I suspect it was more cost driven. Even if the B-1A had gone into production, there would have been some changes. For one thing, the requirement for M1.2 on the deck was going to be lowered to .9; it had been shown that lowering the speed by .3M did not lead to a significant increase in vulnerability, but would save a lot of money, and lighten the aircraft. Also, in production B-1As the variable inlets would be retained, but they would be disabled in peacetime use. There isn't that much proficiency benefit from flying at M2, and a lot of maintenance $ would be saved. IN war, they would push the circuit breakers back in and you'd get back the M2. F-14D (no, not me) did the same thing.

In the B-1B, of course the variables weren't there at all. Given that the B would never fly at ~M2, the decision was made to lighten the wing structure as well to save weight and cost. I suspect, though, they could have gotten the frontal RCS down to nearly that level with the variables in place, but it would take money and time, and they wanted those a/c available soonest. We forget in our now glacial development speeds, that they designed, ordered, tested, produced and delivered 100 a/c in less than seven years. In fact, all 100 B-1Bs were delivered in a space of less than three years.

So simplicity and cost were big factors, which is why I think the seed reduction was cost driven. It's also why, as delivered the B-1B was a less flexible aircraft than the B-1A would have been, although it did have greater range.

 

[hesham]

From Airpower 9/2004.

 

[Skybolt]

Hi all, let me revive this old topic:
link to WIND TUNNEL INVESTIGATION OF A 1/9-SCALE BOEING COMPANY AMSA AIRPLANE- INLET MODEL AT TRANSONIC AND SUPERSONIC MACH NUMBERS.

http://www.dtic.mil/dtic/tr/fulltext/u2/385284.pdf

Aircraft very similar to the traced out sketch published by Scott along time ago. From the wind tunnels model, they tried out three-engined configurations too.

And
Wind Tunnel Investigation of a 1/8-Scale AMSA Aircraft-Inlet Model at Transonic and Supersonic Mach Numbers from GD published here and on which a rather complete report exist on DTIC.

http://www.dtic.mil/dtic/tr/fulltext/u2/385450.pdf

Very similar to the above mentioned well known AMPSS configuration.

 

[overscan (PaulMM)]

Marco! Its been almost 3 years - welcome back

 

[hesham]

Welcome your return my dear Skybolt.

 

[bobbymike]

Welcome back Skybolt your contribution to this forum have been missed.

 

[overscan (PaulMM)]

Hi all, let me revive this old topic:
link to WIND TUNNEL INVESTIGATION OF A 1/9-SCALE BOEING COMPANY AMSA AIRPLANE- INLET MODEL AT TRANSONIC AND SUPERSONIC MACH NUMBERS.
http://www.dtic.mil/dtic/tr/fulltext/u2/385284.pdf

Aircraft very similar to the traced out sketch published by Scott along time ago. From the wind tunnels model, they tried out three-engined configurations too.

And
Wind Tunnel Investigation of a 1/8-Scale AMSA Aircraft-Inlet Model at Transonic and Supersonic Mach Numbers from GD published here and on which a rather complete report exist on DTIC.
http://www.dtic.mil/dtic/tr/fulltext/u2/385450.pdf
Very similar to the above mentioned well known AMPSS configuration.

General Dynamics AMSA from report

 

[overscan (PaulMM)]

All the General Dynamics AMSA materials from http://www.codeonemagazine.com/article.html?item_id=114 posted here for comment and posterity. Note the VG Subsonic design. The Configuration 2906 seems to be the version windtunnel tested above.