punch@tut.cis.ohio-state.edu (William F Punch) (05/03/89)
From: William F Punch <punch@tut.cis.ohio-state.edu>
I got to go to the Wright Pat air force museum this weekend (What a
fantastic place, at worst second only to National Air and Space) and
happened to see the B1A prototype there. My father works for GE and
had worked on those engines before the whole thing got cancelled.
My question is how big a difference is there between the A and B? I
know the A was supersonic and the B subsonic, but how about payload,
range etc. What were the technical reasons for changing the B to
subsonic (or was it all just political/money)? Does the B1 program
suffer a lot from getting only B's instead of the original A's.
To stretch things even farther, how different is the B1A from the
original XB-70 (range, payload, speed)? Were any of the results from the
B-70 program used in the B1, or was all that lost? Why was the B-70
cancelled (I remember a crahs but assume the cancellation was
politics). Thanks for the information.
>>>Bill<<<nak@cbnews.ATT.COM (Neil A. Kirby) (05/05/89)
From: nak@cbnews.ATT.COM (Neil A. Kirby) In article <6185@cbnews.ATT.COM> punch@tut.cis.ohio-state.edu (William F Punch) writes: > > >From: William F Punch <punch@tut.cis.ohio-state.edu> > >My question is how big a difference is there between the A and B? I >know the A was supersonic and the B subsonic, but how about payload, >range etc. What were the technical reasons for changing the B to >subsonic (or was it all just political/money)? Does the B1 program >suffer a lot from getting only B's instead of the original A's. One of the BIG differences is radar cross section. The B1-A had a huge radar cross section. My electromagnetics prof did work on the RCS measurements for the two birds. I'm not sure what they did to reduce the RCS, he wouldn't say. Funny, this work happened about the same time that Carter announced Stealth... Is the B1-B subsonic? Neil Kirby ...cbsck!nak
henry@zoo.toronto.edu (Henry Spencer) (05/05/89)
From: henry@zoo.toronto.edu (Henry Spencer) >My question is how big a difference is there between the A and B? I >know the A was supersonic and the B subsonic, but how about payload, >range etc. What were the technical reasons for changing the B to >subsonic (or was it all just political/money)? ... The differences are mostly modest improvements of one kind and another. For example, lower radar cross-section. The loss of supersonic capability is really pretty unimportant, since it wasn't very useful in the first place. (It was available only at high altitude.) The B-1 would probably have been better off without the original supersonic requirement, actually. I think they just found it inconvenient to retain supersonic speed and said "oh, to hell with it". I don't think payload and range have changed much, although they may have reshuffled the payload-bay layout a bit for bigger cruise missiles. >To stretch things even farther, how different is the B1A from the >original XB-70 (range, payload, speed)? Very. Much. Extremely. Range and payload probably vaguely similar, but the difference between cruising speeds of 600 mph and 2000 mph is not trivial! The XB-70 was built for blazing speed at very high altitude, the B-1A was built for modest speed at very low altitude. > Were any of the results from the >B-70 program used in the B1, or was all that lost? Some of the more fundamental technology may have been relevant, but there is so little resemblance between the aircraft that I'd be surprised if there was much overlap. > Why was the B-70 >cancelled (I remember a crahs but assume the cancellation was politics).... The crash was in fact post-cancellation, I think. The B-70 had three big problems: it arrived at a time when ICBMs were increasingly looking better than manned bombers for the strategic-nuclear role, it arrived at a time when flying slower but lower was increasingly thought to be better than flying fast and high, and it was extremely expensive at a time when the ICBM programs were also spending money like water. The hardware pretty much worked, although with delays and cost overruns, but the political and strategic issues killed it. Henry Spencer at U of Toronto Zoology uunet!attcan!utzoo!henry henry@zoo.toronto.edu
fiddler@Sun.COM (Steve Hix) (05/05/89)
From: fiddler@Sun.COM (Steve Hix) In article <6185@cbnews.ATT.COM>, punch@tut.cis.ohio-state.edu (William F Punch) writes: > > To stretch things even farther, how different is the B1A from the > original XB-70 (range, payload, speed)? Were any of the results from the > B-70 program used in the B1, or was all that lost? Why was the B-70 > cancelled (I remember a crahs but assume the cancellation was > politics). Thanks for the information. The B-70 never went into service because its mission, high-speed, high-altitude penetration of Soviet airspace wasn't going to work with the newer classes of SAM going into service. The B-1A had supersonic dash ability, but it couldn't do it for very long because of high fuel consumption. The gains bought by supersonic dash weren't very great, and the B-1B didn't try for it.
tek@CS.UCLA.EDU (Ted Kim (ATW)) (05/05/89)
From: tek@CS.UCLA.EDU (Ted Kim (ATW)) In article <6185@cbnews.ATT.COM> punch@tut.cis.ohio-state.edu (William F Punch) writes: >... >To stretch things even farther, how different is the B1A from the >original XB-70 (range, payload, speed)? Were any of the results from the >B-70 program used in the B1, or was all that lost? Why was the B-70 >cancelled (I remember a crahs but assume the cancellation was >politics). Thanks for the information. > >>>Bill<<< The XB-70 was going to be the ultimate in high-altitude precision bombing. It did pioneer some titanium construction technologies, which I have heard were later applied to the SR-71. I don't know much about the politics involved. But, I think one of the main reasons to cancel the B-70 was that idea that high-altitude bombing was not the way to go and that a low-alititude penetration strategy was better. Hence, the mods made to the B-52 to switch it to that role. I don't know of any relationship between B-70 and B-1. Ted Kim ARPAnet: tek@penzance.cs.ucla.edu UCLA Computer Science Department UUCP: ...!ucbvax!cs.ucla.edu!tek 3804C Boelter Hall PHONE: (213) 206-8696 Los Angeles, CA 90024 ESPnet: tek@ouija.board
fiddler@Sun.COM (Steve Hix) (05/06/89)
From: fiddler@Sun.COM (Steve Hix) In article <6257@cbnews.ATT.COM>, tek@CS.UCLA.EDU (Ted Kim (ATW)) writes: > The XB-70 was going to be the ultimate in high-altitude precision > bombing. It did pioneer some titanium construction technologies, which > I have heard were later applied to the SR-71. I don't know much about The two aircraft's development overlapped quite a bit, so the SR-71 wouldn't have benefitted much from the XB-70 program. Doubt if Lockheed talked all that much with Northa American, either. The B-70 may have used some titanium, but the majority of its structure and skin was stainless steel. They spent quite a bit getting steel honeycomb bonding down right. Even then, the faster bird (XB-70A) ended up having speed limitations set on it after it lost some skin during high-speed flight because of bonding failures.
maniac%garnet.Berkeley.EDU@ucbvax.Berkeley.EDU (George W. Herbert) (05/11/89)
From: maniac%garnet.Berkeley.EDU@ucbvax.Berkeley.EDU (George W. Herbert) In article <6256@cbnews.ATT.COM> fiddler@Sun.COM (Steve Hix) writes: >The B-1A had supersonic dash ability, but it couldn't do it for >very long because of high fuel consumption. The gains bought by >supersonic dash weren't very great, and the B-1B didn't try for >it. Having seen this mistake float around for ~ 20 articles, it's time to put it to rest. THE B-1B IS SUPERSONIC. The B-1A was designed to do mach 2 plus at mis level, costing all sorts of design penalties. The B-1B was derated to about mach 1.2 max (but still Very supersonic) primarily for radar sig. reasons: the intakes were made more stealthy, and the supersonic effeciency fell through the floor... They don't very often, but that's primarily for range considerations, not airframe.