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sllevin
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Feb 23, 2007 8:21 am

Quoting Scbriml (Reply 22):
Wasn't the Sukhoi T-4 the Russian answer to the XB-70?

Yes, it was also fly-by-wire (since the Soviets decided not to try and solve the hydraulic issues). That coupled with being unstable at supersonic speeds made it quite a handful. There were 10 flights, the fastest at Mach 1.3, but given the flight dynamics an engine failure -- or even an unstart -- would have been catastrophic.

Even in the B-70 unstarts were quite an event. Fitz Fulton described it as "being t-boned by a locomotive and thrown off a cliff"

Going back to the original question about Mach 4 operation; I've never seen or heard of anything past early-paper descriptions involving the XB-70 and speeds beyond Mach 3.2. The limitations of the stainless steel construction would have prevented it, even if it didn't turn out that hypersonic stagnation begins to set in around Mach 3.5 -- and exponentially increases temperatures (something not known during the B-70's design phase).

Walt Spivak's belief was that Ship 3 would have reached the Mach 3.2 design speed, based on the improvements over Ship 2.

Steve
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Feb 23, 2007 9:10 am

Quoting Blackbird (Reply 49):
Does 32:1 Compression Ratio look high, about right, or low for Mach 3?

At this time there is no other aircraft in the XB-70 speed, size, and weight class. Nothing compares. Until there is, the XB-70 simply remains "the best of breed" in this category. The closest to it was the SR-71 but only in speed, The empty weight of the XB-70 is approx. the same as a fully loaded SR-71.



Starglider
 
Blackbird
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Feb 23, 2007 9:15 am

Silevin,

I thought hypersonic stagnation occured at Mach 5.4?


Starglider,

Do you know what the A-12/YF-12/SR-71's inlet compression ratios were?


Andrea K
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sat Feb 24, 2007 5:59 pm

Quoting Blackbird (Reply 52):
Do you know what the A-12/YF-12/SR-71's inlet compression ratios were?

Yes, at Mach 3.2 free stream cruise speed and cruise altitude, inlet pressure ratios are:
- Just behind the inlet shock: 1.62:1
- just in front of the terminal shock: 11.88:1
- at the engine inlet face: approx. 30:1


Starglider
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Tue Feb 27, 2007 7:27 am

Quoting Blackbird (Reply 41):
Can you put the footage of the XB-70 doing mach 3 on youtube or something so I can hear it with my own two ears?

Andrea,

The footage is copied from the tape to a digital format. It can be viewed with windows media player. Before trying to put the footage on youtube, perhaps, if you like, i could send it to you in an e-mail? If so, please send me an e-mail address via the user profile and i will send it to you with a return mail. File size is approx. 17 Mb.




Regards,
Starglider
 
ContnlEliteCMH
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Tue Feb 27, 2007 10:02 pm

Quoting Stitch (Reply 1):
The XB-70 has been a favorite of mine for decades, so I have read a great deal about her and the commercial SST program.

Yup. Me too. I grew up in Middletown, Ohio, which is midway between Cincinnati and Dayton. For reasons I cannot recall but which are most certainly somebody's visit to the nearby USAF Museum at Wright-Pat, a poster of the XB-70 showed up in my bedroom about age 5. I gawked at that thing for years. And I wondered how in the heck you pronounced "Valkyrie" and I was too ashamed to ask.

If you're an XB-70 fan, and you're anywhere near Ohio, you really should pay a visit to the USAF Museum in Fairborn. They have the revered XB-70 sitting in the new(er) wing. It's every bit as fantastic in person as it is on the poster. Oh, and it's not far from an SR-71 either, housed in the same building. Or a B-52. You get my point...
Christianity. Islam. Hinduism. Anthropogenic Global Warming. All are matters of faith!
 
HaveBlue
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Wed Feb 28, 2007 1:10 am

The Valkyrie has also been a favorite of mine, an unmatchable piece of aviation engineering and all the more impressive because it was designed in the age of the slide rule. You look at cars from the late 50's and they look ancient, yet the XB is timeless and still would look appropriate on an active ramp. I've always got a kick out of SlamClick calling it 'the most beautiful thing crafted by man', because I wholeheartedly agree.

And ContnlEliteCMH I love that museum. Simply awesome. I've been there several times, though all in the 1990's. Back then the XB-70 Valkyrie was in the Modern Ages hangar, and had the SR-71 just off and almost under its port wing. It also had the X planes underneath its starboard wing, and some alongside. And having a YF-12 and D-21 drone across the ramp was very cool.

The Valkyrie and Blackbird trio have always remained at the top of my list and been a source of endless admiration. I just wish I had got to see either of them fly...
 
Blackbird
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Wed Feb 28, 2007 3:41 am

I doubt hotmail would allow a 17 mb link Starglider... Max I think is 10 mb.

Can you break the file into two pieces? Like two .wmv files. Just don't use that thing that produces file extentions like XYZ.wmv.001 or XYZ.wmv.002 or something (I've seen those extentions before), my computer can't use it...

Andrea K
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Wed Feb 28, 2007 4:56 am

Quoting Blackbird (Reply 57):
I doubt hotmail would allow a 17 mb link Starglider... Max I think is 10 mb.

Can you break the file into two pieces? Like two .wmv files. Just don't use that thing that produces file extentions like XYZ.wmv.001 or XYZ.wmv.002 or something (I've seen those extentions before), my computer can't use it...

Will see what i can do, one way or another it will work out. Will keep you informed.


Regards,
Starglider
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Wed Feb 28, 2007 5:46 am

Quoting ContnlEliteCMH (Reply 55):
If you're an XB-70 fan, and you're anywhere near Ohio, you really should pay a visit to the USAF Museum in Fairborn.

This aircraft inspired me, more than any other aircraft before or after it, to make aviation my day job as soon as i finished school. This year will be the first time i will see the XB-70 in person. I'm connecting the dots at the moment to plan the trip and jump the pond to pay it a visit and spend several days to see all the exhibits in the museum.


Starglider
 
Blackbird
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Wed Feb 28, 2007 10:24 am

Quote:
Will see what i can do, one way or another it will work out. Will keep you informed.

Thank you


Regarding another issue. The inlet compression ratio thing we were discussing earlier. The XB-70 had an effiency of 90% at Mach 3.0, the SR-71's official inlet efficiency at cruise speed was 80%, which is officially at Mach 3.2, but is actually significantly faster. The SR-71's max mach number was to my knowledge never classified.


Andrea K
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Thu Mar 01, 2007 9:03 am

Quoting Blackbird (Reply 60):
the SR-71's official inlet efficiency at cruise speed was 80%, which is officially at Mach 3.2, but is actually significantly faster. The SR-71's max mach number was to my knowledge never classified.

Andrea,

This link might give you some answers regarding the SR-71 / J58 inlet performance potential:

https://drum.umd.edu/dspace/bitstream/1903/2542/1/umi-umd-2426.pdf

It deals with the original inlet designs as used on the SR-71 at a speed of Mach 3.2 and then modified versions extending the inlet into the hypersonic speed range.



Starglider
 
Valcory
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Thu Mar 01, 2007 11:09 am

What about the compression lift theory (riding the waves)i hear the engines were not that powerful and compression lift had to be used to get to get the airplane at Mach 3
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Thu Mar 01, 2007 9:29 pm

Quoting Valcory (Reply 62):
What about the compression lift theory (riding the waves)i hear the engines were not that powerful and compression lift had to be used to get to get the airplane at Mach 3

Both aerodynamics and engines contrubited its share to make the XB-70 what it is.

An aircraft design is always a compromise, a trade-off between many of its sub-systems. The XB-70 was no exception to that rule. However, the aircraft (A/V-2) met its design goal , Mach 3 cruise in heat soaked conditions, without any aerodynamic changes or significant powerplant modifications.

The XB-70's J93 was an exceptional powerplant for its days. It delivered the performance to cruise at Mach 3.
At those speeds the XB-70 inlet and nozzle pay a major contribution. Thrust at Mach 3 is provided by:
- Inlet 60%,
- Engine 25%,
- and nozzle 15%.

Takeoff thrust on a hot day at MTOW with a single engine failure was taken into account by enabling the other 5 engines to run in a temporary over-speed condition to maintain climb speed. In case of a single engine failure at cruise speed, the aircraft had enough excessive thrust (obviously also thanks to compression lift) to maintain Mach 3 cruise with only a 6 or 7 percent range penalty. The NAA engineers advised to maintain Mach 3 cruise in such conditions. Lower speeds or altitudes would reduce range a lot more. Goes to show how well balanced the aircraft is for its design speed/range. Let me finish by mentioning that the aircraft's full potential (regarding range) was never explored due to its limited budget for research only, and the third prototype that was to come close to that potential, was never completed.

Regards,
Starglider
 
Valcory
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Mar 02, 2007 12:12 am

Quoting ContnlEliteCMH (Reply 55):
And I wondered how in the heck you pronounced "Valkyrie" and I was too ashamed to ask.

I had a hard time spelling it (Valcory) was way much easier. I remember as a kid i had the XB-70 model airplane.My first impression was it was a concorde then i start looking at it closer i was like this is some airplane six engines in the back. The Valkyrie is my all time favorite airplane.
 
Valcory
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Mar 02, 2007 12:17 am

Quoting Starglider (Reply 63):
An aircraft design is always a compromise, a trade-off between many of its sub-systems. The XB-70 was no exception to that rule.

That is a given i was just curious no one mention the compression lift theory.
 
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Mar 02, 2007 4:57 am

Quoting Valcory (Reply 65):
That is a given i was just curious no one mention the compression lift theory.

Compression lift was indeed a major design feature that got North American the contract to build the B-70 over the competing Boeing design. Compression lift as utilized in the XB-70 design reduced drag (increased lift) between 20 to 30% at Mach 3 cruise speed when compared to conventional designs. It was mentioned in another thread i started in Tech/Ops recently, titled "An XB-70 AV-2 Question." In reply 7 of that thread to be precise, compression lift was addressed.



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Starglider
 
SCAT15F
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Mar 02, 2007 4:08 pm

Quoting Starglider (Reply 63):
Let me finish by mentioning that the aircraft's full potential (regarding range) was never explored due to its limited budget for research only, and the third prototype that was to come close to that potential, was never completed.

I've always wondered, with AV-3 (if it had been completed and w/ wingtip tanks) with a mach 3.2 top speed and 7000nm+ unrefueled range, the amazing records it could have set and broken, as the SR-71 had such a limited (2500nm) range unrefueled, explaining why all it's intercontinental distance and speed records were well below 2000mph. In fact, I'll bet AV-2 could have done NY to Paris at mach 3-3.1 making it the first sustained mach 3 transatlantic crossing ever.

Maybe Rockwell/Boeing could take AV-1 out of the museum, overhaul it (fix the skin from detatching), use the entire bomb bay for fuel (plus all that electronics area behind the cockpit), FADEC the J93's/AICS system and start setting some records! Bill Gates could fund the project. Big grin
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sat Mar 03, 2007 6:51 am

Quoting SCAT15F (Reply 67):
I'll bet AV-2 could have done NY to Paris at mach 3-3.1 making it the first sustained mach 3 transatlantic crossing ever.

Maybe Rockwell/Boeing could take AV-1 out of the museum, overhaul it (fix the skin from detatching), use the entire bomb bay for fuel (plus all that electronics area behind the cockpit), FADEC the J93's/AICS system and start setting some records! Bill Gates could fund the project.

Would be a great project, have it ready for flight in 2014 to celebrate the 50th anniversary of A/V-1's first flight in 1964.
Seven years to go to make it happen . . . . . . .
Just imagine, breaking those records, It would still be ahead of it's time after all those years sitting idle in the hangar.

I have been doing such flights on FS2004 many times. I have been tweaking ".air" and aircraft ".cfg" files until the flight characteristics and performance simulated the real specs (of A/V-2) and i've built a virtual cockpit panel that reflects, and functionally simulates the real thing as much as possible. "Flying" it is very realistic. When touching the brakes while taxiing the plane, it behaves like the real 500.000 pound plane.



Starglider
 
SCAT15F
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sat Mar 03, 2007 8:20 am

Quoting Starglider (Reply 68):
have it ready for flight in 2014 to celebrate the 50th anniversary of A/V-1's first flight in 1964

That would be perfect!

Imagine if they kept the project "secret" and sealed off the museum hanger w/ a cover story and do all the refurbishing before the anniversary date, then invite the media, etc. roll it out, start it up and take off ! (they would probably need to extend the runway, of course)  bigthumbsup 
 
Blackbird
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sat Mar 03, 2007 9:20 am

Going back to your first post. The XB-70 to achieve Mach 4, the plane would require more high temp steels in it's construction, but potentially within the abilities of North American (who built the X-15). Believe it or not, it doesn't sound to be all that outrageous. The F-106 would have had to have been made out of more high-temp materials than the slower F-102A since it was substantially faster.

I'm not sure if you'd need as high a sweep angle as you posted in your speculative re-design. The leading edges would have to be sharper, almost no doubt about that, and so would the ECM pods most likely, however I'm not sure how much of a sweep-angle would be needed. Perhaps a sharp 65.5-degree sweep could be retained with a sharper more precisely contoured (possibly extended, and more highly swept) apex, and a reduced curvature along the top of the wing.

The inlets and engines were even openly admitted to be able to perform at Mach 4. The wedge splitter might need a far sharper leading-edge (and might need to be extended further forward) to keep the shockwave under the bulk of the wing.

Systems wise, the Environmental Control System would need a revision to more efficiently use the fuel for cooling purposes, a production design would also need 4 crew-members. JP-7 (Unless the JP6 was rated for Mach 4) may be needed to tolerate the extra heat. A new hydraulic-fluid would be needed since the version used was unsatisfactory. Additionally fuel-tank sealants would need to be able to last more than a thousand hours (and potentially may require tolerance to JP-7 exposure, a problem with the SR-71)


P.S. The video I saw of the XB-70 that you provided stated that by flight 15 they were already at 1,900 MPH for 20 minutes, and on flight 17 they achieved Mach 3. I was always under the impression they did Mach 3 on their 37th flight... Either way the J-93's made a sound that reminds me of a type of siren...

Andrea Kent,
[email protected]
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sat Mar 03, 2007 11:56 am

Quoting Blackbird (Reply 70):
Going back to your first post. The XB-70 to achieve Mach 4, the plane would require more high temp steels in it's construction, but potentially within the abilities of North American (who built the X-15). Believe it or not, it doesn't sound to be all that outrageous.

I agree, the "concept" could very well achieve Mach 4. But not with the aircraft in its present form. Comparing the F-102 with the F-106 is clear to me with regard to the increased speed of the F-106 over the F-102. But i'm sure you know that drag (friction heat) does not increase in a linear way with increasing speed. The increase in temperature (ratio) between Mach 3 to Mach 4 is many times higher than the temperature increase (ratio) between Mach 1 to Mach 2 in case of the F-102 / F-106.

And yes, NAA also designed the X-15 but the XB-70 cannot be compared to the X-15. Although the X-15 reached speeds in excess of Mach 6, which required alloys such as Inconel, it was designed to do so for only a few minutes per flight and its airframe had a very limited lifespan when compared to the B-70. The X-15 contributed very little to the XB-70 development, it is like comparing apples with pears.

The B-70 was designed to cruise in heat-soaked conditions for hours at a time. Designed for a lifespan somewhere between 20.000 to 50,000 hours (the production version).

Quoting Blackbird (Reply 70):
Perhaps a sharp 65.5-degree sweep could be retained with a sharper more precisely contoured (possibly extended, and more highly swept) apex, and a reduced curvature along the top of the wing

NASA has wind-tunnel tested the current 65.5 sweep angle up to speeds of Mach 3.5 and came to the conclusion that aerodynamic performance was most efficient at Mach 3. Aerodynamic performance dropped significantly before reaching Mach 3.5. That is not to say that by tweaking the aerodynamics of the aircraft like you suggest, could not have resulted in improved performance. Only through in-depth research those questions can be answered.

Quoting Blackbird (Reply 70):
(Unless the JP6 was rated for Mach 4)

That would have been a matter of keeping the fuel temperature below 260F (300F at the engine feed lines).

Quoting Blackbird (Reply 70):
I was always under the impression they did Mach 3 on their 37th flight... Either way the J-93's made a sound that reminds me of a type of siren...

Coincidentally, both A/V-1 and A/V-2 reached Mach 3 at their respective 17th flight. A/V-1 on Oct. 14 1965 and A/V-2 on Jan. 3 1966. The J93 near idle, to me, has the most serene sound of any jet engine i've heard so-far. Probably the loudest engine at the other end of the spectrum though. I wondering if the j93s made that "howling wolf" sound (like the J79 in the F-104 did) when the throttles were advanced.

Starglider
 
Blackbird
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sat Mar 03, 2007 12:27 pm

The video you gave me, did it cover all the footage during the acceleration?

Because I remember you covering mach numbers temperature changes, and "there's that big magic number" But watching the video, I don't remember seeing that.

Andrea K

[Edited 2007-03-03 04:28:48]
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sat Mar 03, 2007 5:40 pm

Quoting Blackbird (Reply 72):
The video you gave me, did it cover all the footage during the acceleration?

Because I remember you covering mach numbers temperature changes, and "there's that big magic number" But watching the video, I don't remember seeing that.

Andrea K

Andrea,
For clarity i have copied reply 41 and reply 48 from your thread "General Electric GE-4 Engine Nozzle":

There is nothing missing on the video. It is the complete third section of the tape (see copy of reply 48 below).


Reply 41:

Quoting Blackbird (Reply 39):
The flight tape with White calling out the magic number... can you transcribe what was information was available and stated on the tape?



"Andrea,
As requested, here is the transcript, starting shortly before A/V-1 reached "the magic number":

62,000 ft. Mach 2.6, 540 kt;

67,000 ft. Mach 2.77, 484F;

68,000 ft. Mach 2.82, light buffet, 512 kt. 506F;

Mach 2.9, temp 542F;

White:
"Mach 2.94 at 69,000, 551 on the temp - things are sure looking good - Mach 2.96 at 69,300, total temperature 567."

White:
"Okay, there's that big magic number." (Mach 3 / 70,000 ft)

Ground control almost simultaneously:
"Al, here's that big magic number boy"

White:
"That's a boy"

Ground control:
"Congratulations to both of you"

A minute later, temperature 576F, well within expected value.

White:
"Just a second, I got a little problem here."

A slight nose up trim change at 70,000 ft caught the pilots by surprise. White assumed that it was the primary shock wave coming under the leading edge of the wing. A small correction in pitch attitude was made that caused the aircraft to lose almost 1000 ft. All instruments looked good and the airplane felt good so White started to climb back up, but at about 69,500 ft there was a loud bang. They had been at Mach 3 for about 2 minutes, max Mach number was 3.02. Nobody could identify the source of the bang so they throttled back to slow down and started a descent. At lower speeds and altitude a chase plane caught up and reported that a large piece of skin was missing off the leading edge of the left wing just outboard of the inlet duct. It was decided to go back to base."


Reply 48:

"Quoting Blackbird (Reply 46):
Just before I start, you said Al White was under the impresion that the shockwave from the apex was passing under the wing. Did he specifically say that in the recording? Also, what kind of video/audio recording was used?



"He did not state that on the tape and for completeness, apart from White's shock wave theory, the book referred to below, mentioned the possibility that the pitch up could have been caused by Joe Cotton moving the bypass doors, which he was doing at the time.

The transcript was compiled from a video tape with the title "XB-70 Valkyrie" and from the Jenkins & Landis book named "Valkyrie, North American's Mach 3 Superbomber", published in 2004.

The video contains original North American Aviation footage and is basically divided in 3 sections:

1. Roll-out with the complete speech held by Maj. Gen. Fred J. Ascani.
2. Ground tests, first flight/debriefing and flight tests up-to and including M 1.4.
3. Flight tests from M1.4 and up, ending with the "Magic Number" M 3 flight.

The radio transmissions:

Ground control almost simultaneously:
"Al, here's that big magic number boy"

White:
"That's a boy"

Ground control:
"Congratulations to both of you"

were taken from the video. All other transcript was taken from the mentioned book with references to official documents."


This should answer your question.


Regards,
Starglider
 
Blackbird
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sun Mar 04, 2007 6:23 am

Honestly, I'm listening to the tape....

I don't remember any part hearing White or Cotton or the ATC saying

Quote:
62,000 ft. Mach 2.6, 540 kt;
67,000 ft. Mach 2.77, 484F;
68,000 ft. Mach 2.82, light buffet, 512 kt. 506F;
Mach 2.9, temp 542F;

Or

Quote:
White:
"Mach 2.94 at 69,000, 551 on the temp - things are sure looking good - Mach 2.96 at 69,300, total temperature 567."

I DO remember hearing this...

Quote:
White:
"Okay, there's that big magic number." (Mach 3 / 70,000 ft)

Ground control almost simultaneously:
"Al, here's that big magic number boy"

White:
"That's a boy"

Ground control:
"Congratulations to both of you"

Andrea Kent
 
Starglider
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sun Mar 04, 2007 6:49 am

Quoting Blackbird (Reply 74):
Honestly, I'm listening to the tape....

I don't remember any part hearing White or Cotton or the ATC saying

Quote:
62,000 ft. Mach 2.6, 540 kt;
67,000 ft. Mach 2.77, 484F;
68,000 ft. Mach 2.82, light buffet, 512 kt. 506F;
Mach 2.9, temp 542F;

Or

Quote:
White:
"Mach 2.94 at 69,000, 551 on the temp - things are sure looking good - Mach 2.96 at 69,300, total temperature 567."

Andrea,
Please read my previous reply (reply 73) once more. Only limited transcript was taken from the tape. Most of the transcript was taken from the book mentioned in my previous reply, quoted below:

Quoting Starglider (Reply 73):
The transcript was compiled from a video tape with the title "XB-70 Valkyrie" and from the Jenkins & Landis book named "Valkyrie, North American's Mach 3 Superbomber", published in 2004

Starglider
 
Blackbird
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sun Mar 04, 2007 9:43 am

So the tape did not cover all that was said, but the book did, right?

Andrea Kent
 
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sun Mar 04, 2007 9:54 pm

Quoting Blackbird (Reply 76):
So the tape did not cover all that was said, but the book did, right?

That is correct. This book, in my opinion, is the most comprehensive book on a single experimental aircraft type to date.
It is a beautiful example of printer's art, hard cover, containing 264 pages of well written information. The writers have done magnificent research on this aircraft and any specific issue is backed by references to official documents.

For anyone with interest in the B-70, this book is for you, but even if you are not interested in the B-70 it is for you. In that respect the book will be a mind changer regarding it's capabilities and all the buzz created by politicians who wanted to see the project fail for whatever obscure reasons (easy way out for them is just to say it costs too much). It will become clear how manipulation by politicians of that period, without any aerospace knowledge, killed a truly sound design which only needed to mature to a production ready aircraft, just as those in other countries have done to the AVRO CF-105 Arrow and the BAC TSR-2.


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Starglider
 
Blackbird
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Mon Mar 05, 2007 3:13 am

Yeah, and the ironic thing is that the truth was was that neither All Bomber, or All ICBM was the answer, but both in a well balanced military

Andrea
 
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Mon Mar 05, 2007 4:32 am

How true, with hindsight, having canceled the B-70 as a weapon system because the missiles in their silo's would do the job according to the Secretary of Defence, just calculate how much has been invested/spent in heavy bombers like the B-1A, B-1B and B-2? The price tag of one B-2 just about equals the cost of the entire B-70 project at moment of cancellation. None of the B-70 successors have its capability with respect to response time. Even more ironically, i've read reports that in the early nineties, a supersonic cruiser was on the DoD list of considerations, and all that AFTER procurement of the B-1Bs and B-2s! Why? Because of response time!!



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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Mon Mar 05, 2007 4:54 am

So Ironic it's almost sickening... and the funny part is: If a person could go back in time and tell JFK, MacNamara, the various people in the defense department who were proponents of only bombers, or only missiles, etc that the answer was actually rather than a huge number of one or the other, but a balanced number of both XB-70's and Missiles, none of them would have realized the wisdom, would have agreed with it


Andrea K

[Edited 2007-03-04 21:04:41]
 
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Tue Mar 06, 2007 9:09 am

A quote from one of the books on this topic makes it clear:

"McNamara was noted for his reliance on statistics and little else. If there existed a concept, or even a piece of hardware, that he could not reduce to numbers or charts, there was a good chance that he would question its value. The B-70 was a complex aircraft and the program for its development was likewise complex and expensive.

McNamara did not like the program for the very reason that its complexities could not easily be reduced to figures on a flip-over chart.

At NAA, back in the early 1960s, the work force was proud of their latest creation, the XB-70. They were also proud because secretary McNamara was on his way to visit the plant and look at their latest creation. Everything they worked for rested on the secretary's visit to the plant. Finally he arrived. everyone waited to greet him, but the secretary apparently wasn't interested in polite greetings. He exited his car, and in his best Whiz Kid fashion, took a short walk around the aircraft, got back into his car and drove off. The visit was an anti-climax. Not only were the people of NAA left to wonder what they had done to deserve such cavalier treatment, but they were also left wondering about the very future of the project. Sure, programs get canceled every day but this was different. McNamara's visit provides focus on the real reason the XB-70 was canceled. It was not because of funding shortages. It was not because it wasn't a viable design. and it was not because of insurmountable technical problems. The main reason the airplane was canceled was because the bean-counter mentality rampant in the DOD at the time. The only things that mattered to McNamara were statistics. If the numbers did not add up, scrap the project.

In the case of the XB-70 it was "all or nothing." Most of the time if it wasn't to his liking, it was "nothing." No one knew better how to manipulate figures to prove a point, he couldn't lose. The people, the US Air Force, the producers of the aircraft, and the world of aviation found this out too late."


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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Tue Mar 06, 2007 10:25 am

Quoting Starglider (Reply 79):
How true, with hindsight, having canceled the B-70 as a weapon system because the missiles in their silo's would do the job according to the Secretary of Defence, just calculate how much has been invested/spent in heavy bombers like the B-1A, B-1B and B-2? The price tag of one B-2 just about equals the cost of the entire B-70 project at moment of cancellation. None of the B-70 successors have its capability with respect to response time.

We don't know how expensive the B-70 would have been in service. Inflation, unknown repair issues, weight growth, etc. would have affected the B-70 just as it did the B-1 and B-2. No truly fair cost comparisons can be made. Theoretical solutions often look better then something in service because an estimate always looks better than hard numbers derived from real experience. Any system gets more expensive when deployed in the real world. In the military real world costs are often 2-3 times the estimates.

Quoting Starglider (Reply 79):
Even more ironically, i've read reports that in the early nineties, a supersonic cruiser was on the DoD list of considerations, and all that AFTER procurement of the B-1Bs and B-2s! Why? Because of response time!!

As for response time, if you want ra short time to get to the target you use missiles. That kind of response time is not a big deal for strategic deterrence anyway. The kind of response time that matters in deterrence is amount of time it takes to LEAVE THE SILO OR BASE - the time it takes to get to the target is of secondary importance. You can take a long time to get to the target as long as you don't get nuked on the runway. At this the B70 would be no better than the B1 or B2 - and perhaps worse because it would probably have less endurance on air-born alert and may have been harder to keep in ready status on the ground.

The B-70 would probably have been more vulnerable in the 80's and 90's then low flying solutions like the B1B and cruise missiles. It turned out that stealth and LOW altitude - rather than speed and HIGH altitude - is the way to avoid air defence. Anybody can attack something at faster and higher altitude by just building better performing missiles, and planes like the Mig-25. To counter a stealthy attack under the radar, however, you need a great deal of high tech stuff operated by well trained people. The Soviets could (and did) build things that could take the B-70 but never built anything that would kill any significant number of B2's and cruise missiles - and not for lack for trying.

Quoting Blackbird (Reply 80):
So Ironic it's almost sickening... and the funny part is: If a person could go back in time and tell JFK, MacNamara, the various people in the defense department who were proponents of only bombers, or only missiles, etc that the answer was actually rather than a huge number of one or the other, but a balanced number of both XB-70's and Missiles, none of them would have realized the wisdom, would have agreed with it

We did build a balanced number of land based and sea based ballistic missiles, and bombers. We just built the B1B, cruise missiles, and the B2 rather than the B70. That was a good decision
 
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Wed Mar 07, 2007 2:58 am

Wasn't the B-70 relegated to Test duty before the AMSA (B-1) was conceived, or at least the same time?

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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Wed Mar 07, 2007 9:51 am

Quoting Cloudy (Reply 82):
We don't know how expensive the B-70 would have been in service. Inflation, unknown repair issues, weight growth, etc. would have affected the B-70 just as it did the B-1 and B-2. No truly fair cost comparisons can be made.

True, we don't know because they never went into service but there are figures available about cost:

Total XB-70 program cost for 2.47 aircraft (A/V- 1, A/V-2 and a 0.47 completed A/V-3): $1,036,344,177 as published in April 1972.

The Budgetary and Planning Proposal generated in February 1959 for the production of 62 RS-70 Air Vehicles was analyzed in conjunction with the B-70 Cost Study to provide program growth visibility.

The results of the study showed an RS-70 First Unit Cost for the 62 aircraft proposal of $157 Million, as compared with the XB-70 actual First Unit Cost of $163 Million and Average Unit Cost for the 3 aircraft (actually 2.47) of $123.8 Million. RS-70 Average Unit Cost would have been considerably lower than that. The RS-70 cost did not include the Bomb/Nav or Defensive Subsystems. Furthermore, just as an indication that production costs for an RS-70 fleet would cost less than opponents claimed:

An analysis showed that the large improvement in the structures cost for A/V-3 over A/V-2 was due primarily to the great strides made in honeycomb panel fabrication. For example, the production hours required to fabricate 5200 gross square feet of honeycomb panels for A/V-3, required less than 50 percent of the hours required for A/V-2:

A/V-1: 259 hours per square foot,
A/V-2: 176.5 hours per square foot,
A/V-3: 84 hours per square foot

A quality control study also showed that A/V-3 had 12 percent of the rejection rate that A/V-2 had for the same section.


The B-2 Program total cost is estimated at $44,650,000,000 spread over 20 B-2 aircraft (in 1994 U$ dollars). Cost per plane is $2.2 Billion! Of course inflation over the years has to be taken in consideration.

Quoting Cloudy (Reply 82):
As for response time, if you want ra short time to get to the target you use missiles.

Once you push the button you can not recall a missile. You can recall a manned bomber, even a Mach 3 aircraft so it has deterrence while in the air while a missile in flight has not.

Quoting Cloudy (Reply 82):
You can take a long time to get to the target as long as you don't get nuked on the runway. At this the B70 would be no better than the B1 or B2 - and perhaps worse because it would probably have less endurance on air-born alert and may have been harder to keep in ready status on the ground.

The B-70 would be able to designate several targets during its mission, needing a third of the time to reach each of them when compared to the B-1 or B-2, reducing reaction time of the adversary 3 fold between targets. With a Mach 3 aircraft an airborne alert is a lot less necessary when compared to subsonic aircraft. If the B-70 would have seen service, it would have been delivered with a streamlined alert pod which the aircraft could carry (sub-sonically) to relatively forward bases. With this pod the B-70 was provided with self-sufficient ground power to keep its systems powered up and could be ready for takeoff in less than 3 minutes. The pod would provide all necessary hydraulic, electrical, and pneumatic power to the aircraft while it was on ground-alert status, and during maintenance activities.

It would not have had to rely on transport aircraft to carry it's ground support equipment.

Quoting Cloudy (Reply 82):
Anybody can attack something at faster and higher altitude by just building better performing missiles, and planes like the Mig-25. To counter a stealthy attack under the radar, however, you need a great deal of high tech stuff operated by well trained people. The Soviets could (and did) build things that could take the B-70 but never built anything that would kill any significant number of B2's and cruise missiles - and not for lack for trying.

Sure, stealth has its advantages, until its cover is blown, then it is a sitting duck. The MiG-25 as it turned out is not a mach 3 but a mach 2.8 aircraft with a limited endurance. It is disputable if the Russians had something to take on the B-70. The SR-71 was never seriously engaged during its service life, in some respect the B-70 would have a higher chance of survivability than the SR-71 because it had the range performance to alter its course much more liberally.

Quoting Cloudy (Reply 82):
We did build a balanced number of land based and sea based ballistic missiles, and bombers. We just built the B1B, cruise missiles, and the B2 rather than the B70. That was a good decision

Yes, but at what cost when compared to the original B-70 plan?? And let's not forget the B-52 which will be around until 2040 from what i have read, ironically not stealthy at all but, using your theory, many times more vulnerable than the B-70 because it lacks its speed and the B-2's stealth! But there is enough confidence to keep it active for decades to come? Regarding readiness rate, whereas the B-1 averages a 57% ready rate and the B-2 achieved a 26% in 1997, the B-52 averages 80%.

Perhaps the B-70 is still on time to replace the B-52 as originally planned.  Smile

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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Wed Mar 07, 2007 1:13 pm

The XB-70 had a way bigger radar cross section than the B-52, even with the speed advantage...

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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Thu Mar 08, 2007 5:41 am

Quoting Starglider (Reply 59):
This aircraft inspired me, more than any other aircraft before or after it, to make aviation my day job as soon as i finished school. This year will be the first time i will see the XB-70 in person. I'm connecting the dots at the moment to plan the trip and jump the pond to pay it a visit and spend several days to see all the exhibits in the museum.

Well, then you must surely shoot me an instant message when your plans are finalized. Assuming I have nothing in the way, I would very much like to revisit a museum to which I have been so many times.
Christianity. Islam. Hinduism. Anthropogenic Global Warming. All are matters of faith!
 
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Thu Mar 08, 2007 7:32 am

Quoting Blackbird (Reply 83):
Wasn't the B-70 relegated to Test duty before the AMSA (B-1) was conceived, or at least the same time?


The origins of the B-1 can be traced back to 1961 as the Subsonic Low Altitude Bomber (SLAB). Followed by:

Extended Range Strike Aircraft (ERSA)
Low Altitude Manned Penetrator (LAMP)
In 1963, the Advanced Manned Precision Strike System (AMPSS)
And then in 1964, the Advanced Manned Strategic Aircraft (AMSA)

Quoting Blackbird (Reply 85):
The XB-70 had a way bigger radar cross section than the B-52, even with the speed advantage...


I would not be too sure of that claim. The facts, substantiated by test results, reveal a different story. You'd be surprised how far they were able to reduce the radar cross section when compared to the B-52. These test results also dictated that the production version of the B-70, if it had been built, would have had a few minor changes to it's external contours.

The IR signature was also reduced to an acceptable level for the production version of the aircraft by application of a specially developed finish system (coating), combined with exhausting cooling air around the engines exhaust nozzles, using bleed air extracted from the inlet ducts and porous variable inlet ramps.


Starglider

[Edited 2007-03-07 23:36:17]
 
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Thu Mar 08, 2007 7:56 am

Quoting ContnlEliteCMH (Reply 86):
Well, then you must surely shoot me an instant message when your plans are finalized. Assuming I have nothing in the way, I would very much like to revisit a museum to which I have been so many times.

Thanks for your kind gesture. Will keep that in mind and do that as soon as i have definite arrangements in place. I'm focusing on the second half of July this year.

Regards,
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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Thu Mar 08, 2007 9:01 am

Quote:
I would not be too sure of that claim. The facts, substantiated by test results, reveal a different story. You'd be surprised how far they were able to reduce the radar cross section when compared to the B-52. These test results also dictated that the production version of the B-70, if it had been built, would have had a few minor changes to it's external contours.

Do you have any data regarding the efforts of radar-cross section reduction on the XB-70? What changes would have been made to its external contours?

Quote:
The IR signature was also reduced to an acceptable level for the production version of the aircraft by application of a specially developed finish system (coating), combined with exhausting cooling air around the engines exhaust nozzles, using bleed air extracted from the inlet ducts and porous variable inlet ramps.

What would the modified finish look like? And didn't the XB-70 prototypes also use air taken from the inlet ducts around the engines, the internal bypass doors between engines #3 and #4, and excess air taken from the porous variable inlet-ramps?

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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Thu Mar 08, 2007 10:18 am

Quoting Blackbird (Reply 89):
Do you have any data regarding the efforts of radar-cross section reduction on the XB-70? What changes would have been made to its external contours?

Yes, i do have that information. It is a test report of the University of Michigan dealing specifically with the radar cross section of the B-70, prepared for North American Aviation in 1960.

The biggest source of radar returns was the frontal air intake duct for which they tested several RAM coatings applied inside the inlets. These coatings could withstand 650 F and were tested with success on detailed large scale models. Furthermore, the external vertical sides of the lower fuselage in relation to the wing lower surface were tested and it was concluded that if the wing had 5 to 10 deg. dihedral (A/V-2 was constructed with 5 deg. dihedr. for stability reasons) and the vertical sides of the lower fuselage were canted by 5 deg. That would reduce radar cross section even more. Finally it was concluded that if the vertical tails were canted inward between 5 and 20 deg. (5 deg. turned out to be sufficient), in combination with the former mentioned measure would get the best results. These measures would reduce the B-70 radar cross section way below that of the B-52. Obviously not as much as that of the later B-1 but acceptable to serve its purpose. The report concluded that the full scale aircraft would have most likely shown the same results as the models used in the tests. Also, NASA performed wind-tunnel tests to investigate the aerodynamic consequences for these alterations with positive results, no negative effects at mach 3 cruise.

Will reply to your IR question (modified finish) tomorrow, time to get some sleep.

By the way, did you receive my last 4 files (sent March 5th)?


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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Mar 09, 2007 5:13 am

Quoting Blackbird (Reply 89):
What would the modified finish look like? And didn't the XB-70 prototypes also use air taken from the inlet ducts around the engines, the internal bypass doors between engines #3 and #4, and excess air taken from the porous variable inlet-ramps?

With regards to the principal of using inlet bleed air for exhaust cooling to reduce IR signature, there would be no significant difference between prototypes and production aircraft.

See reply 45 of this thread for a "nutshell" explanation of the IR "finish system." At the time of cancellation there were still some issues that needed refinement. They were close to solving those issues but additional work would be needed to enable application in a production process.



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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Mar 09, 2007 6:03 am

According to the date of that paper, the XB-70 wasn't even built yet (maybe parts of it were), correct? Additionally, I remember seeing a diagram in one of the XB-70 books I have which showed the radar cross section reflection from the front with and without RCS changes. The side-reflection if I recall was way higher. Why didn't they cover the side section of the fuselage with RCS wedges and stuff? Wouldn't that have helped?

Didn't the B-70 model if it was a production design would have had a 51-degree canard LE sweepback? Wouldn't increasing dihedral 5-degrees from the original zero to begin, and then another 5 to a total of 10-degrees dihedral to the production model reduce the overall effects of compression lift? Addionally, wouldn't adding further dihedral aggrevate the dihedral effect problems XB-70 A/V-2 had?

What was the RCS differences between AV-1 and AV-2? Also, how much difference did that modification to the modified canard with the higher LE sweepback have on the RCS?

Would AV-3 have featured these modifications, or just some of them? If just some, which ones did B-70 AV/3 possess?

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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Mar 09, 2007 9:19 am

Quoting Blackbird (Reply 92):
According to the date of that paper, the XB-70 wasn't even built yet (maybe parts of it were), correct?

The RCS paper was released to NAA in February 1960. In 1958 the XB-70 went through at least four design changes:

Big version: Width: 800 Height: 620 File size: 69kb



In December 1958 the basic design was was very close to the aircraft ultimately manufactured:

Big version: Width: 800 Height: 619 File size: 67kb


Over 100 different test patterns are included in the 1960 RCS paper. The basic models used represented the ultimately manufactured aircraft.

The full scale air vehicle mockup was completed on February 9, 1959.

Initial A/V-1 sub-assembly began on 5 august, 1960.

Quoting Blackbird (Reply 92):
Additionally, I remember seeing a diagram in one of the XB-70 books I have which showed the radar cross section reflection from the front with and without RCS changes. The side-reflection if I recall was way higher. Why didn't they cover the side section of the fuselage with RCS wedges and stuff? Wouldn't that have helped?

The diagram you refer to is probably the one published on page 94 in the XB-70 book titled "The Ride To Valhalla" written by Remak and Ventolo. That diagram is not based on the mentioned paper which concluded that a much lower RCS was feasible. Various RCS coatings were tested, one of them, named "Ferroxcube 105", was very promising.

The side-reflection in the diagram from the book is based on the prototype airframes (to be tested on A/V-3) and the reduction in RAM in the inlets does not represent the findings as mentioned in the above-mentioned paper. In March 1961 the program was reduced to 3 prototypes on a limited budget which meant no further development of airframe refinements such as proposed in the paper were undertaken. However, A/V-3 was to be used for RCS tests with RAM coatings in the inlets. It is most likely that if production aircraft were to be built, the recommendations of the RCS paper would have been incorporated.

Quoting Blackbird (Reply 92):
Didn't the B-70 model if it was a production design would have had a 51-degree canard LE sweepback? Wouldn't increasing dihedral 5-degrees from the original zero to begin, and then another 5 to a total of 10-degrees dihedral to the production model reduce the overall effects of compression lift? Addionally, wouldn't adding further dihedral aggrevate the dihedral effect problems XB-70 A/V-2 had?

I know that several changes, including changes to the canard, were on the things-to-do list for incorporation into production aircraft. With regard to 10 degree wing dihedral, it was never persued due to cancellation of the production aircraft in March 1961. At that time it may have been in the planning stages to do more investigation into that matter but since the cancellation, priorities changed and NAA had their hands full on completing the prototypes before anything else. By the way, the 5 deg. dihedral as incorporated in A/V-2 already showed promising results according to the RCS paper.

Quoting Blackbird (Reply 92):
What was the RCS differences between AV-1 and AV-2? Also, how much difference did that modification to the modified canard with the higher LE sweepback have on the RCS?

At the time of the test paper in 1960, the differences between A/V-1 and A/V-2, let alone A/V-3 were not finalized yet. Only half way completion of A/V-1 it was decided to incorporate the 5 deg. dihedral into A/V-2.

Quoting Blackbird (Reply 92):
Would AV-3 have featured these modifications, or just some of them? If just some, which ones did B-70 AV/3 possess?

The paper recommended to incorporate those changes into the production aircraft, perhaps maybe in A/V-3 if it was followed by production aircraft. Will dig into my files a bit deeper to see if i can find answers to your question.

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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Fri Mar 09, 2007 10:55 am

I'm wondering what you mean in regard to the statement of the XB-70 being all or nothing in regards of missiles or bombers. Why couldn't both be persued?

Additionally, McNamara, according to what you said took a look at the plane and left. You said it was because he liked charts and stuff. Why couldn't NAA make charts showing the data on the plane for him? Wouldn't that have been possible?

I'm quite suprized a 10-degree dihedral, with the sides of the inlet-box slanted out 5-degrees wouldn't affect compression lift at all. Was there additional fine-tuning to be made as well to get some extra aerodynamic performance out of the plane? Couldn't they have used some dihedral inboard, neutral at the mid-span and some anhedral near the tips (not massive like with the tips folded down)?

The vertical tails. Why does inward canting work better than outward canting?

RAM on the A-12 came in the form of wedge shaped segments that were on the chine to absorb radar. Triangular shapes tend to be a theme with low RCS-levels. I'm wondering if you would get any benefit in regards to radar-attenuation out of using some kind of fractal pattern using a highly elaborate triangle-wedge or crystalline pattern instead of just regular wedges in areas like the side of the side of the fuselage? (the side of the lower fuslage on the side of the inlet ducts)

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RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sun Mar 11, 2007 5:56 am

Quoting Blackbird (Reply 94):
I'm wondering what you mean in regard to the statement of the XB-70 being all or nothing in regards of missiles or bombers. Why couldn't both be persued?

I hope you have a bit of time:

The answer to that question can be found in the political arena of those days for reasons i will explain later because what happened in the years before played a fundamental role as to why both could, but in that period, were not persued.

"All or nothing" was the way McNamara had approached matters with other contemporary projects as well, not based on knowledge about those systems but on his pragmatic approach to just about everything he dealt with. If it was not of his liking, the feeling was that he considered it "nothing." Why he took that stance about the B-70 will become clear later.

Many who knew him considered McNamara as an icy new defence intellectual, upholding the administrative emblem of Kennedy's "New Frontier." Especially the chief of staff, General Curtiss LeMay, who was a WW2 veteran with first hand air combat experience and had lead the Air Force / SAC ever since (and their bomber acquisitions), stood at the other end of the spectrum relative to the Secretary of Defence. McNamara had ICBMs on top of his list, LeMay had ICBMs at the bottom of his (for the same reasons the B-1 and B-2 were later built). In LeMay's analogy, "McNamara was a reckless amateur who ran the DoD like a hospital administrator who tried to practice brain surgery." But McNamara's decision making had more to it than this, please read on below.

Quoting Blackbird (Reply 94):
Additionally, McNamara, according to what you said took a look at the plane and left. You said it was because he liked charts and stuff. Why couldn't NAA make charts showing the data on the plane for him? Wouldn't that have been possible?

They did, but again for reasons that will become clear later on. McNamara visited NAA with his mind already made up, period. NAA fell victim to politics. Whether for public works or military contracts, dividing the spoils is an age-old custom, and it has flourished in the US and many other countries over centuries. What was different in the aerospace age was not the existence of the political "pork barrel" itself, but its new size and permanence. Now that stakes in profits and jobs were far higher than those of any government program in history, dividing the spoils ensured that the game of politics would be played on a grand scale. Parochial political interests could determine the direction of strategy and the fate of giant companies.

As an example of this, the fate of the B-70 was determined, not by common sense or intrinsic knowledge of its capabilities, but by political "pork barrelling." President Eisenhower prior to the 1960 presidential elections had refused B-70 funding because of the promising ICBM "push button" future. This was a period remembered as the politics of fear. The Soviets, as people were lead to believe, were building their ICBM arsenal so fast that a missile gap in the Soviets favor soon existed. This information, according to the Air Force claim (who did so for more weapon procurement reasons), was gathered using U2 over-flights of the Soviet Union. The focus should be on building as many ICBMs as possible as soon as possible for the lowest possible price. The bomber was obsolete, ICBMs should do the job instead and funds were with-held from the B-70 program.

As the 1960 presidential elections came closer, JFK in his election campaign endorsed the B-70. Teamed up with LBJ as vice-president candidate, both men fully embraced the defence rhetoric of the Democratic platform: "The Communists will have a dangerous lead in ICBMs through 1963, that the Republican administration has no plans to catch up. Our military position today is measured in terms of gaps - missile gap, space gap, limited war-gap."

During the campaign, JFK repeatedly endorsed the B-70, attacking the Eisenhower administration for abandoning it. He told an audience in San Diego, "I whole-heartedly endorse the B-70 manned aircraft." A comment aimed at tens of thousands of southern California aerospace workers worried about their jobs.

Eisenhower, who was convinced that the missile gap, as claimed by the Air Force, was exaggerated, never shared the secret intelligence information to set them straight. He complained the Democratic candidates were "screaming murder" and were getting away with it. He suddenly authorized an additional $500 million in defence spending which he had refused for years, to help the Nixon campaign, the republican presidential candidate running against JFK. The election came down to the wire, the election was too close to call. California was a key to the election, and during their swings through the state both Nixon and Kennedy pledged to revive the B-70, a major source of defence jobs in the LA area. Nixon needed a boost in California, Eisenhower gave him one. In a political move, the DoD announced that $155 million in additional funds would go to a "substantially augmented development program" for the B-70. Nixon carried California on November 8, 1960, but JFK won the elections, by only 18,575 more votes than Nixon.

With JFK as the new president he called for a bold new American defense and foreign policy:

"We shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe to assure the survival and success of liberty."

Taking JFK at his word, McNamara went directly from the inaugural ceremony to the Pentagon, where he began scrutinizing top-secret photographs. Photos of the Soviet union taken by the first US spy satellite and U2 spy planes. He came to a startling conclusion. The "missile gap" that JFK had described did exist. But it was the Soviet Union, not the US that lagged behind. The photos turned up just four SS-7 ICBMs, plus a few more under construction. McNamara disclosed his findings to Pentagon reporters who went public.

Kennedy felt deeply embarrassed, making his campaign look dishonest, when JFK had in good faith believed in the missile gap. The secretary of defence offered his resignation which Kennedy refused. McNamara agreed, however, to a deception. Henceforth, the administration would publicly deny what McNamara had just learned about the relative US-Soviet missile strength. Continuing the fiction of the missile gap provided a vital rationale for JFK and McNamara as the self-confident young leaders of the "New Frontier" implemented a radical change in American defense policy.

Kennedy tripled the budget for Polaris subs and ICBM development and on McNamara's advice backed away from his campaign pledge to build the B-70, returning to Eisenhower's order to fund the project only as an experiment.

That decision essentially sealed the fate of the B-70 program. No matter how hard LeMay fought for the aircraft to succeed. This B-70 episode completely poisoned the relationship between McNamara and the Air Force. McNamara ordered LeMay not to defend the B-70 in congress. When members of Congress protested, McNamara insisted he was not trying to muzzle the general, only to prevent him from presenting "misstatements of facts." In reality, McNamara was trying to enforce the administration's B-70 decision, while the Air Force worked with friends in Congress to overturn it.

Here Carl Vinson came to the Air Force assistance as chairman of the House Armed Services Committee. On March 1, 1962, the Armed services Committee unanimously authorized $491 million to proceed with development and eventual production of the B-70. The committee went beyond simply authorizing the DoD to spend the money, it ORDERED AND DIRECTED the executive branch to build the B-70. Basically, Vinson had issued a constitutional challenge!

McNamara was ready for a head-on confrontation, but Kennedy's legislative aides warned that he would lose on the House floor. On the eve of the crucial House vote, Kennedy and Vinson settled their differences in what became known as "the Rose Garden agreement." Vinson agreed to withdraw his constitutional challenge and Kennedy promised to restudy the B-70 issue, thus effectively killing it. For two more years, Congress voted funds for the B-70 by overwhelming margins (the Senate vote in 1962 was 99 to 1), but Kennedy and McNamara again refused to spend it.

Now you know why NAA, even if they showed their charts with credible figures, meant nothing to McNamara, why he took a short walk around the aircraft and drove off.

Here is a graph with the erratic political decision making history of the B-70:

Big version: Width: 600 Height: 494 File size: 54kb




Starglider
 
sllevin
Posts: 3314
Joined: Wed Jan 30, 2002 1:57 pm

RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sun Mar 11, 2007 6:10 am

Quoting Blackbird (Reply 52):
I thought hypersonic stagnation occured at Mach 5.4?

Full stagnation, yes, but you start to see massive temp risesat speeds below that -- also, remember that localised speeds at different points on the airframe are going to be higher. When NASA's SR-71 did the high speed run, everyone was surprised at how fast heat started to spike at M3.6

Quoting Starglider (Reply 59):
This year will be the first time i will see the XB-70 in person.

Do let us know what you plans turn out to be. I haven't been in 4 years and I'd love to meet you out there!

Steve
 
Starglider
Topic Author
Posts: 659
Joined: Sun Oct 01, 2006 12:19 am

RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sun Mar 11, 2007 7:33 am

Quoting Blackbird (Reply 94):
I'm quite suprized a 10-degree dihedral, with the sides of the inlet-box slanted out 5-degrees wouldn't affect compression lift at all. Was there additional fine-tuning to be made as well to get some extra aerodynamic performance out of the plane? Couldn't they have used some dihedral inboard, neutral at the mid-span and some anhedral near the tips (not massive like with the tips folded down)?

Even though 10 degree angles (dihedral and anhedral) were tested (anhedral had a negative effect). The paper quoted a 5 degree angle (dihedral) as sufficient. A/V-2 flew successfully with the 5 degree dihedral.

According to the paper, tests were performed with the lower fuselage vertical sides canted 5 degrees inwards, not outwards. An outward tilt would be detrimental for the reason given in the explanation for the vertical fins.

Quoting Blackbird (Reply 94):
The vertical tails. Why does inward canting work better than outward canting?

In case of the B-70, outward canting produces greater returns in the lower quadrant. Tilting the verticals inward, on the other hand, deflects the peak return into the upper quadrant where it is of no consequence.




Starglider
 
Blackbird
Posts: 3384
Joined: Wed Oct 06, 1999 10:48 am

RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sun Mar 11, 2007 7:42 am

Starglider...

So basically, the XB-70 didn't have any chance?

Why didn't Kennedy build both once he got into office? He could have overruled McNamara, right? What would happen if Carl Vinson kept his Constitutional Challenge up?
 
Starglider
Topic Author
Posts: 659
Joined: Sun Oct 01, 2006 12:19 am

RE: B-70: Was There Ever A Serious Mach 4 Requirement?

Sun Mar 11, 2007 10:00 am

Quoting Blackbird (Reply 98):
So basically, the XB-70 didn't have any chance?

Nope.

Quoting Blackbird (Reply 98):
Why didn't Kennedy build both once he got into office? He could have overruled McNamara, right? What would happen if Carl Vinson kept his Constitutional Challenge up?

He didn't build both because of the earlier mentioned deception agreed to with McNamara, keeping the fictive need of many ICBMs as the most effective option on the table. He relied on McNamara and his "Whiz-Kids" judgement to make it happen. On the basis of systems analysis an cost-benefit ratios, the McNamara team decided that the B-70 simply was not cost-effective (an excuse for promoting ICBMs). There would be a much bigger bang for the buck from Minuteman and Polaris missiles. When one of McNamara's "whiz-kids" testified before Congress, he overwhelmed the generals with charts and graphs showing that the B-70 would add minimal extra firepower at huge cost.

Still the military rejected the notion that a computer-generated "truth" provided better answers than the judgement and experience of men who had actually fought a war. As general Thomas White, then retiring Air Force chief of staff said, "I am profoundly apprehensive of the pipe-smoking, tree-full-of-owls type of so-called professional defence intellectuals." And, "I don't believe a lot of these overconfident, sometimes arrogant young professors, mathematicians, and other theorists have sufficient worldliness or motivation to stand up to the kind of enemy we face." With a man at the controls, bombers were more flexible than missiles, permitting bomber pilots to seek out targets of opportunity. The Air Force presented their arguments to a skeptical McNamara, "The bombers could also carry conventional bomb loads, the intended missiles would always have a nuclear warhead. With manned systems you can maneuver them, you can change their position. You can launch them and recall them, and you have all the flexibility in the world necessary to do things that might well prevent the war from ever starting." All to deaf ears as far as McNamara was concerned . . . . .


What would happen if Carl Vinson kept his Constitutional Challenge up:
By seeking to force President Kennedy, who had unceremoniously impounded monies the Congress had voted for the B-70 in 1961, to produce the bomber now, the Armed Services Committee's unprecedented "directive" had posed a "direct challenge to Executive control of the military."

At the same time, the committee, by explicitly basing its order to the executive branch on its own belligerent interpretation of the federal legislature's powers under the Constitution to provide for and maintain the armed forces, had deliberately set the legislative and executive branches of the American government in a collision course. A constitutional crisis was at hand, one which conceivably could wind up in the Federal courts, and, at least, theoretically, with the House serving articles of impeachment on the President.

For one thing, Kennedy was wary of attacking the powerful Congressional chairman in public and jeopardizing other aspects of the administration's program. "So far the President has said very little," James Reston of The New York Times wrote on March 8th, "not because he fears Mr. Vinson's argument, but because he fears Mr. Vinson, who has the power to fowl up [his] trade and medical care programs, with or without the B-70."


The source of much of the above and my previous reply is quoted from a book titled:

"Wild Blue Yonder - Money, Politics, and the B-1 Bomber", written by Pulitzer Prize winner Nick Kotz.

A very interesting book to read. The first 80 or so pages deal with the B-70 as a prelude to the real topic of the book, the development and struggles of the B-1 program.


Starglider

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