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XB-70 Valkyrie Inlets  
User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Posted (6 years 6 months 6 days 21 hours ago) and read 6563 times:

I own a few books about the XB-70 Valkyrie, and in at least two of them I get conflicting information.

One says that the B-70 was fitted with a variable-geometry inlet somewhere along the development process (after the contract was awarded to the B-70) obviously implying the inlet was originally fixed. The other states that the B-70 had variable-geometry inlets from the get-go.

Which is correct?


Andrea Kent

16 replies: All unread, jump to last
 
User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12181 posts, RR: 51
Reply 1, posted (6 years 6 months 6 days 20 hours ago) and read 6546 times:

The XB-70A would have had to have some type of inlet system to reduce high mach speed from hitting the engines. It could have originally been a simple extendable ramp system. I do know the one surviving XB-70A at the Museum of the USAF does have the variable geometry inlet system.

User currently offlineBlackProjects From United Kingdom, joined Jul 2007, 756 posts, RR: 3
Reply 2, posted (6 years 6 months 6 days 8 hours ago) and read 6438 times:

Have a nose here Blackbird.

It is worth reading it all.

http://www.labiker.org/xb70.html

 old 


User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 3, posted (6 years 6 months 5 days 16 hours ago) and read 6259 times:

BlackProjects,

I am familiar with that page and in the past have contacted the owner on many occasions.

However, from what I read, I found nothing regarding my question.


Andrea Kent


User currently offlineBlackProjects From United Kingdom, joined Jul 2007, 756 posts, RR: 3
Reply 4, posted (6 years 6 months 5 days 4 hours ago) and read 6190 times:

Belive it or Not most of the Information on How the Intakes work is still SECRET which means unless you are going to get a Security Clearence or can get access to it via the US Freedom of Information Act you may never get to find out Exactly how it works.  old 

User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 5, posted (6 years 6 months 5 days 3 hours ago) and read 6164 times:



Quoting BlackProjects (Reply 4):
Belive it or Not most of the Information on How the Intakes work is still SECRET which means unless you are going to get a Security Clearence or can get access to it via the US Freedom of Information Act you may never get to find out Exactly how it works.

If in fact the intake system of the B-70 is still classified, which I doubt, you could not obtain it thought the Freedom of Information Act. Any classified material is on a "need to know" basis. Just because you have a clearance does not mean you can get classified information you do not have a "need" for.


User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 6, posted (6 years 6 months 4 days 23 hours ago) and read 6108 times:

Blackbird,

My I suggest the following:

Do a goggle search for XB-70 Inlet Ramps, I got a real good NASA paper titled:

"Investigation of digital simulation of the XB-70 inlet and its application to flight-experanced free stream disturbances at mach numbers 2.4 to 2.6."

I could not get the link to work but the site does come up with a search.

[Edited 2008-06-19 13:43:05]

[Edited 2008-06-19 13:43:34]

User currently offlineBlackProjects From United Kingdom, joined Jul 2007, 756 posts, RR: 3
Reply 7, posted (6 years 6 months 4 days 22 hours ago) and read 6086 times:

Well the Digital Computors from the Concorde are Secret as in the Soft ware that allowed them to work even though the aircraft has stopped flying.

So if the B-70s systems are similar to those on Concorde they would probably still be Secret as well.

The Concorde digital computors were Made by the Guided weapons devision of BAC at Weybridge which also made all the Anti tank and anti aircraft/Shiping Guided weapons for what is now Bae Systems military devision.


 old 


User currently offlineGST From United Kingdom, joined Jun 2008, 938 posts, RR: 0
Reply 8, posted (6 years 6 months 4 days 21 hours ago) and read 6071 times:

It probably will still be under some form of security, as who wants Bin Laden to build himself a supersonic strategic bomber?

But seriously, given that the aircraft was intended as a bomber, and was not expected to be pulling many high G maneuvres and such, I'd guess the designers initially started on the drawing board with fixed geometry, but kept the options in there to later change (which they eventually did) to variable geometry to expand the envelope of the engine performance.


User currently offlineZuluLima From United States of America, joined Jul 2007, 338 posts, RR: 3
Reply 9, posted (6 years 6 months 4 days 20 hours ago) and read 6052 times:

From what I've read in the book "XB-70 Valkyrie - The Ride To Valhalla" the (variable) inlet shape was so critical to Mach 3 flight that I don't see how it could have originally been designed as fixed. Like the SR-71 with it's inlet cones, proper control of the pressure and shockwave was absolutely vital to engine operation. They did, however change from manual control of the duct by the copilot in A/V 1 to automatic control from A/V 2 onwards.


I didn't get a 'Harumph' outta that guy!
User currently offlineXT6Wagon From United States of America, joined Feb 2007, 3432 posts, RR: 4
Reply 10, posted (6 years 6 months 4 days 20 hours ago) and read 6036 times:

The first plane only had manual control of the inlets. The second had "automatic" control, though it wasn't exactly perfected, and then the crash of #2 kinda wrecked the work on it.

User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 11, posted (6 years 6 months 4 days 16 hours ago) and read 6003 times:

BlackProjects,

Quote:
Belive it or Not most of the Information on How the Intakes work is still SECRET which means unless you are going to get a Security Clearence or can get access to it via the US Freedom of Information Act you may never get to find out Exactly how it works.  old 

Dude, I wasn't asking EXACTLY how the system worked, or the exact geometrical data... I was just wondering: Was the original design that won the competition over the Boeing 804-4

- Initially have fixed-ramps which were later modified into variable-geometry ramps?
- Always have variable-geometry ramps?

Quote:
Well the Digital Computors from the Concorde are Secret as in the Soft ware that allowed them to work even though the aircraft has stopped flying.

Wow, I would have never known that. Weird considering the Concorde is a civilian plane, but who knows why the government keeps some of the secrets they do.

Quote:
The Concorde digital computors were Made by the Guided weapons devision of BAC at Weybridge which also made all the Anti tank and anti aircraft/Shiping Guided weapons for what is now Bae Systems military devision.

Maybe that's why it's classified.


ZuluLima,

Quote:
From what I've read in the book "XB-70 Valkyrie - The Ride To Valhalla" the (variable) inlet shape was so critical to Mach 3 flight that I don't see how it could have originally been designed as fixed. Like the SR-71 with it's inlet cones, proper control of the pressure and shockwave was absolutely vital to engine operation. They did, however change from manual control of the duct by the copilot in A/V 1 to automatic control from A/V 2 onwards.

The book may very well be right, but I should tell you that the book is not exactly the best source of data on the XB-70.

I'd recommend getting your hands on
-Valkyrie: North American's Mach 3 Superbomber by Dennis R. Jenkins and Tony R. Landis (One of the best books in terms of size -- 264 pages, pictures, and details)

and

-Valkyrie: North American XB-70 by Steve Pace
-WarbirdTech: North American XB-70 Valkyrie by Dennis R. Jenkins and Tony Landis

Additionally, I should mention after the second Valkyrie crashed, the first one was fitted with an automatic inlet system...


XT6Wagon,

Quote:
The first plane only had manual control of the inlets. The second had "automatic" control, though it wasn't exactly perfected, and then the crash of #2 kinda wrecked the work on it.

As I said in the previous reply, the first Valkyrie was refitted with an automatic inlet-control system after the second one crashed.


Andrea Kent


User currently offlineFTOHIST From United States of America, joined Mar 2004, 73 posts, RR: 0
Reply 12, posted (6 years 6 months 4 hours ago) and read 5795 times:

I'd be inclined to think that in order to find something so obscure, you'd have to either find an Air Force numbered historical study (if one exists for the B-70), or other official report through an agency such as the AFHRA (Air Force Historical Research Agency). I have been helped several times by AFHRA when it comes to fairly obscure items--the staff there either knows how to get what you want or knows who to contact.

If that route does not work, I'm afraid the only other place to look is in NAA's archive (now owned by Boeing, of course), which probably contains a more complete design and development history of the project. Of course, the archive is most likely not able to accessed by the general public, and even if it were, it is not staffed to provide research assistance. I have been down this road several times with both the NAA and Douglas archives, and it is really a dead end. Boeing historians have tried to help with my research on the XB-43 and the F-86D, but the stuff I'm after is locked away probably never to be see again. You'd almost have to know someone inside the company who can get a visit scheduled for you--and even then you never really know if those archives fell victim to document purges over the years or just before the facility was turned over to Boeing.

I have the same problem researching GE's flight test history--documents were only held on to for so long, and then destroyed after they were no longer useful--it takes money to keep and store boxes full of old documents, and it doesn't benefit the company or organization to keep them for 50-plus years. For me, it is the main problem with researching old aviation programs from the 1940's-1960's--if I want to see something for myself without reading it in a book that has been filtered through the author's preception or beliefs, then I need to see either company documentation or official governernment studies, but getting my hands on that stuff is getting harder and harder to do.

That's my rant on the subject.....


User currently offlineStarglider From Netherlands, joined Sep 2006, 679 posts, RR: 44
Reply 13, posted (6 years 4 months 4 days 11 hours ago) and read 4954 times:

Quoting Blackbird (Thread starter):
I own a few books about the XB-70 Valkyrie, and in at least two of them I get conflicting information.

One says that the B-70 was fitted with a variable-geometry inlet somewhere along the development process (after the contract was awarded to the B-70) obviously implying the inlet was originally fixed. The other states that the B-70 had variable-geometry inlets from the get-go.

Which is correct?


Andrea Kent

Both are correct. Originally the B-70 (Weapon System 110A) design was a subsonic cruise, supersonic dash design with a totally different air intake configuration. This was before the contract was awarded to NAA and this design was rejected. From its genesis onward, the Mach 3 design, which became the XB-70 as we know it, which design was the contract awarded to NAA, has had variable geometry inlets.

There is no "smoke and mirrors" regarding classified information on the inlet design.

It is very well documented and available in a NASA/North American Rockwell report:

NASA-CR-115702, B-70 Aircraft Study Final Report, Vol. I, Vol. II, Vol. III, Vol. IV. Published in 1972.

Volume IV deals with the air induction system.

Here is a link to Volume IV:

http://ntrs.nasa.gov/archive/nasa/ca...asa.gov/19950002361_1995102361.pdf


Regards,
Starglider

[Edited 2008-08-19 01:36:32]

User currently offlineFlighty From United States of America, joined Apr 2007, 8765 posts, RR: 3
Reply 14, posted (6 years 4 months 3 days 23 hours ago) and read 4845 times:

Went back to my hangar and my XB-70 VIP has the inlets. My friend Dick Cheney gave me this fine private aircraft.  Smile  bouncy 

User currently offlineDeltaGuy From , joined Dec 1969, posts, RR:
Reply 15, posted (6 years 4 months 2 days 22 hours ago) and read 4642 times:

I love how everyone on here jumps to the conclusion that anything seemingly cloudy must be top secret. A 40 yr old aircraft doesn't strike me as classified.

DeltaGuy


User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Reply 16, posted (6 years 4 months 2 days 1 hour ago) and read 4539 times:

Actually considering the contract was awarded in late 1957, the plane technically could be argued as being a 50 year old design

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