XB70 Valkyrie
- Thread starter Gixxerman
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WJPearce
Airman 1st Class
The guy you are thinking of was Stuart Symington, Secretary of the Air Force. He wanted Northrop to merge with Convair, which was later bought by General Dynamics. It should also be noted that after being the Secretary of the AF, Stuart Symington's next job was president of Convair.
Messy1
Master Sergeant
I remember this story, always wondered the details of all this. Seems pretty fishy to me! I'll have to do some research and refresh my memory.
WJPearce
Airman 1st Class
I agree, always seemed fishy to me. Sorry to go off topic from the XB-70, one of my favorites. But I think the wings suffered from instability which effected their use as bombing platforms. I think if we were to compare the XB-35 to the B-36 and the YB-49 to the B-47, we might see the wing was not the better ship. So I understand why it would not be selected for production. But I feel all that is a separate issue. Even if the thing was a flaming death trap, not saving one is simply criminal.
To bring it back to the XB-70, the summary of the accident report for the crash of AV2 is published in Valkyrie by Jenkins and Landis. It basically says that Walker in the 104 would not have a good reference to maintain separation. The report says that the 104 gradually moved out of position and given the configuration of the two aircraft, the XB-70 with its huge delta wing and drooped tip, and the 104 with its high tail, Walker would not be able to see or know that the tail of the 104 was about to hit the tip of the XB-70s wing. Even though Walker was 70 feet to the right and 10 feet below the XB-70, that puts the tail of the 104 into the wingtip of the XB-70.
To me, the XB-70 is the most awesome aircraft ever to fly, especially for its time.
evangilder
"Shooter"
The final landing of the XB-70 at Wright Patterson was a defining moment in my interest in aviation. Being able to see it fairly regularly until I was about 13 really reinforced that. It was really quite a ground breaking aircraft and a lot was learned from it's testing that was used in later aircraft designs.
WJPearce
Airman 1st Class
When I was 13 (or so) my dad, uncle, cousin, and I visited the AF museum in Dayton, OH after going to Oshkosh. I need to go back again, but I will never forget the XB-70. I tried to get photos of it but that was nearly impossible because of its size. I think that plane triggers an emotional response for a lot of people.
A couple more interesting points about the loss of AV2. The photo shoot has been approved by the local commander but had not gone through the official approval process. I think some people were demoted or resigned because of it. Clay Lacy was flying one of his Learjets as the photoship. An SR-71 was in the area and was possibly going to join up if it had the time/fuel after completing its flight (I also remember somewhere stating that this was just a rumor, but I think all parties distanced themselves from the flight after the accident). Curtiss-Wright built the "power hinge" device which articulated the wing tips. There were six of them for each wing. Eight of the 12 were salvaged from the wreckage of AV2 and used as spares for AV1. Even though CW was just a shell of its former self at the time, no longer making aircraft or aircraft engines, I guess they still could make some damn strong parts.
johnbr
2nd Lieutenant
nasa pdf
johnbr
2nd Lieutenant
johnbr
2nd Lieutenant
johnbr
2nd Lieutenant
swampyankee
Chief Master Sergeant
- 4,034
- Jun 25, 2013
There wouldn't have been an SR-71 in that photo shoot; the formation flight was a publicity shot for GE. The SR-71s were propelled by J58s, which were products of Pratt & Whitney Aircraft.
johnbr
2nd Lieutenant
Cutaway net
Good stuff!
johnbr
2nd Lieutenant
Nice shots!
Actually it has, but not in much detail.
This forum really is kind of about three subjects in one
- Aviation: Which divides into...
- WWII: The bulk of it
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- Interwar
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- Vietnam to Present
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- Sausage
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- Chocolate: Because chocolate makes nearly everything better -- it raises one's mood and all that stuff.
- Women
- There are some female members, but they seem to be few in number; most members are male and, statistically, more men are heterosexual than otherwise, so there you go...
Actually, the engines and inlets were good to speeds well beyond that. The engine was rated for Mach 4 (not sure if that's full tilt, or the normal operating speed), and from what I was told, the designer (Walt Spivak) said the inlets were good for it too. The overall construction was designed to tolerate high temperatures, but the devil was in the details (there were some imperfections in the early skin fabrication), and A/V-1 had a tendency to shed skin on an occasion or two.
I would assume A/V-2 could have done it, though I'm not sure if it ever did.
That's a good book, I have it. I'd also recommend 'Valkyrie: North American's Mach 3 Superbomber" by Dennis R. Jenkins and Tony R. Landis. It's kind of the authoritative book on the aircraft.
Unsure, but that is the secret purpose of the modern internet...
Yeah it was, plus it had that a quality that made it look like it came out of science fiction (the F-22 and YF-23 had that quality), in a good way.
It probably would have bankrupted us: I remember hearing some amazing cost figures for the plane.
- $22 million: I have reason to suspect terminological inexactitude on that one. It's a practice to sometimes hide parts of a program's funding in other programs as a way of concealing cost. From what I remember, the B-52 costed around $14.4-14.6 million, and the B-58 between $12.4 to 30.1 million. If this figure was, somehow correct, you would need 5.5 billion to cover SAC's 250 x B-70 proposal
- $50 million: That figure I heard before, and if so, we'd have needed $12.5 billion to fund the 250 bombers intended
- $150-160 million: I was told this figure came from the cost of the prototypes, and other variables that would lead to the lines to produce 250 B-70's. Since I don't know the math, it's pure conjecture. Regardless, to fund 250 x B-70's you'd see $37.5-40.0 billion.
If I recall, the arguments against it were as follows
- Cost
- WS-110: This was the B-70 program
- Original requirements: Overall range of 7500 nm, 3000-4000 nm supersonic (Mach 2.0 or faster), at some specified altitude (forgot), with a payload of either 25000 lb., or 10,000 lb. for normal mission, with loads of 25000 lb. over shorter ranges.
- Later requirements: Range of 7500 nm, cruise portion to be flown at Mach 3.0 or faster, at some specified altitude (forgot), while carrying 10,000 lb. payload (25000 lb. over shorter distances), in a shirt-sleeve environment (no requirement for pressure-suits, ejection-capsule required). Maximum weight of 500,000 lb., and able to use existing runways and facilities in use by SAC.
- Cost $1.85 billion for program including the F-108 Rapier
- WS-125: This was a proposed nuclear-powered aircraft
- Early requirements: Subsonic cruise on nuclear power; extended dash at supersonic speed using chemical fuel. I forgot what payload and altitude requirements were required, but I wouldn't be surprised if it was similar to WS-110. That said, the design was deemed unfeasible.
- Later requirements: Cruise to be supersonic (forgot payload and altitude requirements), navigation systems the same as WS-110. It seemed the program was given new life because the USAF, in an effort to embarrass Flight-magazine (at minimum -- part of me suspects it was also to create a requirement for the aircraft -- the Cold War was basically one of the world's biggest and most expensive dick waving contest), published them some bogus information about the M-50 being a nuclear powered bomber. When it was released, it became a Cold-War issue (whether by intent or not), for dick-waving rights.
- Cost: $2.05 to 2.1 billion.
- Basically: It wasn't just the XB-70 program, it was WS-125 as well.
- WS-110: This was the B-70 program
- Enemy Missile-Defenses
- The SA-2 managed to get a substantial fear-factor over it's ability to shoot down the U-2
- I assume part of this issue was an argument to avoid having to fund the B-70, more than the actual capability of the SA-2. Remember the cost would have made a lot of people look for an "out", and the argument matters more than the facts in legal and political matters (that's all I can say, there's a no-politics rule on this forum).
- SAC had proposals for high altitude penetrations into the USSR as late as 1962 (though I assume a sizable number would be done as nap of the earth, or NOE).
- There were some new SAM's that appeared to be able to shoot-down a high-speed bomber like the XB-70, some either had or appeared to have ABM capability.
- The SA-5 Griffon was suspected of being an ABM: At least one of the proposed developments was a work of disinformation
- The SA-5 Gammon was capable of shooting down high speed, high altitude targets
- The XB-70 was designed to carry a defensive-missile capability for use against fighters and SAM's: The best contender was a lenticular (disc-shaped) weapon that could supposedly reach 250g at as little as Mach 3.0, which basically means that...
- You'd get a turn-radius of 1048.8-1155.2' (319.7-352.1m), and a turning-circle of 6589.6-7258.6' (2008.5-2212.4m), based on the speed of sound at 25000-75000'.
- For comparison, an F-15 flying at Mach 0.72 on the deck in a sustained 9g turn, you'd see a turn-radius of 2231.4' (680.1m), and a turning circle of 14020.3' (4273.4m).
- That said: If the missile was racing along at Mach 8 (same g-load), you'd get a turn-radius of 7457.9-7215.1' (2273.2-2504m), and a turning circle of 46859.4-51617' (14282.7-15732.9m); at 25000', you'd probably see an F-15 doing a radius around 2931.3-3407.2' (893.5-1038.5m), and a circle in the ballpark of 18418.2-21408.2' (5613.9-6525.2m), so it could probably shake it loose. Consider that the primary threat would be missiles which don't take evasive action, and supersonic interceptors.
- There was a proposed lenticular missile that could be used as an ARM, which would probably be more useful.
- While the initial XB-70 proposals had a single bomb-bay, it was quickly amended to a two bays of equal size, making possible the carrying of up to 50,000 pounds of ordinance (by volume, at least); as time went on, the forward bay was reduced to a smaller size (capacity was 10,000 lb., so both bays would provide a total load of 35,000 lb.) due to the cancellation of the zip-fuel program (they actually had contemplated removing one of the bays entirely, but the addition of JP-6, which burned more cleanly, combined with various aerodynamic refinements, made it possible to fit a smaller bay); as time went on, they eventually were able to recover most all performance (a redesigned canard, more room for fuel in the wing-tips), and eventually were able to restore the original bomb-bay size, but instead of two bays, each able to carry 25000 lb. of ordinance, it was now one HUGE bay that could carry 40,000 pounds (not sure why the weight reduction, by volume, you'd expect 50,000), and that would allow respectable room for ordinance. Remember, there are bombs that are not just heavy, but BIG.
- The SA-2 managed to get a substantial fear-factor over it's ability to shoot down the U-2
- Ballistic-Missiles
- The argument was that manned bombers were obsolete, and ballistic missiles were the wave of the future
- For some time they actually were looking into cruise and ballistic missiles (for intercontinental use), but for the most part, it seemed that Sputnik kind of resulted in a favoritism towards ICBM's. That said, they were fast and hard to shoot down (and the cost of just one getting through are catastrophic); that said, there was the SLAM/Pluto project which involved a nuclear powered ramjet engine (direct cycle), which could carry one warhead, or carry a bunch of smaller ones (sanity, fortunately prevailed).
- Ballistic missiles are not recallable: Any self-destruct mechanism used for tests would probably be removed for actual operations as the enemy would be able to trigger it and stop our missile without even firing a shot. Admittedly, I'm not sure how many bombers would return if they received the orders to abort their attacks, as they could perceive it as being a spoofing-attempt (something which has happened in WWII when the costs were actually far lower).
- Ballistic missiles generally lacked the accuracy required for conventional ordinance delivery: Even if they did in those days (they do now -- some can pull off a CEP of around 400 feet, which was the same as a B-17), they could only be used once, whereas bombers can be used repetitively (while there were some cruise missiles that could land, the only one I recall that could separate payload from the rest of the missile was the Snark, and once that happened, landing might not be possible as the CG would be thrown so badly out of alignment). The enemy would not be able to necessarily distinguish a nuclear weapon from a conventional one, all they could tell is a weapon is racing over the pole at an ungodly rate of speed, and they would probably be more likely to fire their nuclear weapons than take the risk.
- We assumed the USSR would abandon manned bombers and just develop ICBM's: They largely did, but not totally. This belief lead to the cancellation of the F-108.
- In order to save money, the F-108 was sharing funds with the XB-70: It looks good on paper because for about $350 million extra dollars you can procure two aircraft instead of one; furthermore, the plan was for 450 F-108's.
- The problem is when it was cancelled, it basically made the XB-70 seem grossly more expensive (which it sort of was)
- The argument was that manned bombers were obsolete, and ballistic missiles were the wave of the future
And, if the Standard Aircraft Characteristics' Sheets are accurate, it would have had good maneuverability: The aircraft's stall speed was around 119-128 kts (these were the latest ones) and that's actually quite good. Better than the F-4 (152 kts).
NAA seemed to kind of use lots of cross-pollination. The LRIX/WS-202 (later F-108) had the all moving tail it seemed before the XB-70 did (the XB-70 originally had twin-tails with normal rudders). The A3J/A-5 had twin tails at first, but they weren't all moving AFAIK
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I didn't know he became the President of Convair. I do know that one of the early Secretary of Defenses sat on the Convair board.
The first and second prototype, in some ways were very similar in handling; they did have some significant differences in other ways.
- Similarities
- Both aircraft seemed to be stressed for similar g-loads: According to a Jenkins/Landis' book on the XB-70 (largely considered the authoritative book), as well as another book I have on the design, there were simulator tests done to evaluate vibration loads to the pilots for gust-loads. Since, it seems unlikely that they would simulate for conditions the plane couldn't take, it seems likely that 6-7G was entirely possible (probably at combat weight, which is around 300,000-350,000), though it produced some vibrations that were highly unpleasant to the pilot (by highly unpleasant, I mean it caused a feeling of pressure in your chest). At high altitudes, 3G was entirely possible. Not sure about 3.5G.
- Both aircraft seemed to have similarities in control (dis)harmony: Aileron forces were fairly light, and roll-rates were fast, and felt fighter-like; elevator loads were heavier and felt more bomber-like; supposedly rudder loads were similar to elevator loads.
- A/V-1 (62-0001 / 20001)
- Handling
- The aircraft had poor directional stability, which usually resulted in the pilots lowering the wing-tips partially down at M=0.75 instead of M=0.9, and all the way down at M=1.4 instead of M=2.0.
- Roll-stability is poor at higher speeds, which has to do with the lack of dihedral.
- Configuration & Systems
- The aircraft's construction had some defects in honeycomb construction: It had to do with the fact that, as they began constructing it, they made various errors. Some were caught, others managed to escape detection, and this resulted in a Mach 2.5 limit to the aircraft. At a later period, there were some fixes made to some of the honeycomb panels, which might have allowed a performance increase (there were some descriptions of the aircraft outrunning a B-58).
- There was also a miscalculation in the wing apex's structural load-bearing capacity, and this resulted in a failure of the apex, which damaged all six engines.
- The aircraft didn't have any significant dihedral to it's wings
- The wing-fold mechanism included 3-settings: Up; 25 degrees down; 64.5 degrees down
- The A/C lacked an automatic inlet control system as built
- Two of the fuel-tanks were inoperative: During the construction of the aircraft, they pressurized the tanks with gas to identify any possible signs of leakage. Upon detecting leakage, they disassembled the aircraft partially, and used a short term sealant (1000 hours service life) to cover up the known leakage points. Two of the tanks (Tank 5 Left & Right) were effectively impossible or difficult to get inside. So, they simply deactivated them.
- Handling
- A/V-2 (62-0207 / 20207)
- Handling
- The aircraft was more directionally and roll-stable
- The aircraft had adverse yaw as a result of the dihedral, which required firm inputs on rudder, and monitoring the sideslip indicator, as it was possible for large angles to form that weren't always easy for the pilot to detect.
- Configuration & System
- The aircraft's honeycomb construction was far better designed than A/V-1, as they had largely been able to avoid making the various mistakes, as seen in A/V-1.
- The hydraulic and fuel lines were flexible, which handled expansion better
- The aircraft had 5-degrees of dihedral: The wing folding mechanism went down an additional 5-degrees (A/V-1: 25 & 64.5 degrees; AV-2: 30 & 69.5 degrees)
- The aircraft had an automatically controlled inlet system with manual back-up.
- Handling
While they never explained this, they did see some smoke shoot out of the engine. I'm not sure if it was a compressor stall as they approached the aircraft, or if the engine had a malfunction which distracted General Walker.
