Saturday, March 9, 2024

A Technological Appendix to Postblogging Technology, November 1952, II: Around the Gyrotron

 The biggest industrial and technological story of this week is the collision of ongoing talk about civil defence or continental air defence with ongoing planning for OPERATION CASTLE, in which the BRAVO test blast of 1 March 1954 will demonstrate the feasibility of noncryogenic, "dry" hydrogen bombs. It will also detonate with two-and-a-half times the predicted yield, and catch Daigo Fukuryu Maru within its unexpectedly large fallout radius. With its usual maladroitness (I seriously  do not get the Eisenhower revisionism school at this point), the Administration tried to cover up the enormous screw-up and blame the crew of the trawler at a very delicate moment in American-Japanese postwar relations, and possibly leading (not a Japan expert!) to the confirmation of the postwar "pacifist"  constitution, and certainly to Godzilla. Would we have otaku culture without Godzilla? I don't know. Probably. 

Hydrogen bombs are a few things. First, they make civil defence seem vaguely ridiculous. Second, they need even less precise aiming than the previous generation of mere atomic bombs. Third, they can be lighter than that previous generation. People have been talking about intercontinental ballistic missiles since before the end of the war in Europe. Hydrogen bomb-tipped missiles actually make sense, because with an error of 3 km at the delivery end, you can still aim at "Moscow" and blow up all the strategic tarets in the Moscow vicinity, along with the rest of Moscow. That being said, ICBMs are a lot harder to build than to imagine. In the rough sketch of a plan for the future of the British nuclear deterrence that developed within its aviation-technical community after WWII, the ICBM would be preceded by an intermediate range ballistic missile. In April of 1954, the outgoing Minister of Supply in the Churchill government, Duncan Sandys, pushed through the concrete realisation of this schedule: the BLUE STREAK, a somewhat more advanced counterpart to the American Thor and Jupiter missiles that would deploy in underground bases in 1964, following several generations of life extensions for the V-bomber fleet and preceding an all-British ICBM that would never be ordered.

Today we are not talking about the BLUE STREAK so much as its guidance system, and we have been led to that discussion via a technology which was not used in it, the "tuning fork" gyroscope. My inspiration for this was taken from an article in Aviation Week about this new "gyratron" or "vibragyro," and an offhand mention of the fact that it had been tried by Smiths in the Smith's Automatic Pilot, SEP2 militarised as  the RAF Mk10. The Sperry vibrayro of 1953 doesn't appear to have gone any further. The idea was revived by Westinghouse for the space programme in the 1960s, but it wasn't until they were made piezoelectric that they became common in such vital gyrostablising applications as electric skateboards. 

So instead I'm going to talk about the technology that was used, and the concept of the BLUE STREAK as a total weapon system.

By Bubba73 at English Wikipedia, CC BY-SA 3.0,
In the course of 1954/55, the three American services (leaving the Marines out for some reason) began developing two IRBMs in a typical example of the complete procurement mess that was the Pentagon of the day. The earliest, the Air Force's PGM-17 Thor, reached operational service in 1959 with 20 RAF missileer squadrons in the United Kingdom, the only place from which this 1500 mile radius missile could hit strategic Soviet targets that was a politically viable basing area. (I guess we can leave the Turkish deployment to another day.) Thor, like Jupiter and the proposed BLUE STREAK, was a single-stage, liquid-fueled missile, and preliminary studies of the design began at Ramo-Woolridge, the startup created by the Hughes walkouts that is another big technology story of the fall. (And by Herr Dr. Ing. Adolph Karl Thiele, understudying Werner v. Braun in the role of Dr. Strangelove.) The contract specification, issued on 30 Nov 1955, was for a missile using existing technology in order to enter service as quickly as possible as an interim strategic deterrent. Douglas won the role of lead contractor, with Rocketdyne as engine developed and AC Spark Plugs getting the guidance system. (Because of course AC  is who you look for to make sure your H-bomb hits the target. It is a complete coincidence that it is a GM subsidiary.) The Thor flight trials contributed heavily to Cape Canaveral's late Fifties reputation as the place where hapless American missiles went to die in gigantic explosions whilst socialist rockets reached for the stars, a problem retrospectively attributed largely to the Rocketdyne LR-79 engine's "marginal" turbopump design, although there were plenty of other bugs to work out. The AC-Delco guidance system seems to have worked satisfactorily, but the Army/Navy/Redstone Arsenal alternative, the shorter-ranged Jupiter, was sustained through interservice rivalries as a more-accurate but more expensive alternative for high value targets, and its inertial guidance system achieved a CEP of 1800m. While this was not an AC objective, it does point to the limits of the Thor weapon system, which was quickly superseded in service by the Atlas ICBM; but not, of course, BLUE STREAK, which was cancelled in 1960. 

BLUE STREAK was originally pitched as part of a collaborative international programme, with the British taking on the IRBM role while the USAF moved directly towards the Atlas ICBM. This seems to have fallen afoul of the ambitions of the Army and the Redstone Arsenal and its associated v. Braun team, with the Navy getting roped in to make it two-to-one. The Thor project proposal then became a concrete proposal-to-tender once the Air Force decided that it needed to be in the game with the other services. BLUE STREAK was significantly beefier than its American counterparts, using two Rolls-Royce licensed LR-79 engines, firing together as opposed to pioneering  two-stage rocket technology. This gave the proposed British IRBM a significantly greater range than even Thor, at the expense of more than doubling the takeoff acceleration to in excess of 18g. De Havilland Propellers got the prime contract, fresh off fucking up the Britannia (which, to be fair, was just asking for a rogering-over like all of the big early turboprop planes, Gannet excepted for some reason), and Sperry Gyroscope's British subsidiary got the guidance contract. I've found an interesting paper on the programme online, Benjamin Cole, "Soft Technology and Technology Transfer: Lessons from British Missile Development," (originally published in the Nonproliferation Review for Fall of 1998) from a fellow "independent researcher" with an  interest in discovering what this experience tells us about the timeframe for a North Korean ICBM. 

Compared with Rolls Royce and De Havilland, Sperry was soon identified as a weak sister in the development team. At one point in 1955 it came under heavy criticism for having only 10 engineers working on the programme, explaining that "numbers are not necessarily a criterion of progress. At this stage of a new project, we believe that quality of thinking is perhaps rather more imporatant than quantity." (Ibid, 7; original pagination, 62)  Pathetic excuse  making? WELL,

I mean, how hard can it be? Sperry intended to  use a well established gyro, the Sperry Type B/RAF Mk. 10, and no, I have no idea why it is the same mark number as the then-current autopilot. The real design issue was the Ferranti-subcontracted integrated gyro-accelerometers, and a 1958 review focussed on a shortage of machine tools and testing facilities. Or, rather, it was with the 18 g acceleration requirement, which by 1958 had left the Type B behind. Sperry could have probably caught up, but not within the deployment time frame.  This led Sperry to adopt the American "Kearfott T2502 gyro." Kearfott was new to me as I was reading, but still exists today, and even has a (useless) company history resource at its web page. It might have been a navy contractor back in the day? The eventual use of an American gyro represents an important datum in Coles' overall assessment of the likely path of "soft technology transfer" programmes and so bears heavily on any model of proliferation based on his work. It would therefore be considerable interest to know more about the "Kearfott T2502.' Thanks to a helpfully-posted Ministry of Aviation research note, (R. R. ALLAN, B.Sc., Ph.D, Kinematic Rectification in Damped Single-Axis Gyros" [1964]  find the T2502 described as a "damped single-axis gyro of the fluid-floated type. Elliott Brothers worked extensively on interfaces with the T-2502 in 1962/3, and while it was otherwise working on BLUE STEEL and a VC10 autopilot. This is confirmed in Flight's 1960 Farnborough special issue, in which a visit to the Ferranti stand turned up numerous applications of the Kearfott gyro. At this point thinks make a bit more sense to the cynic, as we see the Ferranti subcontractor supplanting Sperry management and Sperry gadgets in favour of a license that held a brighter future for Ferranti. One wonders if, in the end, it was Kearfott's low profile that gave it the advantage, as a firm that would be more willing to play junior partner to Ferranti in a host of programmes more likely to survive the budgetary axe as of 1960. 

The thumbnail of Ian Clark's 1994 Nuclear Diplomacy and the Special Relationship, of which UBC's copy is held hostage by the robot uprising in the automated retrieval facility, says that the inertial navigation system played a role in BLUE STREAK's cancellation after the design was economised by removing the "insurance" of a second [clip ends], presumably guidance element. So one of the reasons for cancelling BLUE STREAK was that the prior cheaping out on the guidance system had led to concerns that it would miss Moscow after all. The Wikipedia article attributes cancellation to a combination of cost concerns, fears of pre-emption by a Soviet first strike, and interservice intrigue, with Mountbatten pressing for the Polaris solution. Clark is not cited in the Wiki article, but C. N. Hill's more recent Vertical Empire is, and I think that I will stretch my book budget to  this more recent and economical offering and leave off this post for dinner. 

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