Bird on A Wire:
The Saga of the Regulus II
by Nick T. Spark
(Originally published in “Wings” Magazine, and reprinted with permission).
On January 31, 1952, the Navy’s experimental Regulus I missile was launched by JATO rocket from the Point Mugu Naval Air Missile Test Center. Once the Regulus was airborne, the JATO boosters ejected and the missile headed out over the Pacific. Controlled by radar from the submarine USS Cusk and by chase aircraft, the missile flew at altitudes above 30,000 feet and at its top cruising speed: Mach 0.93. After a 25-minute flight, chase pilot Roy Pearson placed the missile into a terminal dive.
Racing straight down, the missile tore a hole through the sound barrier, and smacked into the ocean with a terrific roar. The impact was about a mile from the planned target – accurate enough considering that the deployed version of the Regulus I would carry a nuclear warhead. “Operation Splash”, as the test was known, had been an overwhelming success. The last three major hurdles to deployment of the missile – boosted launch, control by a submarine, and terminal dive to target – had been accomplished in one fell swoop. The Navy now had its first operational cruise missile and, with its nuclear capability, a genuine power projection tool. Over the next decade (1953-1964) Reg I would be deployed aboard submarines, cruisers and even aircraft carriers, a front line weapon in the Cold War.
The origins of the Regulus I could be traced directly back to the Nazi V-1 “buzz bombs” of World War II. The V-1, more of a bomb with wings than a true guided missile, had proved an effective terror weapon during the War. Yet its small conventional warhead and lack of accuracy prevented it from producing real tactical results. Another shortcoming with the V-1 was that it proved vulnerable to massed anti-aircraft fire and the guns of English fighter pilots, who could easily outfly the pulse-jet powered V-1s. Chasing V-1s was such sport that on some occasions English pilots actually sidled up beside flying bombs and tipped them over in flight. Thus, of nearly 10,500 V-1s launched, only about 3,500 actually struck England.
The Navy certainly recognized that the Regulus had vulnerabilities similar to the V-1, and took steps to minimize them. Its supersonic terminal dive capabilities seemed to guarantee invulnerability at the most critical moment of its mission, and the high-speed jet engine, coupled with a lightweight airframe, produced a machine which could blow past almost any plane in the inventory circa 1952. Yet anyone could see that, as jet aircraft improved and anti-aircraft missiles were developed, an advanced version of the missile would be a necessity. Thus, shortly after “Operation Splash” had succeeded, the Navy began drawing up specifications for a new, supersonic missile: the Regulus II.
The builder of the Regulus II would be Chance-Vought Aircraft, under whose auspices the Regulus I had come into existence. The design specifications for the II would answer many of the I’s shortcomings. It would have a much greater range – 600 nautical miles as opposed to 300 – and be capable of flying that distance entirely at Mach 2.0, and at 60,000 feet. Like the Reg I, Reg II would be capable of flying under radio control from a plane, ship, or submarine. But it would also be equipped with a new, highly sophisticated inertial guidance system. Inertial guidance would rid the Regulus of its one real Achille’s heel, making the missile immune to jamming of guidance signals or beacons. “Inertial guidance was going to make it completely independent of a submarine or aircraft after launch,” notes historian Dr. David Stumpf, author of Regulus: The Forgotten Weapon. “It would find its target, 1000 or 1500 miles distant, and dive to that target by itself.”
The design of Regulus II took shape in a hastily-organized engineering office in the old North Station, in Boston. It was a peculiar situation, especially since Vought was headquartered in Dallas, having recently moved there from Stamford, Connecticut.
“We had to design it in Boston,” recalls George Sutherland, a Reg I test program veteran who helped design the Reg II and eventually became Project Manager. “All the engineers in Dallas were busy working on a Navy fighter competition (Vought’s F8U-3 versus the Douglas F-4H1). We were short of people, and there were a lot of people who had stayed in New England when the company moved. So I ended up taking a lot of trips back there.” Bill Albrecht, a veteran of the Regulus I test program, relocated to Boston for the better part of a year to work on the design. “All I remember was that there were a lot of drafting tables and no air conditioning that whole summer,” Albrecht remembers. “But we did get the design done.”
What Albrecht , Sutherland and the Vought engineering team eventually proposed clearly represented an evolutionary advance over the Regulus I. While it shared many of the same characteristics that had made the Regulus I successful, Regulus II would be a great leap forward. True, it would be an air-breathing, surface launched (using JATO technology) guided cruise missile. Like the Reg I, Reg II had a cruciform shape and lacked a horizontal tail. (It would rely upon a set of elevons in the wing for pitch and roll control.) But at just over 67 feet nose boom to tail, it would be a great deal larger than the Reg I (which was 34′ long). And while the II’s wings were just about the same size as the I’s, they were sharp and radically swept for supersonic flight. It also boasted forward canards, stationary winglets designed to support the nose both in flight and during landing. Overall, Reg II had a trim, racy, space-age look compared to its somewhat stubby brother. “The real difference of course was in performance,” notes Sutherland. “The Reg I cruised at subsonic and went supersonic in the terminal dive. Reg II, from the time it got to altitude, would maintain supersonic speed and high altitude. That was a very big step forward. And of course it was a prettier bird.”
“Chance Vought capitalized on the Regulus I program as they built the Regulus II,” notes David Stumpf. “The same concept was used: it was essentially a pilotless aircraft.” The proposed Regulus II flight tests, naturally enough, would mirror the highly-successful Regulus I program. Like its sibling, the test version of the Reg II would come equipped with landing gear, allowing it to take off and land like a jet. This ingenious feature had saved a tremendous amount of frustration during the Regulus I flight test program, and in point of fact may have accounted for its success. By recovering expensive test vehicles and reusing them, and conducting separate JATO boost tests after the airframe had proven itself, Vought had saved a fortune. It had also delivered a complete, well-tested, thoroughly proven weapons system in less than eighteen months.
“One thing we did that was the key to success for both Regulus I and II,” says Bill Micchelli, a Chance Vought engineer involved in both programs, “Was to beef up the safety factor. The Snark, Navaho, Mace, Matador, all these missiles that failed had in their stress analysis the old aircraft thing, of yield over ultimate strength, 1.5 safety factor. We knew we had to land the Regulus II at a tremendous speed, and with nobody at the controls. And we knew it was going to come up sometimes pretty damn hard, so we upped that margin of safety in our stress factor by 2. We built it rugged. And that turned out to be critical.”
Initially, Regulus II was to be powered by the Wright Aeronautical J-65 engine and, indeed, the first seven flight test vehicles were delivered with this power plant. Equipped with aluminum compressor blades, the J-65 had limitations: it could not fly above 35,000 feet and Mach 1.8 for sustained periods. A much more robust power plant, the new General Electric J-79 turbojet, replaced the J-65 in all other Reg IIs. The J-79 could produce 15,600 pounds of thrust at sea level and could sustain Mach 2.0 flight at 60,000 feet. Since the first seven missiles were to be used in preliminary testing, the use of the J-65 was not a limiting factor. In fact, it may have advanced the test program since that engine was readily available in 1956, whereas the J-79 would not be manufactured in quantity until 1957. “By using the J-65 we actually were able to start earlier, to gain some time,” recalls Sutherland. “And so we ended up with seven missiles equipped with the J-65. We didn’t care because we knew the initial tests would take time, and we could accomplish 90% of our work with it.”
The range of the Regulus II would be about 1,000 nautical miles at 32,000 feet and Mach .94. At Mach 2.0 and at 65,000 feet, this range would slip to 635 nautical miles. Vought engineers suggested that the range could be doubled through wing or saddle tanks (although neither was ever produced). One unique feature of the Reg II was that, owing to its narrow profile, it had multiple independent fuel tanks which were automatically trimmed through a pump system. One feature of this design was that it allowed fuel to be used to change the static margin. “For example, you wanted it to have a different center of gravity when you came in for a landing than what you had in cruise,” says George Sutherland. “So we actually had it transfer ballast during flight to get the c.g. right for landing.”
Design of the Regulus II had begun on a preliminary basis in 1951, and Vought submitted a development proposal on December 16, 1952 – the same day that a Regulus I was first launched from an aircraft carrier, the Princeton. In April 1954, after a great deal of negotiation, full design studies and wind tunnel tests with mock-ups, a formal development contract was signed with the Navy. For a little over eight million dollars, Vought would produce four flight test articles. They would receive the designation XSSM-N-9: experimental, surface to surface Navy missile number nine. Assembled in the Vought factory in Dallas, the first bird, tail number GM-2001, was transported to Edwards on February 6, 1956. There, at the same North Base hangar where Reg I had its start, on the edge of the windswept Rogers dry lakebed, the Reg II team got down to business.
“I remember the first time I saw it,” recalls Joe Engle, a Vought field engineer turned Reg II test pilot. “On March 16, 1956. I showed up at Edwards and there were two of ’em sitting in a hangar. They were working on them, getting them ready. And I thought to myself, that is a beautiful airplane. That is, it would be with the gear up. With the gear down I thought it looked like a pig!”
In addition to Engle, the flight test team consisted of many hardened veterans from the Regulus I program. Nevin Palley, the gutsy, resourceful Project Manager who had seen the weapon system through tragedy (the first flight of a Regulus ended with a crash) and triumph (Operation Splash), had left for greener pastures. In his place was Sutherland. An experienced engineer – he had done a great deal of field work at Patuxent River in the 40’s and worked not only on the Reg I but Vought’s first missile system, the P/A-6 – Sutherland was a firm believer in ground testing and simulation. He’d witnessed the success of such protocols in his work with Regulus I, and resolved to mold the Reg II tests after them. Sutherland was excited at the prospects for Regulus II. “It was a job I was bucking for,” he remembers, a glint of that early enthusiasm still audible in his voice. “Was I intimidated by it? No, I thought it was going to be fun. I loved running flight test programs. I loved testing.”
If Sutherland wanted a challenge well, he had it. The bird in hand would have to meet some truly awesome performance parameters. The sheer size of the airframe, not to mention the number of unproven systems aboard it, should have given everyone sleepless nights. Yet the test team felt strangely confident. The tough yet ultimately triumphant experience with the Reg I gave everyone a boost. They had already proved once that a missile could be flown and landed by remote control, launched by JATOs, and dived to a target at supersonic speeds. Doing it a second time should be a cakewalk. “Everyone had worked out all their nervousness on Reg I,” Joe Engel suggests. “And that made me confident because I could see they know what’s going to happen. Plus, the people were great. George Sutherland was smart and understood the systems and management. And Bill Albrecht was a brilliant engineer who did outstanding work. So you always expect problems but we had a lot of confidence.”
During flight tests, Engle and his fellow pilots would use a variety of aircraft to control the Regulus II. For landings and takeoff they would utilize the T-33, which had been used extensively with the Regulus I. Although it would cruise at high speeds, the Reg II’s landing speed would be “only” 255 knots – a comfortable speed for the T-33. For high speed chase and control, there weren’t many options. “We knew we’d have trouble with it going even Mach 1.6, which is what it could do with the J-65,” Engle notes, “We had the FJ-3 and you could get supersonic with it, but then it might drop like a rock. Later on, we got three brand new F-4Ds from Douglas. That airplane would go supersonic but we found you could only get about 1.2 out of it. We also found you had to be careful because if you came out of burner and popped the speed brake at the same time you’d shed both outer panels. That could ruin your whole day,” Engle sighs. “After the F-4Ds we got the F-8U, and then that made it easy, although in the beginning our planes didn’t have the ventral fins on them so we could only go to Mach 1.6.”
The first three months of testing used T-33s, and the prototype missile – airframe GM-2001 – never left the ground. It either sat on test stands or performed taxi runs on the lakebed. These tests helped determine the missile’s stability and reliability, landing gear integrity, and control response. The last few runs were conducted at extremely high speed in order to check the integrity of the bird’s tires. “We actually went overboard,” says George Sutherland. “But blowing a tire (on landing) could be catastrophic. So we did a whole series of tests. On the fifth one we actually went twenty knots above the normal liftoff speed, which was 250 knots, just to make sure that the tires wouldn’t come apart. We tore the tires up pretty bad but we didn’t have any catastrophic failures.” The tests may have been perceived as overkill, but Sutherland knew how important the first flight of the bird would be. He’d been getting phone calls for months from Navy brass, his own bosses in Dallas, and a bunch of current and former Vought employees and test pilots, all of whom wanted to know the date of the big day. As Sutherland puts it, “Everyone and his brother wanted to know when we were going to have the first flight!” Failure therefore, was not an option.
Sure enough on May 29, 1956, a large crowd of people materialized to watch the first attempted flight. “I’ll never forget it,” says Sutherland. “All the wheels were out there, my brass and the Navy brass, and it was just a great day. The first flight… was so easy that it seemed unreal.” GM-2001 became airborne after a 2.3 mile run down the lakebed. It flew like a dream. “From my standpoint it was a beautiful first flight,” says Engle, who flew as Baker pilot in a T-33 while Howard Mabey controlled the Reg II. “It roared down the lakebed, took off, and climbed out. We didn’t even retract the gear. We just kept it in afterburner and Howard did a superb job of keeping the speed right where the aerodynamicist had said to put it.” The missile climbed to nearly 11,000 feet, reaching a speed of 365 knots. After about 30 minutes, Mabey brought the bird down towards the lakebed for a high speed landing. The missile hit the deck, bounced back into the air and then settled resolutely on the ground. When it glided to a stop about a half-mile down range, team members had every reason to be ecstatic. The Regulus II had performed flawlessly. “It really was,” Sutherland remembers, “a piece of cake. In fact, it was the best day of my career.” The bar bill that night was pretty high, but the Vought brass picked it up. Their new weapon looked like a winner.
It had been a spectacular debut. In fact, the only difficulty encountered during the flight was that as expected, even with the J-65 engine, it was obvious that the bird was too fast and far too nimble to be chased properly by control aircraft. The missile’s abilities might have been a headache for the flight test coordinator – chase aircraft had to be continuously vectored in on intercept courses and the missile throttled back – but it boded well for the bird’s mission profile. Its chances of penetrating enemy airspace looked very good indeed.
By June, six successful flights had been attempted with GM-2001. The only significant problems encountered were with deteriorating tires (“We learned that everytime you’d take off from the lakebed you’d need a new set of tires,” notes Engle. “Landings were okay but takeoffs would tear the tread off”) and parabrake failures (“We shed a couple parachutes,” Engle comments. “Good thing we had the lakebed, because we could just shut the missile down and let it go. It took about four miles to stop!”)
During the seventh flight, GM-2001 successfully broke the sound barrier, reaching a speed of Mach 1.5 at 35,000 feet. This triumph was tempered by a horrific incident during the landing. With the engine in full afterburner and gear extended, the bird stalled and tumbled into the lakebed, and was a total loss. “We got the airplane back in enough pieces,” Sutherland remembers, “Where we could tell exactly what (the cause) was. There was a cold solder joint in a throttle servo that short circuited. And that failure caused the servo to go full throttle and all the way back to idle. It was one of those things. That servo was a closed unit that we’d gotten from a supplier and we’d never checked it.” Because the culprit was located quickly, and because the accident came at the end of a string of successful flights, the crash did little to the trajectory of the program, which was by now looking charmed. In fact, Sutherland actually remembers some peculiar thoughts going through his mind. “I remember worrying,” he laughs, “What are we going to do with all the extra test missiles? Because we’d had seven airframes, and here we’d made seven flights with just the first missile.”
In September, another supersonic flight occurred, with GM-2003. This was followed by the first high altitude flight – 56,000 feet at Mach 1.6 – in October. On November 7, a second high altitude flight took place with the same bird. After reaching Mach 1.8 and 43,000 feet, GM-2003 was commanded to perform a sharp right turn. The missile responded with a violent pitch up and then went into a steep, spinning dive and disappeared into the wastelands of the Pacific Missile Test Range. An extensive search ended up having to be conducted by Marines. Eventually, with the help of an old prospector who knew the area, the wreckage was located. Almost nothing was left, and that fact, coupled with an almost complete loss of telemetry data from the last moments of the flight, left George Sutherland and his engineers completely in the dark. Had the missile’s airframe failed, or was there another cause? No one had a clue.
Thus began a month of debates. After determining that there really was no hard evidence to pinpoint the cause of the accident, Sutherland found himself in the disconcerting position of having to recommend a second flight test mirroring the circumstances of the first. “We didn’t know what had happened,” Sutherland remembers, “And I did have a big fight convincing the powers that be that we should fly again. I said, ‘We’ll probably lose the missile trying to figure out what happened, and that’s the price we’re going to pay.'” All those “extra” airframes now looked like they might get some use after all.
On December 11, GM-2005 took off and was put through a set of maneuvers identical to those performed by GM-2003 on its fatal flight. To everyone’s dismay, the missile experienced a nearly identical failure. This time, however, enough of the airframe survived the crash to indicate that structural failure had not occurred during the flight. And complete telemetry data had been recorded. With these vital clues in hand, Sutherland had confidence that the problem could be identified and fixed. Nevertheless, the Navy suspended all Regulus II flight operations until a full explanation of the back to back failures could be provided.
“I think the Navy was really whizzed off about it,” Joe Engle adds. “Because we were supposed to be smarter than that. There was some concern about the delay, but we really weren’t sure what was wrong, although after the second one we thought maybe it might be…turbulence…or what we now call wind sheer.”
“We did have what I’d call first generation computers and we were able to take the telemetry data and work backwards,” Sutherland remembers. “And what had happened was a bit complicated. When the missile was cruising at altitude, it would automatically kick into a ‘Mach Controller’. It would then climb at a constant Mach number. It had one horrendous rate of climb – I think 20,000 feet per minute, really screaming. What we didn’t realize, that people realize now, is that if you fly through a wind sheer the Mach Controller thinks that the missile’s speed is changing. And what happens then is that it over-controls like crazy, and begins to pull a lot of g’s. The data on the second missile said it was pulling three g’s, and it was in a turn. Well the missile wasn’t designed for that.” In fact, engineers had never contemplated that the missile would have to make radical high speed turns as part of its mission profile. The limited expanse of the test range, however, had necessitated such maneuvers.
Just to double-check the theory, Sutherland sent Joe Engle up in an F-4D on a cloudy day, and asked him to simulate the actions of the Mach Controller by flying at a constant speed. “See, in turbulence, as a pilot you let the airplane fly itself,” Sutherland comments. “And so when Joe Engle went up and tried to fly a constant Mach number in the clouds, well he found he couldn’t. He radioed, ‘I can’t keep it steady and I’m pulling three g’s!’ There you go.”
By mid-January Sutherland thought he had a fix. The pitot ports supplying air speed data to the Mach Controller were relocated, and the Controller was modified slightly to allow a more gradual climb to altitude. In May, flight tests resumed using GM-2005, which successfully performed a flight profile identical to that which had destroyed its brethren.
It appeared the problem had been corrected, and certainly Sutherland looked vindicated. His decision to sacrifice GM-2005, which had drawn all sorts of criticism, now seemed quite sage. But just to make certain the problem really was taken care of, a second flight was ordered using GM-2006. This time a new problem occurred. Just after the missile had gone supersonic at 35,000 feet, it began to develop roll oscillations. Despite desperate efforts to keep the bird airborne, the missile began pitching wildly, and moments later tumbled out of control, and out of the sky. This time telemetry data indicated that the gyros were the source of the trouble, something which didn’t make anyone very happy. Yet a similar flight conducted in the wake of this accident with GM-2002 went perfectly, as did two subsequent flights. The problem, as David Stumpf noted in his book, was “a subtle one.” Eventually, by analyzing telemetry data, further tweaking of the yaw gyros was indicated. To Sutherland and the Navy’s relief, this turned out to be the solution, and no other missiles were lost as a result of oscillations.
Now that the Reg II had gained its baby teeth, some serious chewing could begin. The first order of business was to attempt a JATO rocket launch of the missile. Experience with the Regulus I had shown how difficult and dangerous this could be. Regulus I was launched to flying speed by a pair of rocket bottles capable of producing about 30,000 lbs of thrust for 2.2 seconds. They had proved to be tricky customers. During one early test launch, one of the two bottles detached from the missile and corkscrewed a hundred feet into the air, while its partner dutifully pushed the missile off the launcher and into the ground. Occasionally a defective JATO would explode during launch, setting off the missile and producing a huge fireball. And every now and then a bottle or affiliated launcher mount (“slipper”) would fail to eject from the missile after launch, making it almost impossible to keep the missile airborne. The most common problem with the bottles, however, was the fact that both exhaust nozzles had to be precisely aligned through the center of gravity of the missile. Improper alignment in either one resulted in the missile being pushed right or left, or up or down to its doom.
The Bureau of Aeronautics and Vought had no interest in repeating the tough lessons of the Regulus I dual JATO system, and determined that the Reg II would have a single booster. Aerojet proposed a massive unit, capable of producing a whopping 115,000 pounds of thrust for four seconds. (In all fairness it should be noted that recent advances in the casting of solid fuel propellants – an outgrowth, in part, of the Polaris fleet ballistic missile development program – made such a thing possible. At the time the Reg I boosters were designed, JATO bottle sizes were severely restricted and far less reliable than they were in later years.) The single booster concept for Reg II potentially solved many problems; the question of how to attach it in such a way that ejection was guaranteed was another.
Bill Albrecht, now the Reg II’s field engineer, came up with a solution so elegant and profound that almost no one believed it could work. The launch slippers and all affiliated equipment, Albrecht proposed, should be attached to the JATO bottle. The missile would then be mounted atop it. Quite literally, the bird would sit atop the JATO like a hen on an egg. When the bottle fired, it would lift the missile skyward. But as soon as the bottle’s thrust diminished enough that it could no longer support its own weight, it would fall clear. The missile would then continue on its merry way unencumbered.
Albrecht’s concept turned out to be fool proof, and it quickly won adherents after a series of wind tunnel tests proved it was possible. “There were unbelievers,” Albrecht recalls wryly. “The idea of just using the thrust of the rocket to hold it on, and not having any kind of ejection system, was uppermost in people’s minds. When I got the idea to the design groups, they all kept trying to lead me back to having nitrogen gas on board the missile and an ejection system. You know, folks just shook their heads at the thought of that thing taking off with nothing holding it on except thrust. They kept saying, ‘What if the thrust fails?’ Well I said, you don’t get a launch anyway if the thrust fails! So anyway, we tried it and it worked. And in fact it never failed.”
As with the Reg I, the nozzle on the JATO bottle would have to be aligned through the center of gravity of the bird to ensure a proper launch. The procedure developed for Regulus I, which involved hanging the missile in a giant sling, was also used for the Regulus II. The various dummy warheads, fuel loads and electronic packages on each airframe meant that each bird had to be assessed independently. The experience of placing a 20,000+ pound missile in a sling to make the measurements were daunting, but the consequences of a misalignment were severe enough to warrant it. “You had to get within a tenth of an inch of accuracy on the alignment,” Sutherland remembers. “Or you’d be in trouble.”
Two significant tests of the JATO system took place before a boosted launch took place. First, a giant pig iron dummy sled, weighing approximately the same as a Reg II, was attached to a booster, placed in a protoype Reg II launcher, and shot out into the desert. The test was a complete success, with the dummy cleanly leaving the launcher and then tumbling into the ground.
The second test arose out of concerns raised by Sutherland’s staff and Navy brass. “There was this other missile called the Snark and it had a lot of problems with vibration on launch,” Sutherland recalls. “Some of our people went to a symposium and found out that it had been torn apart at launch – the fuel turned to jelly, and so forth. So we had some people who felt that we shouldn’t fly. Couldn’t fly. So we decided to put a (fully fueled) Reg II on a skid with a special JATO bottle to simulate the impact of a launch on the bird. We fired it, and nothing bad happened. But that was quite a big hurdle to persuade them to let us do that.”
On November 13, 1957, GM-2008 became the first Reg II launched by JATO. It left the launcher in spectacular fashion, and flew for 49 minutes, reaching an altitude of 35,000 feet, and a speed of Mach 1.1. “The launch was great,” Albrecht remembers. “It just slid off the launcher rails and right up into the sky. It was sensational… That big bottle made a lot of noise and it was pretty stupendous to see one go off. To me, the idea of that huge beast being motionless and then – in the space of two to three seconds – having a flying speed of 200 odd knots was pretty dramatic.”
Joe Engle, again flying Baker position in a T-33 while Howard Mabey controlled the missile, was also stunned by the power and majesty of the launch. “I came sailing in and I knew that with this huge booster it was going to take off flat,” he laughs. “But that thing went from 0 to 250 knots in three seconds, golly!” After he’d recovered from the shock, Engle closed on the bird. “I came in purposely a little fast and close to make sure there were no panels off the missile. A missing panel can be bad news,” he remembers. “But it was fine.”
One minor engineering oversight became apparent on the ground just after the JATO smoke cleared. The cables holding down the massive mobile launch platform had parted, and astonishingly the behemoth launcher had slid forward by several feet. There was a moment of head scratching and then some good-natured back-slapping. “Well, it was something we’d forgotten altogether,” Albrecht says, “With the thrust of the engine driving against the release system in the launcher, the cables that restrained the launcher were stretched like springs. So once the missile was launched, the launcher snapped back with a lot of force.” On board a ship or submarine, this would not be a problem since the launcher would be affixed to the deck. The test launcher was eventually fitted with a compression column to absorb the launch energy. “It was an easy cure,” Albrecht grins. “But it was a bit of an oversight!”
Despite the snafu with the launcher, the flight was a complete success. And when GM-2008 landed safely on the Muroc lakebed, the test team had every reason to be excited. Only two areas of flight testing remained unexplored: flight with the inertial navigator system, and a supersonic terminal dive of the missile to a simulated target.
On July 16, 1958, the first terminal dive flight profile was attempted using GM-3001, the first bird to be equipped with the J-79 engine. After a JATO launch, the missile zoomed skyward. Thirty six minutes later, at 45,000 feet and a Mach 1.8, the missile’s terminal dive controller was given the “dump” command. The missile began the terminal dive maneuver uneventfully, automatically decelerating as the engine switched to idle, and pitching over on its nose. Twenty-two seconds into the maneuver, however, a small side slip occurred and piece of the airframe detached. Ten seconds later the missile was tumbling violently, and the right wing collapsed. A complete structural failure occurred almost instantly. Chase pilot Earl Holcomb, who had been observing the dive when his F8-U experienced a flame-out, regained control of his jet just in time to observe multiple pieces of the missile impacting the ground. For a moment, he feared that it had actually collided with another chase aircraft, a chilling possibility made all that much more real when his wingman did not respond to repeated radio calls. It turned out, however, that Holcomb’s wingman was fine. He had been unable to answer the radio because, in order to avoid the rapidly-disintegrating missile, he’d had to initiate some severe evasive maneuvers of his own!
A photo-theodolite film of the accident gave engineers all the evidence they needed to ascertain the cause. The small piece of the airframe seen detaching at the beginning of the maneuver, they deduced, was the “buzz plate.” “At high mach number,” George Sutherland explains, “and at high dynamic pressure, we knew the missile had a buzz – a real high frequency oscillation that could cause structural damage. So we had what we called a buzz plate. At the time you’d start to push over into the terminal dive, the engine would throttle back to idle and drop this plate in front of the duct. Well, in this first dive that plate wasn’t there.” The buzz plate failure obviously had catastrophic consequences, but engineers were uncertain whether the plate itself had failed structurally, or whether the actuators which lowered it into position hadn’t worked properly. In the end, a new set of steel buzz plates were manufactured, a small lower ventral fin was added to increase stability, and the plate actuators tested repeatedly. The fixes worked brilliantly. On November 1, 1958, GM 3003 made a terminal dive, impacting at a speed of Mach 1.6. A slight crater lip was the only evidence of what must have been an unbelievable impact. (After a bit of digging, engineers actually recovered one of the buzz plate actuators from the site, and presented it to George Sutherland. He still has it today.)
While the terminal dive problem was being solved, tests had begun with the Regulus II’s inertial navigator. This state of the art self-contained guidance system would be immune to electronic countermeasures, and promised deadly accuracy (600 yards error after a 500 mile flight with proper in-flight radio beacon updates; 6000 yards error without them). Despite a great deal of work in the inertial guidance field in the early 50’s, it was a science then still in its infancy. It would very shortly come into its own as part of the Polaris program, which relied on inertial navigators to guide both the submarines and their missiles.
One of the biggest hurdles for any inertial navigator are the gyroscopes, which have to be kept at constant RPMs to maintain freedom from linear acceleration. Just finding a low viscous fluid to allow this to occur without producing severe bearing wear had posed a nearly insurmountable problem. The solution turned out to be a chemical developed at M.I.T. known as fluorolube. Unfortunately, fluorolube had a shortcoming. It had to be maintained at 160 degrees Fahrenheit or it would expand, causing the bearings to seize. As a result, the Reg II’s inertial navigation unit had to be fitted with heaters which, when the missile wasn’t flying, were powered by an external source. This situation led to some amusing events. “It caused a lot of grief,” recalls Bill Albrecht, “Because the units had to be powered day and night. So we set up a secluded room for these guidance packages with a guard and a alarm. If the power went off the alarm would buzz, and the guard had a list of people he would call. The first one he got ahold of had to go in there and run a checklist. You only had about an hour before it would cause damage. Anyway, my name was at the top of the list and I remember getting called, a couple times, after midnight.”
The first tests with the inertial navigator began in January of 1958, and were not promising. Shortly after take-off GM-2010 became unstable and control had to be switched from the inertial navigator to a ground station. A second test ended abruptly when one of the gyros seized. By November however, the bugs had been worked out and GM-3002 flew under inertial guidance all the way to a target and initiated a successful terminal dive. Another test, about a month later, confirmed that the inertial navigator was performing correctly, as a Reg II assumed a great circle navigational heading at launch and acquired the correct target track after only ten minutes of flight. Clearly, the teething problems had been solved and the bird was ready for fleet acceptance and evaluation.
In July 1958, the Regulus II program received a major boost with the arrival of one of the Navy’s newest weapons, the submarine USS Grayback, at Port Hueneme (a Navy facility near Pt. Mugu). The just-commissioned Grayback, one of four diesel Regulus guided missile boats, would test launch Regulus I and Regulus II dummy sleds as part of its qualification program, and test the new Mark 7 launcher (compatible with both missiles). Launching the Reg II dummy sled would be also serve as the precursor to a full-fledged test launch of a Reg II.
Like its mate USS Growler, USS Grayback had been built with the Regulus II in mind. With its wings, tail and nose folded, a Reg II would just fit into one of the Grayback’s twin hangars. It could carry two Reg IIs or, alternately, four Reg I’s, or a combination thereof. The other two diesel Regulus submarines in commission, Tunny and Barbero, were modified WWII boats and would not be able to carry the Reg II. Their presence would hardly be missed, however, once the USS Halibut – then under construction at Mare Island – and its three planned sister ships slid down the ways. A nuclear-powered SSG, Halibut would be capable of carrying four missiles in an absolutely gigantic forward hangar – so large that it contained more volume than a WWII fleet-type submarine.
On July 25, Grayback set sail for the Carcenas Straights, where it tied up against a wooden pier to perform the dummy sled test launches. The Reg I test went well, but the Reg II test ended up being scuttled. “We got out there,” recalls Lt. Commander Bob Owens, “And started to put the ignitor into the Reg II booster. Well, the threads galled. We couldn’t get it in or out, so Commander Nott decided we’d better go back to Mare Island. Well, we get there and we’ve got this great big, 115,000 pounds of thrust booster with an ignitor on it. We had lots of fire trucks! The Aerojet people ended up taking the whole front off the booster, and replacing it with another one. Then we could put on a new ignitor.”
The next day, the dummy sled made a successful flight, shooting off the deck and careening into the ocean. The JATO bottle worked beautifully, but it left behind a scene reminiscent of Warsaw, 1939. “It just tore the (Mark 7) launcher to pieces,” Owens remembers, a bit of awe sneaking into his gravelly voice. “There were bits of the launcher every place, hydraulic hose parts everywhere. We tore the boards off this wooden pier we had been tied up to, too. It even tore the fairings off the launcher, just wrecked the middle of the launcher, and took the deck plates with it. We had no idea that the booster would do that much damage. So they had to rebuild it of course and change all the aluminum there to steel.”
On September 16 Grayback, now outfitted with a beefed-up launcher and Reg II launch control and support gear, cruised off Point Mugu. The submarine made quite a sight, with a massive missile – GM-2016 – sitting just forward of the sail on the launcher, its weight giving the boat a slight list. The sheer power of the J-79 engine was made apparent immediately after ignition, as it pushed the entire submarine to starboard as if it were an outboard thruster.
After a few minutes of engine run-up and checkout, the order to fire was given by Commander Hugh Nott. The Reg II leapt off the deck in a cloud of smoke, the JATO separated and the bird disappeared into the sky. “It was pretty interesting, let me tell you,” says Bob Owens. “When we put that thing into full military power, and went into afterburner with it, it moved the Grayback like nothing flat. And boy the fuel pump was just going crazy trying to keep up with it, because it was on external fuel till we launched it. When the bottle went off – it burned for something like four seconds – it was just a boom and a swoosh. It just pushed us all over the place.”
Controlled by chase aircraft, GM-2016 sped out towards Edwards at 325 knots. Control was handed off to ground stations at Pt. Mugu and then Edwards. The flight was a stunning success right up until the last minute, when the bird’s gear failed to extend and it had to be brought in for a wheels-up landing. GM-2016 touched down gently, slid along the lakebed and then, almost as an afterthought, burst into flames.
The picture perfect launch and flight with the botched landing at the end somehow neatly symbolizes the story of the Regulus II. For even though by now every phase of the missile’s operation had been demonstrated successfully (48 flights had been made, with a success rate above 80%), and even after the Grayback launch and two subsequent launches off the converted LST King County, in December 1958 Secretary of the Navy Thomas Gates unexpectedly cancelled the program.
The reason was simple: recent stunning advances in the Polaris ballistic missile program had convinced the Navy that it would be operational by 1962. Unbeknownst to many of the people who worked on it, Regulus II had been the Navy’s “ace in the hole”, ready to be deployed should the Polaris effort falter. Now, even though Polaris had yet to have a successful flight (and wouldn’t until April, 1959), the head of the Special Projects Office, Admiral “Red” Raborn, had convinced the powers that be that his team had things well in hand. He had also convinced them that his effort needed the Navy’s undivided attention and all of its treasure, right down to the milk money. Polaris’ development costs, after all, were staggering, and the idea of supporting both it and the Reg II was untenable.
“It was shocking, when they cancelled us. Because we were having three operations a week! That was unheard of in those days,” Bill Micchelli notes. “That missile was reliable as hell and we were real proud of it. So it was a black day.”
“I think we were all surprised,” recalls Bill Albrecht. “It was cancelled rather abruptly. But then of course I started thinking about what I’d heard from friends at Lockheed, that they’d managed to get the underwater launch system to work, and had dummy Polaris’s popping out of the water. Anyway, this was right before Christmas, and just about the same time the F-8U3 , which was our candidate for Navy fighter, lost its bid against the McDonnell F-4H1. So it was a bleak Christmas for Chance Voughters.”
George Sutherland remembers it well. “It ruined everyone’s Christmas,” he declares. “And I think the hardest job I ever had was this pink slip routine just before Christmas. We had to notify literally hundreds of people. And then we had to scramble to get what we could.” This would eventually include some business from NASA – the Scout booster system – and a missile for the Army. But Vought would never again build a cruise missile like Regulus.
“My personal feelings were of great disappointment,” Bob Owens sighs, the memory of the day he heard about the II’s cancellation still fresh in his mind. “I was surprised because we had a lot of faith in that Reg II. It was an excellent missile. And I could foresee a use for Reg II even with Polaris. Because Reg II had a low-level attack capability. I thought we were putting all our eggs in one basket to just have Polaris. If they built a defense against ICBMs, I thought, we’d want to have a low-level attack capability.”
In hindsight it is clear that the cancellation of Regulus II in favor of Polaris was certainly the correct decision. “The irony of the cancellation,” says historian Stumpf, “was that Reg II was ready for deployment to the fleet. The submarines were built which could carry it, and the inertial guidance system had proven itself reliable and accurate. Polaris wasn’t working yet. But in the end, it was an appropriate choice.” The reasons he gives are multiple. The Polaris ballistic missile not only had a longer range, but could be fired from underwater. The Regulus boats, which had to surface to launch, were certainly more vulnerable. Plus, although the Regulus II sported a bigger warhead than Polaris, the Polaris submarines could carry sixteen missiles – twelve more than the Halibut-class Reg II boats. Beyond that, the Polaris IRBM was completely invulnerable to enemy countermeasures. Despite its high speed and maneuverability, and inertial guidance, a chance always existed that the Regulus II could be blown out of the sky by a new Soviet anti-aircraft missile or supersonic fighter. (Advocates of the Reg II discount this; the bird was so fast, they argue, and when fired from a submarine it would arrive over its target in a matter of minutes. “By the time they’d figured out what’s happening,” notes Captain William Gunn of the USS Growler, “It wouldn’t have mattered. They would have been looking at a mushroom-shaped cloud.”)
The cancellation of the Regulus II certainly did have negative repercussions. The Navy would have to wait a generation before its cruise missile capability would be restored, and once the Regulus I was withdrawn from service (in 1964) it would again be forced to depend upon aircraft to perform the cruise missile mission. Moreover, the cruiser Navy – four Los Angeles class cruisers carried the Reg I and seven would have carried the Reg II – temporarily lost their atomic strike capability. In the overall scheme of things however, Polaris was a real necessity and the kind of weapon needed to stabilize the Cold War. Plus, the idea of nuclear submarines carrying sixteen nuclear missiles, unseen and undetected and within striking range of enemy bases, seized the imagination of the nation in a way the Regulus II never could. Eventually, Congress authorized 41 Polaris boats to be built – far more than Raborn had ever proposed. The Cold War’s ultimate weapon of deterrence, Polaris would keep the nation safe from Soviet attack. And in the end, Regulus II would be reduced to a mere footnote in weapons development history.
“It is somewhat ironic now, with the success of the Tomahawk cruise missile in the Gulf War, Bosnia and elsewhere,” says Stumpf ruefully. “The whole concept, including the first successful use of inertial guidance and even radar map matching – which they tried with Reg II – is an outgrowth of Regulus I and II. That’s quite a tribute, I think, to the impact these programs had.”
THE REGULUS KD2U-1 DRONE ERA
The fact that the Regulus II was all but operational at the time of its cancellation, and that there were over forty missiles either delivered or nearly complete, presented a rare opportunity for…someone. The question was, who? Vought drew up plans within a week of the Navy’s cancellation, proposing a transfer of the remaining Reg IIs to Europe, where they could form a land-based deterrent missile force. The idea did have merit, but in the end was rejected by NATO for both political and practical reasons. (Interestingly enough, David Stumpf has noted in his book that, approximately 27 years after this proposal was rejected, the Air Force actually deployed ground-launched cruise missiles in Western Europe, and did so in nearly identical fashion.)
George Sutherland and a team at Vought also worked on a plan, which was submitted to the Air Force, to build a small “Regulette” cruise missile which could be launched from a B-52. “There were some people who believed we could launch a Reg II that way, but I didn’t think that was practical. Anyway, they rejected the idea and ended up building the Hound Dog,” Sutherland notes. In his view, looking back on it, Reg II should have been picked up by the Air Force since, after all, it was far superior to any of the weapons they had developed, and similar to weapons they had tried to develop. That included the ill-fated Navaho supersonic cruise missile, a veritable carbon-copy of the Regulus II which had been cancelled after multiple failures. More than anything else, fierce intra-service rivalries probably put the kibosh on any non-Navy use of the Regulus II. The Air Force didn’t want a hand-me-down, even if it was hardly worn.
Even before the rejection of the NATO staging plan in March, 1959, the Navy had decided to put some of the Reg IIs at Pt. Mugu to use as target drones. The missiles’ high speed flight characteristics, proven ability to fly under radio control, and recoverability features made them ideal for this role. And so, redesignated the KD2U-1, and equipped with target beacons and near miss indicators (so that airframes would not have to be expended by direct hits), the Reg II was drafted into a new role, one which would end up becoming its primary mission. It would show its wings against some of the Navy’s newest air-to-air guided missiles, including Sidewinder 1C, Talos, Sparrow II and the USAF ASG-18, and school the Navy’s emerging anti-aircraft arsenal.
Navy pilot Cmdr. Al Thayer, who had trained as a carrier-based Regulus control pilot, ended his Regulus career by becoming a KD2U-1 drone controller with Guided Missile Unit 55 at Mugu. It was a task he relished. “The Regulus II was a Mach 2.0 plus, 70,000 foot airframe,” he remembers enthusiastically. “It would cruise at 70,000 feet in minimum afterburner. It was about the only thing we had at Mugu that would provide a target in that area in 1959. Wow. It would automatically take off and climb to 35,000 feet in 40 seconds or so, accelerate to Mach 2 in another 30 seconds, and climb to 70,000 feet in another 45 seconds or so. It was something.”
The flank speed of the Regulus II made for some outstanding moments. Thayer remembers one incredible day in particular when, as he flew over San Nicolas Island, a pilot in an F-4 near Catalina fired a Sparrow missile at an expendable Reg II target. “The Regulus was at maximum afterburner all the way,” he recalls. “The F-4 was closing at Mach 2.4, and the Reg was going at Mach 2. And I watched the F-4 fire the Sparrow – it was an absolutely clear blue day – and I saw the Reg II just stop. And you can’t imagine what a sight that is! And the Sparrow worked perfectly.”
Landing the gigantic drone, especially on the narrow runways of Pt. Mugu or nearby San Nicolas Island, also made an impression. “I remember vividly the first time we joined up on a Regulus II to land it at San Nicolas Island,” Thayer muses. “I remember my view of that Regulus II as I pulled up formation wise on the starboard side. It was a lot bigger than the Regulus I! It seemed like it was a, can I use the word, dragon? It had a lot of panels of things that I saw were oscillating and the engine was so loud that I could hear it. And it was a beautiful landing. The runway in those days was only 7,000 feet long, so it was a welcome surprise when it didn’t go off the end!”
There were some white knuckle moments affiliated with the drone program at Mugu. On at least one occasion, one of the giant JATOs detonated on ignition. Shrapnel from the explosion penetrated the missile’s fuel tank and the bird had to be destructed by the range safety officer. “It was probably caused by a cracked grain in the booster,” notes Thayer, who witnessed the incident. “The propellant burned too rapidly, which pressurized the case, causing an explosion. It made you a believer that it wasn’t too wise to get too close to that thing (as a control pilot) during the boost phase.”
Another notable incident occurred when a KD2U-1, equipped with a special fuel tank in place of a dummy warhead, was launched from the Mugu blockhouse. The bird had been running in full afterburner for several minutes before ignition, and the rapid depletion of fuel in the new tank radically altered the bird’s center of gravity. It lifted gracefully into the air, arched over backwards as if it might loop, and then stalled and plopped unceremoniously into the Mugu shallows. “About the only thing I can remember on that one,” says Al Thayer, who watched the spectacle from the ground control center, “Is that it looked like it might come down on the launch pad or the building I happened to be in! But actually it came down in front of the launch pad, and fortunately no one was hurt.”
While the Navy was busy employing the Regulus II as a drone at Mugu, the Air Force found itself in need of a high speed target to train crews for the BOMARC ground to air missile. BOMARC, a Mach 2.8 interceptor with a range of 250 miles and an altitude ceiling of 60,000 feet, was designed to take out wings of enemy bombers with a nuclear airburst. The Regulus II would make a perfect simulated target for it.
So beginning in 1959, a team of Chance Vought engineers and control pilots, including Joe Engle, deployed to Eglin Air Force Base in Florida to begin drone flights. Operating out of a strip of land near the Venice airport, KD2U-1s were JATO launched, flown out across the Gulf of Mexico for interception, and then recovered on the runway at Eglin. The drone program was extremely successful, with 46 separate launches. There were occasional hitches, some of which Joe Engle remembers vividly. “This one time the BOMARC takes off and started to head towards New Orleans. So the range safety officer says, ‘Destroy the bloody missile!’ The guy controlling the BOMARC was at Montgomery Alabama. Well, that guy in Montgomery regained control and he was so good, he ended up flying the BOMARC right into our missile. I mean, skin to skin contact. Destroyed them both.”
On another occasion, which he will probably remember until his dying day, Engel and his control pilot discovered their KD2U-1’s afterburner would not light. “We could not land the thing without afterburner. Well, we thought we’d try to bring it in anyway. We had it wired, absolutely wired, but at the last second before touchdown that numb nut at the controls screwed up. It skipped, and the control surfaces went 60 degrees up, and I’m sitting right next to this thing, watching the gear collapse, and a strut go flying, and now the missile was going straight up, and rotating. I said, what am I doing here? So we got out of there. Later, let me tell you, I had a long chat with that airframe about its ancestry and heritage.”
The BOMARC / KD2U-1 program came to a close in 1961, as obsolete F-104 and B-47 aircraft became available for drone services. The remaining three KD2U-1s at Eglin were then moved to NAS Roosevelt Roads, Puerto Rico where they were used against Tartar, Terrier and Talos missiles. These tests ended in 1963.
Meanwhile, KD2U-1s continued to be flown out of Pt. Mugu, where they had compiled an extremely impressive record. 17 drones flew on a total of 64 flights. None, perhaps, was as impressive as the very last one. In late December 1965, GM-2048, flying on its tenth mission as a drone, was fired on five times by a B-58 “Hustler” (launching AIM47As) during a sustained flight at Mach 2.0, at 58,000 feet. When GM-2048 successfully landed at San Nicolas Island, the drone era at Mugu drew to a close. Regulus II had flown its last flight.
Two years ago, volunteers from the Chance Vought “Retiree Club” followed up on a lead provided to them by historian David Stumpf – that there was a Regulus II airframe extant at the New England Aviation Museum at Windsor Locks, Connecticut. Stumpf had it right. There, buried sadly in the mud, its paint faded and scarred, its wings gloomily folded, sat a once-proud bird. And not just any bird. This Reg II, it turned out, was none other than GM-2048, the last Reg II to fly and the last survivor of the II’s modified to serve as a target drone.
After a bit of negotiation and consultation with the Navy, possession of GM-2048 was handed over to the Retiree Club, who promptly shipped it back to the Vought Aircraft Industries factory (now part of Northrup Grumman) by flatbed truck. When hoisted off the truck by crane, power was supplied to the landing gear’s nitrogen bottle. After 30 years of sitting around in the New England rain and snow, no one expected anything to happen. “But wouldn’t you know it,” said Bill Micchelli, who founded the Retiree’s Club and is a leader in the restoration effort, “The gear extended as if it had just come out of the shop. Two of the tires required no air. The other needed a few pounds because of a small leak in the valve stem. Other than that, it was factory new.” The bird had been built rugged, there was no denying that.
Recently stripped and prepared for painting the airframe, its launch cradle and an expended JATO bottle are undergoing a complete cosmetic restoration. Someday soon it will be placed on display at a still-to-be determined location, a lasting tribute to the people who built and flew this bird on a wire.
Incidentally, the Retiree’s Club, which is nicknamed the “Vought Survivor’s Club”, has come up with a new name for GM-2048. “It went through 10 launches and recoveries, was shot at repeatedly as a drone, spent all that time in the rain and so on,” Michelli muses. “So, we call it our ‘Real Survivor.'”
Special thanks to Dr. David Stumpf, who contributed a great deal of content to this article, and the Chance Vought Retirees Club.
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