The Japanese Spruce Goose: The Kawanishi H11K Soku

Profile of the H11K from the Anigrand 1/144 scale kit
(Anigrand Craftswork)

By 1944, the US Navy's unrestricted submarine warfare against Japanese shipping had reached its highest totals in terms of shipping sunk and it was taking its toll on Japanese industry. As an island nation with few natural resources, Japan was dependent upon shipping for the importation of raw materials and oil for not just its industry but also for it military forces. The Imperial Japanese Army Air Force looked at using transport gliders to bring oil from Sumatra to Japan, but the fuel costs to do so outweighed the volume of oil brought in. The Imperial Japanese Navy, however, with its experience in operating large seaplanes, asked Kawanishi to develop a large transport seaplane to make up for the shipping losses. Kawanishi had already designed and put into production two large flying boats, the H6K (Allied code named "Mavis") and the H8K (Allied code named "Emily"). The H8K in particular was avery well-regarded flying boat design, even by the Allies. Kawanishi had also modified its production flying boats for the transport role as well. The transport version of the H8K was designated H8K-2L Seiku ("Calm Sky") and the company had built 36 for the IJN for transport duties aside from the prototype which was converted from a front line H8K. Most of the defensive positions were deleted to save weight save a 13mm machine gun position in the nose and a 20mm cannon in the tail position. The fuselage fuel tanks were reduced in size to allow for more cargo volume. An H8K-2L could carry up to 62 fully-equipped troops.

Overall configuration of the H11K Soku
(Airwar.ru)

The earlier H6K also had a transport version. It didn't have the space or load carrying capability of the larger and later H8K, but 20 aircraft designated H6K4-L were built and another two were converted from former front line H6K4 flying boats. And earlier production run of 18 aircraft designated H6K2-L were primarily passenger aircraft used by Japan's wartime airline, Dai Nippon Kokku. As passenger transports, they could accommodate 18 passengers and had sleeper berths.

Kawanishi's design for a large purpose-designed transport flying boat was designated H11K Soku ("Blue Sky"). Since metal alloys were desperately needed in the production of fighters for homeland defense, Kawanishi's H11K would have been made of wood wherever possible- making it in a sense a Japanese counterpart to the Hughes HK-1 "Spruce Goose". Starting out by scaling up the H8K but having a nearly identical fuselage keel, the H11K was powered by the same four Mitsubishi MK4Q Kasei 22 1,850-hp radial engines, each engine driving a large four-bladed propeller 14 feet in diameter. By comparison, the large Martin JRM Mars had 16 foot, 8 inch four bladed propellers. Most of the wings and fuselage made of wood. Under each wing was a fixed float for water stabilization. The fuselage had two decks- the upper deck had not just the flight deck but also quarters for the crew of five. The lower main deck could accommodate over 80 fully equipped troops, vehicles or an equivalent volume of cargo. To speed loading and unloading operations, the nose had split clamshell doors. Three machine gun positions were located in the fuselage for self-defense. 

The H11K mockup with its nose clamshell doors
(RC Groups Forum)

After presentation of the H11K proposal to the Imperial Japanese Navy, full design work began in 1944 with Kawanishi building a full-scale mockup of the H11K for inspection and review by the IJN at one of its facilities on the west coast of Japan. However, the deteriorating war situation meant that  the full-scale mockup which was nearly completed on was destroyed along with most of the Kawanishi facilities in a bombing attack on 1 April 1945. No further work was attempted on the H11K Soku after the attack.

Some comparisons with other large Second World War-era flying boats to give you an idea of the Soku's size:

Dimensions
Span: 47.97m 157.4ft
Length: 37.70m I23.7ft
Height: 12.55m 41.2ft
Wing area: 289.95m2 3,121ft2
Wing loading: 156.72kg/m2 32.1 lb/ft2

Weights
Empty: 26,405kg 58,213lb
Loaded: 45,550kg 100,420 Ib
Useful load 19,095kg 42,097b

Performance
Max speed: 470km/h 292mph at 5,000m at 16,404ft
Cruise speed: 369km/h 229mph
Landing speed: 144km/h 89mph
Range: 3,890km 2,417 miles
Climb: 11 min 30 sec to 3,000m (9,842ft)

Source:  Japanese Secret Projects: Experimental Aircraft of the IJA and IJN 1939-1945 by Edwin M. Dyer, III. Midland Publishing/Ian Allan Publishing, Ltd, 2009, p63-64.

Martin, the Titan I, and the Titan II Ballistic Missiles

Titan I ICBM elevated out of its silo for laugh
(USAF Museum)

When George M. Bunker took over the reins of Martin Aircraft from Glenn Martin in 1952, Bunker wanted to diversify Martin which up to that point had produced only aircraft. With an able group of lead engineers that Glenn Martin had literally hand picked in the years prior to his retirement from his company, Bunker moved some of Martin's engineering and research efforts into the rocket and missile arena that bore first fruit with the Viking research rocket and the Vanguard light satellite launcher built for the Navy. While many in the growing rocket and missile division were focusing their efforts on the Vanguard program, it was Jess Sweetser, Martin's VP for Sales and Requirements, who pushed the company to bid for the second USAF ICBM contract. At the time, General Bernard Schriever was heading the Western Development Division (WDD) in Los Angeles which directed the ICBM effort that started off with the Atlas ICBM built by Convair. Schriever wanted a second ICBM system fielded as a backup to the Atlas and the WDD issued a requirement that spelled out the range, guidance and throw weight (the payload of the missile, which was the nuclear warhead). Left up to the contractors would be the missile configuration, liquid vs. solid propellants, staging and number of engines.

Sweetser got to know General Schriever so well they became golfing buddies* in their free time and as a result, he was able to anticipate the need for a second ICBM program from his conversations with the general. As a result, when the WDD issued the requirement, Martin's team of engineers was already doing preliminary work in addition to their work on the Vanguard launcher for the Navy. It became clear from further directions from the Western Development Division as well as the operator of the ICBMs, the Strategic Air Command, that not just a backup ICBM was wanted, but one that was a true alternative to the Atlas ICBM and if possible, more advanced. With both Boeing and Lockheed in the competition for the alternative ICBM contract, George Bunker split the rocket and missiles team into two parts- one group stayed on the East Coast and worked on the Vanguard launcher, the other group set up shop in Los Angeles next to the WDD to work on their ICBM design. Martin's design was based on work that had been already done for the Vanguard launcher- instead of the thin, pressurized balloon skin arrangement used on the Atlas, the Martin proposal used two liquid propellant stages made of a rigid framework of copper-aluminum alloy with the tank wall integral to the rocket walls for weight savings as had been done on the Vanguard. The first stage would use two powerful 150,000 lb thrust engines and the second stage used a single 80,000 lb thrust engine that would be ignited in zero-gravity in near-space, a first for such a large engine. The Vanguard had proved that near-space ignition of the second stage was possible, but this would be the first large-scale application. 

In addition, Martin's ICBM design would be modular, allowing the design to be enlarged over time for heavier payloads. The sweetener of the proposal that would win the USAF contract for Martin in December 1955 was the creation of an all-new development, testing, and production facility in one location at the base of the Rocky Mountains in Littleton, Colorado. This was chosen for two reasons- first, the valleys in some of the mountains could house engine test stands with the mountains acting as natural sound insulators for the surrounding area, and secondly, Martin pointed out that a mid-continent facility was furthest away from the coasts which could be vulnerable to Soviet submarine missile launches and bomber attacks. Ground was broken on the Littleton facility outside of Denver in February 1956 for the missile that the USAF christened the Titan. As a result of the USAF's requirement that everything that went into the Titan missile be thoroughly tested, the first facilities built were the test stands, some of which replicated full size launch pads were complete Titan missiles could be tested. 

Just three years after the start of construction on the facility itself, the first Titan I missile was flight tested from Cape Canaveral on 6 February 1959. The second, third, and fourth test flight were a success, unprecedented in a new rocket or missile program. The fifth and sixth flights were failures with explosions on the launch pad, but the seventh flight was a success and by 1960 Martin had 11 more successful Titan I test flights. Out of 18 test flights, only two Titan I test flights failed, a success rate that was stunning and groundbreaking given the technology of the time. 

Titan I 3x3 ICBM base layout
(USAF Museum)

The first Titan I silos were built in 1959 in the Lowry AFB gunnery range just east of Denver. The first Titan I ICBMs went on nuclear alert on schedule in August 1962 at Lowry AFB. As the Titan I used liquid oxygen as an oxidizer, the missiles were kept the silos until the launch order was given. At this point a massive elevator lifted the Titan I out its silo to an above ground position where it was fueled for launch. All of the necessary facilities were deep underground, even the propellant storage tanks. Each ICBM squadron had nine Titan Is in groups of three. Each group of three missiles were part of a single launch complex. Once the missiles were fueled, the radio guidance domes also were elevated from their own silos. The radio guidance system tracked the missiles after launch and fed the necessary course corrections, much like the guidance system used on the Atlas ICBMs. 

With advances in Soviet ICBMs, though, while the Titan I flight test program was taking place, Martin's engineers were already working on a successor, Titan II. Titan II had an even bigger warhead and the modularity of the Titan design paid off as the engineers merely had to fatten the second stage to the same diameter as the first stage and then lengthened both stages for a bigger missile. To replace the radio guidance system on the Titan I, AC Delco and MIT created a new inertial guidance system that set the standard for ICBMs. No longer would radio signals from the launch site be necessary, minimizing the Titan II's vulnerability to a counterstrike. The liquid oxygen was also replaced as the oxidizer and Titan II now had non-cryogenic storable liquid propellants- Aerozine-50, which was a mix of hydrazine and unsymmetrical dimethylhydrazine (UDMH) and dinitrogen tetroxide as the oxidizer. As a result, no fueling process was needed. 

Titan II silo "hot launch"
(USAF Museum)

The simplification of the Titan II launch complexes compared to the Titan I was dramatic. Major underground structures dropped from 42 to just 18 structures, 6,000 feet of service tunnels were reduced to just 945 feet, the power requirements dropped from 12,000 kilowatts per squadron to just 2,700 kilowatts. Only half the wiring connections were needed and the need for periodic checkout of missile systems dropped by an astounding 90%.  As a result, the silos could be more widely dispersed. With a formal contract awarded in 1960, the Titan II flight test program went smoothly- of 33 test launches, 25 were successful- in fact, the last 13 test launches were so successful and reliable, the Titan II was selected by NASA to be the launcher for Project Gemini. 

With this reliability came the need to solve the basing issue. The Titan I was housed in silos, but it was lifted out of the silo for launch. Martin's engineers argued that it was possible to launch the Titan II right out of its silo, dramatically reducing its response time. Significant debate ensued about the feasibility let alone the safety of launching the 110-foot Titan II with its 430,000 lbs of first stage thrust right out of a silo. On 19 February 1963, a test Titan I was successfully launched from a Titan II test silo at Vandenberg AFB in California, validating the concept so clearly that the USAF had Boeing incorporate silo-launch on its Minuteman ICBM. The first Titan II missiles went on nuclear alert in 1963 just one year after the first Titan I missiles went on alert! 

The Titan I missile squadrons were operational from 1962 to 1965 at Lowry AFB in Colorado, Ellsworth AFB in South Dakota, Beale AFB in California, Larson AFB in Washington, and Mountain Home AFB in Idaho. Only Lowry AFB was home to two Titan I missile squadrons while the other bases only hosted a single squadrons. The Titan II missile squadrons were grouped three squadrons to a missile wing and were operational from 1963 to 1987 at McConnell AFB in Kansas, Little Rock AFB in Arkansas, and Davis-Monthan AFB in Arizona. The modularity of the Titan design, though, made it a versatile heavy-lift space launcher. Not only did the Titan II launch the manned Gemini missions, but it was also used as a satellite launcher until 2003. Titan III and Titan IV were exclusively space launchers, with the last Titan IV launch in 2005. In 1995, when Lockheed merged with Martin Marietta, the Colorado facility became part of the Lockheed Space and Missiles Division. Since the retirement of the Titan IV launcher, the Littleton facility is now the headquarters of United Launch Alliance, the joint venture of Lockheed Martin and Boeing for the Delta and Atlas launch vehicles. Although no production takes place there any longer, ULA still has its mission control, testing and engineering facilities at the same location that was the birthplace of the Titan missile when ground was broken over fifty years ago.

Historical tangent: 

I had mentioned above how Martin Aircraft's VP for Sales and Requirements Jess Sweetser, had become a golfing buddy of USAF General Bernard Schriever. Before he came to work for Martin Aircraft, Jess Sweetser was a championship golfer in the 1920s. While a student at Yale, Sweetser had won the National Intercollegiate Championship in 1920, placed 11th at the US Open the following year despite his youth, and won the Metropolitan Championship  in 1922 in his junior year at Yale. He then won the US Amateur Championship that same year and then became the first American to win the British Amateur Championship in 1926 despite having the flu. He played on the first Walker Cup team (a trophy for amateur golfers in the United States, Great Britain and Ireland) in 1922 and five more teams in years following. After graduation from Yale, he worked as a stockbroker and played golf on weekends. His first job in aviation was with Curtiss-Wright before he came to Martin Aircraft. 

Source: Raise Heaven and Earth: The Story of Martin Marietta People and Their Pioneering Achievements by William B. Harwood. Simon and Schuster, 1993, p299-325

The Unconventional Genius of Carl Norden

Carl L. Norden

After the Manhattan Project to develop the atomic bomb, the next biggest top secret defense program in the United States at the time was the development and production of the Norden bombsight. The Norden sights were used in all of the United States Army Air Forces heavy bombers (the Boeing B-17 Flying Fortress, the Consolidated B-24 Liberator, and the Boeing B-29 Superfortress) primarily and it was a Norden sight that bombardiers used to drop the atomic bombs on Hiroshima and Nagasaki that brought the Second World War to a close. Despite its crucial role in strategic bombing campaigns in both the European and Pacific Theatres, the Norden bombsight was a Navy program and every Norden sight used by the US Army Air Force had passed through the hands of Navy inspectors. How this state of affairs came to be is the story of how an unconventional but brilliant Dutchman, Carl Norden, came to be employed by the Navy prior to the start of the Second World War. 

Carl Norden was born on 23 April 1880 in Semarang, Java, in what was the Dutch East Indies (modern day Indonesia), the middle child of five siblings in a household with absent father. From a young age, his mother considered him the most reliable and responsible of his siblings- in a sense, he became the "man of the family". He had wanted to become an artist, but when his older brother decided to pursue an artistic career, Carl decided to pursue a lucrative career in order provide for his mother and his siblings, enrolling in the Federal Polytechnic Institute in Zurich, Switzerland and graduating in 1904 as a mechanical engineer. Although Dutch by birth, Norden's father was a naturalized Dutch citizen from German and Norden's own wife was from Austria. Norden's German ties dovetailed into his natural engineering and mathematical prowess- it was said that Carl Norden viewed everything in life in mechanical terms governed by mathematical formulas, the universe being nothing more than a great mechanical timepiece. After his graduation in 1904, he emigrated to the United States where he had a wealthy uncle who had made his fortune in the cotton business. Norden worked for a series of companies as a mechanical design engineer, but it was painfully obvious that he was difficult to employ as he was very much a prima donna. But there was no question of Norden's brilliant mind and after a series of employers over six years, he finally came to work for Elmer Sperry Sr. and his sons, Elmer and Lawrence at the Sperry Gyroscope Company. Norden's mechanical aptitude fit well into the work the Sperrys were doing for the Navy in developing gyroscopes to improve the accuracy of naval gunnery from moving ships. Norden's work with Sperry was invaluable for the company and Norden made many contacts within the Navy as a result. Norden tolerated Sperry as the work was interesting, but the relationship soured when, after solving the problem of gyroscopic oscillation, Norden got what he thought was an insulting $25/week raise as a reward. Norden quit and became a consulting engineer to the Navy, but it was the start of a feud between Norden and Sperry for years. Norden often dismissively told people Sperry "would patent gravity if he could" and Sperry for years tried to legally dispute many of Norden's later patents. 

In 1913, Norden set up shop near the Brooklyn Navy Yard and continued to work on the ship stabilization project for the Navy much to Sperry's chagrin. The Navy was enamored with Norden's genius and that relationship in large part protected Norden from Sperry's multiple legal challenges. With the progress on the ship stabilization project slow in coming, the Navy astutely put Norden's mind to work on other projects, starting the aerial gyroscopes for the aerial torpedo project as well as designing catapults and arresting gear for aircraft carriers. The arresting gear of the USS Lexington and USS Saratoga were designed by Norden himself on his dining room table!

At the time, the Navy was pursing a bombsight program as it felt that the best way to sink ships from the air was via high altitude level bombing. General Billy Mitchell's ship-bombing tests in the summer of 1921 against captured German warships convinced the Navy that it had to find a way to sink ships at sea. The Navy's Bureau of Ordinance (BuOrd) was responsible for the bombsight program and many different types, including some from Sperry, were tested. Officers with the Aviation Section of BuOrd came to know Carl Norden from his work on the aerial torpedo project as he had been consulted as an outside expert to evaluate Sperry's work (something which truly irritated Sperry to no end). They were impressed with the comments made in the reports and not knowing who Carl Norden was, found a report signed "Norden". A quick check of the Brooklyn telephone book and a few calls got the officers from BuOrd in touch with Norden who agreed to review the Navy's bombsight program. The gyroscopic stabilization work he had done for the ship and aerial torpedo project dovetailed neatly into the bombsight problem as Norden recommended that the bombsights be not only gyroscopically stabilized, but also connected to either an autopilot or pilot director so that during the bomb run, the bombardier was the one "flying" the aircraft. Eventually modifying existing bombsights turned out to be a failure and the BuOrd and Norden decided to start from scratch and create a whole new bombsight that would launch the Norden bombsight into aviation history. 

That's not to say that Norden's genius resulted in success. For most of the 1920s, many of the literally handcrafted Norden sights had dismal performance. But Norden wasn't one to give up and the Navy was an incredibly accommodating employer. Well aware of Norden's personality- they nicknamed him "Old Man Dynamite", they gave him tremendous latitude as long as he kept delivering results in the form of progressive improvements to his bombsight designs. Unlike most engineers, Norden did his own drafting. He didn't have an extensive engineering library, he preferred to work with his slide rule, a set of engineering tables and a few select references. He often stayed at his mother's home in Zurich, Switzerland, to ponder mechanical problems and develop solutions. His drawings and correspondence were then delivered to the US Navy by diplomatic pouch from US embassy in Switzerland. The State Department wasn't keen on this but high level pressure from the US Navy encouraged diplomatic officials to be as accommodating to "Old Man Dynamite" as possible. Sometimes it was his family he sent to Switzerland so he could be alone to solve some problems back in New York. Also unique to the Navy's relationship with Norden was that any patents were held by the Navy and classified as top secret. In this way, not only was Norden shielded from Sperry's legal challenges, but it also meant that the Navy didn't have to follow the prescribed competitive bidding rules to pay Norden for his work. Many of Norden's patents sponsored by the Navy from the 1920s and 1930s weren't even declassified until 1947! In contrast to the US Army Air Corps (forerunner of the US Army Air Forces) who held open competitive bidding in its own bombsight program and trialled bombsights from several different manufacturers, the Navy only did business with Norden and Norden alone. In fact, the Navy was Norden's only client! 

Theodore Barth at a circus held for Norden employees

As work on the Norden sights continued in the 1920s, BuOrd recommended that Norden partner up with an engineer to start moving the bombsight project towards mass production. Knowing Norden well, the Navy partnered him up with a former Army colonel and engineer by the name of Theodore Barth and it was the start of a very close relationship between the two men for many years. Norden's own children regarded Barth as a secondary father figure in their lives, so close was Barth to Norden. It was Barth who was tasked by the Navy to take Norden's designs and put them into production. Compared to Norden, Barth was very personable and possessed quite a bit of business acumen as well- Norden may have been the brains of the operation but it was Barth who made everything work and kept everyone happy. During the Second World War, Barth took it as his job to take care of all of the employees that were building bombsights. He often gave away baseball tickets and even rented out Madison Square Garden for a circus just for Norden's employees. 

From the time Norden was contacted by the Aviation Section of the Bureau of Ordinance to the delivery of the first production bombsight to the fleet, the Norden Mark XI, nine years had elapsed. During those nine years Norden progressively refined the design of what was essentially a clocklike analog computer that was gyroscopically stabilized and linked to the autopilot. The Navy, though, did hedge its bets just a bit- during that time it had contracted with General Electric for a back up bombsight design called "Scheme B" or the Mark XIII. After three years, the Navy found the GE bombsight was woefully inferior to Norden's designs and canceled "Scheme B". 

Norden M-1 bombsight

By the early 1930s, the US Army Air Corps became aware of the Norden program and was keen to get its hands on the bombsights for its own testing. The head of the Army Air Corps, General Henry "Hap" Arnold (who would head the USAAF during the Second World War), was shocked to hear of the working arrangement between the Navy's BuOrd and Carl Norden, from Norden not even being a US citizen to the fact that Norden did a lot of his work abroad in Switzerland and then sent drawings back via diplomatic couriers to New York City for Theodore Barth and Navy officials to review. The Navy wasn't about to change the way it did business with Carl Norden to assuage General Arnold's concerns, though. It basically came down to something along the lines "If you want Norden bombsights for Army bombers, this is the arrangement you have to live with!". As a modest concession, though, the Navy had the FBI provide a security detail for Norden and agents were planted in Norden's production facilities in New York City to root out any foreign spies. At all times, at least two armed agents were with Norden at all times. There is an apocryphal story that when Norden wasn't getting his way with the Navy, he'd insinuate he'd leave the United States and go to work for the British. He would later remark it was empty threat "As no self-respecting Dutchman would ever work for the British!"

By 1928, Norden was at work at a massive improvement to the Mark XI sight called the Mark XV. He delivered the Mark XV prototype to BuOrd in 1930 and it was this sight that pretty much ended the GE alternate bombsight program. The bombsights that came from the Mark XV design were known as the Norden M-series sights and those would become standard on American heavy bombers.  By this point, however, the Navy was drifting away from relying on high altitude level bombing at sea as dive bombing was explored by units in the fleet. But the arrangements between the Navy and Carl Norden remained with his New York City factory essentially being a Navy factory! By 1934, Norden's bombsights became the standard for the Army Air Corps, first being installed on Martin B-10s. It's estimated that approximately $1.5 billion was spent on the development and production of Norden bombsights. 

Carl Norden was passed away in 1965 in his beloved Switzerland. His company lived on as Norden Systems to be acquired by Westinghouse which was in turn acquired by Northrop Grumman. Norden and Barth also set up a second company called Barden to manufacture bombsight components- Barden is still  around today, fabricating ball bearings for a variety of industries including aerospace. Carl Norden was inducted into the National Aviation Hall of Fame in 1994. 

Source: America's Pursuit of Precision Bombing, 1910-1945 by Stephen L. McFarland. Smithsonian Institution Press, 1995, pp 45-76. Photos: Norden Systems Division via Stephen L. McFarland's book, Wikipedia

The North American XB-28: Too Much, Too Late

The sole XB-28 prototype. Note the remotely operated turrets.

With the North American B-25 Mitchell prototype (internal company designation NA-40B) already in the hands of the US Army Air Corps for flight testing in 1939, the promise of cabin pressurization offered a leap in bomber performance by being able to fly higher and faster. Accordingly, in August 1939, the Army issued the XC-214 specification which called for a pressurized medium bomber to supplant the medium bomber types that were soon to become operational. Only Martin and North American responded to XC-214. Martin's submission was for the XB-27 but the USAAC felt Martin didn't have a full grasp of the challenges of high altitude pressurization in their design and North American's submission, the XB-28 won the development contract. This took place on 15 November 1939 just three months after the Army issued its specification with North American inking a contract to begin formal design work on the XB-28. To give you an idea of the pace of development and the pressure of the looming clouds of war, the contract for the development of the XB-28 was signed around the same time that the Army ordered the B-25 Mitchell into production! The XB-28 had started out as a pressurized version of the B-25 Mitchell with a circular fuselage and Pratt & Whitney R-2800 Double Wasp engines with GE Type-C turbosuperchargers replacing the Wright R-2600 Twin Cyclone radials used on the B-25. Design work proceeded rapidly since the company was already at work on a pressurized successor to the B-25 at the time of the release of the XC-214 specification in August 1939. As design work progressed, changes were made stating with abandoning the Mitchell's twin fins for a single fin. Eventually the XB-28 as designed bore little resemblance to the Mitchell. The contract for three prototypes was signed on 13 February 1940. 

The five crew all sat in a pressurized compartment in the forward fuselage. 

Besides the change to more powerful R-2800 Double Wasp engines with GE turbosuperchargers, a third supercharger was also fitted to provide cabin pressurization. Heaters powered by gasoline warmed the air in the pressurization ducting for the pressure cabin located in the the forward fuselage. The elongated nacelles had an opening in the rear for the turbo-supercharger exhaust which added some forward propulsive power. The four bladed propellers were counter-rotating to cancel each other's torque to ease handling. Integral self-sealing fuel tanks took up most of the wings. Relatively unique for the day nose wheel steering was fitted and controlled by a lever in the cockpit similar to modern nose wheel tillers. Another unique feature was the use of fluorescent paint on the instrument panel and instruments that would glow at night from overhead UV lamps as an aid to night flying.

Overall configuration of the XB-28.

To simply the structure of a pressurized aircraft, the pressure cabin only occupied the forward fuselage. All the joints were sealed during assembly and the interior sprayed with a plastic sealant before installation of the cabin items. The cabin atmosphere was maintained at the equivalent of 8,000 feet up to an operating altitude of 33,000 feet. The crew of five was crammed into this space- with the pilot and co-pilot sitting side by side, behind them sat the primary gunner and the radio operator/secondary gunner. The bombardier/navigator sat in the nose compartment but could access the cramped flight deck via a floor panel by the co-pilot's feet. The bomb bay could carry up to 4,000 lbs of bombs and the three defensive turrets consisted of twin 50-caliber guns in dorsal, ventral and tail turrets that were operated remotely by the primary gunner and the radio operator/secondary gunner. Each gunner had a hemispheric observation window next to them and sighted the guns via a periscope system that protruded from streamlined twin fairings above and below the fuselage just aft of the flight deck. Initial plans for were for North American-designed turrets tied to a Sperry fire control system, but Sperry's resources were tied up with current production aircraft. It was decided to switch to General Electric for the remote fire control system and to have them be responsible for the turrets as well well. This imposed delays in the development as changes needed to be made to accommodate GE's equipment and systems. There was also a prevailing opinion at North American that Sperry's system was more advanced. A compromise was reached with the XB-28 defensive systems to use GE turrets and the Sperry sighting system. It's worth noting at this point that when the work on the remote turret fire control system on the XB-28 was under development, both Sperry and GE were working on getting the contract for the remote turret fire control system on the Boeing B-29 Superfortress- ironing out the kinks in the XB-28 gave GE valuable experience that helped the B-29 and made its system the production standard on the Superfortress.

Engine run up test at Mines Field in the summer of 1942.

The US entry into the Second World War slowed development of the XB-28 as priority shifted to production types and much of North American's resources were devoted to the production of the B-25 Mitchell and the P-51 Mustang. The maiden flight of the first prototype took place on 24 April 1942 at Mines Field (the site of today's Los Angeles International Airport/LAX) and the flight test program showed the XB-28 to be quite fast at high altitude, capable of 372 mph at 25,000 feet. Following the conclusion of North American's flight test program, the USAAF portion of the flight test program took place with the XB-28 operating out of Wright Field outside of Dayton, Ohio, for service trials. It was decided during the service trials that the third XB-28 prototype would be completed as a reconnaissance and photo-mapping aircraft designated XB-28A. North American was instructed to set aside work on the second XB-28 to get the XB-28A variant flying. The speed and altitude performance of the XB-28A was increased by reducing weight as well as installing more powerful versions of the R-2800 engines. The XB-28A made its maiden flight on 24 April 1943 (exactly one year after the first XB-28) but was unfortunately lost in flutter incident during dive testing on 4 August 1943 with the crew able to parachute to safety. At the time of the accident, design work on the production B-28 was underway with the most significant change being some extra scanning windows on the nose compartment for the bombardier/navigator.

By this point, however, it was realized that despite the outstanding performance of the XB-28, the realities of war showed that medium bombers already in service like the B-25 Mitchell and the Martin B-26 Marauder were most effective at low to medium altitudes flying interdiction missions where pressurization wasn't necessary. In the Pacific, B-25s equipped with extra forward firing machine guns were becoming very effective low level anti-shipping weapons while in the European theater, B-25s and B-26s operated most effectively at medium altitude (though some low level anti-shipping missions were flown in the Mediterranean against Axis vessels along the French and Italian coasts). The final nail in the XB-28's coffin was the Douglas product that was also first flown at Mines Field just a few months after the XB-28's maiden flight. The prototype Douglas XA-26 Invader first flew on 10 July 1942. It used the same engines as the XB-28, carried the same bomb load, but lacked pressurization which made it simpler to build and it only had a crew of three versus the crew of five on the XB-28. The sole XB-28 prototype was still at Wright Field at the time of the program's cancellation- it had its outer wings removed and sat out the war as a ground test article for pressurization tests before being scrapped.

Anigrand released a 1/72 resin kit of the XB-28 and this page has a great series of photos of a completed model that show the overall configuration of the XB-28. Take note of the hemispheric scanning bubbles on the upper lateral fuselage ahead of the wing for the gunners as well as the streamlined twin fairings above and below the forward fuselage for the sighting system to control the remote turrets.

Source: American Bomber Aircraft Development in World War 2 by Bill Norton. Midland Publishing, 2012, pp 66-69. Photos: USAF Museum, Anigrand

Flying High This Past Week (Spring Break Edition): 1 March-15 March

I was on the road last week on Spring Break (at least here in Texas last week is our Spring Break), so there wasn't an installment of Flying High This Past Week last week. I'll thrown in a bit extra this week! So here's what's been getting a lot of page views this past week here at TAILS THROUGH TIME:

• The 24th Combat Mapping Squadron: Unsung Heroes of the Pacific War: The crews of the 24th CMS fought their battles not with bombs but with rolls of film. They were instrumental in getting good quality maps made of the China-Burma-India theater but also participated in postwar mapping efforts for several nations.
• The US Navy's First Nuclear Bomber: From 1948-1951 the strategic deterrent of the US Navy rested with three-plane detachments of Lockheed P2V Neptunes aboard the three aircraft carriers of the Midway-class. Their crews were tasked with essentially one way missions should the balloon have gone up and they had to strike Soviet targets. There was no recovery back aboard the carrier- the P2Vs lacked the provisions. The crews were to make for a shore base or bail out. After 1951, the North American AJ Savage took over the role and it wasn't until 1958 that the Navy had a submarine based deterrent when the first Regulus patrol went to sea.
• The Birth of Indian Commercial Aviation and Its Father: Unsually amongst Britain's colonial possessions in the 1920s and 1930s, commercial aviation development was neglected in India. Imperial Airways was only concerned with connecting India with London and it would take a growing merchant class in India to nuture airline development with J.R.D. Tata, head of the Tata Sons industrial conglomerate, to lead the way. Tata Air Lines became Air India International in 1946 with the technical assistance of TWA.
• Fox Two! The Birth of the AIM-9 Sidewinder Missile: Probably one of the most significant air combat weapons since the gun, the Sidewinder's simplicity stemmed from its humble beginnings as a free-time project by small group of engineers at China Lake. The push for simplicity made the Sidewinder successful and its operating principles influenced a generation of heat-seeking air to air missiles as a result. 
• The Story of "5 Grand", the 5000th B-17 Flying Fortress Built: A flying tribute to the employees of Boeing that made their contribution to the war effort building the B-17, sadly the aircraft was lost to history out of penny-pinching by government officials. 

Now for the special Spring Break edition, here are five articles from the archives you may have missed or might be of interest to new readers to my blog: 

• The Cadillac of the Constellation Line: In my opinion, one of the most graceful airliners built along with the Vickers VC-10 is the Lockheed L-1649 Starliner. The Starliner's new wing gave it the highest aspect ratio (12:1) of any propliner along with 2,000 lbs more fuel than the Super Constellation. In a lot of ways, the Starliner was the propliner counterpart of the Boeing 747SP as few airlines in the world of the day had routes long enough with demand for nonstop service that dovetailed with the Starliner's performance. 
• Foxbats Over the Sinai: From 1971 to 1972, Russian-operated Mikoyan MiG-25 Foxbats reconnoitered Israeli defenses in the Sinai that assisted with Egyptian planning for the 1973 Yom Kippur War. The Sinai deployment proved the Foxbat's capabilities in an operational environment, convincing the Soviet Air Force to accept the aircraft for service. 
• The Australian Canberra in Vietnam: From 1967 to 1971, No. 2 Squadron of the Royal Australian Air Force flew combat missions all over South Vietnam from Phan Rang AB. The Aussie Canberras got very good at visual bombing from altitude and as a result, the RAAF Canberra force was the only combat unit to routinely use level bombing with visual bombsights from altitude.
• The L-1000: Lockheed's Own Jet Engine: Probably one of the more interesting turns in aviation history would have to be when Lockheed was developing its own jet engine that compared to contemporary engines of the day, was quite a bit more advanced.
• Martin, the Titan I and the Titan II Ballistic Missiles: The Titan program started out as a back up to the Convair Atlas ICBM but soon become an advanced successor to the Atlas. The modular design of the Titan and its rock-solid reliability led it to become a stalwart of the space program starting with Project Gemini and its use as a heavy-life satellite launcher until the last Titan IV launch in 2005.

 

The Boeing PBB Sea Ranger: The Best Flying Boat at the Worst Possible Time

The Boeing XPBB-1 Sea Ranger prototype

Despite being a dated pre-war design, the Consolidated PBY Catalina was already successful before America's entry into the Second World War. Martin Aircraft decided to go one step further than the Catalina realizing the potential of newer, more powerful engines with its 1937 offer to the US Navy for what became the PBM Mariner. With a bigger hull but the same speed and payload of the PBY Catalina, Martin's proposal was eagerly received by the US Navy and the Martin XPBM-1 prototype made its first flight in February 1939. Seeing what Martin had accomplished with the design, in the following month the Navy issued a new specification for an even more powerful twin engine flying boat using the new powerful Wright R-3350 Duplex Cyclone radial which had made its first bench run in May 1937. The Consolidated PBY Catalina used the Pratt and Whitney R-1830 Twin Wasp radials developing 900 hp each. The Martin PBM Mariner used Wright R-2600 engines developing 1600 hp each. The Wright R-3350 in development developed 2200 hp, so the potential for an even better twin engine flying boat was obvious to the Navy. With Martin and Consolidated busy with their respective flying boat designs, the Navy invited Boeing and Vought-Sikorsky to submit designs that used two R-3350 engines. Vought-Sikorsky had extensive flying boat expertise with pre-war designs used by both the Navy and civilian airlines. Boeing had just flown what many considered the pinnacle of commercial flying boats, the Boeing 314. 

Note the long tapered wings that were based on the B-29's 

Boeing's initial submission featured a tapered straight wing using the Davis airfoil with retractable outboard floats and a bomb bay within the hull. The flying boat was also pressurized to allow high altitude transit to patrol areas. The Navy preferred the Vought-Sikorsky design but the company had little resources to spare was it was busy with other priority projects. The Navy then asked Boeing if they would be willing to build the Vought design on 24 February 1940, but Boeing expeditiously redesigned their submission and the following month responded the US Navy's request with a presentation of an improved design that had a narrow, low drag hull, fixed outboard floats, bomb bays moved into the inner wings and deletion of the cabin pressurization. The new design was larger and more capable and dispensed with the Davis airfoil with a new Boeing in-house design that was also used on the B-29 Superfortress project. The Navy was suitably impressed and ordered one prototype for evaluation as the XPBB-1 on 29 June 1940. The mockup review went quickly in January 1941 with the XPBB prototype starting construction in June 1941. With the potential of the new design to be superior to both the PBY and PBM, the Navy went ahead and ordered 57 PBB-1s on 8 October 1941 despite the XPBB prototype not having made its first flight yet. To accommodate production for the PBB Sea Ranger as it was called, a new Boeing plant was built on the southern shores of Lake Washington at Renton. With the clouds of war on the horizon that fall, the Navy indicated to Boeing that as many as 500 Sea Rangers would be needed before 1943. 

Note the bomb bay doors on the underside of the inner wings

The PBB Sea Ranger was a remarkable clean aerodynamic design for a flying boat. The outer wing and horizontal stabilizers were near-identical to that used on the B-29 Superfortress (which would make its first flight in September 1942). The Wright R-3350 engines developed 2300 hp and drove a 16.5-foot diameter three bladed prop. The original proposal was for counter rotating props, but designing the gearing for a contraprop proved to difficult at the time. Instead of fuel bladders, the wing was wet with integral tankage which not only saved weight, but gave the Sea Ranger an enormous fuel capacity that would make 72-hour patrols possible. As the tanks were emptied, carbon dioxide gas under pressurization would purge and inert each tank. Each wing had five bomb bays that were between the wing ribs with a roller door covering each bay. The payload of the ten bays would have been 20,000 lbs of bombs (identical to the B-29 bomb load). Pylons could be fitted between the bays to carry torpedoes or other weapons too larger for the wing bomb bays. The defensive guns were eight 50-caliber guns with a twin dorsal turret and twin tail and nose ERCO turrets that were similar to the nose turret of the Consolidated PB4Y Privateer. A single 50-caliber gun was used on two waist mounts which were teardrop shaped also like the waist mounts on the Privateer. Below the nose turret sat the bombardier whose front window could be protected by doors when the Sea Ranger was landing or taking off. In addition to the bombardier, two pilots, the flight engineer, navigator and radio operator sat in the flight deck with the remainder of the crew rounded out by five gunners. 

The Sea Ranger's wings were its key to long endurance patrols

On 9 July 1942 the XPBB-1 Sea Ranger prototype made its first flight from Lake Washington. There were remarkably few issues that arose during the flight test program. The aircraft was formally delivered to the Navy on 12 January 1943 but the prototype remained in the Puget Sound area for the Navy's trials. The production Sea Ranger would have differed only in details from the XPBB-1 prototype. It was during the flight test program that the fortunes of the Sea Ranger began to wane. It was clear by that point that the B-29 Superfortress program was a national priority for the war effort. This was taking on more and more of Boeing's resources and worse yet for the Sea Ranger, it used the same engines as the Superfortress and production priority for the R-3350 was earmarked for the B-29. This was also the same time that the Navy began shifting patrol missions to land-based aircraft like the PB4Y-2 Privateer. The same year that the Sea Ranger made its first flight, the Navy had also asked Consolidated about a variant of the B-24 Liberator that was more dedicated to the patrol bomber mission than the first PB4Y-1s which were Liberators with modest changes for the naval mission. The PB4Y-2 was the definitive patrol bomber version and it made its first flight in the same year as the Sea Ranger. As the Privateer didn't use the same engines as the B-29, it didn't have to compete for R-3350 production like the Sea Ranger. As a result, the Sea Ranger was canceled with only a single aircraft built. 

The Sea Ranger prototype was flown anyway further by the Navy to its flight test center at Patuxent River, Maryland, on 5 October 1943 and given a formal evaluation despite the cancellation. The Navy was immensely impressed with the Sea Ranger, believing it to be the best flying boat ever developed. Even though the Renton plant where the Sea Ranger was to be built was turned over to B-29 production, the Navy reconsidered its cancellation and approached Martin Aircraft about producing the Sea Ranger for Boeing. The R-3350 engines would have been swapped out with Pratt & Whitney R-4360 Wasp Major engines for a power boost along with two booster jet engines for added performance. The Wasp Major was even more powerful than the R-3350 and production was to begin on that engine in 1944. The Sea Ranger, even though a Boeing design, would have had the Navy designation P4M in recognition of Martin's production of the type. For obvious reasons, Martin wasn't enthused about building someone else's design and at the time of the Navy's proposal, work had already started at Martin on a land-based patrol bomber with two R-4360 Wasp Major engines and two Allison J33 booster jet engines. That design was what became the P4M Mercator which made its first flight in October 1946. 

News reel footage of the Sea Ranger's maiden flight

While the Sea Ranger presented a promising opportunity for Boeing, it ended up being a dead end that arrived at the twilight of the flying boat as a maritime patrol aircraft. Stuck competing with resources with the much more important B-29 Superfortress, the Sea Ranger's historical legacy is not so much its design but rather the Renton facility that was built in anticipation of production. The Renton facility became home to the B-29 program but in the post-war era was where Boeing was launched into the jet age with production of the KC-135, 707, 727 and 737 taking place at Renton. In fact, the Navy's newest maritime patrol aircraft, the Boeing P-8A Poseidon, is built at the Renton alongside commercial 737s.

Source: American Bomber Aircraft Development in World War 2 by Bill Norton. Midland Publishing, 2012, pp 117-120. Photos: Boeing, San Diego Aerospace Museum.

Dr. Hans Multhopp's Raven and Its Legacy

Dr. Hans Multhopp and a model of his Ta 183 fighter

By 1942 both Messerschmitt and Heinkel had flown jet fighter prototypes but other great fighter aircraft manufacturer of Germany at the time, Focke-Wulf, was lagging behind in jet aircraft development with the technical director of the company, Kurt Tank, still working on preliminary ideas for a jet fighter aircraft. Tank's first designs resembled the Heinkel He 162 with a single, dorsal-mounted engine. As Tank refined the design further, the engine moved into the fuselage with a nose intake, then it got lateral intakes, twin fins and finally ended up as a single-engine twin-boom fighter that resembled the De Havilland Vampire and was named the "Flitzer" (Dasher). However, Tank's protege in the company, Hans Multhopp, had been working on something even more spectacular than the Flitzer. Multhopp joined Focke-Wulf in 1938, having been recruited by Tank himself from the University of Gottingen where he worked under the famed aerodynamicist Ludwig Prandtl. By 1940 Multhopp was second-in-charge of the company's aerodynamics department and by 1943 Tank had promoted him to head the company's advanced design bureau. It was here that Multhopp developed what was called Project V. Multhopp had christened his design "Huckebein" after a mischievous raven in a children's cartoon of the day. The Huckebein had sharply swept wings and a raked back T-tail that gave it an appearance that was nothing like any design in the works anywhere at the time. 

Kurt Tank's Flitzer design

Tank was dubious about the features of the Huckebein and had scale models of both the Flitzer and the Huckebein built and tested. Despite the tests not uncovering any flaws with the Huckebein, Tank continued work on his own Flitzer but by 1944 it was quite apparent that it couldn't deliver the performance the Luftwaffe desired, which was for a jet fighter aircraft that could outperform the Messerschmitt Me 262. Even though the Me 262 was quite capable in many respects, the German air ministry, the RLM, had overstated the progress of the Allies in jet fighter aircraft development. In addition, by 1944 it was apparent that the Boeing B-29 Superfortress could outperform the B-17 and B-24 bombers that were hitting the Reich regularly. The main drawback of the Me 262 was that in using two engines, it used up per aircraft twice the scarce materials than a single-engined aircraft. Because of this, the RLM and the Luftwaffe exercised even tighter control over fighter aircraft development that in hindsight, were excessively bureaucratic. 

In 1944 with Tank having to accept that the company would have to focus its development resources on the Huckebein, the RLM issued a specification for a high performance fighter powered by a single Heinkel HeS 011 jet engine. Messerschmitt submitted what was to become the P.1011 fighter. Focke Wulf submitted Multhopp's Huckebein and even seaplane builder Blohm und Voss submitted a fighter design. Through the winter of 1944-1945 RLM officials and Luftwaffe staff endlessly deliberated the merits of each design and even discussed revamping the specification- as Allied armies were approaching the Rhine in the West and the Soviet Red Army was continuing its relentless push on the Eastern Front. Junkers was then invited to submit their design as well. With no progress being made, the Luftwaffe High Command called an emergency meeting in February 1945 to resolve the matter and the Focke Wulf Huckebein was selected as the Ta 183 ("Ta" in reference to Kurt Tank) to be the interim design while the Messerschmitt design was regarded as the optimal design for further development to supplant the Ta 183 in service. Plans were drawn up sixteen test Ta 183 aircraft with a maiden flight planned for May or June 1945 with the first production fighters being delivered to the Luftwaffe in October 1945. 

Ta 183 Design III, this influenced the Saab J29 Tunnan

The Ta 183 was aerodynamically very advanced with a 40 degree, thin, swept wing that had low wing loading for high altitude performance and maneuverability. The sharply raked back vertical fin mounted a T-tail unit that was used only for trimming purposes with pitch and roll to be handled only by the wing surfaces. The cockpit was pressurized and aircraft was armed with hard-hitting 30mm cannon. An alternate variation of the Ta 183 was also envisioned with a less sharply swept wing, a conventional tail unit and longer fuselage- this was the Design III which Tank worked on while Multhopp refined the original Ta 183 which was designated Design II. 

The Ta 183 is a popular subject of "What-If" modeling

Work proceeded quickly after that February meeting, but the following month the Allies crossed the Rhine into Germany and work on the Ta 183 under Hans Multhopp and Kurt Tank ground to a halt when the British Army captured Bad Eilsen, the location of Focke-Wulf's design department. The fall of Nazi Germany left the Allies an impressive treasure trove of aeronautical progress. The British initially failed to realize the technological leap the Ta 183 represented when they sifted through the captured material at Bad Eilsen. The Soviets, however, were quick to realize the Ta 183's potential, having found a complete set of plans on microfilm when they captured the RLM headquarters in Berlin. While the plans were examined by Artyom Mikoyan and Mikhail Gurevich of the MiG design bureau, it would be fallacy to say that the MiG-15 is a copy of the Ta 183 as Mikoyan and Gurevich were talented designers in the their own right. Perhaps their examination of the Ta 183 plans confirmed their own intuitions on how best to proceed with the MiG-15. There is no doubt, though, that Sweden managed to get a hold of the Ta 183 plans and data and that it is believed to have influenced their own design work on the Saab J 29 Tunnan fighter. 

Following the end of the Second World War, Kurt Tank and Hans Multhopp parted ways, with Tank moving on to work on projects in Argentina and India (subject for future blog posts, stay tuned!). Multhopp and a team of his assistants went to work at Farnborough in the UK and developed plans for a transonic research aircraft powered by an Rolls-Royce Avon turbojet with 60-degree swept wings and a T-tail with the pilot sitting prone in the shock cone of the nose intake. However, Britain was economically spent after the war and Multhopp's design never got built. In 1949 he moved to the United States and went to work with the Glenn L. Martin Company where he worked on two designs that also had T-tails- the XB-51 tactical bomber and the P6M Seamaster jet flying boat. He would later become the chief scientist for Martin Aircraft and his career would culminate with Martin's pioneering work on lifting body spaceplane designs like the X-23/PRIME and the X-24 which provided much data for the NASA Space Shuttle program. 

While the Ta 183 was only one of many advanced designs being worked on in Germany during the Second World War, it is probably the most emblematic of Germany's influence on postwar aircraft design. Many designs that were considered ground breaking in the 1940s like the Boeing B-47 Stratojet and the North American F-86 Sabre, originally began as less-than-spectacular straight wing designs that were reworked to incorporate what was being learned from the analysis of captured German aeronautical research.

Source: Aircraft, January 2011, Volume 44, Number 1. "The Luftwaffe's Last Hope" by Bruce Hales-Dutton, p46-50.

Martin Bets on Orlando and Wins the Pershing Missile Contract

I had posted several weeks ago how George M. Bunker, the president of Martin Aircraft that succeeded Glenn L. Martin in 1952, diversified the company by getting into the missiles and rockets business. The year 1956 was a tremendous year for Martin, having won the Air Force's Titan ICBM contract as well as the Navy's Vanguard satellite launcher contract as well. With a major missile contract with the USAF, a major rocket launcher contract with the Navy, no one would have thought that Martin would get an upcoming Army contract for a medium-range ballistic missile. But then again, no one thought Bunker to be a betting man, either. At the time, the Army hadn't even issued a formal Request for Proposals to the industry for such a program. But early in 1956, Bunker paid a visit to Major General John Medaris, the commanding officer of the newly-formed Army Ballistic Missile Agency at Redstone Arsenal in Huntsville, Alabama. It was General Medaris who was the boss of German rocket scientist Werner Von Braun and his team of German engineers. The ironic aspect of the visit was that Bunker didn't stop by to solicit the Army's business. As General Medaris would recount the visit years later, Bunker simply asked "how might the Martin Company could best be of service to the Army's missile objectives." The general didn't offer any specifics on what the Army had in mind, but did point out to Bunker that it would be "extremely advantageous" to the Army if an aerospace company saw fit to have a production facility somewhere between Huntsville and Cape Canaveral Air Force Station, the primary test launch site for all US long-range missile programs. Bunker would thank the general for his time and departed. 

Bunker decided that the best location would be Orlando, Florida, which in 1956 was a quiet banking town surrounded by orange groves and ranches. Most in the aerospace industry only knew of it as it was the nearest airport to Cape Canaveral one hour away. Many reporters, scientists, and engineers transited through Orlando on their way to and from the Cape. In August 1956 Bunker and one of his VPs called on the chairman of Orlando's largest bank, First National Bank, inquiring on the purchase of 500 acres for a manufacturing plant. Before the day was over, Bunker would be introduced to the mayor of Orlando, the head of the Orlando Industrial Board, and one of the city's prominent real estate brokers. A few days later, Orlando city leaders traveled to Baltimore to brief the Martin board of directors on candidate sites. Bunker directed the purchase of 6,400 acres at $200/acre. The site chosen was completely undeveloped and the Martin board asked about the need for roads, sewers, and utilities and that very same day not only did they secure the guarantee from the city leaders to provide all of what was needed, they also secured the support of the governor of Florida. Ground was broken five months later and in December 1957 Martin formally opened its Orlando facility to great fanfare. 

Mind you, Martin had yet to win any contract that would allow them to use that sprawling new facility! To bring their new missiles facility up to speed, several Martin missile programs like the Lacrosse and Bullpup missile programs were moved to Orlando. It would be Martin's third manufacturing facility- the first one being the aircraft plant in Baltimore, the second one being the Titan missile facility outside of Denver. On 7 Janaury 1958, General Medaris formally issued the RfP to industry for a new solid-propellant Army ballistic missile to replace the Redstone rocket. An amazing 121 companies submitted proposals and this was quickly winnowed down to seven with two absolute requirements- ballistic missile experience and a manufacturing plant near Cape Canaveral to facilitate testing. The new missile had a nuclear warhead, had to be road mobile and easily air-transported. The missile had to be easy and quick to deploy and fire by combat units in any weather condition. The seven companies were Chrysler (which was responsible for building the Redstone missile), Lockheed (which was already working on the Navy's Polaris missile), Douglas (which was building the Thor IRBM for the USAF), Convair (who was building the Atlas) as well as Goodyear and Sperry-Rand which had extensive missile systems experience even though the two companies hadn't built a missile. The seventh company was Martin. The seven companies were required to give a four hour presentation to General Medaris and his team on their submission in thirty days. The new missile would be named Pershing in honor of General John J. Pershing from the First World War. 

The Secretary of the Army, Wilber Brucker, was a former governor of Michigan and was under tremendous political pressure to have Chrysler's submission selected for the Pershing contract. General Medaris wasn't going to have any of this on his watch as Martin was the favored submission based on their technical merit and having a manufacturing facility already in place near the Cape in Orlando. In fact, Martin even offered to demonstrate the mobility of their Pershing design by driving it out from Orland to the Cape for test firing. Brucker did attempt to stall the program to prevent Martin's selection but on 22 March 1958 the Army Ballistic Missile Agency awarded the Pershing contract to Martin. 

The first version of the missile, the Pershing I, was mounted on tracked vehicles and was first delivered to Fort Sill, Oklahoma in 1962 where the Army formed its first Pershing battalion. The missiles went on nuclear alert in Europe in 1964, with some of the battalions under joint control with the US Army and West Germany (Geilenkirchen AB, the home of the NATO E-3 Sentry AWACS force, was a former German Pershing base). When the Army wanted to improve the mobility of the Pershing battalions with wheeled vehicles and an even faster reaction time should the order to launch come, Martin quickly developed the Pershing Ia system and in an amazing three-month span in 1969, Martin managed an unique swap system to upgrade the units in Europe. New equipment rolled out of the Martin factory in Orlando and was driven to Port Canaveral. One battalion's worth of equipment were loaded onto a Navy ship and transported to Bremerhaven in Germany, where a Pershing I battalion had driven, met the Pershing Ia equipment being unloaded, and drive it back to their bases. Martin would win a follow on contract for an improved version of the Pershing Ia, the Pershing II, in 1975. A deadly accurate missile, the Pershing II had triple the range of the Pershing I/Ia and could even reach Moscow. From 1958, the Pershing program would run for 34 years and generate $4 billion in revenue for Martin. The program consistently ran under budget and ahead of schedule for its entire life. A total of 754 Pershing I and Pershing Ia missiles were built, as well as 276 of the highly accurate Pershing II missiles as well as all the associated support equipment and land vehicles. 

The role of the Pershing missile in Cold War deterrence cannot be underestimated. The threat and accuracy of the Pershing missile was once described by a former Soviet defense official as a "scapel held to our throats". It was common knowledge that the Pershing missiles targeted Soviet command and control facilities and in a sense, it didn't threaten Soviet forces, it threatened Soviet leadership. On 8 September 1988, then Vice-President George H.W. Bush spoke at the Longhorn Army Ammunition Plant on the occasion of the disposal of the Pershing missile under the terms of the Intermediate Nuclear Forces Treaty: "The Pershing missile system strengthened deterrence and was concrete evidence of United States resolve. If we had not deployed the Pershing, there would not be an INF Treaty today."

Not a bad payoff for a gamble by George M. Bunker back in 1956. Oh, you might be wondering what the "M" stands for in his name- "Maverick".

Source: Raise Heaven and Earth: The Story of Martin Marietta People and Their Pioneering Achievements by William B. Harwood. Simon and Schuster, 1993, p327-348.

The Martin XB-48

In November 1944 the US Army Air Forces looked ahead to the future of jet technology in issuing a specification for a jet-powered bomber with a range of 3,000 miles, a service ceiling of 45,000 feet and a maximum speed of 550 mph. By January of the following year the requirements were increased with the necessary ability to carry specific types of large bombs in the USAAF inventory. Four companies would eventually come to submit designs that would reach the flying hardware stage- the North American XB-45 Tornado, the Convair XB-46, the Boeing XB-47 Stratojet, and the Martin XB-48. With the XB-45 and XB-46 being four-engined bombers, they were paired up to compete with each other for a production contract and the XB-47 and XB-48 both being six-engined bombers, ended up being paired up to compete as well. By December of 1945, the Glenn L. Martin Company in Baltimore signed a contract with the USAAF for its submission, the Model 223 which received the designation XB-48. A newer contract superseded the original contract which called for two XB-48 prototypes with a first flight date no later than the end of September 1947. 

While the general layout of the Martin XB-48 was conventional (straight wings, for instance), there were many features on the XB-48 that were unique and ground-breaking for aircraft technology of the day. Since the wings were too slender to carry the main undercarriage, the XB-48 featured a bicycle undercarriage with outrigger wheels that retracted into the outer sections of the underwing jet nacelles. This landing gear arrangement was first tested on a modified Martin B-26 Marauder nicknamed the "Middle River Stump Jumper" and designated XB-26H. The other significant unique feature of the XB-48 was that in order to keep the wingspan reasonable, the three engine nacelles on each wing were grouped together to form a lifting surface in which the nacelles top surface was faired into the wing and contributed to the overall wing lift. The General Electric J35 engines had their own sub-nacelles with an air duct passing between each nacelle and exhausting out the back of the nacelle. The jetpipes were also adjustable via flaps that deflected the jet exhaust. 

The first XB-48 made its first flight at the Middle River plant's airfield on 22 June 1947 and flew to NAS Patuxent River 80 miles away for more flight testing. The J35 engines proved to be one of the biggest headaches in the flight test program. The first XB-48 aircraft went through fourteen J35s in only 44 test flights! By this time the USAAF was an independent military branch as the United States Air Force and flight testing of both the XB-48 and the Boeing XB-47 showed that the Stratojet was clearly the superior aircraft thanks to its more powerful J47 engines and highly refined aerodynamics with its thin swept wing. Martin's XB-48 ended up being 50mph slower than its original design speed and as a result, the XB-48 program was canceled by the USAF in September 1948 with an order of the first production B-47A Stratojets. 

However, the USAF did make enough funds available for the completion of the second XB-48 prototype and for its flight testing. The second XB-48 first flew on 16 October 1948, three months behind schedule. But the delay was of little significance since the USAF had already terminated the program. Martin then offered to modify the XB-48 design in 1949 with XT40 turboprops which would have been more capable than the B-50 Superfortress, but by this point the USAF was interested only in pure jet bombers, not to mention that the XT40 was a Navy-funded engine and in those days, intraservice rivalries played a significant role in weapons development. In March of that year, Martin was formally notified of the USAF's lack of interest in the XT40-powered version of the XB-48. 

With the formal end of the flight test program in the summer of 1949, Martin elected to keep flying the XB-48 as test beds. The first aircraft would be used as a spares source to keep the second aircraft flying and test schedules were drawn up to test items like autopilot systems, engine cooling technologies and hydraulic equipment. In the end, though, even those tests got canceled and the second XB-48 ended up only flight testing a thermal de-icing system. In September 1951 the sole remaining XB-48 was flown to the Aberdeen Proving Ground in Maryland and static tested to destruction. 

Source: American X & Y Planes: Volume 2; Experimental Aircraft Since 1945 (Crowood Aviation Series) by Kev Darling. The Crowood Press, 2010, p14-17.