19 November 2015

C.E. Woolman and the Founding of Delta Air Lines

C.E. Woolman (Minnesota Public Radio)
Collett Everman Woolman was born in Indiana in 1889 and was raised in the academic environment of Champaign-Urbana, Illinois, where his father taught physics at the University of Illinois. Woolman's interest in aviation began at an early age when he and his friends appropriated every clothesline in his neighborhood to build a giant passenger-carrying kite which fortunately for history, crashed before anyone tried to take flight in it. As a freshman, he even built a crude airplane which had to make a forced landing on his university campus. In his sophomore year of collge at the University of Illinois, he learned of the first aviation world meet to be held in Reims, France, and the ambitious Woolman managed to get a job tending a herd of 800 travelling calves to get to France. On his return, he helped pioneer aviator Claude Grahame-White overhaul a rotary engine in the passenger steamer's cargo hold in preparation for an airshow in Boston. 

He graduated in 1912 from the University of Illinois with a bachelor's degree in agriculture. That's right, farming. The legendary founder and head of Delta Airlines studied agriculture in college, hardly the field to propel him into aviation, but in those days, aviation as a business and industry hardly existed and was more the realm of half-cocked mad scientist types to be shunned by the general population. In fact, if you wanted to look up Glenn Martin's aircraft company in Los Angeles in those days in the phone book, it was listed under "Amusements"! With a fresh degree in agriculture, Woolman moved south to farm various locales in Mississippi before becoming the manager of a 7000 acre plantation in northern Louisiana. 

In 1913 he joined the extension department of Louisiana State University at Baton Rouge as an agricultural sciences instructor who travelled out to farmers to pass on the latest techniques. In 1914 the US Congress passed the Smith-Lever Act which formalized the extension cooperative system in which universities would reach out to farmers to formally educate them on the latest developments in agriculture. With this new law, the young C.E. Woolman became LSU's first extension agent in Lousiana and based his operation in Monroe, Louisiana. 

Travelling throughout Louisiana, he not only met with farmers and plantation owners but also consulted with financial institutions on investing in agriculture as well as liasing with the agricultural scientists back at the LSU campus. It was during this time that the boll weevil infestation was ravaging the US cotton crop. A chemical had been developed which was effective against the boll weevil; calcium arsenate was a dry powder which worked well, but was cumbersome and inefficient when applied from the ground. 

The federal government had experimented with US Army planes in rudimentary crop dusting efforts, but a grant was given to an entomologist by the name of Dr. Bert Coad at the US Department of Agriculture's Delta Laboratory in Tallulah, Louisiana. Coad had difficulty finding an airplane that possessed a good load carrying capacity to carry enough calcium arsenate powder to dust an entire cotton field. Coad hooked up with a small company called Huff-Daland which was trying to market a military training biplane. Struggling for cash, Huff-Daland eagerly cooperated with Bert Coad in his crop dusting trials.

Huff-Daland Duster at the National Air & Space Museum
(Smithsonian Air & Space Museum)
Given Woolman's job with LSU's agricultural extension, he observed many of Coad's trials with interest. Encouraged by Woolman's favorable assessments of the effectiveness of aerial crop dusting against the boll weevil, Coad tried to get more federal grant money to expand the enterprise. Woolman had enthusiastically spread the word to area farmers that there was a new weapon against the boll weevil and soon Coad found he didn't have the resources to meet the demand. But the US Department of Agriculture saw Coad's trials as only an experiment and failed to provide more resources. 

In 1923, the vice president of Huff-Daland happend to stop by Tallulah, Louisiana, on his way to Texas to demonstrate a Huff-Daland trainer to the US Army. There he ran into Coad and Woolman at the airport and found their work intriguing and thought it would make for a great commercial opportunity with the right amount of investment. He convinced Huff-Daland to set up a crop dusting division in northern Louisiana and he put Coad in charge. But Coad wasn't the best of salesmen and he asked Huff-Daland to hire C.E. Woolman as it's head of sales. Huff-Daland Dusters was originally based in Macon, Georgia, with the bulk of their original business being the spraying of peach orchards. However, by 1925 the company moved to Monroe, Louisiana, with the promise of local investment that Woodman had secured. Coad's former laboratory in Tallulah was close by and Woolman's work with the farmers there brought them a ready-made clientele. Woolman, in that classic Southern genteel style he would become famous for, convinced local business leaders in Monroe to invest in Huff-Daland Dusting Company and by the mid 1920s, Woolman had expanded the dusting operation to include Texas, Arakansas, California, North Carolina and even a contract to do crop dusting for the Peruvian government. In a few short years, Huff Daland Dusters would have one of the largest private fleets of aircraft in the United States, even more than some of the airlines of the day.

Delta's first logo (Delta Flight Museum)
Within a few years, Woolman himself would buy the entire dusting operation from Huff-Daland while Huff-Daland Aircraft itself moved to Pennsylvania and was renamed Keystone Aircraft, one of the pioneering aircraft companies of the day. Woodman wanted a simple name preferably with five letters and it was his long time administrative assistant Catherine Fitzgerald, who suggested the name "Delta". Given its long time service area of the Mississippi Delta region, the name was perfect and the triangle was not too dissimilar to the Huff-Daland Dusting Company logo. One of Delta's first non-dusting contract came from the Army Corps of Engineers who wanted aerial surveys done of the levees along the Mississippi River after some disastrous floods in 1927. Woodman likely was considering starting an airline around that time, a federal airmail survey passed through Monroe and he had been looking at a proposed air mail route that connected Shreveport, Monroe, Jackson, Meridian, Tuscaloosa, and Birmingham. In 1929, he even went as far as got advice from a Minneapolis-based airline (Northwest) who offered him suggestions on operating a passenger-carrying airline. However, Delta's finances at the time weren't in a position to get the Ford or Fokker trimotor airliners used by the major airlines of the day. As luck would have it, in a small town not far from Monroe was a businessman named John Fox who had just started a local air service that concentrated on taking people up for joyrides in Travel Air biplanes. Fox had ordered a larger aircraft, a high-wing monoplane with a six-seat enclosed cabin Travel Air S6000. Fox and Woodman met in 1929 and hit it off well given their mutual aspirations of starting an airline. Delta purchased the assets of Fox Flying Service in exchange for Delta stock which made John Fox the biggest Delta shareholder. Fox was named an officer of the company by Woodman and moved to Monroe to help Woodman get their airline off the ground.  Delta Air Service carried its first passenger from Dallas, Texas, to Monroe, Louisiana in on 17 June 1929. Though Delta's agricultural operations would dominate for a while longer, it was a humble beginning for a Southern farmer and his airline.........

Historical Tangent: Thomas Huff and Elliot Daland started their company in 1920 as Ogdensburg Aeroway Company in 1920 in Ogdensburg, New York. They soon became the Huff Daland Aero Company and in 1924 their chief designer was James S. McDonnell (yes, *that* McDonnell that would go on to establish McDonnell Aircraft in St. Louis during the Second  World War). Thomas Huff sold his share of the company in 1926 and it was acquired by a securities firm who invested a significant amount in Huff Daland and moved the operation from New York to Bristol, Pennsylvania and renamed it Keystone Aircraft. Keystone merged with Loening Aircraft in 1928 and the following year Keystone-Loening was taken over by Curtiss Wright. The Loening plant on the East River in New York City was closed by Curtiss and operations transferred to Bristol. A handful of Loening workers and management, though, all New Yorkers, elected to stay and form their own company to stay in New York. The leader of the group was none other than Leroy Grumman. Yes, *that* Grumman!

Sources: Delta: The History of an Airline by W. David Lewis and Wesley Phillips Newton. University of Georgia Press, 1979, pp 1-24. Delta: An Airline and Its Aircraft by R.E.G. Davies. Palawdr Press, 1990, pp 8-13. 

14 November 2015

Refining Anti-Submarine Warfare: The Grumman AF Guardian

Grumman XTB3F Guardian prototype
(San Diego Air and Space Museum)
By 1944, the United States was already laying down plans for the invasion of Japan and if the stiff resistance in the island hopping campaign across the Pacific was any indication, the Japanese were far from defeated and planners expected the worst may yet to come. Navy torpedoes delivered by Grumman TBF Avengers were notoriously unreliable and required a relatively slow approach of 120 mph during their drops at low level. Navy torpedo research languished in the years before the Second World War and torpedo bomber crewman paid the price in their lives. Wartime urgencies caused a reinvestment of torpedo development by the Navy. New air-launched torpedoes in the works could be dropped at higher speeds and further stand-off distances from enemy warships, but by this point in the war, in order to take advantage of the new designs, something with twice the engine power of the venerable Avenger was needed. The first design Grumman submitted for a new carrier-borne torpedo bomber was for the large XTB2F. With two Pratt & Whitney R-2800 Double Wasp radials, the XTB2F was a big aircraft with a maximum takeoff weight of nearly 43,000 lbs which was 8,000 lbs heavier than the maximum takeoff weight of a late model B-25 Mitchell medium bomber! The XTB2F reached the mock up phase before the program was canceled in June 1944 as it was simply too large of an aircraft for the Essex-class fleet carriers. 

The XTB2F mockup before the program cancelation
(Wikipedia/Grumman Archives)
Under the G-70 in-house designation, Grumman offered several variations of a new single-engined design, some of which were mixed-propulsion designs with a big radial engine (either the Wright R-3350 or the Pratt & Whitney R-4360) and a jet engine in the rear fuselage for extra speed on the target runs. When it became clear the R-3350 and R-4360 radials wouldn't be ready for the planned production schedules for what was designated the XTB3F, the Navy asked Grumman for a redesign with the more widely available Pratt & Whitney R-2800 engine which was the same engine used on the B-26 Marauder and P-61 Black Widow. A Westinghouse J30 would be installed in the rear fuselage- the J30 was the first all-American jet engine to run and was only the second production axial-flow engine in the world after the German Junkers Jumo 004. Using the R-2800 engine only cost the reconfigured XTB3F 30 mph of speed which was acceptable to the Navy. Despite the ending of the war by this point, the Navy still wanted the XTB3F, now named Guardian, as a replacement for the Avenger and on 23 December 1946, the prototype aircraft made its first flight. 

As designed, the J30 turbojet in the rear fuselage of the aircraft had 1,330 lbs of thrust and was fed by air intakes in the leading edge wing roots that fed ducts that ran to the engine. During ground test runs, the intake ducting wasn't big enough and strong enough to handle the mass flow to the J30 and would collapse. The engine was only run on ground tests and never used during the flight test program. Ultimately the intake duct problems resulted in the engine being removed and would be absent from the production Guardians. 

With a spacious weapons bay for the Navy's latest torpedoes, the Guardian also had two 20mm cannons in each wing as well as provisions for underwing bomb racks and rocket launchers. Most remarkable about the Guardian, though, was its size. It was the largest single engined piston aircraft to be operated from an aircraft carrier and was 2/3 the size of a Douglas DC-3. In fact, its production maximum take off weight was nearly that of a DC-3! The big R-2800 radial up front was canted down slightly to improve pilot visibility in the carrier approach pattern and it was also canted 3 degrees to the right to help offset the torque of the big engine. It's large tail was to help its stability in low altitude regimes but it did make the Guardian difficult to handle in a crosswind. 

AF-2S and AF-2W hunter/killer team
(San Diego Air and Space Museum)
On the day following the Guardian's maiden flight, the Navy imposed a stop-order on the program to give funding priority to the Douglas AD Skyraider and Martin AM Mauler programs which were also capable of dropping torpedoes and as optimized attack aircraft, were more flexible than the Guardian not to mention smaller in size. It might have been end of the Guardian had it not been for the rapid postwar expansion of the Soviet Union's submarine force. Navy carrier forces needed a specialized anti-submarine aircraft and the XTB3F Guardian best fit that need. As a result, in January 1947, the Navy redesignated the Guardian as the AF (this would be a whole topic for a complete article on how the Navy consolidated the scout, bomber and torpedo roles in the new "A for Attack" designator). Given the state of the art of anti-submarine warfare of the time, though, a single AF Guardian couldn't carry both the necessary detection equipment and weapons, so the Navy brought back the hunter-killer team concept that had worked well during the Battle of the Atlantic were Avengers hunted U-boats and were assisted in their attacks by F4F/FM-2 Wildcats. One Guardian would be equipped with the AN/APS-20 radar in a large under fuselage radome and this would be the AF-2W "hunter". The other Guardian of the pair would be the AF-2S "killer". In operational service, the AF-2W was nicknamed "Guppy" while the AF-2S was nicknamed "Scrapper". 

Interestingly the AN/APS-20 radar started out as a crash program to give the Navy its first airborne early warning aircraft to warn of incoming Kamikaze attacks. Fitted to an Avenger designated the TBF-3W under Project Cadillac, the first AEW Avengers were in Hawaii conducting carrier qualifications when the war ended in 1945. The radome and radar installation on the Guardian was for all intents and purposes, pretty much just moved over from the TBF-3W to the AF-2W. With the J30 engine and its intake ducting gone, space was available for the radar and electronics on the AF-2W and more fuel on the AF-2S. 

Production was launched in October 1947 with an order for 23 early examples which would be devoted to operational testing as well as further flight testing. The first operational examples were delivered to the fleet in September 1950 with VS-24 being the first ASW squadron to get their Guardians. The first carrier qualifications took place that November and in December 1950, VS-24 embarked on the USS Palau (CVE-122) on the Guardian's first operational cruise. Now imagine an aircraft as heavy as a DC-3 that's just 2/3 the size of a DC-3 operating off the decks of escort carriers like the Palau! While a tough and reliable aircraft, a significant number of AF Guardians were involved in deck accidents. Most deck crews were used to handing aircraft half the size of the Guardian and one ASW squadron commander got so frustrated at the incidence of handling accidents just moving the Guardian on the carrier that he required a pilot to be present and in the cockpit if needed when an AF was being moved, even if it was just in the hangar deck!

Operationally, the AF hunter/killer team would form a protective ASW screen around the carrier battle group with the idea to detect and attack any submarines as far away from the carrier as possible. During the Second World War, the protective ASW screen was handled primarily by destroyers and destroyer-escorts- with the arrival of the Guardian, aircraft could now provide the ASW screen for the task force. Guardian teams would fly up to 500 miles out from the carrier with the AF-2W "Guppy" flying a search pattern using its radar to either detect a surfaced sub or a snorkel. Once detected, the "Guppy" would summon the AF-2S "Scrapper". Once in the area, the AF-2S had it's own pod-mounted radar under the right wing (and a search light under the left wing if it was needed at night) to prosecute the attack using vectors from the "Guppy". A periscope sight aft of the wings in the belly was used to release depth charges. If needed, the "Scrapper" could come back around and use rockets and bombs to finish the job. Late model Guardian "Scrappers" designated AF-3S were fitted with magnetic anomaly detection (MAD) gear to improve the chances of note just detecting a sub but sinking it. 

A total of 386 Guardians were built and from 1945 to 1954, it was the US Navy's premier front-line carrier-based ASW aircraft. Of that nine year span, only three of those years was the Guardian truly operational as part of anti-submarine squadrons at sea. Its replacement, also from Grumman, the S2F Tracker, would combine the hunter and killer roles in the same aircraft and the design of the Tracker was heavily influenced by the canceled XTB2F, the design that was replaced by the AF Guardian. Of all the Guardians built, five survived and were used by Aero Union as 800-gallon capacity water/retardant bombers against forest fires from 1957 to 1974. That final year the US Forestry Service instructed its water bomber operators that single engined aircraft could no longer be used. Most were scrapped but a single Guardian was saved and restored to its original configuration and is now on display at the Naval Aviation Museum in Pensacola, the last of its breed in existence. 

Sources: Ironworks: The Story of Grumman and Its Aircraft by Terry Treadwell. Tempos Publishing, 2000, p150-154. "Grumman's Guardian" by Budd Davison. Flight Journal, September 2011.

08 November 2015

Arthur Young Gets Bell into the Helicopter Business

Lawrence Bell, founder of Bell Aircraft
(Airport Journals.com)
In his book The Bell Helicopter Textron Story, David Brown says of Larry Bell, the founder of Bell Aircraft, "Larry Bell was different. With the visionary's eye, he saw his first helicopter and was impressed. When he saw his second (helicopter), he understood that here was an industry waiting to be born." Larry Bell was one of the early American aviation pioneers- after high school he worked as his older brother Grover's mechanic for several years while his brother conducted barnstorming flights. In 1913, his brother was fatally injured in a crash and Bell resolved to stay away from aviation. It wouldn't last, though. He first went to work for his brother's flight instructor, Glenn L. Martin, as a stockroom clerk in Martin's fledgling aviation company. He advanced quickly through the company and ultimately ended up as the Martin Aircraft vice-president and general manager. It was Bell who hired the first college-educated aeronautical engineer for the company- a young MIT graduate named Donald Douglas. It was Bell who got the Army interested in a heavy bomber called the Martin MB-2 that was one of Douglas' early projects. And it was Bell who convinced a brash Army aviator named Billy Mitchell to use the MB-2 to prove that bombers could sink battleships. In 1925, Bell asked to own stock in Martin but Glenn Martin rebuffed his offer of part ownership of the company. Bell resigned and within three years was hired by Rueben Fleet, the president of Consolidated Aircraft. Fleet allowed Bell to own a sizable portion of Consolidated shares and by 1929 he was promoted by Fleet to be the general manager of Consolidated. In 1935, Fleet wanted to move Consolidated from Buffalo, New York, to southern California to take advantage of the better flying weather. Bell didn't want to move, so he resigned but a group of investors backed him in purchasing Consolidated's facilities in Buffalo for the new Bell Aircraft Company. Interestingly, Bell was the third tenant of the factory- it was originally built in 1916 for Glenn Curtiss and at the time was considered the largest aircraft factory in the world. 

Bell's first aircraft was the YFM-1 Airacuda (Bell Model 1) which was a heavy bomber destroyer twin engined fighter. Only thirteen of the unique pusher twins were built and only a single squadron of Airacudas was activated as it was an aircraft ahead of its time. But the US Army Air Corps liked Bell's innovative thinking and asked him for a heavily-armed single engined fighter and this became the Bell Model 12, better known as the P-39 Airacobra which first flew in 1938. It was a remarkable start for Bell's fledgling company and in 1938, President Franklin D. Roosevelt asked Bell to join a group of American industrialists who had been invited tour Nazi Germany. Roosevelt wanted an expert opinion of Germany industrial capacity from the group and Bell was asked to join to assess the Nazi's aviation capabilities. Bell witnessed a flight demonstration of the Focke-Wulf Fw 61 helicopter flown by Hanna Reitsch and he considered the most impressive thing he'd seen on his tour of Germany. 

That was the first helicopter Larry Bell saw- to get to the second helicopter he saw in 1941, we have to step back a bit to look at the story of a unique inventor named Arthur Young. A native of Pennsylvania, while a student at Princeton University, Young was very interested in philosophy and tried to develop an original line of philosophical thought but was unsuccessful. He decided that he wouldn't be able to do so without some real-world experience solving problems. Graduating from Princeton in 1927 with a mathematics degree, Young searched for a technical challenge. He scoured city libraries in the East Coast and made regular visits to the US Patent Office in Washington in his search. He came across a book in his searches by German helicopter pioneer Anton Flettner who had invented a ship that used the Magnus effect from rotary drums to sail across the Atlantic. Flettner had described improving windmill efficiency by using small propellers at the tips. Young thought Flettner's concept could be applied to aircraft and of course that aircraft would be the helicopter, one of the unique flying machines of the day. He set himself on the task of developing a successful helicopter. 

Arthur Young and one of his late helicopter models
(State Archives of Florida, Steinmetz Collection)
Young set up an experimental workshop in a barn on his wealthy family's large estate in Pennsylvania. He refined his ideas using small models and his first design flew in 1931 using parts he obtained from a local toy shop- using rubber bands, hand-carved wooden blades with propellers at the tips and a balsa structure, his first model had a rotor diameter of six feet and it flew for only ten seconds. For the next nine years he worked at improving the Flettner concept, moving to the use of electric motors. He went through so many crashed models he literally learned how to mass produce his own helicopter blades. One of the problems Young encountered was getting his models into a stable hover. Over time he used his mathematics background to calculate stresses and build his own components based on his stress calculations. In doing so, he developed many of the concepts and tools used to measure rotor lift, propeller efficiency as well as equations to calculate a variety of power requirements for helicopters. 

In 1938, Young attended a conference of helicopter designers and learned of the pioneering work of Igor Sikorsky. Sikorsky himself gave a lecture on the use of a tail rotor to counter the torque of the main rotor. Young was fascinated by Sikorsky's lecture and set about to revise his model testbeds with tail rotors, disposing of the complex gearing that he had been working on to drive tip propellers. Stability in a hover continued to plague his efforts- he had tried a pendulum within the fuselage, but the pendulum arrangement he designed couldn't distinguish between the force of gravity and the force of acceleration. He then came up with the stabilizer bar- a bar with weights on the end that was perpendicular to the rotor. The weighted bar when spinning acted as a gyroscope that stabilized the helicopter in a hover. He used an electrical control system that ran to a box where he controlled the helicopter with extreme precision. He took his models on demonstrations to various aircraft companies where he showed how he could fly his helicopter models indoors and even in and out of doorways. He even gave a demonstration to the Army's aeronautical development center at Wright Field in Dayton, Ohio, but failed to find any financial backers. 

Dr. John Sharp was a physician who had seen one of Arthur Young's demonstrations. Sharp had a unique hobby in that he designed gearing systems in his free time and was working on a new gearing concept for a variable pitch propeller was pitching his ideas to Bell Aircraft. In 1941, Sharp was meeting with a Bell engineer named Jack Strickler and in casual conversation, Sharp spoke highly of Young's helicopter flight demonstrations. Strickler than passed on what Sharp told him to Larry Bell himself. Since Bell was impressed with what he had seen with the Focke-Wulf Fw 61 helicopter in his 1938 tour of Germany, he invited Arthur Young to come to Buffalo to give a demonstration of his helicopter design.

On 3 September 1941, Young arrived at Bell's Buffalo plant and was taken to a hangar where P-39s were prepared for delivery. Bell ordered the personnel in the hanger to stop work and move the P-39s outside to give Young room for his demonstration. Not only did Young fly a successful demonstration for Larry Bell, he also reviewed with Bell films showing his previous design efforts and showed him his notes on the design process he had developed to solve the problems of vertical flight. Bell was enthralled by Arthur Young and wanted to hear Young's ideas on a full-size piloted helicopter design. In a matter of weeks they reached an agreement where Young would come to Buffalo and work for Bell in developing a new helicopter based on his designs. Young assigned his patents to Bell Aircraft and Larry Bell funded the development of two full-sized helicopters. Young wanted two aircraft in case one crashed and Bell insisted that the second prototype be a two-seater so he could go on a ride! 

The rest, as they say, was history! That first helicopter, the Bell Model 30, will be the subject of a future article here at Tails Through Time. Stay tuned!

BONUS: A three part interview with Arthur Young in his later years about his design efforts

Sources: The Bell Helicopter Textron Story: Changing the Way the World Flies by David A. Brown. Aerofax Publications, 1995, pp 1-19. "Arthur Young: Maker of Bell, Part 1" by Robert Tipton, http://www.arthuryoung.com/maker1.html. 

03 November 2015

Regulus: The US Navy's First Operational Nuclear Missile

Regulus missile on an aircraft carrier deck.
Following the defeat of Germany in May 1945, the US Navy began experimentation with the German V-1 "buzz bomb" as a submarine-launched weapon called the JB-2 Loon. Both the Navy as well as the Army drew up plans to use the JB-2 during the planned invasion of the Japanese Home Islands, but the war in the Pacific ended in August of that year before the plans could be put into place for use of the Loon. This didn't put a stop to development work, though- in March 1946, Secretary of the Navy James Forrestal approved plans to convert two submarines to operate the Loon on an experimental basis. While the Loon was never planned in the postwar period to be an operational missile, it was planned to give the submarine force experience in operating cruise missiles. In 1947 the Navy began development of several supersonic land-attack cruise missiles- one was the Mach 2 Rigel and the other was the Mach 3.5 Triton, both powered by ramjets. At the time, ballistic missile technology was at a point where they weren't practical nor compact enough to be fired from submarines, so the Navy was hitching its submarine nuclear deterrent on the cruise missile. The level of technology required for the Rigel and Triton were far above what was state of the art for the late 1940s, so while development work continued and technology matured, an interim cruise missile for the sub force was needed and this task was given to Vought Aircraft who then developed the Regulus missile- originally planned to carry a 4,000 lb conventional warhead, in 1949 Vought was directed to use a nuclear warhead on the Regulus, making the first US Navy missile to carry a nuclear warhead. 

The Regulus featured folding wings and a tail fin to allow it to be carried aboard a submarine. Powered by an Allison J33 engine (also used on the Lockheed F-80 and T-33 Shooting Star), Regulus was a subsonic missile with an approximately 500 nautical mile range. It was boosted from the missile by two solid rocket boosters that fell away once the J33 engine took over propelling the missile. The missile guidance was by radio command- the system was called "Trounce" and it directed the missiles nearly all the way to the target. Not only were submarines and ships capable of guiding Regulus using Trounce, but the Navy also had specialized Regulus guidance squadrons equipped with the North American FJ Fury that could be embarked aboard fleet carriers as needed. The first Regulus flight took place on 29 March 1951- this early Regulus missile had its own landing gear to take off and land under its own power and was controlled from another aircraft. Test launches were made from surface ships the following year. 

Firing a Regulus from the USS Tunny.
Two diesel-electric submarines were the first to be converted to carry and fire the Regulus. The USS Tunny (SSG 282, the "G" for missile) and the USS Barbero (SSG 317) were fitted with a rather cumbersome hangar aft of the conning tower which itself was modified to carry the Trounce guidance equipment. Converted at the Mare Island shipyards near San Francisco, the Tunny was recommissioned in March 1953 and the Barbero returned to the fleet in October 1955. The first submarine launch of the Regulus took place on the USS Tunny on 15 July 1953. On both ships, the Regulus missile hangar would hold two missiles- to fire the Regulus, the submarine had to surface and the missile had to be manually rolled out of the hangar and manually unfolded to prepare it for launch. 

While the submarine force got ready for the Regulus, the Navy went ahead and deployed it from surface ships (several cruisers and aircraft carriers deployed with the Regulus) with the 50 kiloton Mk 5 warhead starting on May 1954. The first overseas deployment of the Regulus actually took place with surface ships- in 1955 the cruiser USS Los Angeles (three missiles) and the aircraft carrier USS Hancock (four missiles) deployed to the Western Pacific to cover Soviet targets in the Far East. It wasn't until 1958 that the Regulus went to sea aboard a submarine. Joining the USS Tunny and USS Barbero were two purpose-built diesel electric subs that were modifications of an existing design- the USS Grayback (SSG 574) and the USS Growler (SSG 577) were completed in 1958- the Grayback was built at Mare Island and the Growler was built at the Portsmouth shipyards in New Hampshire. There were plans initially to have Regulus capability on the first nuclear submarine, the USS Nautilus, but it was felt to minimize risk, the Nautilus was completed as a non-cruise missile submarine. However, funds were made available for a nuclear-powered Regulus submarine, and in 1960 the USS Halibut (SSGN 587) was commissioned, giving the US Navy five Regulus-armed boats. 

The first submarine nuclear deterrent patrol took place during the 1958 Lebanon crisis when the USS Tunny was ordered to patrol in the North Pacific to make up for the usual aircraft carrier that would have been present to hold Soviet targets in the Far East "at risk". This was more than two years before the first ballistic missile submarine, the USS George Washington, went to see with the Polaris SLBM. The USS Barbero was assigned to the Atlantic fleet and carried out deterrent patrols there from April 1956 to late 1958 before the Navy consolidated its Regulus subs with the Pacific Fleet. From September 1959 to July 1964, the Navy had at least one submarine on deterrent patrol in the North Pacific- the diesel electric boats would refuel at either Adak, Alaska, or Midway Island, before going out on the patrol. The sole nuclear-powered Regulus boat, the USS Halibut, didn't need the refueling stops. During that period, forty-one Regulus patrols were conducted, sometimes two of the subs were on patrol at once. The Regulus missiles during this period were armed with two megaton W27 warhead which replaced the earlier Mk 5 warhead.

Regulus launch from the USS Halibut.
The successor to the Regulus was to have been the supersonic Regulus II with twice the range and a heavier warhead. The development got as far as having a Regulus II fired from the USS Grayback in September 1958, but three months after the sub launch the Regulus II program was canceled as the decision had been made to accelerate and enlarge the Polaris missile program which was shaping up to be a much more practical system than cruise missiles. The Regulus missiles were retired as the Polaris come on line, the last Regulus deterrent patrol taking place in July 1964 which was five months before the Polaris missile patrols commenced in the North Pacific. Both the Barbero and Tunny were scrapped, but the Growler would become a museum boat in New York City at the Intrepid Sea-Air-Space Museum (it has a Regulus missile displayed in launch configuration). The USS Grayback become a special forces transport and served in this role until 1984. The USS Halibut had an impressive second career as an intelligence platform to carry out clandestine ocean operations. It served in this role until 1976. 

The Regulus ended up being an interim placeholder for the US Navy until the arrival of the ground-breaking Polaris missile. For almost five years, the Regulus subs patrolling the North Pacific were the only submarine nuclear deterrent. In fact, the USS Halibut was the second nuclear sub to be built to operate missile armament- the honor of the first actually goes to the USS George Washington with its Polaris missiles. It was launched five days before the USS Halibut in 1960, but it wasn't until late 1964 that it went on an operational deterrent patrol with Polaris.

Source: Cold War Submarines- The Design and Construction of US and Soviet Submarines by Norman Polmar and KJ Moore. Potomac Books, 2004, p86-93. Photos: US Navy Historical Center, Wikipedia.

29 October 2015

The Douglas F6D Missileer

The F6D Missileer's resemblance to the F3D Skyknight is apparent
In 1957 the US Navy issued a specification for carrier-based fleet defense fighter that could loiter for long periods of time at long distances from the carrier. In addition, the aircraft had to be able to engage enemy aircraft at 100 nautical miles with a powerful onboard radar and long-range air-to-air missiles. Under the assumption that enemy aircraft were to be destroyed at well beyond visual range, dogfighting capability was not necessary and the need for long endurance dictated a subsonic design. Six hours was the specified endurance for this fighter and in turn this meant a large fuel load. The complex radar systems planned called for a three-man crew, with the pilot and co-pilot on each side of the radar intercept officer, this way both of the flying crew man could share some of the same displays with the radar intercept officer (RIO). 

There were four components to 1957 concept for fleet air defense that would be issued to industry for submissions. The first, of course, was for the aircraft itself, which was awarded to Douglas Aircraft Company in 1959 for what was designated the F6D Missileer. But in addition, a contract was awarded to Westinghouse for the AN/APQ-81 radar that would be used by the F6D to track and engage enemy aircraft. The third component was a contract awarded to the Bendix Corporation for the large AAM-N-10 Eagle missile. What is little-known about the F6D program was the fourth component, for an advanced airborne early warning aircraft to search out targets for patrolling Missileers. This contract would go to Grumman Aircraft which resulted in the W2F Hawkeye (later redesignated E-2 Hawkeye) with its advanced AN/APS-125 radar which could scan an area 400 miles in diameter and cue several F6D Missileers. 

Overall configuration of the F6D Missileer
The F6D itself resembled a scaled-up version of the Douglas F3D Skyknight twin-seat all-weather/night fighter. The nose section was quite bulbous to house the Westinghouse AN/APQ-81 radar and the three man crew were seated side-by-side in a cockpit that resembled that of the Grumman A-6 Intruder. Two non-afterburning Pratt & Whitney TF30 turbofans were mounted on each side of the fuselage just under the unswept wings. At the time, the use of a turbofan engine in a combat aircraft was a new concept and the TF30 was selected for its fuel economy. Since the Missileer didn't have to be supersonic, there was no need for a heavy and fuel-hungry afterburner. 

The Westinghouse AN/APQ-81 radar would have been the most advanced radar of its day using pulsed-Doppler technology years before the first production pulse-Doppler radars would enter service. The radar had a maximum range against large aircraft of 120 miles and could track as many as eight targets at once. The radar could also send mid-course corrections to the Eagle missiles. 

Overall configuration of the AAM-N-10 Eagle missile
The Bendix AAM-N-10 Eagle was the first of the four components from the 1957 fleet defense concept to be awarded. A large solid rocket booster would boost the Eagle to Mach 3.5 after launch on a loft trajectory for maximum range. After the booster was jettisoned, the Eagle's own sustainer motor ignited and further accelerated the missile to Mach 4.5. The use of a loft trajectory gave the Eagle missile a range of 160 miles and on final approach to the target, the missile's own onboard radar system (based on the radar used on the Bomarc surface-to-air missile) switched on. The Eagle could be armed with either a conventional or nuclear warhead.

Despite the advanced nature of the technology used in the F6D Missileer program, many quarters in the Navy fundamentally opposed the concept, arguing that once the Missileer had fired its six Eagle missiles, it was left vulnerable and unable to defend itself as it lacked any other armament and its large subsonic size precluded any evasive maneuvers. Once firing its missiles, the Missileer faced a long return flight to the carrier to refuel and re-arm. In 1960, the building opposition within the US Navy won out and the F6D Missileer program was canceled along with the Westinghouse AN/APQ-81 radar and what was becoming an enormously complex AAM-N-10 Eagle missile. The cost of developing the missile itself was estimated to be more than the aircraft development cost. 

However, the development of the Grumman W2F/E-2 Hawkeye continued and the aircraft is still in production today, albeit with more advanced radar systems, and is perhaps sole remaining legacy of the ambitious, but flawed, F6D Missileer program. 

Source: American X & Y Planes: Volume 2; Experimental Aircraft Since 1945 (Crowood Aviation Series) by Kev Darling. The Crowood Press, 2010, p60-61. Photos: Wikipedia, various internet forums.

24 October 2015

Fox Two! The Birth of the AIM-9 Sidewinder Missile

An early Sidewinder test round- note the early constant chord fins
At the end of the Second World War, the Navy had been focusing its weapons development work at the remote Naval Ordnance Test Station Inyokern, California (today known as China Lake). Three hours northeast of Los Angeles in the high Mojave Desert and with 1,200 square miles of land to blow things up, the site tended to attract some of the more innovative if not unconventional minds in weapons design. A CalTech graduated named Bill McLean was working on a few ideas to improve the lethality of unguided air-to-air rockets. At the time, outside of guns, the only other air-to-air option in widespread use were rockets which were notoriously difficult to employ even against ground targets. One USAF Air Defense Command pilot once remarked that "the only thing you were sure to hit with air-to-air rockets was the ground."(In 1956 two USAF F-89 Scorpions tried to down an errant drone, firing over 200 rockets and failing to score a single hit.) The best options of the day were radar guidance, but the technology of the late 1940s and early 1950s meant a radar-guided missile would be heavy. McLean wanted something lightweight and simple that could be bought by the thousands. He reasoned that a self-contained guidance system would simplify the use of such a missile and he and a group of volunteers in their free time worked on infrared guidance- the missile could home in on the hot jet exhaust. 

At the time the Navy had been using 5-inch rockets since the Second World War in the air-to-ground role. Work on refining the 5-inch rocket had continued at China Lake (one result was the Zuni air-to-ground rocket still in use today). McLean wanted to combine the simplicity of a 5-inch rocket with infrared guidance. A rotating, gyroscopically-stabilized mirror looking through a transparent nose dome would reflect heat energy to a lead-sulfide photocell. Rather than focus on the target, the detector looked at the target's change in position and this way it automatically "led" the target and could hit from angle instead of just a tail chase which would require a significant speed advantage. This sort of guidance is called "proportional pursuit". Using his free time and the volunteer help of his fellow engineers, McLean developed a way to translate the seeker's findings to control inputs to the missile's fins. Another one of the team's ingenious solutions for the missile was a simple way to stabilize the missile so it didn't rotate about its long axis and complicate the work of the infrared seeker. Discs with spurs to catch the airstream to spin like roller wheels were installed on the edges of the main fins and were called "rollerons". By spinning up in the air stream, the rollerons acted like gyroscopes, keeping the missile from rotating on its long axis. It was an elegantly simple solution to a complex flight control problem. 

In 1950, the name for the missile was adopted, Sidewinder- after the predatory snake common in the Mojave Desert that used heat to sense its prey. Other names had been mooted, one of which was "Low IQ Homing Head" in reference to the missile's simplicity. By August 1952, the first aerial test shot was ready to take place. Future astronaut and Navy test pilot Wally Schirra fired the Sidewinder prototype from a Douglas AD-4 Skyraider at a Grumman F6F Hellcat drone. And it missed. And so did the next eleven test shots. Finally on 11 September 1953 after many fixes and revisions, the Sidewinder finally scored a proximity hit on its thirteenth test shot against a Hellcat drone. Four months later it scored a direct hit on a QB-17 drone square in its No. 1 engine. On 17 February 1954 McLean's small cadre scored another victory when another Sidewinder prototype destroyed another QB-17 that was thought to be indestructible because it had survived so many missile hits. 

The early test Sidewinder shots required the test pilot to monitor a small voltmeter in the cockpit to determine if the missile seeker was properly sensing the target's heat source. Realizing this was an unnecessary distraction in combat, McLean's small team came up with another simple solution- with just one additional wire from the missile, they could generate a tone that could be heard in the pilot's headset to let them know the seeker had the target- the famous "Sidewinder growl". The Navy was enamored with the Sidewinder's simplicity- at the time the US Air Force was bringing the Hughes AIM-4 Falcon into operational use. Developed by a vast engineering team at Hughes' southern California facilites, it was a much more complex weapon despite also being infrared guided. In fact, in 1956, a Navy team came to Holloman AFB in New Mexico (which sits astride the White Sands Missile Range) to prove to the USAF that an Air Force pilot who had never fired a Sidewinder before could destroy a target drone. It was an official shoot-out between the Navy's Sidewinder and the Air Force's Falcon missile and it was wildly successful for the Navy team- the story goes that the Navy test pilot on the team bet everyone in the test teams that the Sidewinder would work as advertised. Despite this, the USAF deployed the Falcon anyway and it proved to be dismal failure in the skies of Vietnam, quickly getting replaced by the Sidewinder in what was called the "Falcon Fiasco".

Evolution of the Sidewinder family
The first production Sidewinders (AIM-9A and AIM-9B) refined the aerodynamics from the straight, constant-chord fins of the prototypes. Still retaining the 5-inch diameter body, the seeker would feed commands to the forward set of fins while the larger aft set of fixed fins housed the rollerons, a layout that would be retained to this day until the debut in 2001 of the AIM-9X variant. The Sidewinder would have its combat debut in the 1958 Taiwan Straits Crisis when PLAAF MiG-17s used their high altitude advantage and cannon weaponry against the Taiwanese F-86 Sabres. In a secret program, several Taiwanese Sabres were quickly modified to fire the Sidewinder (again, reflecting the simplicity of the missile) and were used 24 September 1958 to ambush the Chinese MiGs. 

The Sidewinder missile so significantly changed the nature of aerial combat that it was even copied by the Soviet Union as the Vympel K-13 (NATO designation AA-2 "Atoll". It wasn't until the end of the Cold War that Russian designers admitted to what had been widely suspected for years. Even the parts numbers of the Sidewinder were replicated on the K-13! Hundreds of thousands of missiles have been built for United States military but also under license in Europe. China even copied the K-13 for its own use. The US Army fielded a surface-launched version that mounted four AIM-9D missiles on a tracked vehicle and was called the Chaparral. Older AIM-9C missiles pulled from service were converted in the 1990s into lightweight anti-radar missiles designated AGM-122 Sidearm. And the basic principles of the Sidewinder have influenced a large number of other infrared-guided missiles from around the world, from Israel's Python family to the French Magic family.

Navy deck crew lift a Sidewinder onto a Hornet's missile rail
The first Sidewinder missile's electronics consisted of only seven vacuum tubes and five moving parts. Over the years since then, the missile has retained the 5-inch diameter but has gotten longer from 109 inches to 119 inches as well as lighter, from 155 lbs to 118 lbs. The latest production model of the Sidewinder is the AIM-9X, the first missile to change the basic layout and seeker function completely. Instead of the rotating mirror, the seeker has a staring focal plane array using a pixel-based sensor derived from digital camera technology. The rollerons are gone and the fins are considerably smaller, now only making the -9X lighter but also making internal carriage easier. Jet vanes are now in the motor exhaust at the tail end to give it thrust vectoring which makes the rollerons unnecessary, makes the fins smaller and lighter, and gives the missile tremendous maneuverability. 

Not bad for missile that started out as a free time project with less than 25 engineers!

Source: Air & Space Smithsonian, November 2010, Volume 25, Number 5. "Sidewinder: The Missile That Has Rattled Enemy Pilots Since 1958" by Preston Lerner, p54-61. Photos: Wikipedia

19 October 2015

Mike Grimm, Father of the Night Stalkers

Michael Grimm, Father of the Night Stalkers
Conventional wisdom in aviation history points to the tragic debacle at Desert One in Iran during the hostage rescue mission as the watershed moment that culminated in the formation of the US Special Forces Command (SOCOM). While I do think that the story of the failed 1980 Iranian hostage rescue mission should be held near and dear to every military leader of this nation, there was actually someone else who sounded the warning bells three years before that fateful day in 1980. His name is legendary amongst US special forces personnel to this day, but I'd bet hardly any of us enthusiasts had ever heard of his name- Mike Grimm.

Long before he would make his mark on the history of US special forces, Mike Grimm was already a decorated hero of the Vietnam War when as a second lieutenant in 1968, assumed command of his platoon and managed to fight off through the night two entire companies of Vietcong before they could be extracted by helicopter from the battle zone. He stayed on with the US Army after the end of US participation in the war in 1973, eventually becoming a helicopter pilot and stationed in Hawaii in 1975. But serving in Hawaii was boring for Grimm, when the most serious decision they ever had to make was whether he would fly clockwise or counter-clockwise around Oahu. In 1976, the world was electrified with the stunning Israeli raid at Entebbe, Uganda, to rescue the passengers of a hijacked Air France flight. In less than one hour, Israeli commandos stormed the Entebbe Airport, killed nearly all the terrorists, rescued nearly all the hostages and only losing one commando. And they also manged to destroy most of the MiGs of the Ugandan Air Force in the process.

Mike Grimm realized that the United States lacked the capability to do what the Israelis managed to do- project power over 2,000 miles into hostile territory and effect a hostage rescue with minimal losses. Austerity was the key word in the post-Vietnam defense budget and even training exercises were canceled to save money. Once he had become the Divisional operations officer in 1977, he decided to use the Division's entire budget for training on a single exercise. He called it an Emergency Deployment Readiness Exercise (EDRE) and in the training scenario, his men and pilots would have to fly 200 miles to the island of Hawaii where a select group of soldiers playing terrorists were holding hostages. Grimm's men would have rescue those hostages with minimal losses. The tactics he developed for the exercise would be the blueprint for all future missions to come, even to this day.

Men from the First and Fifth Infantry Battalions at Schoefield Barracks on Oahu were selected to be the "raiders." Their helicopter element consisted of 10 Bell UH-1H Hueys and two Bell AH-1G Cobra gunships from A Company of the 25th Aviation Battalion. After an alert and planning period, the men and their helicopters flew from Schoefield Barracks to Hickam AFB to be loaded aboard USAF Lockheed C-141A Starlifters to simulate strategic deployment. The men were flown to Hilo Airport which would function as the "intermediate staging base" for the exercise. On 14 November they arrived in Hilo where the helicopters were readied for flight and they flew onward to Bradshaw AAF in the Pohaku Trainng Area in the center of Hawaii. This would be their "forward operating base" for the mission exercise.

The "hostages" were being held in the fire station of Waimea-Kohala Airport just 30 miles north of their forward operating base. The raid would be carried out at dawn as no night vision equipment was available. At ten miles from the target, the "terrorists" heard the team coming and "executed" the hostages. When Grimm's raiding force landed, they were wiped out to the last man.

The next day at Bradshaw AAF the After Action Review took place and everyone but Mike Grimm thought their Army careers were over when the Division commander, Lieutenant General Willard Scott arrived. He began the debriefing with the statement "This exercise was a really bad idea." As he continued for several minutes on the inappropriateness of using helicopter-borne infantry on anti-terror operations. "Our Army will never enter into this area. This is NOT our role."

At that moment, Mike Grimm stood up and interrupted his commander.

"Respectfully, sir, that is NOT correct." Here he was, a newly minted major, holding a two-star general to task. "Not only do we need to create this capability, sir, but if we don't, we are going to find ourselves at some point in our history embarrassed as a nation!"
Emblem of the 160th SOAR

Three years later, on the morning of 25 April 1980, in the Iranian desert, that embarrassment took place. The wrecks of five Marine RH-53D Sea Stallions and one USAF C-130 Hercules lay smoldering in the desert with the bodies of eight American servicemen. That year Mike Grimm was the commander of A Company of the 229th Aviation Battalion of the 101st Airborne Division where he was working with a handpicked group of men to transform the Hughes OH-6 "Loach" into what would become the MH-6/AH-6 "Little Bird" for night time special forces missions. On the night of 7 October 1981, Mike Grimm was flying one of the unit's MH-6s at low level over the Cumberland River when he hit the side of a power line tower and was killed instantly. One week later, in memorial to Mike Grimm, the new 160th Aviation Battalion uncased its colors. It was the birth of the Army Special Force's aviation element (Special Operations Aviation Regiment, or SOAR), the "Night Stalkers".

Source: The Night Stalkers: Top Secret Missions of the US Army's Special Operations Aviation Regiment by Michael J. Durant and Steven Hartov. GP Putnam and Sons, 2006, p33-64. Photos: US Army, Wikipedia

14 October 2015

The Spyplane Codenamed "Pie Face": The Birth of the Big Safari Program

The Big Safari emblem
(Big Safari Association)
At the end of the Second World War, Germany was divided into four occupation zones administered by the victorious Allied powers. The capital, Berlin, was in turn also divided into four zones. When The Soviet Union established East Germany from its occupation zone, West Germany was formed from the American, British and French occupation zones. Berlin was also divided into East Berlin and West Berlin with the western part of the capital surrounded on all sides by East Germany. By agreement, there were travel corridors to allow surface and air connections to West Berlin from West Germany. The air corridors were only 20 miles wide at a maximum altitude of 10,000 feet. The northern air corridor followed a Hamburg-West Berlin line, the central air corridor followed a Hannover-West Berlin line and the southern air corridor followed a Frankfurt-West Berlin air corridor. In the summer of 1952, the head of United States Air Forces Europe, General Lauris Norstad, made a special request to the USAF Chief of Staff, General Hoyt Vandenberg, for reconnaissance aircraft to use in Europe that in particular, could fly unnoticed in the West Berlin air corridors as a routine courier flight. Vandenberg convened a group of specially selected officers and civilians who would develop not just the aircraft needed for the requested USAFE mission but also a set of rule and procedures in order to field such an aircraft quickly and in secrecy. Lieutenant General Thomas Rhodes worked with a reconnaissance systems specialist, Furman E. O'Rear, to develop the procedures that would get the specialized aircraft into service. 

Rhodes and O'Rear laid down the "ground rules" for the project: 
  1. Only the minimum amount of documentation was needed. Personal contact and direct communication was preferred. 
  2. Strict security clearances would be issued on a need to know basis with a minimum of personnel. 
  3. No limit on funds for the project. Special capabilities needed in the field shouldn't worry about funding. 
  4. Primary responsibility for the program lay with the Director of Air Force Maintenance and Engineering (this later became Air Force Systems Command) who would direct the Air Force Materiel Command (this later become the Air Force Logistics Command in 1961).
  5. Coordination was the utmost importance between the different commands of the USAF and the intelligence community. A single project head would act as the point of contact for all the diverse interests involved. 
  6. Aircraft contractors selected would also issue strict security clearances to a closed off work area for any aircraft modifications. 
  7. The contractor selected would be responsible for yearly upgrades to any aircraft system. 
  8. It was agreed upon ahead of time that any modifications or changes needed to the aircraft systems would be approved to expedite the fielding and subsequent upgrades to any special capability aircraft. 
In addition to these ground rules, it was also agreed that any project would make use of an existing aircraft rather than develop a new aircraft. The project office was authorized initially with a five year commitment on the reconnaissance aircraft that would be fielded by the USAFE for use in the Berlin air corridors. When it was realized in 1953 that the program's set up lent itself well to other special projects, it was given its own code name by which it is still known today: BIG SAFARI.

The Boston Camera the USAF Museum
(USAF Museum)
The year before General Norstad's 1952 special request for a reconnaissance aircraft, a very large special optical camera had been flight tested on a Convair B-36. The camera, developed by optical scientists and engineers at Boston University in 1947-1949, was designated the K-42 but was known as the Boston Camera as well as the code names BIG BERTHA and DAISY MAE. With a 240 inch focal length (6096mm), it weighed nearly three tons and used very large 18x36 inch frame film. It would be the largest aerial camera ever built. The lens was fixed at f/8 with an electrically tripped shutter speed of 1/400 second. Allegedly it had the resolution to image a golf ball on the ground from 45,000 feet. During the flight test program it was decided that a bomber carrying the Boston Camera would have been conspicuous if not downright provocative and it would be better used mounted in a transport aircraft. The aircraft had to be large so as not to have any external modifications that would give away its carriage of the large camera. PIE FACE was the code name assigned to the effort to mount the camera in a transport aircraft. The first PIE FACE contractor was actually Boeing who had offered a YC-97 Stratofreighter- one YC-97 in fact had flown a handful of Berlin Airlift missions. Boeing at the time was preoccupied with other programs and afforded the PIE FACE program little attention to the point that security was constantly being compromised with the aircraft frequently parked in the open at the property perimeter fence line in Seattle. 

As a result, the PIE FACE contractor was changed from Boeing to Convair Fort Worth. This would become Detachment 1 of the Big Safari program. The general manager of Convair, August Esenwein, took a personal stake in the project and made sure the USAF had the necessary secure hangar space as well as any engineering personnel needed make sure PIE FACE was fielded quickly. Esenwein's personal involvement pleased the USAF and the working relationship between the USAF and Convair at Detachment 1 set the standard for future contractor relationships in the Big Safari program. In fact, Detachment 1 would run for twenty years with 87 different aircraft passing through Convair Fort Worth over that time span. 

PIE FACE would have looked just like this KC-97
While the Boston Camera did fly in Europe for six weeks on the YC-97, it was clear that as an early variant of the Stratofreighter it was less capable than the later KC-97 variants already in service. With less powerful engines, the YC-97 with the Boston Camera onboard was significantly altitude restricted. Given that the camera was used for stand-off oblique photography, a higher altitude meant that more of East Germany could be photographed from the air corridors. From 19 December 1952 to 23 February 1953, the Boston Camera was moved from the YC-97 to a KC-97 that had its boom removed, 49-2592. Both aircraft were literally cut in half behind the cockpit to move the camera from one aircraft to the other. The manual controls of the camera were upgraded with electrical and electromechanical controls as it was installed on the KC-97. Covert sliding doors were used to cover the camera ports when it wasn't in use. In addition to the installation of the Boston Camera, a 100-inch K-30 camera and a trimetrogon system of three K-17 cameras were also installed, all synchronized with the Boston Camera to give wider angle photographic coverage of the target areas and assist with mapping. A camera operator's station was installed in the cockpit with a special slaved sight to trigger the camera system. 

West Berlin air corridors
(German History in Documents and Images,
After flight testing with specially selected USAF crews, the PIE FACE KC-97 was assigned to 7499th Support Squadron (later renumbered to the 7405th) at Rhein-Main AB, the main USAFE transport hub in Europe. With each of the three air corridors to West Berlin being 20 miles wide, that was already 1/6th of East Germany that lay underneath any aircraft within the corridors. The addition of oblique photography added tremendously to the area surveilled- at the 10,000 foot maximum imposed by the Soviets, the majority of East Germany could be photographed by the PIE FACE aircraft. In addition to flying in the air corridors, perimeter flights along the border were also flown at altitudes as high at 32,000 feet. Just in the last six months of 1953 when it was first fielded, the specially-equipped aircraft had flown 13 missions (quite remarkable given the complexity of maintaining the camera system). The aircraft also stood alert for short notice missions and flew as far as the Arctic and the Middle East. Intelligence requirements soon outpaced the abilities of the aircraft and eleven other aircraft were added to supplement PIE FACE starting in 1954. Those aircraft will be the subject of a future article here at Tails Through Time, so stay tuned!

PIE FACE was scheduled to end in 1962 and 49-2592 was flown back to Convair Fort Worth for demodification. By that point the aircraft had already rotated through Fort Worth eight times for upgrades and further modifications. Engineers there had developed a pneumatic shutter system for the cameras in only 28 days that became the standard for any Big Safari photoreconnaissance system. But PIE FACE wasn't over just yet as the Cuban Missile Crisis erupted just as the aircraft was about to be demodified. Approximately 17 missions were flown from MacDill AFB in Tampa around the periphery of Cuba, PIE FACE's imagery supplementing that taken by the Lockheed U-2 overflight missions. In March 1965, 49-2592 returned to Convair Fort Worth for good as the airframe was worn out and given over for salvage. The Boston Camera ended up at the National Museum of the United States Air Force in Dayton, Ohio, where it can be seen today displayed with a Convair B-36 Peacemaker. 

Source: The History of Big Safari by Col. Bill Grimes, USAF (Ret). Archway Publishing in cooperation with the Big Safari Association, 2014, pp 1-16. 

09 October 2015

General Giulio Douhet, the First Air Power Visionary

Giulio Douhet, air power visionary
Those of us interested in aviation take it almost for granted the unyielding pace of technological development that has driven aviation forward through time. But even less heralded are those in aviation history who have shaped the thinking of aviation- it's easy for us to lay eyes on an aircraft or even to put our hands on one. They're very tactile and sensory experiences in aviation- to see one, hear one, feel one, even ride an aircraft. But how do you experience aviation doctrine? How do you grasp the thought processes that have shaped aeronautical progress? They're very abstract and not prone to enjoyment and appreciation by most of us. However, technological progress is a rudderless boat in chaotic waters without visionaries and thinkers to provide steering and direction. Of course we can name designers like Jack Northrop or Andrei Tupolev. Or pilots like Charles Lindbergh or Chuck Yeager. But the subject of today's blog posting is none of those- he didn't design any aircraft, he didn't even fly aircraft. But his writings on air power have left an indelible mark on aviation, if not history itself. 

Born in 1869, Giulio Douhet was a rare breed of Italian army officer who was both an infantry and artillery officer and what we might call a technocrat, having studied science and engineering as well. His earliest writings as part of the General Staff of the Italian Army covered mechanization and the incorporation of what would be come tanks in military doctrine. But with the arrival of lighter-than-air aircraft like dirigibles and the first practical biplanes prior to the First World War, Douhet quickly appreciated the advantages of aviation in war- aircraft could move in three dimensions and operate above and out of the reach of ground and naval forces with relative impunity. In 1912 when the Italians first used aircraft in combat in Libya, he wrote Rules for the Use of Airplanes in War, one of the first efforts to create a doctrine for military aviation- despite his own background as an artillery and infantry officer, Douhet felt that the current military leadership lacked an understanding of the inherent advantages of air power and an almost zealous desire to educate the establishment on air power would be Douhet's mission in his life. 

When the First World War broke out in Europe in August of 1914, Douhet was forty-five years old and no less energetic than officers half his age. With a near-insatiable appetite for the latest developments in aviation, he advocated the building of a force of 500 bombers that could bomb enemy forces from above without having to engage in prolonged combat. He worked closely with the Italian engineer Gianni Caproni in advising him on his own Caproni line of bomber aircraft. But Douhet would find the Italian military leadership incompetent as defeat after defeat was suffered by Italian forces. Convinced that aviation technology could reverse the lagging fortunes of the Italian military, Douhet wrote and spoke frequently to anyone and everyone in the military and government establishment. By 1916 his superiors had had enough when he had ordered construction of Caproni bombers without authorization. He was stripped of his rank and imprisoned on charges of "issuing false news" and "disturbing the public tranquility". It didn't stop him, though. He continued to write and refine his theories from his cell. 

In the fall of 1917, the Italian Second Army was completely routed at the Battle of Caporetto (in modern day Slovenia), suffering over 300,000 casualties. The Italian government in desperation released Douhet from prison and commissioned him as a general in charge of coordinating the nation's aviation strategy and doctrine. It would be too little too late as the entrenched Italian bureaucracy was unwilling to enact his plans and he resigned in protest in June 1918. With the Armistice in November of that year ending the First World War, Douhet's trial verdict was reversed and he was promoted, but by this point in his life he had lost faith in the Italian government and refused to return to duty. During the interwar period he traveled Europe visiting other nation's air arms, consulting with air officers and meeting with aircraft designers. In 1921 he wrote his landmark work Command of the Air which advocated an relentless air campaign of bombing an enemy's population and production centers, reducing their moral and material means of resistance. Properly conducted, he reasoned, such an air assault could force a quick decision and save millions of lives in the long run by avoiding a costly ground war. Douhet also pointed out that the efficient and proper means of carrying out such an air campaign would require an independent air arm led by an aviation-minded general staff. At the time, this was a revolutionary concept and only in Great Britain was the nascent Royal Air Force an independent air arm. For other industrialized nations of the 1920s, their air arms were subordinated to the army. 

Billy Mitchell, USAAC
Reception of Douhet's work outside of Italy was mixed. It wasn't even required reading at the RAF Staff College. But his work would find converts primarily in the United States- at the time the Air Force was part of the Army as the US Army Air Corps. One officer in particular would even meet with Douhet- Brigadier General Billy Mitchell. It was the year after Mitchell had demonstrated the vulnerability of warships to bombers by sinking several captured German warships off the Virginia coast. Mitchell had copies of Command of the Air sent to his superiors and he got banished to Hawaii and then Asia as a result. In 1925 Mitchell wrote a book of his own, Winged Defense, in which he refined Douhet's ideas of a strategic air campaign further and even declared the battleship obsolete as aviation technology matured. As a result, Mitchell was demoted in rank back to colonel. He would later be court-martialed for publicly criticizing the US military following the crash of the airship USS Shenendoah in a storm. But his six week court martial provided Mitchell the perfect forum for advocating views shaped by his mentor, Giulio Douhet. 
Sir Hugh Trenchard, RAF

Douhet died of a heart attack in 1930 and Mitchell himself would die in 1936, neither man living to see how their views of air power would come to fruition in the Second World War. While Command of the Air got little attention in the Royal Air Force, the most influential individual in the RAF at the time fortunately was a proponent of Douhet's theories- Sir Hugh Trenchard, Chief of Staff of the RAF and the man known as the "Father of the RAF". Trenchard, like Mitchell, would refine Douhet's ideas. By the time of the Second World War, Trenchard was every bit the irritant to the establishment as Douhet and Mitchell were, but had enough influence to avoid their fate. Following the disastrous loss of Norway to the Germans in 1940, Trenchard used his position in the House of Lords to criticize Prime Minster Neville Chamberlain's prosecution of the war which contributed to his replacement by Winston Churchill. Trenchard used in influence to put like minded officers in key positions in the Royal Air Force. After the war, Trenchard advised General Henry "Hap" Arnold in his own push for an independent United States Air Force.

The same year Mitchell died in 1936, contracts were issued to both Boeing and Douglas for a large four-engined bomber- while both companies' designs, the XB-15 and the XB-19, respectively, remained experimental, the engineering and design work on such a unprecedentedly large bomber would shape aviation technology throughout the Second World War. 

Source:  Whirlwind: The Air War Against Japan, 1942-1945 by Barrett Tillman. Simon and Schuster, 2010, p9-16.

04 October 2015

Birth of a Breed: The Development of the Douglas DC-1

The Douglas DC-1 at its 1933 handover to TWA
(San Diego Air and Space Museum Archives)
The crash of a TWA (Transcontinental & Western Air) Flight 599 on 31 March 1931 served as a major catalyst in the airline industry for adoption of all-metal aircraft. The Fokker F.10 was on a scheduled flight from Kansas City to Los Angeles when it encountered turbulence on its first leg between Kansas City and Wichita. As the Fokker F.10 airline had wings of wood laminate, accumulated moisture had caused a weakening of the glue used which led to delamination and structural failure. Aboard Flight 599 was the famed Notre Dame head football coach Knute Rockne, who along with five other passengers and two crew, were lost in the crash when the aircraft went down between the rural Kansas towns of Bazaar and Matfield Green. As a result of the crash, the Bureau of Air Commerce required operators of aircraft with wood wing structures to undergo frequent inspections- as this was economically unfeasible for most operators, all-metal designs were procured as soon as possible. TWA nearly shut down for good while its Fokker fleet was grounded for  inspections. Most of the types that were procured were interim types- but in 8 February 1933, a new airliner made its first flight that was a quantum leap over anything that had proceeded it, and that was the Boeing 247 which entered service with United Air Lines just fifty days later. All metal with a retractable undercarriage, the Boeing 247 was sleek and much faster than anything that had flown passenger services up to that point. Even the most current designs were instantly obsolete- for example, the Curtiss Condor biplane airliner had entered service with Eastern Air Lines and American Airlines just five weeks before United put its Boeing 247s into service. 

United's main rival on the transcontinental market was TWA- the Boeing 247 could now make the east to west transcontinental run in only 21 hours 30 minutes including technical stops. By comparison, TWA's Fokkers took 28 hours 43 minutes to fly from New York to Los Angeles. When TWA learned of United's order for the Boeing 247, he contacted Boeing about ordering the aircraft for TWA, but at the time, United and Boeing were part of the same holding company, United Aircraft and Transport Corporation and Boeing was contractually bound to deliver 60 Boeing 247s to United before it could supply airframes to other customers. TWA's vice president for operations, Jack Frye, wasted little time in sending a letter to other aircraft manufacturers soliciting interest in building at least 60 three-engined airliners for the airline. That letter went to Consolidated Aircraft, Curtiss-Wright, Douglas Aircraft, General Aviation Manufacturing, Stout (Ford) Aircraft, and Glenn Martin Aircraft. The letter included general performance specifications that any design had to meet: 

Jack Frye of TWA

1. All metal, trimotor preferred, combination structures and biplane would be considered, but the internal structure had to be metal. 
2. Thee engines of 500-550 hp. 
3. Maximum gross weight of 14,200 lbs. 
4. Weight allowance for radio and mail carriage of 350 lbs. 
5. Weight allowance for full instrumentation, including night flying, fuel to fly 1,080 miles at 150 mph, crew of two, at least 12 passengers in comfort. Payload had to be at least 2,500 lbs with full equipment and fuel for maximum range. 
6. Minimum top speed of 185 mph, cruising speed at least 146 mph. Landing speed not to exceed 65 mph, rate of climb at least 1,200 feet/min, minimum service ceiling of 21,000 feet and a minimum service ceiling with one engine out of 10,000 feet. 

The specifications page also emphasized that any design, fully loaded, "must make satisfactory take-offs under good control at any TWA airport on any combination of two engines." This landmark letter from Jack Frye is considered the "birth certificate" of the DC-1. When Donald Douglas received the letter in Santa Monica, he immediately convened a meeting with his top heads- James "Dutch" Kindelberger (of P-51 Mustang fame) who was his chief engineer, Arthur Raymond who was the deputy to Kindelberger, and Harry Wetzel, the Douglas Santa Monica plant director. With the United States in the midst of the Great Depression, it didn't take long for them to decide this was a tremendous business opportunity for the company. Just ten days after Jack Frye sent his letter of proposal, Douglas dispatched Arthur Raymond and Harry Wetzel with a ten-person team by transcontinental train to New York to meet with TWA. The Douglas team by this point had moved quickly and concluded that even though TWA was leaning towards a three engined design, they would offer a twin engined design that would be equal if not superior to TWA's specifications. The design would be an all-metal monoplane with a retractable undercarriage that would have passenger comfort as a priority. With Kindelberger supervising the design work in California and telephoning design details to Raymond and Wetzel as they were enroute to New York, the design was refined as the team prepared for its presentation to the TWA evaluation team which consisted of Jack Frye, Richard Robbins, president of TWA, and Charles Lindbergh, the airline's technical consultant. Also present were the teams from four other aircraft manufacturers, all of whom tendered three-engined designs. 

Having prior flying experience with other Douglas designs, Frye was favorable to the Douglas proposal, but Lindbergh had his doubts that a twin engined design could meet the airline's stringent specifications. Lindbergh in particular was concerned about single-engined performance at TWA's hot and high airports in the southwestern United States. The Douglas team in consultation with the engineerings staff in California rechecked their calculations repeatedly to be sure that their design could take off with a single engine from any of TWA's airports. With considerable trepidation, Douglas instructed his team meeting with TWA that he would agree to a contract provision guaranteeing this particular specification to satisfy Lindbergh's concerns. On 20 September 1932, TWA signed a contract for the first Douglas DC-1 for $125,000 (about $2 million of today's dollars) with options for 60 more aircraft based on the flight tests and performance of the DC-1. As an insurance policy against a possible failure of the DC-1, General Motors, which owned TWA, had its General Aviation Manufacturing subsidiary work on the GA-38X which was a three-engined larger derivative of the smaller single engined GA-43 airliner. Construction had started on the prototype, but work ceased early on when it became clear the DC-1 would be successful. 

Arthur E. Raymond, chief designer for the Douglas DC-1
(General Aviation News)
With a signed contract in hand, Donald Douglas assigned Arthur Raymond as the DC-1 project manager. Assisting him would be the legendary Jack Northrop, who was at the time managing the Douglas El Segundo division and would be managing the structural design of the DC-1. Other able Douglas engineers were put in charge of various systems and components for the DC-1. In addition and a first for a transport aircraft, extensive wind tunnel testing at Cal Tech's facilities in Pasadena, California, would be an integral part of the design and development process. Cal Tech's aeronautical faculty would head this effort to uncover as many issues as possible before any metal got cut for the prototype- it was wind tunnel testing that found the planned wing design was unstable and further wind tunnel testing at Cal Tech showed that sweeping the wing leading edge back addressed the stability issue. This was how the DC-1 and later DC-2 and DC-3 got their unique wing shape. 

With passenger comfort a priority, it was decided that the benchmark would be the interior noise of a Pullman rail car. The DC-1 cabin had to have the same level of noise or less. As the design effort proceeded, the early specifications for the Boeing 247 were published in Popular Mechanics and Arthur Raymond had copies of the article posted everywhere with the admonition "Do Better than Boeing!" It was vital at every step of the design process that the DC-1 be more comfortable than the Boeing 247 and an important design step was Northrop's wing design that would fit at the bottom of the fuselage without intruding into the cabin as was the case with the Boeing 247. Northrop's wing center section was relatively flat with the engine nacelles at the ends, outboard of which the outer wing panels were attached with the needed dihedral for stability. In a unique feature of the day, the passenger seats could also be reclined. Heating, ventilation, and the aforementioned soundproofing efforts were as considerable as any aircraft system to meet Douglas's desire for the DC-1 to be comfortable. The aisle width was a then-generous 16 inches (Americans in those days were nowhere near as obese as they are now) with a cabin height of 6 feet 4 inches. This would lay down the reputation of Douglas aircraft for years to come to be considered passenger-friendly.

Note the faired struts ahead of the wings on the DC-1
(San Diego Air and Space Museum Archives)
Both the Pratt and Whitney 9-cylinder R-1690 Hornet radial engine and the Wright 9-cylinder R-1820 Cyclone radial engine were evaluated with the Douglas team selecting the Hornet as the DC-1's power plant. Fixed pitch metal propellers were to be used for the prototype. Developments of both engines would figure prominently in American aircraft of the Second World War- the Cyclone would be progressively developed into larger versions that would power the B-17 Flying Fortress, the TBF Avenger, the B-25 Mitchell and in its ultimate development, the B-29 Superfortress and Lockheed Constellation. The Pratt and Whitney Hornet radial engine was a modest success but was developed into a twin row radial as the Twin Wasp which would be used on the DC-3 which in turn was developed into the outstanding Double Wasp and Wasp Major engines. The engine development is of course a future topic here at Tails Through Time! The engines of the DC-1 were one of the first transport aircraft to use the NACA cowling which streamlined radial engines by as much as 60%. When the prototype was rolled out in the summer of 1933, there were also faired struts that connected the forward fuselage with the engine nacelles ahead of the wings- in the prototype these carried sensor cables from the engines for test instrumentation but were later removed. 

On 9 April 1934, Dutch Kingleberger and Arthur Raymond filed for Patent No. 94,427 "Design for an Airplane" which described the layout and configuration of the DC-1 and later DC-2 development. Despite the patent's rather sparse documentation, it was issued by the US Patent Office in the following year. 

On 1 July 1933, the DC-1 would make its first flight as the birth of the Douglas breed of airliners. The story of the flight test program and service history of the DC-1 will be the subject of a subsequent article here, but it should be noted that in 1918, a very young Donald Douglas was working for Glenn L. Martin where he designed bombers for Martin but it was a transport derivative of his bomber designs that fascinated Douglas- the GMT or Glenn Martin Transport was a 15 seat aircraft that had a fully enclosed cockpit. Only one was built and it was destroyed in an accident in March 1920. The GMT was the first Douglas-designed transport and it was where Donald Douglas resolved that his dream was to design and build an aircraft that whose sole purpose was to carry passengers in comfort. That was in 1919-1920, the DC-1 when it made its maiden flight in 1933 was just the start of Donald Douglas's dreams coming true. 

Source: Douglas Propliners: Skyleaders, DC-1 to DC-7 by Rene J. Francillon. Haynes Publishing, 2011, pp 9-11, 46-53.