27 February 2010

Long before the Cirrus SR22 series of composite aircraft flew, and even long before the composite Beech Starship flew, there was a general aviation aircraft that was made of all glassfiber plastics in an effort to make an affordable two-seat training aircraft that was easy to build. In mid-1958, Piper Aircraft started development of the PA-29 Papoose with the intent of putting an aircraft to market that would cost substantially less to build than other comparable types that used standard construction techniques and materials.

The Papoose was to be made entirely of a honeycomb sandwich material with the top and bottom layers made of 0.79mm glassfiber cloth surrounding a 9.5mm core of paper honeycomb and the sandwich was formed in high-temperature epoxy plastic moulds. As parts and airframe components could be pre-moulded, the entire Papoose airframe had just over 100 parts. The engine used was a 108-horsepower four-cylinder Lycoming engine. Flight trials started in 1963 but details are limited and the difficulty in reliably reproducing the composite components led to Piper abandoning the Papoose project and the sole prototype is now on display in the Piper Aviation Museum in Lock Haven, Pennsylvania.

Now be honest. You were entertained by saying to yourself "Piper Papoose Plastic Plane now in Pennsylvania." I know I did.

Source: Air Enthusiast, Volume 5, Number 3 (September 1973), "Plane Facts" by William Green, managing editor, Gordon Swanborough, editor. Pilot Press Ltd, 1973, p147.

26 February 2010

One year before Boeing announced the go-ahead of the Boeing 727 program on 5 December 1960, there were serious reservations within the manufacturer about whether or not to proceed with the 727. At the time Boeing's commercial division was still quite a bit smaller than the military aircraft division and the company's desire to have wide customer base resulted in numerous variations in the Boeing 707/720 family that stretched the company's resources to the point that for every 707 delivered, Boeing was taking a $1 million loss. At this point, the De Havilland in Britain was about a year ahead of Boeing on work on its own trijet, the DH.121 Trident which was designed to broadly meet a similar set of specifications as that of the 727.

De Havilland saved itself a lot of time as it was specified from the start to have three engines while Boeing's design studies alternated between four and two-engined designs before settling on three engines. Before a T-tail design was settled upon for the 727, a group of Boeing engineers visited De Havilland's Hatfield factory to review the progress on the Trident and the visit was reciprocated shortly afterwards when a group of engineers from De Havilland visited Boeing's Seattle facilities to review the progress on the 727. At this point, the British firm suggested an Anglo-American alliance with Boeing building the Trident under license and worldwide sales markets divided between the American Trident team and the British Trident team. De Havilland would have a bigger customer base and lower unit price for its Trident design and Boeing wouldn't have to commit what was estimated to be $100 million to get the 727 program to completion of the prototypes and first flight.

As surprising as it may sound today, Boeing was very unsure of itself in the commercial market and the De Havilland proposal offered a low-risk way of getting into the short-haul market and there was a considerable amount of convergence in the two designs. However, Boeing wanted the capability to operate from a 5,000 foot runway, a specification that didn't factor into the Trident design (as a matter of fact, the Trident's early versions had a reputation amongst pilots as "ground grippers"). The two teams then looked at the possibility of putting the 727's high lift wing on the Trident, but the costs of the engineering required were identical to that of proceeding with the 727 program. The proposal for the alliance quietly died and to many at De Havilland came as no surprise.

When the 727 was rolled out, there were accusations in the British press that it was copied from the Trident, but De Havilland's engineers were adamant in interviews in dismissing the furor and reminded a skeptical public that Boeing did have first-class wind tunnel facilities and some of the finest aerodynamicists and engineers in the world would would have arrived naturally at some of the conclusions that resulted in the layout of both aircraft!

Source: Boeing 727 (Modern Civil Aircraft:13) by Peter Gilchrist. Ian Allan Press, 1996, p7-16.

25 February 2010

Several weeks after the disastrous Munich Pact was signed in 1938, the British Air Ministry initiated a massive expansion of the Royal Air Force in anticipation of the coming war. As the planned expansion was beyond the capacity of British aircraft factories at the time, the Air Ministry also looked abroad at foreign sources of aircraft to meet the needs of an expanding RAF. In January 1939, Air Ministry representatives visited the Caproni factory in Milan, Italy to examine the Caproni Ca 310 light twin which had potential as a crew trainer. Surprisingly, in light of the European tensions at the time, the visit by the British was officially sanctioned by the Italian government.

Though no contracts were signed, the interest was significant as high-ranking officials with the Air Ministry visited Caproni again in December of that year (and I should note that the Second World War had already started in September 1939 but Italy had yet to declare war on the Allies) and informed Count Caproni himself that the RAF wished to acquire 200 Ca 310s and a further 300 examples of a more powerful derivative under development, the Ca 313. The French had already placed orders for 200 Ca 313s in September 1939.

In January 1940, an Italian delegation from Caproni arrived at the Air Ministry's headquarters in England to finalize the purchase of the Caproni twins. The RAF submitted a series of changes they wanted on their aircraft and in exchange, RAF representatives were dispatched to the Caproni factory to oversee the RAF-specific modifications. The purchase was confirmed by the end of that month and the aircraft were to be partially-completed in Milan and then shipped to France where the RAF operated out of the airfield at Istres. At Istres the Caproni aircraft would be completed, flight tested, and flown to the UK.

If things weren't surreal already with this deal, the Italian government notified the Nazis that Caproni had a sizeable order on the books with the French and British and if there were any objections in light of the close relationship between Mussolini and Hitler. Surprisingly, the Germans in March 1940 indicated that they had no objections to the deal! However, a month later the Germans indicated that the contracts should be canceled. Count Caproni himself met with the heads of the Air Ministry and arranged for the aircraft ordered to be "completed" by Caproni's subsidiary in Portugal and the UK would then "buy" the aircraft from Portugal instead of the Italians.

However, on 10 June 1940, with France near defeat, Italy declared war on Great Britain which effectively canceled what at the time was the largest aircraft contract ever received by the Italian aircraft industry. It proved to be fortuitous for the Royal Air Force, though. Sweden did take delivery of a substantial number of the Caproni Ca 310/313s and found them to have unreliable engines and poor build quality. The fuel lines to the engines ran right next to the exhaust stacks for the engines which resulted in the Caproni twin having a reputation for being highly flammable. After local modifications to hold the aircraft over until replaced by Saab designs, the Caproni twin was quite robust, but nearly fifty Flygvapen personnel lost their lives in accidents due to the technical deficiencies of the Ca 310/313.

Source: Air Enthusiast, Volume One, William Green, managing editor, Gordon Swanborough, editor. Pilot Press Ltd, 1971, p95-99.

22 February 2010

Tabasco/Purple Flash: Sensor Pods Delivered by U-2 Spyplanes

Last month I had posted about Steel Eagle, a modern-day counterpart to the Igloo White acoustic/seismic sensors dropped on the Ho Chi Minh Trail during the Vietnam War. The use of such remote-sensing pods that embedded themselves in the ground after being dropped by an aircraft weren't just limited to tactical use- a similar program was under taken in the 1960s called Tabasco (the unclassfied project name was Purple Flash) to drop sensor pods from Lockheed U-2 spyplanes flying some of the longest range flights in the aircraft's history over the Chinese nuclear tests sites at Lop Nor, deep in the desert basins of northwest China.

Corona satellite imagery detailed the Lop Nor installation ever since the first Chinese nuclear detonation in 1964 caught Western scientists off guard. The Department of Energy's Sandia Labs in Albuquerque had been working on adapting US seismic equipment used to analyze nuclear tests in Nevada to fit into the air-dropped pods that weighed 285 lbs. The pods were carried under the U-2 wing and a parachute deployed after the drop to slow the pod just enough to not damage the sensors but allow the spike-shaped pod to embed itself in the ground. Once on the ground, a 10-foot telescopic antenna deployed to transmit data to listening posts on the periphery of the People's Republic of China.

On 29 April 1966 the first prototype pod was dropped over the White Sands Missile Range from a U-2 and landed only 800 feet from the target but the sensors were damaged. While the design was being reworked by Sandia, Lockheed and the CIA embarked on a series of long-range flights to see just how much range they could get out of the U-2 to demonstrate the Lop Nor site could be reached from Takhili AB in Thailand.

By 1967 Taiwanese pilots with the RoCAF were training in the United States for the Tabasco flights. On 7 May 1967 the first operational Tabasco mission successfully dropped two sensor pods at Lop Nor, but for whatever reason, no signal was received from them. Another Chinese nuclear test took place that June while the CIA was still trying to interrogate the sensor pods in the desert. Needless to say, it was frustrating for intelligence officials. It was concluded the only way to know for sure was to send another U-2 flight to Lop Nor carrying interrogation equipment to try and activate the pods. On 31 August 1967 another RoCAF pilot took a U-2 to Lop Nor and was nearly ambushed by a salvo of SAMs but no signal was received from the pods.

After two high-risk flights, a second set of Tabasco pods were dropped at Lop Nor, this time by a Lockheed C-130 flown by Taiwanese pilots flying at low level. The outcome of that mission remains classified. After the second Lop Nor mission, the six year program of overflights of the People's Republic of China by the Taiwanese pilots of the "Black Cat" squadron came to an end as improved defenses made further flights too risky.

Source: 50 Years of the U-2: The Complete Illustrated History of the "Dragon Lady" by Chris Pocock. Schiffer Publishing, 2005, p246-252.

21 February 2010

While most nations that had used assault gliders operationally in the Second World War had already abandoned the concept with the end of the war, development continued in the Soviet Union on gliders not only for combat assault, but also for use internally for the delivery of cargo to inaccessible areas of the country. In 1947, the Soviet Air Force issued a specification for an assault glider for use by the Aviation of the Airborne Troops that could transport over 3.5 tons of cargo. Both OKB Yakovlev and OKB Ilyushin were selected to build prototypes- Ilyushin instructed to develop an all-metal design (the Il-32 and was generally unsatisfactory) and Yakovlev's design was to be all-wood and became the second use of the designation Yak-14 (the first Yak-14 was the original designation of the Yak-10 light liason aircraft and was one of the reasons the NATO code name system was created to avoid confusion).

The Yak-14 had a wooden structure with fabric skinning with a hinged nose section as well as a hinged tail section, both of which could be swung to one side to allow straight-through loading and unloading to a square-section cabin with a floor strong enough to carry tracked vehicles. The cockpit was curiously offset to one side and was above the cabin and the high-mounted wing. Up to 35 fully-equipped troops could be carried.

Flight testing of the Yak-14 began in 1948 with the planned tow aircraft either a Tupolev Tu-2 light bomber or a Ilyushin Il-14 transport. In March 1954 four Yak-14s were used to deliver heavy equipment to a research station on an ice floe in the Arctic Ocean, becoming the first glider to overfly the North Pole in the process.

With the arrival of twin- and four-turboprop transports from Antonov in the late 1950s, the Yak-14s were phased out as the last assault gliders in operational use. Approximately 413 were constructed and assigned the NATO code name "Mare".

Source: Air Enthusiast, Volume Two, Gordon Swanborough, editor. Pilot Press Ltd, p134, 163, and 252-253.

20 February 2010

Scandanavian Airlines System Pioneers Polar Commercial Routes

Only seven weeks after being established on 1 August 1946, Scandinavian Airlines System (SAS) inaugurated its first long-haul services across the Atlantic with Douglas DC-4s from Stockholm to New York La Guardia via Copenhagen, Prestwick, and Gander for a flying time of 25 hours. The New York services quickly become profitable for SAS and despite an expansion of its international network to South America and Asia in the years that followed, the US market remained SAS's most profitable overseas destination. Wishing to expand its network to the US West Coast (San Francisco and Los Angeles), SAS didn't want to put its DC-4s on a long transcontinental run across the United States after a trans-Atlantic crossing.

Route planners decided the best "short cut" was a polar flight on the Great Circle Route from Scandinavia to California. But it was 1947 and the most advanced aircraft in the SAS fleet, the Douglas DC-4, didn't have the range. Even more problematic, no airline had ever operated in the polar regions, so in that year SAS set out on a series of trial flights to gain polar operating experience as well as refine polar navigational techniques. Since magnetic compasses didn't work in the regions around the North Magnetic Pole, SAS worked with US avionics manufacturer Bendix to create a precision gyro compass to replace the traditional magnetic compass. During the summer months, the sun would prevent use of a sextant for stellar navigation, so the airline worked with another US avionics company to develop a solar compass that used polarized light to determine the direction of the sun. The airline also developed its own polar charts that laid down a grid over the polar region with the Greenwich meridian as the starting point.

Having created the navigational aids, SAS then set about establishing radio stations across Norway, Greenland and Northern Canada since the only existing radio stations in the region were for military use only. In 1952 sixty trial flights were conducted using the new Douglas DC-6 between Copenhagen and Sondre Stromfjord in Greenland. In December of that year SAS took delivery of its first long-range DC-6B in Long Beach, christened "Arild Viking" and flew it from Long Beach to Copenhagen via Edmonton and Thule. The trip took 28 hours and was the first commercial flight over the Arctic.

With all the pieces in place, all that awaited were route authorities from the United States. The first rights granted were only to Seattle, but persistence on the part of the Los Angeles Chamber of Commerce gained SAS its prized rights to that city. Specially provisioned with Arctic survival equipment, the SAS DC-6B "Helge Viking" departed Copenhagen for Los Angeles on 15 November 1954 via Sondre Stromfjord and Winnipeg. Taking off from Los Angeles and headed in the opposite direction was the DC-6B "Leif Viking".

On 24 February 1957 SAS made its first flight over the North Pole with services between Copenhagen and Tokyo via Anchorage, saving 18 hours and 2,400 miles over previous routings that passed via the Mediterranean and South Asia. That same year, SAS introduced the Douglas DC-7C on its polar routes and the flying time between Copenhagen and Tokyo was cut from 50 hours to 32 hours. By this time, however, SAS's monopoly on the polar routes was over as Canadian Pacific, TWA, Pan American, and BOAC introduced services using the "short cut" over the Arctic region.

Pure jets were introduced by SAS on the polar routes with the Douglas DC-8-33 in 1960, then the DC-8-62 in 1967 and the DC-8-63 in 1968. In 1974, widebody service arrived on SAS polar services with the introduction of the Douglas DC-10. With the liberalization of travel markets, deregulation in the United States, the end of the Cold War (which opened up Russian airspace) and open skies agreements, the polar routes have diminished in importance for SAS but there is still nonstop service between Copenhagen and Tokyo taking only 11 hours.

Source: Aircraft, January 2010, Vol. 43, No. 1. "Polar Pioneers- How SAS pioneered airline services over the inhospitable polar regions" by Roy Allen, p62-66.

19 February 2010

At the time of Project Mercury, the Atlas as a launch system had a reliability rating of 90%, while acceptable for a weapons system, was unsuitable for a manned rocket launch vehicle. As a result, a whole series of initiatives under the umbrella of what was called the Pilot Safety Program was put into place to improve not just the reliability of the Atlas rocket for Project Mercury, but also to improve its safety. The most visible of the resulting efforts as the escape tower on the Mercury spacecraft that could pull it away from the Atlas in case of a malfunction.

But from the production floor at Convair-San Diego to the launch pad at Cape Canaveral in Florida, steps were taken with the Atlas rocket wherever possible to provide what would later be called a "man-rating" for the vehicle. As every possible malfunction couldn't be prevented or accounted for without unreasonable cost, Convair created the ASIS system- Abort Sensing and Implementation System. In short, ASIS was a collection of sensors placed at key points and components of the Atlas rocket. A malfunction detected by any of the ASIS sensors could trigger the escape tower that would pull the Mercury spacecraft clear of the Atlas. It was estimated that 1/3 of the cost of the Mercury-Atlas vehicle was invested in ASIS. In addition, redundancy had to built into ASIS to prevent any malfunctions of the safety system itself.

Part of ASIS was a key ability for the astronaut to trigger the abort should there be a failure of any sort that didn't trigger the system. There was a switch on the instrument panel of the Mercury spacecraft that if flipped by the astronaut, would trigger the rockets of the escape tower and pull the spacecraft away from the booster. The engineers nicknamed it the "Chicken Switch" and Convair management was adamant that it not be referred to as such and in particular with the Mercury astronauts as they feared what it would do to their morale. On their first visit to the Atlas plant in San Diego, the first question from the astronauts was "So what's this Chicken Switch we've been hearing about?"

Source: Atlas- The Ultimate Weapon by Those Who Built It by Chuck Walker with Joel Powell. Apogee Books, 2005, p232-234.

18 February 2010

The First Torpedo Bomber: The Shorts 184 of the First World War

Captain Murray F. Sueter, Director of the Air Department of the Admiralty of the Royal Navy, was one of the most enthusiastic proponents of British naval aviation during the First World War. One of his most passionate causes was championing naval torpedo bombers, though in those days a "proper" torpedo bomber was felt to be a seaplane. Working with the Short Brothers, a large two-seat biplane called the Short Type 184 was produced in significant numbers (650 in all) during the First World War. With a pilot and observer and floats, the 225-horsepower Short 184 was the first reliable torpedo bomber to not only go into production, but to prove itself in combat.

Despite successful tests showing that it was possible to air drop a torpedo against a surface vessel, Captain Sueter's ideas got little support within the Admiralty. However, he was given a chance to prove his theories with the Short 184 during the disastrous Dardenelles Campaign on the Gallipoli Peninsula against Turkey in 1915. Four Short 184s were embarked aboard a converted steam packet to serve as a seaplane tender, arriving on station in the northern Aegean Sea in June 1915.

On 12 August 1915, Flight Commander C.H.K. Edmonds and his observer flew a Short 184 carrying a single torpedo toward the Straits of the Dardanelles. Sighting a Turkish freighter in the Sea of Marmara that was carrying 3,000 Turkish troops to reinforce the Gallipoli Peninsula, Edmonds slowly descended from 800 feet to only 15 feet and closed within 300 feet of the vessel before releasing his torpedo, which struck the troop transport amidships, making the world's first successful combat aerial torpedo attack.

Five days later Edmonds and his observer again sortied in their torpedo-armed Short 184 along with a second Short 184 piloted by Flight Lieutenant G.B. Dacre. Approaching the Turkish coast at low altitude, both aircraft came under ground fire from Turkish gun batteries on the coast. Weaving at low altitude, Edmonds sighted three Turkish merchant ships and homed in on the largest of the three vessels, again descending to near-wavetop height for torpedo release, scoring a direct hit that set the vessel ablaze.

Edmonds' wingman found himself forced down due to an engine failure. While on the water getting his engine re-started, Dacre noticed a Turkish steam tug cross his nose and he fired his torpedo while still sitting in the water. The torpedo hit the tug squarely and sank it immediately. Having finally gotten his engine restarted, Dacre nursed his Short 184 into the air under heavy fire.

Despite this success, the Admiralty remained lukewarm to Sueter's ideas. He had requested a force of 200 torpedo bombers to act in conjunction with the Grand Fleet in the North Sea in action against the German High Seas Fleet, but his ideas were considered too radical and risky for the Royal Navy. Sueter then proposed using the Short 184 to attack the High Seas Fleet at anchor at Wilhelmshaven, but again was rejected. He then proposed an attack on the Austro-Hungarian fleet at its naval bases on the Adriatic- he managed to win over the First Sea Lord, Earl Jellicoe, who approved the deployment of Short 184s to a seaplane base in Italy to attack the Austro-Hungarian fleet at anchor at its main harbor base in Pola.

The attack was to take place on 2 September 1917 but on the eve of the operation a storm arose and the aircraft were unable to depart. The attack was postponed indefinitely and not resurrected before the war ended in 1918 as many in the Royal Navy felt that the seaplanes were better used for scouting and reconnaissance than for attacks on surface vessels.

Source: Ship Strike: The History of Air-to-Sea Weapons Systems by Peter C. Smith. Airlife Publishing, 1998, p9-12.

17 February 2010

With the Martin M-130 flying boat operating on Pan American's prestigious trans-Pacific route between San Francisco and Hong Kong, the airline in 1937 sought out newer and larger equipment to expand the Pacific network. Martin was the incumbent, having built three M-130s for Pan American that were christened "China Clipper", "Philippine Clipper", and "Hawaii Clipper." The M-130 served as the basis for enlarged derivative designated the M-156 which had essentially an M-130 fuselage mated to an enlarged wing with four more powerful radial engines and a twin-fin tailplane mounted on a pylon on the aft fuselage.

In a surprise to many, Pan American rejected the M-156 and instead with the M-156's competitor, the Boeing 314 flying boat. The Boeing 314 was a bigger, faster and more spacious aircraft that easily won the airline's chairman, Juan Trippe, over with comforts that were possible due to its bigger size.

Martin, however, had already been in negotiations with the Soviet Union for the M-156 not just for purchase, but also for license production. The M-156 design was far more advanced in design and capability than what either was in production in the Soviet Union or up for sale by the nations of Western Europe. The contract signed with the Soviet government was for the transfer of production drawings and equipment to allow the Soviets to build their own M-156s for Aeroflot passenger services in the Russian Far East. In December 1937, the M-156 prototype was transferred to the Soviet Union along with a series of production drawings that had to be converted from imperial units to the metric system (which would lead to problems for the Soviets). Rather unusually, though, it was transported by ship to Leningrad rather than being flown across the Atlantic.

Plans were in place, however, to use the M-156 (dubbed "Soviet Clipper" by Martin) as the basis of a long range bomber operated by the naval aviation. A full-scale fuselage mockup was built that incorporated bomb bays and defensive gun turrets. Stalinist purges of the aircraft industry, though, impeded progress on the bomber version of the M-156 but the prototype aircraft by 1940 was already flying passenger services in the Russian Far East for Aeroflot. As the Second World War dragged on, spare parts problems, fuel shortages and accidents cut into the Soviet Clipper's flying hours and by 1944 the aircraft was effectively grounded and is believed to have been scrapped sometime around 1946.

Source: Pan American's Clippers- The Golden Age of Flying Boats by James Troutman. Boston Mills Press, 2007, p49. Supplemental material from www.airwar.ru/enc/cw1/m156.html

16 February 2010

After a series of accidents and maintenance problems with their McDonnell Douglas F-4J Phantoms in the 1973 air show season, the Blue Angels canceled the rest of the season and stood down for an overview of the program by the Secretary of the Navy, John Warner (who would later serve six terms in the US Senate representing the state of Virginia). Warner appointed a panel of six senior flag officers to review the Blue Angels program and they unanimously recommended its continuation as "prime recruiting asset" and the Chief of Naval Operations, Admiral Elmo Zumwalt, wanted a reorganization of the Blue Angels and instituted a review for an aircraft type to replace the F-4s.

Former Blue Angels team leader Captain Ken Wallace, who at the time was in charge of tactical air planning in the CNO's office, was appointed to make recommendations on a new aircraft type for the demonstration team. He preferred the Grumman F-14 Tomcat, which was the Navy's prime fighter aircraft, but the cost of the keeping the aircraft ready for flight demonstrations and maintaining the costly AWG-9 radar and Phoenix missile weapons system flight ready were daunting. At that time the flight control system was also undergoing refinement as well as the fighter was being introduced into service.

The next choice in Wallace's evaluation was the Vought A-7 Corsair II, then the Navy's newest front-line attack aircraft, but they couldn't be spared as they were needed in Southeast Asia even as US involvement in Vietnam was winding down as units replaced older Corsairs and combat losses. This finally led to the selection of the McDonnell Douglas A-4 Skyhawk, specifically the A-4F variant. Approximately 150 A-4Fs were built to stand-in for the A-7 Corsair II in some of the Navy's attack squadrons as there were operational problems in getting the A-7 ready several years earlier. Now that the A-7 was a mature system, the A-4F was in plentiful supply and particularly appealing to the Blue Angels were the 100 F-models that were re-engined with a more powerful version of the J52 engine that boasted 11,200 lbs of thrust compared to 9,300 lbs of the older version of the J52 that most Skyhawks used- this gave the "Super Fox" as the re-engined A-4Fs were called, a near 1:1 thrust to weight ratio, something the Blues never had in a display aircraft.

The Blue Angels' new A-4F mounts had several modifications for air show display:

1. Wing slats were locked into place to prevent asymmetrical slat deployment which would have been disastrous in close formation.
2. Smoke oil tanks added.
3. Modification of internal fuel plumbing to allow an additional 30 seconds of inverted flight time.
4. Horizontal stabilizer altered to allow 3 degrees more of down trim.
5. Modulated stick forces in the pitch axis- one setting for displays and the other for cross-country flying.
6. Stowable crew ladder in what was the left hand gun bay.
7. Removal of the dorsal avionics pod and some of the weapons delivery avionics.
8. A drag chute for use at smaller airports.

The final change was the raise the status of the Blue Angels to that of a full Navy squadron, giving the team leader the same powers and position as a squadron CO. This now meant that the flight surgeon, supply and administrative officers and the public affairs and maintenance teams were no longer loaned to the team.

The Skyhawks debuted in the 1974 show season and flew for the Blue Angels until 1987 when they were replaced by the McDonnell Douglas F/A-18 Hornet.

Source: Wings of Fame, Volume 8. Aerospace Publishing, 1997. "Blue Angels" by Harry S. Gann, p14-18.

15 February 2010

The Politics Behind the French Stratotanker Purchase

On 13 February 1960 France exploded its first thermonuclear weapon, a 60-kiloton device in the Algerian desert, making France the fourth member of nuclear-capable powers. In December of that year, President Charles De Gaulle formally announced his intentions to establish an autonomous nuclear strike force independent of US control based on the Dassault Mirage IV supersonic strike bomber which had made its first flight the year prior.

But the Mirage IV lacked the range to reach targets in the Western Soviet Union and defense planners in the Armee de l'Air (AdA- French Air Force) wanted to acquire an aerial tanker that could launch at a moment's notice with the Mirage IV force, refuel the bombers at high speed and high altitude, and offload fuel quickly to the Mirages. Only the Boeing KC-135 Stratotanker met these stringent requirements and negotiations began to purchase 10 KC-135As- 9 tankers for every four Mirage IV in the Force de Frappe (Strike Force) plus one spare. However, with the 1960 election of John F. Kennedy came a change in US nuclear strategic doctrine from massive retaliation to one of flexible response- to the new US president, his Secretary of Defense Robert McNamara, and his Secretary of State, Dean Rusk, an autonomous French nuclear deterrent would undermine the new strategic doctrine and increase the chance of premature use of nuclear weapons without American oversight.

The sale of the KC-135 to France was seen as equal to nuclear proliferation as the tankers were necessary for the Force de Frappe to reach Soviet targets. By 1962 France increased its Mirage IV force to 50 aircraft and wanted more than just 10 tankers which were agreed on principle by military officials in the US Defense Department. President Kennedy, however, vetoed the sale and even announced at a press conference that the tanker sale was a dead issue. On that very same day, however, the Deputy Secretary of Defense Roswell Gilpatrick approved the sale of 12 KC-135s to be designated C-135FR (ostensibly to hide their purpose as tankers for the Force de Frappe).

Two weeks later at a commencement address at the University of Michigan at Ann Arbor, Defense Secretary McNamara reiterated official US policy of opposing any aid that allowed an independent French nuclear deterrent. Despite this, a month later, both McNamara himself and Secretary of State Dean Rusk signed off on the tanker sale worth $50 million. At the time the sale was rationalized as an offset for American gold losses to France and concern by the US Treasury Department about foreign accumulation of gold. However, with the end of the Cold War, declassified documents show the sale was undertaken quietly in an effort to improve strained relations between France and the United States.

The first AdA C-135FRs arrived in France at Istres in 1964 following completion of KC-135 crew training by the French at Castle AFB in California. The last C-135FR arrived in October of that year which coincided with the Force de Frappe's first operational Mirage IV nuclear alert. Initial Mirage IV operations included a 24-hour airborne alert of Mirage IV bombers supported by the C-135FRs, but these were ended in 1967 as they could not be afforded by France unlike the US Strategic Air Command's "Chrome Dome" airborne alert.

In 1966, President De Gaulle went ahead and pulled France out of NATO's military command, an action that was only reversed in March of 2009 when President Nicholas Sarkozy signed a decree supported by the French legislature re-integrating France into NATO.

Source: Boeing KC-135 Stratotanker- More Than Just A Tanker by Robert S. Hopkins III. Aerofax, 1997, p73-75.

14 February 2010

When Colonel William J. Donovan formed the Office of Strategic Services (OSS), the CIA's antecedent organization in World War II, one of his first acts was to create a research and development branch headed by noted chemist Dr. Stanley Lovell. Lovell's R&D section of the OSS was composed of engineers, chemists and other technical professions he recruited from American industry and academia. Their purpose was to develop the tools and weapons not just for espionage but for unconventional warfare and weaponry.

One of the projects the OSS examined was suggested by a civilian dentist, Lytle Adams. Project X-Ray sprang from Adams' suggestion that small incendiary device could be attached to a bat. These bats would be released over Japan and the bats would roost in inaccessible places on buildings that were predominantly of wood construction. After a time-delay, the incendiary would go off, and fires would break out all over Japanese cities.

Louis Frieser, the inventor of napalm, created a one ounce timed-delay incendiary that was attached to the Mexican free-tailed bat, a prolific bat species found throughout the American Southwest. The bat bomb itself had forty trays, each holding 26 bats. Dropped from at least 5,000 feet, the bomb descended by parachute before the casing opened at 1,000 feet, dispersing the bats. By dropping the bombs at dawn, the bats would instinctively seek shelter in buildings. It was estimated that 10 Consolidated B-24 Liberators each carrying 100 bat bombs staging from Alaska could release over 1 million bats over the industrial cities around Tokyo and Osaka.

Tests conducted at Carlsbad Army Air Field in New Mexico resulted in the burning down (unintentionally) of several new hangars at the base. Further tests validated the concept but by 1944 the project was canceled it as it wouldn't be ready by 1945.

Source: Spycraft- The Secret History of the CIA's Spytechs, from Communism to Al-Qaeda by Robert Wallace and H. Keith Melton. Plume Books, 2009, 11-13.

13 February 2010

Mohawk Airlines Gets the BAC One-Eleven

When the BAC One-Eleven was developed, it faced competition from two other short-haul twinjets in the form of the Sud-Aviation Caravelle and the Douglas DC-9 Series 10. And further ahead lay Boeing's 737-100/200. BAC's sales team as soon as the One-Eleven was launched wasted no team in getting themselves set up in the United States, keen to follow on the success of the Viscount turboprop in the world's most lucrative air travel market. However, the BAC sales team found opposition not from the airlines, but from a completely different quarter.

Shortly after the launch of the One-Eleven letters of intent came in from local service carriers Ozark Air Lines (five aircraft) and Frontier (six aircraft). However, the US airlines of the day were tightly regulated by the Civil Aeronautics Board which not only set fares and routes, but also administered government subsidies to maintain "competition". The local service carriers of the day were particularly dependent on the government subsidies for what were usually uneconomic short-haul routes to smaller cities. In the case of Frontier and Ozark, the CAB felt that operating pure jets would require increased subsidies and threatened to withdraw financial support. As a result, Ozark and Frontier had to abandon their plans to buy the BAC One-Eleven.

The following year in 1962 Bonanza Air Lines signed a letter of intent for three One-Elevens. This time the CAB refused to guarantee Bonanza's loan and the purchase had to be canceled. When Bonanza was able to later on order the Douglas DC-9 Series 10 (as well as Ozark), accusations of protectionism flew from the British government and press.

Though success came with Braniff's order for six One-Elevens and options on six more (Braniff was much less dependent on government subsidies), the next local service carrier to order the One-Eleven, Mohawk Air Lines, was determined to make a case for operating the jet. When Mohawk ordered four One-Elevens, the CAB again tried to intervene and prevent Mohawk from getting jet equipment. The CAB stated in their denial that Mohawk's Convair twins carried on average 20 passengers and at least 30-35 passengers would be needed on the One-Eleven to operate without an increased subsidy.

Mohawk's president, Robert Peach, wasn't going to accept the CAB's verdict. In a very detailed rebuttal and analysis written by Peach himself, he pointed out that the CAB had just awarded Mohawk route extensions as well as nonstop route authorities between major cities in the Northeast that brought Mohawk in direct competition with the trunk carriers like American and United. Peach argued that modern equipment was needed to compete on these routes and that failure to acquire jets would mean an increase in subsidy would be needed for Mohawk to maintain those very routes.

Peach then detailed the rationale for the One-Eleven purchase, showing that operating the One-Eleven over a 200-mile route would break even at a load factor of 46%, something he pointed out that Mohawk had easily done historically. Mohawk wasn't getting jets for sake of getting jets, Peach concluded, the airline was doing it to meet economic and customer demand for modern aircraft on its route network.

It was one of the rare victories against the CAB that increased Robert Peach's stature amongst the other local service carriers. The CAB conceded and Mohawk operated their first BAC One-Eleven service on 15 July 1965 between Utica, New York, and New York City.

Source: BAC One-Eleven by Malcom L. Hill (Crowood Aviation Series). The Crowood Press Ltd, 1999, p25-27.

12 February 2010

The First Serious Proposal for Air Refueling on a Combat Mission

The first serious proposal to use air-to-air refueling in a combat mission came in early 1942 just weeks after the Japanese attack on Pearl Harbor. The United States wanted to strike back as expeditiously possible at Japan and early efforts focused on the US Army Air Corps inviting the British firm Flight Refueling Ltd to send some engineering staff to Wright Field in Dayton, Ohio, to discuss converting the Consolidated B-24 Liberator into a tanker and the Boeing B-17 Flying Fortress into a receiver aircraft. The USAAC (soon to become the US Army Air Forces) ordered on set of inflight refueling equipment similar to what Flight Refueling used in its 1939 trans-Atlantic trials.

With the assistance of Flight Refueling engineers, Pennsylvania Central Airlines modified a B-24 and a B-17 with the refueling equipment (PCA would later be renamed Capital Air Lines which was then absorbed by United Air Lines in 1961). By April 1943 the first flight trials were conducted at Eglin Field in Florida. By this time, however, the Doolittle raid on Tokyo had already taken place but the USAAF wanted to further examine the feasibility of air refueling in strategic bombing operations.

Using Flight Refueling's grapple method, the B-17 receiver trailed a hauling line with a weight and hook at the end. The B-24 tanker approached from the side and below and deployed a contact line that crossed over the hauling line of the B-17 and engaged the hook. The B-24 tanker then moved above the B-17, pulling in the hauling line with the contact line. The refueling hose was then attached to the hauling line and it was then pulled down to the B-17 which had a refueling receptacle in the tail gunner's position and refueling commenced.

At the conclusion of the tests, the B-17's range with a full bomb load could be extended to 5,800 miles (compared to its standard 2,000 mile range). Plans were conceived to have B-17s based in the Aleutian Islands and strike Japan with air-refueling, proceed on to bases in China and then reverse the process. However, the time needed convert and train sufficient bombers and crews to sustain a strategic bombing campaign on Japan were seen as too long with Boeing getting ready to produce the B-29 Superfortress and Admiral Nimitz's successes in the Central Pacific in securing possible islands to use as bomber bases.

Source: History of Air-to-Air Refueling by Richard M. Tanner, MBE. Pen & Sword Books, 2006, p24.

11 February 2010

The original Navy contract with Douglas for the D-558 high-speed research program specified six turbojet-powered aircraft of various configurations centered on a straight wing design. It was amended in January 1947 to come in two parts- Phase I was for three turbojet-powered straight wing aircraft (which became the D-558-1 Skystreak) and three turbojet/rocket-powered swept-wing aircraft for Phase II, which became the D-558-2 Skyrocket. Although the Skyrocket did set records, the main emphasis of the Phase II program was data collection as opposed to chasing records.

One of the major areas of study in the Phase II program using the Skyrocket would be drag reduction. With a new generation of supersonic aircraft already taking shape on the drawing boards of aircraft companies, the bulky and boxy shapes of the external stores like bombs and fuel tanks of the Second World War generation still in use needed an overhaul lest they negate the high performance of the aircraft to come. Legendary Douglas Aircraft designer Ed Heinemann and his engineers set about developing a new aerodynamic shape for external stores that would be flight tested on the D-558-2 Skyrocket's wing pylons. In addition, Heinemann was tasked to develop a data set on the optimum shapes for external pylons.

The two basic shapes were very similar in profile to the fuselage of the Skyrocket- the first shape was an external tank that was 180 inches in length and could hold 150 gallons of fuel. The second shape was a general-purpose bomb that was 120 inches long and weighed 1,000 lbs. Both shapes were extensively flight tested on Skyrocket number three, validating Heinemann's calculations on drag reduction. The pylon shape was also tested, both with and without the stores on the Skyrocket.

The flight tests were so successful that the layout of the external tank formed the basis of a whole family of external tanks of different sizes used by US military and the 1,000 bomb became the now-common Mark 80 series of bombs that over the years have permutated into different variations from the Snakeye air-retarded bomb to the Paveway series laser-guided bombs and the GPS-guided JDAM munitions.

Interestingly, the shape and size of the external tank tested on the Skyrocket was very similar to that of the Mk-7 nuclear bomb. Sandia National Laboratories, the developer of that nuclear store, followed the Skyrocket external stores tests very closely.

Source: Skystreak, Skyrocket, and Stiletto: Douglas High-Speed X-Planes by Scott Libis. Specialty Press, 2005, p78-80.

10 February 2010

In an earlier entry I had featured the RB-69 spyplane conversion of the Lockheed P2V Neptune that was the Skunk Work's first CIA contract. That CIA program to operate low-altitude overflights of the People's Republic of China starting in 1957 was codenamed ST/POLLY by the CIA. The program had generated much useful intelligence on the military activities of the the PRC that the CIA contracted with E-Systems of Greenville, Texas, to convert three Lockheed P-3A Orions to a similar configuration but with more intelligence-gathering systems under the codename ST/SPIN, starting with the arrival of the first P-3A to the naval aviation depot in Alameda, California where E-Systems began the conversion work.

The most obvious modification (apart from its all black color and abbreviated tail sting as the MAD sensor wasn't needed on the clandestine overflights) was a widening of the crew entry door on the aft fuselage with a duplicate door right next to the existing door- this gave a just over six foot wide entry with two inward-opening doors- like the earlier RB-69 Neptunes, this was to allow the infiltration of field agents, special equipment, arms and ammunition and on occasion, propaganda leaflets by the boxload.

The ELINT receivers from the RB-69 Neptunes were taken out, upgraded, and installed on the ST/SPIN Orions. Additional sensors were added thanks to the increased performance of the Orion over the Neptune- a SLAR was added for peripheral reconnaissance missions along the Chinese border, communications intercept equipment, an infrared detector and allegedly even a sensitive acoustic detector. Slant-range and oblique photography cameras were also installed and to also perform intelligence on the Chinese nuclear program, air-sampling equipment was also installed connected to ram air scoops near the cockpit.

The first ST/SPIN operational mission took place in 1964. All the personnel aboard the aircraft were Taiwanese trained and led by the CIA. Missions ranged from gathering radar ELINT data for the Strategic Air Command to even flights into Tibet to gather information on the PRC's suppression of Tibetan nationalists.

However, the Taiwanese general running the program would staff each plane with as many as 27 crew when only 13 to 14 were needed. Taiwanese personnel got a bonus for flying on ST/SPIN missions and he was taking a kickback to assign extra crew to each mission. Operatives of the PRC were able to penetrate the ST/SPIN program to the point that during an ST/SPIN mission, PRC radio operators would call out the aircraft and ask to speak to specific crewman by name.

By 1965 the Taiwanese general was arrested and sent to prison for his staffing scheme and the CIA and NRO (National Reconnaissance Office) withdrew funding from the ST/SPIN program before the third P-3A Orion could be completed. The aircraft were returned to the United States.

Source: Wizards of Langley: Inside the CIA's Directorate of Science and Technology by Jeffrey Richelson. Westview Press, 2002, p96-98.

08 February 2010

In the spring of 1966 the airbases of the Vietnamese People's Air Force (VPAF) were targeted for the first time by American aircraft. Previously considered off-limits by Washington (and later in the war the bases were not allowed to be attacked), the attacks on the MiG airfields at Dong Hoi and Vinh forced a rethink of North Vietnam's air strategy against a numerically superior American military.

To provide rapid repair of the airfields, over 70,000 steel-reinforced concrete plates were stockpiled at the airfields. Large amounts of bamboo stems were also stockpiled to be used in airfield repairs. Camouflaged revetments were created and some were even disguised as huts along with the construction of underground command centers for the base staff. To protect the VPAF's small MiG-17 force, the aircraft were dispersed out into the country side, carried by large Mil Mi-6 helicopters to the dispersal sites and carried back to the airfields when missions were to be flown. Later in the war, fuel and ammunition were also dispersed at these sites as it was found an Mi-6 could carry a fully-fueled and armed MiG-17 to the airfields from as far away as 30 miles. Underground shelters were built into the mountains near the bases where the aircraft were prepared for their missions against incoming American strike packages. An Mi-6 would then carry the fighter as an underslung load to the nearest airbase where it would take off, fly the mission and then return to base to be carried back to the underground shelters miles away by the helicopters.

In areas where the terrain prevented construction of underground shelters for the MiG force, the fighters were dispersed into villages and agricultural co-operatives as well.
Source: Wings of Fame, Volume 8. Aerospace Publishing, 1997. "MiG-17 Over Vietnam" by Zoltan Buza and Istvan Toperczer, p106-107.

07 February 2010

When famed test pilot Alvin "Tex" Johnston came to Boeing just before the first flight of the XB-47 Stratojet prototype, it was on the recommendation of the USAF based on Johnston's prior experience with jet aircraft at Bell and that he had flown just about every aircraft in the Air Force's inventory. He had the nickname "Tex" as he always wore cowboy boots when he flew.

The flight test program of the Stratojet was quite literally exploring uncharted territory as it was the first large jet-powered swept-wing aircraft to fly. It fell to the Boeing test pilots like Tex Johnston to uncover all the aerodynamic pitfalls and report them to the engineers. At times, Johnston could be a constant irritant to the Stratojet engineering team but somehow his observations always seemed on the mark even if he wasn't seeing eye-to-eye with the engineers.

One famous example concerned the discovery that at high speed, the XB-47's nose would start pitching up as the Mach number increased. The oscillations had the potential to throw the Stratojet out of control and into a spin. Many of the test pilots had noted this high-Mach instability, but it took Tex Johnston's larger-than-life personality to get it taken seriously. After a test flight, he informed one of the Boeing engineers, T.A. Wilson (who would later head the B-52 program and eventually lead Boeing through the 70s and 80s), that the vibrations would get severe enough to cause a stall warning. Wilson wanted to know at what point the oscillations began as he wasn't seeing it on the flight data recording equipment printouts.

"I don't see anything that shows me it's a high-Mach stall".
"Goddammit, I felt it!"
"You felt it? Where?"
"Wilson, right in my ass!"

So T.A. Wilson decided to settle it once and for all. He removed the pilot's seat cushion and installed a data recorder right in the seat and had Tex Johnston take the XB-47 back up. Once he landed, Wilson took a look at the data and sure enough, the recorder picked up the signature of the onset of a high-Mach stall.

As the Stratojet approached higher Mach speeds, a forming shockwave from the wing's leading edge disturbed the airflow over the outer wings, causing them to lose lift. The solution was to put a series of vortex generators on the outer wing which energized the airflow over the outer wing and maintained lift at high speeds.

Source: Legend & Legacy: The Story of Boeing and Its People by Robert J. Serling. St. Martin's Press, 1992, p97-98.

06 February 2010

Pan American and the Boeing 314 Toilet Scandal

When Pan American signed a $4.8 million order with Boeing for six Model 314 flying boats with options on an additional six, at the time in the 1930s it was the most expensive airliner sale yet with a cost of $512,000 per flying boat, five times the cost of a Douglas DC-3. Not only did Boeing manage to break into the large transport aircraft market for the first time with as prestigious a customer as Pan American, but the Boeing 314 was a quantum leap on performance and luxury over the previous Martin and Sikorsky models the airline was using on its worldwide network.

The Boeing 314 boasted a 3,500 mile range (with a wing based on that of the Boeing XB-15) with a cruising speed of 183 mph and carried up to 74 passengers in ocean liner luxury. Boeing engineer Wellwood Beall who supervised the Model 314's development, even included a bridal suite and spiral staircase connecting the upper and lower decks of the spacious flying boat. Pan Am chairman Juan Trippe was so enamored with the interior accommodations of the 314 that despite the delays in the program, he refused to invoke the contractual penalty clauses in the contract. Trippe even ignored his most famous technical advisor, Charles Lindbergh, who was unhappy with the Boeing 314's design as he didn't believe Boeing could build commercial aircraft.

But the least-publicized groundbreaking feature (and the one Wellwood Beall was most proud of) was that the Boeing 314 was the first airliner to have flushing toilets. Beall himself was responsible for the design of the flying boat's toilets. When the seat lid was closed, the bowl of the toilet sat inside a rotating drum that turned 180 degrees to upside down which emptied the toilet bowl's contents out a vent into the sea and then righted back up again for the next passenger.

The toilet, however, nearly caused a rift between Wellwood Beall and Andre Priester, a fiery Dutchman who was in charge of Pan American's engineering department. On the inaugural Boeing 314 flight from San Francisco to Honolulu, Beall was an invited guest on board and was asleep in his berth when Priester angrily woke him up to complain that neither of the airliner's two toilets were working. Beall managed to get them working again, but on the return flight to the mainland, the toilets malfunctioned again and this time Beall couldn't get them fixed. Priester was furious and Beall hurried back to Seattle to consult with Boeing's engineers. They were mystified- they'd tested the design for over a year and were confident that it would work flawlessly.

It turned out that the the toilet paper Pan American was using was quilted and thicker than what Boeing used in its tests. The thicker and heavier Pan American toilet paper would clog the system and prevent the drum in the flushing mechanism from rotating. It's said that it was one of the few times in Andre Priester's career that he laughed and admitted he was wrong!

Source: Legend & Legacy: The Story of Boeing and Its People by Robert J. Serling. St. Martin's Press, 1992, p38-41.

04 February 2010

Though notoriously short-legged and cursed with less-than-ideal handling, the Douglas F4D Skyray was famous for its climb performance. In 1958, Marine Corps Maj. Edward N. LeFaivre shattered five world records in the time-to-height category by flying a Skyray from NAS Point Mugu to 49,212 feet in only 2 minutes and 36 seconds. Designed to intercept high flying bombers attacking a carrier battle group, the Skyray's hot climbing performance made it the only Navy fighter to be formally assigned NORAD air defense duties as a land-based interceptor.

On 2 May 1958 All-Weather Fighter Squadron THREE (VFAW-3) was formed at NAS North Island, San Diego to stand air defense alert for the southern US West Coast. Wearing the tailcode "PA" and an attractive blue spine and tail with yellow stars, NORAD's shield was in the squadron's North Island hangars but not on the aircraft themselves. Armed with four 19-shot rocket pods and later Sidewinder missiles, VFAW-3's Skyrays were a leap on capability over the F9F Panthers and F3D Skynights that were originally proposed by the US Navy to serve NORAD alert on the US West Coast.

Led by 23-victory World War II ace Eugene Valencia, VFAW-3 would twice win NORAD's highest honors for efficiency and readiness, topping all other USAF and Canadian air defense units.

Source: Combat Aircraft Monthly, January 2010. "US Navy Fighters of the Fifties: F4D Skyray" by LCDR Rick Burgess USN (Ret), p70-77.

03 February 2010

The Lockheed SR-71 Blackbird's first operational mission took place on 21 March 1968 out of what was designated OL-8 (Operating Location 8) which was Kadena AB on the Japanese island of Okinawa. The 9th Strategic Reconnaissance Wing of Beale AFB, California, had just been formed two years prior to bring the two-seat Mach 3 spyplane into service. For several years prior to the Blackbird's entry into service, the CIA had been operating its single seat predecessor, the A-12, which had the code name "Oxcart" and this particular variant was retired in the same year that the SR-71 became operational.

Though the A-12 in CIA hands had made several overflights of North Vietnam in support of the war effort in Southeast Asia (the first flight having been made to see if North Vietnam did have any surface to surface short range ballistic missiles, which they didn't), the first SR-71 operational mission would fly over North Vietnam on a similar routing as the CIA flights just 10 months earlier. With Major Jerry O'Malley flying and Captain Ed Payne as his RSO (Recon Systems Operator), the Blackbird's first mission not only carried a battery of optical cameras but also a side-looking radar (SLAR) in the nose bay. After making their first run across North Vietnam, the SR-71 crew conducted an airborne refueling over the South China Sea before accelerating back to Mach 3 for a second run, this time over the DMZ area. On this second run, the SLAR would be the primary instrument.

Although the flight had to abort landing at Kadena due to weather and instead diverted to Taiwan, the high-definition SLAR imagery around the Marine Corps base at Khe Sanh which was under siege at the time revealed numerous artillery emplacements and a large supporting truck park that had eluded the optical sensors of other reconnaissance aircraft. Within a few days of that first operational mission, US aircraft targeted the artillery emplacements and staging areas uncovered by the SR-71 SLAR run and effectively broke the 77-day siege of Khe Sanh. Both Major O'Malley and Captain Payne were awarded the Distinguished Flying Cross for their flight that was instrumental in saving Khe Sanh.

Source: Wings of Fame, Volume 8. "Lockheed's Blackbirds: A-12, YF-12 and SR-71" by Paul Crickmore. Aerospace Publishing, 1997, p61-64.

02 February 2010

Initially deemed unsuitable as night bombers by the RAF, the first Consolidated LB-30 Liberators were found with their long range to be ideal in the transport role. In mid-1941 the North Atlantic Return Ferry Service began to bring RAF flight crews to Canada where they would pick up US Lend-Lease aircraft to fly back to Europe. As a result, the Liberator was the first aircraft to make the North Atlantic crossing carrying passengers on a regular service. On 24 September 1941 BOAC took over the North Atlantic services from the RAF and also took on the Liberator transports.

The BOAC Liberators wore either civil registrations or RAF roundels but could be identified by the Speedbird logo on the nose of the aircraft. Flights connected Prestwick with St-Hubert in Quebec via Gander, Newfoundland. In January 1942 the first BOAC Liberators started passenger services to Cairo (via North Africa) and in the following year passenger services extended to Moscow (via North Africa and Iran to avoid occupied Europe).

By 1947 the RAF had already withdrawn its own Liberators from service but BOAC continued use of the Liberator in cargo services London and Montreal via Prestwick and Gander. From 4 February to 28 May 1948 BOAC inaugurated nonstop Liberator service between London and Montreal using inflight air-refueling. Flight Refueling Limited, an early pioneer in aerial refueling, purchased four Avro Lancastrians from Trans-Canada Airlines and converted them into refueling tankers. Two of them were based in Shannon, Ireland, and the other two were based in Newfoundland. The Liberators flying eastbound needed only a single refueling usually about 200 miles east of Gander. Flying westbound, two refuelings were needed to fly against prevailing winds- the first one 200 miles west of Shannon and the second one in the vicinity of Goose Bay, Labrador.

Of forty-five refuelings, only three were aborted- one due to radar and heating problems in the tanker, one due to fuel transfer problems and a third one due to a nervous BOAC captain who refused to carry out the aerial rendezvous! Despite the success of the trials and Flight Refueling's attempt to convince BOAC that aerial refueling was feasible for civilian flights, BOAC instead opted to use Lockheed Constellations and Boeing Stratocruisers to carry out nonstop North Atlantic services.

Source: International Air Power Review, Volume 15. AIRtime Publishing, 2005, "RAF Liberators at War- Part 1: UK-based Operations" by Jon Lake, p160-161, 172-173.

01 February 2010

One item of historical interest attached to British Airways' Boeing 777s relates back to the flight testing phase when one of the 777 prototypes was at Edwards AFB conducting RTO (Rejected/Refused Take-Off) testing- an RTO test is the most demanding test of an aircraft's braking systems. The aircraft is loaded with ballast to represent a typical fuel/pax/cargo payload, taken up to takeoff speed, and then the engines are throttled back and the brakes slammed to stop the aircraft before it reaches the end of the runway. No thrust reversers/spoilers are used in the RTO certification tests. These are some of the most dangerous tests in flight testing as the brakes absorb tremendous amounts of energy, glowing red hot and often the tires will also explode. In an RTO test, the fire trucks stand by and do NOTHING for five minutes to simulate the time needed for them to reach an aircraft on the runway.

When the 777 was in flight testing, the Boeing and FAA engineers were preparing for the maximum RTO test called "The Big One"- this was the worst case scenario- full payload, maximum brakes, and brakes purposely worn down to remove any additional safety margin. As test preparations were under way, British Airways notified Boeing that they planned to use the 777 on the London Gatwick-Dallas route and this would require an increase in the payload weight and takeoff speeds (and thus maximum braking forces) than what the engineers were originally prepared to perform as "The Big One". It was BA's worst case scenario- an aborted takeoff out of DFW on a hot summer day and it was worse than what the Boeing engineers had considered the worst case scenario in the RTO tests.

Long story short, after a lot of hand-wringing, they went ahead and conducted "The Big One" using BA's Dallas parameters. The 777 was loaded to a takeoff weight of 632000 pounds, accelerated to 183 knots, then 100% braking applied as thrust went to idle. The 777 stopped in 4000 feet, the brake temperatures went off the scale past 3000 degrees Celsius, and as the 777 turned off the runway, smoke could be seen from the brakes as they glowed white hot.

With the fire trucks standing by for the required five minutes, the first tire blew (in a controlled manner using what's called a fuse plug in such emergencies- the plug melts and lets air out without a blowout) before the plane stopped. All 12 tires' fuse plugs blew and steam billowed out from the wheels as the fire trucks began to pump water on the undercarriage. The 777 passed "The Big One".

It was estimated that about 97 million foot-pounds of energy were absorbed by the brakes in this test. By comparison:

-A general aviation aircraft weighing about 2000 pounds uses 200,000 foot pounds of brake energy.
-A typical jetliner lands and uses about 3-4 million foot-pounds of energy.
-The Space Shuttle uses 30-36 million foot-pounds of braking energy when it lands at the Cape.
-A carrier landing can require as much as 74 million foot-pounds of stopping power.

Source: Twenty-First Century Jet: The Making and Marketing of the Boeing 777 by Karl Sabbagh. Scribner Press, 1996, p291-305.