29 July 2009

Following the 1979 Islamic Revolution in Iran, considerable debate developed within the new government on the fate of the 77 Grumman F-14A Tomcats that were acquired under the regime of the Shah of Iran. Throughout the rest of 1979 there were low-intensity negotiations with the United States to buy back to Tomcats for refurbishment to put into service with the US Navy, possibly even the USAF as an interceptor. Discussions even revolved around selling them to a foreign customer.

In February 1979 it was suggested to fly them to Saudia Arabia or Egypt for sale to the Saudis. In the following month the new prime minister Mahdi Bazargan and Ayatollah Khomeni's son-in-law Sadeq Tabatabaie suggested the Tomcats had to be sold as they were to complex to operate by the new Islamic republic. Bazargan wanted them sold back to the USA for a quick sale. The Pentagon welcomed the move as they were looking to possibly sell the F-14s to the United Kingdom. In April the Canadians were rumored to be willing to buy them at 1/3 of their original price.

The defense minister, General Riyahi, and General Bagheri, the head of the IRIAF, wanted to hold on to the Tomcats for the defense of Iran. Official spokesmen for the new government disavowed any intent to sell the Tomcats and by August Ayatollah Beheshti and Ayatollah Khameni (today's supreme leader in Iran) with the support parliament speaker Hashemi Rafsanjani overrode the first president of the Islamic republic, Abolhassan Bani-Sadr, and declared that the F-14 fleet was an essential defense asset of Iran.

Source: International Air Power Review, Volume 23. "Air Combat: The Nine Lives of the Cat- Iran's Tomcats at War" by Tom Cooper and Farzad Bishop, p113.

28 July 2009

On 7 September 1941 the first 24 Hawker Hurricanes arrived at Vaenga-Pervaya airfield near Murmansk to form Royal Air Force's 151 Wing composed of both No. 81 and No. 134 Squadrons. This first group was departed the carrier HMS Argus which delivered them into the Soviet Arctic. The rest of the wing's aircraft arrived five days later via cargo ship at the port of Murmansk and the 40 Hawker Hurricanes flown by RAF pilots was code-named Force Benedict.

For over a month the RAF pilots of the two squadrons flew combat missions over the Kola Peninsula against the Luftwaffe and also flew escort missions for the bombers of the Soviet Union's Northern Fleet Air Force. Fifteen Luftwaffe aircraft were shot down with only the loss of one pilot and one Hurricane.

On 11 October 1941 Soviet Admiral Nikolai Kuznetsov signed an order creating the 78th IAP (Fighter Air Regiment) to operate the RAF's Hurricanes after the RAF pilots departed back for the UK. Four days later the 78th IAP (made up of three squadrons) was declared operational and became the first unit in the Soviet Air Force to operate foreign aircraft in wartime.

Source: Aeroplane Monthly, September 2007. "A Biting North Wind" by Yuriy Rubin, p23.

27 July 2009

On the last night of World War II, a Northrop P-61 Black Widow from the 548th Night Fighter Squadron from Ie Shima was on nocturnal patrol and in low-altitude pursuit of a Japanese fighter when the enemy aircraft hit the water before the Black Widow could fire a shot. The war officially ended at midnight that night, but there remained the possibility of kamikaze attacks on American airfields despite the surrender, so the P-61s remained on alert.

The following night on August 15, another P-61 was vectored by ground control on Saipan towards another Japanese fighter flying at low level. This time the Japanese pilot was dropping window to confuse the Black Widow's radar operator. Like the previous night, a low altitude pursuit ensued, but before the P-61 could open fire, the plane impacted the water.

The P-61 Black Widow in effect made the final two kills of World War II without firing its guns!

Source: Aviation History, November 2008. "Bite of the Black Widow: Northrop's P-61 was the ultimate nocturnal predator in the Pacific War" by Warren Thompson, p54-55.

26 July 2009

After a quarter century of using the Dassault HU-25 Guardian on sea patrols, the US Coast Guard is transitioning to the EADS CASA HC-144A Ocean Sentry which is based on the CN-235 transport. Though it may seem backwards to go from a pure jet to turboprop aircraft, the HC-144A carries the same fuel load as the HU-25 but burns it at half the rate which translates longer time-on-station, eight to nine hours versus the Guardian's four hours on-station. The per-hour operating cost has improved as well with the HC-144A costing less than $1000/hour compared to the Guardian's $1500-$1800/hour.

In addition, the HC-144A has a rear cargo door/ramp as well as a belly-mounted observation bubble allowing SAR crews to do something not previously possibly on other USCG aircraft- look below the aircraft. The last of the Guardians should be retired in 2020 (of the 21 in service now) and replaced with 36 HC-144A Ocean Sentries. Five are now in service with pilot training taking place at CGAS Mobile, Alabama.

Source: Air & Space Smithsonian, January 2009. "Then & Now: Frozen Moments as Time Marches On" by Paul Hoversten, p68.

25 July 2009

The US Marine Corps had initially required the Grumman A-6 Intruder to meet an STOL requirement to take off in 1500 feet over a 50 foot obstacle. To accomplish this, the first seven A-6 Intruders had tilting tailpipes in which the exhaust of the twin J52 engines was vectored downward 23 degrees on takeoff and landing. There was a knurled knob on the outboard throttle that the pilot used to activate the feature. During testing, the Navy evaluation team set out to see if the feature worked as advertised and found the tilting tailpipes only marginally effective in meeting the USMC requirements- in fact, in many configurations the approach speeds were actually lower than they had been in propeller-driven aircraft.

The Navy team recommended deleting the feature at a cost savings of $25,000 per aircraft. After some back and forth arguing between the Marines and the Navy, the tailpipes and the associated actuation mechanisms were deleted beginning with aircraft number 8.

Source: Intruder: The Operational History of Grumman's A-6 by Mark Morgan and Rick Morgan. Schiffer Publishing, 2004, p16-17.

22 July 2009

Since 2005 UAV builder Aurora Flight Sciences has been working on an innovative hybrid turbine-electric propulsion for VTOL flight. The Excalibur demonstrator features a Williams F145 turbofan engine (the same used on the Tomahawk cruise missile) in a mid-fuselage tilting nacelle combined with battery-powered electric lift fans in the wingtips and nose. In VTOL flight, the lift fans augment the vertical lift provided by the jet engine and in conventional flight, the engine also recharges the batteries for the lift fans.

The challenge for VTOL flight is that the high power needed for vertical flight means that the engines are larger than necessary for cruise flight. By using electric lift fans, the engine can be sized for cruise flight, thereby lighter, and can more easily use off-the-shelf engines than one designed for vertical flight. In VTOL flight, the Excalibur's jet engine provides 70% of the lift thrust with the fans providing the balance.

The Excalibur is a small proof-of-principle aircraft that is already flying and plans are for a second Excalibur with the necessary changes to make a full transition to high speed level flight.

Source: Aviation Week & Space Technology, July 20, 2009. "Hovering Hybrid: Aurora flies turbine-electric UAV designed to combine high speed and vertical flight" by Graham Warwick, p38.

21 July 2009

The airport for La Paz, Bolivia, sits at 13,313 feet elevation and is the highest elevation airport in common use and is the reason many jets are certified for airports up to an elevation of 14,000 feet above sea level. Recently, however, the Cessna Citation XLS received approval to operate at airports up to 15,000 feet elevation. The flight inspection division of China's Civil Aviation Administration operates seven Citations and recently it made its first landing at the airport of Qamdo Bangda in Tibet which sits at 14,219 feet above sea level. The Citation XLS' certification is to 15,000 feet as there are no other runways in the world higher than that of Qamdo Bangda.

Source: Flying, July 2009. "Airways: Industry News & Notes", p17.

19 July 2009

In 1945 there wasn't a large body of technical knowledge on supersonic flight when the design of the Bell X-1 was formulated. Many engineering and design decisions had to be made based on the best possible estimates of the aircraft's performance. The fusleage's shape was the end product of the study of the .50 caliber bullet, as it was known to be stable at supersonic velocities. Bell's engineers tried to fill in the data gaps on supersonic flight by observing objects known to fly at supersonic speeds- in this case, the .50 caliber round. Discussions with ballistics experts concluded that little was known about the aerodynamics of the round after it was fired, but since there was no question that it was stable at high speeds, its shape formed the basis for the X-1's fuselage.

Source: Bell X-1 Variants, Aerofax Datagraph 3 by Ben Guenther and Jay Miller. Aerofax, 1988, p6.

18 July 2009

In 1955 De Havilland began work on the Blue Steak, a medium-range ballistic missile that would have been based in underground silos in eastern England. Powered by two Rolls-Royce RZ.2 liquid-fuelled engines (which were based on the earlier RZ.1 which themselves were based on the US Rocketdyne S-2 engine), it would have been armed with a single nuclear warhead. Several complete systems minus the warhead were live-fired at test stands at RAF Spadeadam and were shown to be very robust and reliable.

In 1960 the Blue Streak was cancelled in favor of the Douglas Skybolt air-launched ballistic missile which was to have been carried by Avro Vulcans in RAF service. Work on the Blue Streak continued as a space launcher, though, with its proven live-fire reliability an asset as a satellite launcher. However, later that year it was cancelled altogether, but all was not lost. The Blue Streak formed the basis for the Europa booster which in turn led to the Ariane launcher used by the European Space Agency.

Source: British Secret Projects, Hypersonics, Ramjets, & Missiles by Chris Gibson and Tony Buttler. Midland Publishing, 2007, p125.

16 July 2009

On July 7 of this year the Antares DLR-H2 motor glider became the first piloted aircraft to fly powered only by a fuel cell. The DLR-H2 has a fuel cell and hydrogen tank in underwing pods which powered an electric motor and propeller. Flying for the first time in Hamburg, Germany, the DLR-H2 has a range of 466 miles and a maximum speed of 106 mph with no emissions other than water vapor. The fuel cell delivers 20 kW of power and only 10 kW is needed to maintain level cruise flight. Total efficiency of the system is 44%- approximately twice the efficiency of a conventional piston engine.

Source: Aviation Week & Space Technology, July 13, 2009. "Industry Outlook" edited by Edward H. Phillips, p14.

15 July 2009

Forty-three percent of the empty weight of the Rockwell/MBB X-31 is made up of over 600 items from other aircraft. In an effort to reduce costs and development time, off-the-shelf components were used wherever possible in the design and construction of the X-31.

McDD F/A-18 Hornet: Windscreen, canopy, electrical generators, airframe-mounted accessory gearbox, leading edge actuators, cockpit instrumentation, cockpit controls

Lockheed F-16: Main undercarriage, rudder pedals, nosewheel/tire, emergency power unit, fuel pump

Lockheed F-16XL: leading edge flap drives

Lockheed C-130 HTTB: Flight control computers

Bell/Boeing V-22: Rudder acutators, trailing edge control modules

Cessna Citation III: Mainwheels and brakes

Vought A-7: Main tires

Rockwell T-2: Zero-g fuel accumulator

Northrop F-20: Emergency air-start system

Rockwell B-1B: Canard pivot and spindle

Source: World Air Power Journal, Volume 24 (Spring 1996). "Rockwell/MBB X-31" by Robert F. Dorr.

13 July 2009

In 1955 the US Air Force evaluated ground-launched version of the Navy's RIM-8 Talos shipboard air defense missile to provide Strategic Air Command bases and Atomic Energy Commission sites with a capable point-defense system from Soviet air strikes. The evaluation stemmed from a USAF concern with relying on the Army's Nike-Ajax system for protection of its installations. The following year, the USAF had requested Defense Department funding for site surveys for Talos installations and had survey teams ready to go once funding was secured; instead the DoD had the evaluation program transferred to the Army's Air Defense Command (ARADCOM) and after a period of testing, it was decided to proceed with the Nike-Hercules missile instead.

The Talos, however, served successfully with the Navy until 1979.

Source: Rings of Supersonic Steel- Air Defenses of the United States Army 1950-1979 by Mark L. Morgan and Mark A. Berhow. Fort MacArthur Press, 2002 (Second Edition), p28.

12 July 2009

Quickly superseded by the swept-wing F9F-6 Cougar, the Grumman F9F Panther was only exported to a single nation, Argentina. In December 1958 the Argentinian naval aviation service took delivery of 24 F9F-2 Panther fighters to operate from its carrier, the ARA Independencia. The aircraft were exclusively land-based as the catapults on the carrier could not handle the Panther at its normal operational weights but a Panther did land once on the vessel.

The only action Argentinian Panthers participated in was during an abortive three-day coup in April 1963 when the Air Force destroyed four Panthers on the ground and one was lost in a collision with a Corsair. The Panthers were used to strafe Army units during the coup. In 1966 the Panthers flew patrols during a period of tension with neighboring Chile. The Panthers were retired in 1969 and replaced with A-4Q Skyhawks.

Source: Combat Aircraft, June-July 2009. "F9F Panther" by LTCDR Rick Burgess, USN (Ret), p71.

11 July 2009

The Grob G115 two seat general aviation aircraft is a development of Grob's G110 and G112 light training aircraft and first flew on 15 November 1985. Subsequent improvements in the G115 led to the G115E to become the first aircraft made from glass-fiber reinforced plastics to be certificated by the FAA.

In 1998 the G115 was selected as the Tutor for elementary flight training for the RAF to replace the Chipmunk T.10 and the Bulldog T.1. With 92 aircraft stationed at 14 airfields, the Grob Tutor T.1 is the second most numerous type in RAF service after the Panavia Tornado GR.4 and is also the most widely dispersed single type in Royal Air Force service.

Source: Air International, April 2009. "Grob Tutor: Aircraft of the RAF Part 12" by Jim Winchester, p52.

10 July 2009

In 1943 a DeHavilland Mosquito in BOAC markings landed at RAF Leuchars in Scotland carrying a valuable passenger- Danish physicist Niels Bohr, the 1922 winner of the Nobel Prize in physics. In a conference in Washington DC in 1939, Bohr detailed how the uranium isotope U-235 could be used to create a chain reaction in an atomic bomb. By 1943 the Nazis were rounding up and deporting the Jews in Denmark and as his mother was Jewish, Bohr was at risk. Word got out that he was about to be arrested and given the choice between joining Hitler's atomic weapons project or be sent with his family to a concentration camp.

With the help of the British secret service, Bohr was smuggled to Sweden and then flown in an improvised bunk in the bomb bay of the Mosquito from Stockholm to Scotland. From there he was flown onward to England and then the United States to join the Manhattan Project.

The Mosquito flew approximately 200 flights in BOAC colors between Stockholm and the UK during the war conveying clandestine personnel and war materiel. Only the Mosquito was fast enough to evade patrolling German fighters over the North Sea.

Source: Aviation History, September 2009. "The Magnificent Merlin" by Nicholas O'Dell, p32.

09 July 2009

In 1965 seven US oil companies were prospecting Alaska's North Slope for oil and found that getting drilling equipment to the area was near impossible- there were no roads to the North Slope and the only way would have been to barge the equipment in via the Arctic Ocean but that could only take place for a few weeks each summer.

The problem was solved by Alaska Airlines who "wet-leased" the civilian Lockheed L-100 Hercules demonstrator from Lockheed for one month. In what became known as the "Thirty Day Miracle" the sole Hercules transported over 2 million pounds of equipment and cargo to dirt strips in the North Slope. Richfield Oil subsequently struck oil at Prudhoe Bay and that set off the great Alaskan oil rush.

Source: Herk: Hero of the Skies, by Joseph Earl Dabney, Copple House Books, 1979, p237-241.

08 July 2009

According to the 2008 General Aviation Manufacturers Association report, general aviation contributes more than $150 billion to the US economy each year and employs over 1.2 million workers. About 2/3 of all hours flown by general aviation aircraft are for business purposes. In the United States, general aviation aircraft fly more than 27 million hours and transport 166 million people annually.

Source: Aviation Week and Space Technology, July 6, 2009. "Vision Plan: Cirrus team seeks new financing to fund and revive Vision program" by Frances Fiorino, p30.