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.

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.

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.

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.

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.

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.

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.

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.

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.

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.