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Cutaway Thursday: Northrop P530 Cobra
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Cutaway Thursday: Yakovlev Yak-141
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Buran: Soviet Space Shuttle
Like most of Soviet/Russian aerospace the Buran Spacecraft is still an enigma. Buran was seen from the outset as a carbon copy of the NASA’s Space Shuttle and from the picture below, the case can be easily made.
However, Amy Shira Teitel at ARS Technica has another aspect to the story:
Faced with the poorly understood threat of a military space shuttle, the Soviets decided that copying the American spacecraft exactly was the best bet. The logic was simple: if the Americans were planning something that needed a vehicle that big, the Soviets ought to build one as well and be ready to match their adversary even if they didn’t know exactly what they were matching.
Cold war “misunderstandings” as to the purpose of the Space Shuttle program? I’m not so sure but it makes for interesting reading. The Space Shuttle was designed to take military payloads into orbit and was tested at the US military’s space launch facility at Vandenberg, AFB (rolled up to the launch pad but not launched) but the Challenger disaster changed all that. The military applications for space are just too beneficial to ignore.
Go check out the article at ARS Technica, it makes for some interesting history.
The Buran is now on display at various locations in Russia and Europe. Check out the airliners.net collection.
This test model is on display at the at the Baikonur Museum in Kazakhstan.
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Cutaway Thursday: Aero L-39 Albatros
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Shockwaves, and the Beauty of Supersonic Flight.
Aviation week has an interesting article on Schlieren photography and it’s application in NASA to not only models of supersonic airplanes but also the actual airplanes themselves.
Schlieren photography is a visual process that is used to photograph the flow of fluids of varying density. Invented by the German physicist August Toepler in 1864 to study supersonic motion, it is widely used in aeronautical engineering to photograph the flow of air around objects. Its role is changing due to the increasing use ofcomputational fluid dynamics, which reduces the need for all such experimental fluid flow measurement techniques.
The av-week article features interesting Schlieren photographs of modern (again actual) supersonic military aircraft:
F-15B at Mach 1.2 and 40,000ft
F/A-18B at Mach 1.1 and 44,000ft
From the article:
Optical schlieren uses a collimated light source that shines on the target from behind. Variations in the density of air as it flows over the object, and is compressed and expanded by shockwaves, change its refractive index and distort the beam, causing changes in the light intensity that can be visualised using a shadowgraph.
The Ground-to-Air Schlieren Photography System (GASPS), developed by MetroLaser and tested by NASA Dryden FLight Research Center, uses two telescopes, digital cameras – and the Sun as the collimated light source. The test subjects were a NASA F-15 and F/A-18 flying supersonically over Edwards AFB in California.
Transonic shock wave visualization will enable researchers to optimize the airframe shape of a future civilian supersonic transports. Controlling the shockwave around the airframe, most notably around the engine air intakes, would help to reduce the acoustic noise “foot print” when traveling over populated areas. Perhaps leading to overland commerical supersonic flights.
Aside from the scientific benefits the pictures are quite visually stunning as they were taken as the aircraft flew in front of the Sun.
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Cutaway Thursday: Bell OH-58D Kiowa Warrior
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Cutaway Thursday: Alenia Aeronautica C-27J Spartan
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Cutaway Thursday: Chengdu J-10B “Vigorous Dragon” or “Firebird”
Too bad it’s in Italian 
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Cutaway Thursday: Lockheed S-3B Viking
WAR HOOVER!!!
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Cool Interactive Thingy: X-Planes at Dryden.
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Cutaway Thursday: IAI Kfir
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Cutaway Thursday: Northrop X-21
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Concept Art: The Bell X-22
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Cutaway Thursday: Martin WB-57F
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Luneburg Lens
I’m always running into interesting things while doing research for content here. Yesterday, I ran into something called the Luneburg Lens.
Let’s start with the picture:
From Wikipedia:
A radar reflector can be made from a Luneburg lens by metallizing parts of its surface. Radiation from a distant radar transmitter is focused onto the underside of the metallization on the opposite side of the lens; here it is reflected, and focussed back onto the radar station. A difficulty with this scheme is that metallized regions block the entry or exit of radiation on that part of the lens, but the non-metallized regions result in a blind-spot on the opposite side.
This is an Edwards AFB, F-22 Raptor launching an AIM-9L Sidewinder during testing. If you look aft of the missile’s exhaust plume you’ll notice an odd shape dorsally mounted on the aircraft fuselage. At first you may think it’s a camera that mounted to record launch of the missile but it’s a device meant to enhance the radar signature of the aircraft, called a Luneburg Lens.
Luneburg Lenses are used in radar reflectors to enhance radar signature of low-observable aircraft to operate in airspace that’s being controlled/observed by air traffic control. Here’s a closer look on how it appears on the F-22:
It’s kind of a grainy image so we’ll try another view of the lens on the F-22:
Here’s a close-up (again apologizes for the graininess):
The Luneberg Lenses are also used in target drones such as this Teledyne-Ryan Firebee II drone (the lens appears above the forward wheel of the dolley and aft of the air intake):
In this case the Lenses are used to enhance the radar signature in order to more accurately simulate radar signature of threat aircraft.
I’m sure that most readers are already familiar but, since I don’t work in aerospace, I thought it was an interesting aside.
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Cutaway Thursday: MiG-31 “Foxhound”
Work and personal commitments kept me from posting last week so here’s one a day early:
The Aviationist has an interesting story on the Foxhound “intercepting” the Blackbird:
“The scheme for intercepting the SR-71 was computed down to the last second, and the MiGs had to launch exactly 16 minutes after the initial alert. (…) They alerted us for an intercept at 11.00. They sounded the alarm with a shrill bell and then confirmed it with a loudspeaker. The appearance of an SR-71 was always accompanied by nervousness. Everyone began to talk in frenzied voices, to scurry about, and react to the situation with excessive emotion.”
I’ve heard rumors of Foxhound intercepts of Blackbirds before and given the technology involved in the Foxhound’s Zaslon (it was the world’s first passive electronically scanned array installed on a fighter) I suppose it’s possible. At certain aspects the -71s RCS is large enough to get a decent return for a fire control solution.
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Cutaway Thursday: De Havilland Sea Venom FAW.22
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Cutaway Thursday: Saab Gripen
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F-16 Diverterless Supersonic Inlet (DSI)
This F-16 was modified with a diverterless supersonic inlet (DSI) for testing in support of Lockheed’s F-35 program.
From Wikipedia:
(DSI) is a type of jet engine air intake used by some modern combat aircraft to control air flow into their engines. It consists of a “bump” and a forward-swept inlet cowl, which work together to divert boundary layer airflow away from the aircraft’s engine while compressing the air to slow it down from supersonic speed. The DSI can be used to replace conventional methods of controlling supersonic and boundary layer airflow for speeds of up to Mach 2, such as the intake ramp and inlet cone, which are more complex, heavy and expensive
The F-16 DSI was first flown 11 December 1996 and test program lasted twelve flights flown in nine days in December 1996.
In addition to the F-35, DSI has also been used in the JF-17 Thunder:
and the J-10B:
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Cutaway Thursday: Convair F-106 Delta Dart
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