Mach-3 SR-71 Blackbird’s HOT COCKPIT

Blackbird onboard USS Intrepid – Photo © Xavier Cotton http://www.passionpourlaviation.fr

As you may have heard, the mythical Lockheed SR-71 Blackbird was a strategic reconnaissance aircraft able to fly at more than Mach 3 – Mach 3.3 ie around 3,500 km/h; or 1,900 kts; and at a maximum flight level of… FL 850 or 26 kilometers high!

The Blackbird indeed had a unique flight envelope with a particular doghouse plot (since she could not exceed 3.5 G), and an exceptionnal coffin corner limited by her CIT – Compressor Inlet Temperature of 427°C maximum.

This aircraft was also unique for her engines were two J58 ramjets fuelled by JP-7 especially refined for extreme flying purpose. This special fuel could drip and leak abundantly as the airframe made up of titanium was retracted while taxiing, and became airtight only when it got its operating shape while flying very fast and very high because of the air density, and surrounding pressure plus the heating caused by the air friction at such speeds. In short, the whole structure considerably expanded when airborne.

The irony – I heard it on the grapevine, or read it somewhere on the web – that titanium which turned into dark blue while flying (SR-71s probably deserved those unofficial other nicknames « Bluebird », or « Habu » viper) was « imported » from… USSR!

Pilots must have taken significant risks inherent in flying such an aircraft as mentioned in this previous post. These pilots used to fly over the USSR to take strategic reconnaissance photographs during the Cold war. They wore pressurized spacesuits so that their blood could not boil in case of decompression or ejection at such altitudes.

The Blackbird travelled faster than a rifle bullet, and the air friction could have melt aluminum-skinned aircraft. At Mach 3.2, fuel cycled behind the chine surface in order to cool the aircraft! The inner windshield temperature could reach 120°C even though a heavy-duty cooling system was on a full function. On landing, the outside temperature of the canopy could reach 300°C, and it must have been far beyond on the fuselage, and wing surfaces while flying at high speeds. The pilot could feel the heat behind his protective gloves!

Special thanks to Xavier Cotton for the Blackbird photos. Please, visit his website on http://www.passionpourlaviation.fr

9/11 FIREFIGHTERS more likely to develop CANCER

According to a new study, New-York City firefighters would be 19% more likely to have cancer than their colleagues who did not work at the site following the 9/11 attacks:

F-16 G-suit, stick, and dogfight

Pilot’s G-suit

Anti-G coveralls   -  © www.tpub.com

… or ANTI-G COVERALLS

When in flight, the body can have trouble adjusting to stresses produced by rapid changing of speed or direction. In situations such as seat ejection, ditching, or parachute opening shock, the short duration of the excessive force has little effect on the body.

However, changing the direction of flight produces stress forces equal to several times the normal pull of gravity for much longer periods of time. These longer duration forces can have dangerous effects. At 5 g’s (5 times the force of gravity), the aircrewman’s body is exposed to a force that increases its weight 5 times.

This increased weight has many effects. Your body is pushed down into your seat. Your arms and legs feel like lead, and operation of equipment becomes more difficult. The extra weight on your internal organs causes stomach and chest pain. Most important, however, is the effect on your circulatory system. At 5 g’s, your heart cannot pump enough blood to your head. When this happens, you will pass out. Wearing anti-g coveralls will help prevent this from happening.

The Navy uses two models of anti-g coveralls (commonly called « G » suits). These coveralls provide protection against blacking out, loss of vision, and lowered mental efficiency caused by high g-forces experienced in high-performance aircraft. Figure 11-4 shows a typical anti-g coverall. Anti-g coveralls compress your legs and stomach to prevent blood from pooling in your lower body.

This increases your stress tolerance an average of about 2 g’s. Without an anti-g coverall, you may be able to withstand about 4.5 to 5.5 g’s without losing vision or blacking out. With a coverall, you can withstand 6.0 to 7.0 g’s.

This protection is available only for sustained accelerations of 4 to 5 seconds. Anti-g equipment does not offer protection in snap maneuvers where 10 to 12 g’s are applied in about 1 second. Such extreme forces for a short time are not as harmful to the body as are lesser forces sustained for a longer time.

www.tpub.com courtesy