This Dallas Fort Worth air traffic controller well deserved her NATCA award two years ago. Had she not responded quickly, the pilot would have passed out on board his Piaggio P180 Avanti (registration N501PM, callsign shortened into N1PM) and could even have passed away. Another pilot was alerted by slurring in the pilot’s speech. Video:
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 This special fuel could drip and leak abundantly as the airframe made up of titanium was retracted while taxiing, and became airtight only when it got its operating shape while flying very fast and very high because of the air density, and surrounding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!
This is the brand new project being designed by EADS, and supported by Japan as well as the French DGAC (Direction Générale de l’Aviation Civile – FAA or CAA equivalent). The European consortium has just unveiled its ZEHST project as the Paris Air Show 2011 is opening. ZEHST stands for Zero Emission Hypersonic Transportation.
This aircraft would be both a commercial airplane, and a rocket. It could cruise at « flight level 1056 » i.e. 20 miles or 32 kilometers above the mean sea level… The ZEHST specifications feature a speed of Mach 4 but according to the video below, it might reach Mach 4.5 i.e. 5,500 km/h or 3,000 kts through the stratosphere. It would use two independent turbojets for taking off, then it would gain speed thanks to two cryogenic rocket engines, finally two ramjets would propell the aircraft to hypersonic speeds.
The ZEHST is supposed to pollute far less than the Concorde as it would have a main cruise stage in the stratospheric layers, and according to EADS, its carbon footprint should be very low. There could between 60 and 100 passengers on board who could join Tokyo from Paris in 2.5 hours instead of 11.5, and New-York in 1.5 hours instead of 8! The prototype is expected to fly by 2020, and the first passengers might enjoy stratospheric flights around 2050.