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Startup: What Could Be More Awesome Than Flame Shockwaves?

The Pratt & Whitney J58 showing off its shock-waves.

For those of you unfamiliar, please meet the astonishing Pratt & Whitney J58, which may be the most convincing argument in favour of hybrid technology I’ve ever heard. Oh sure, it’s not a hybrid in the boring sense of a Toyota Prius, but strap one of these to a Prius and I’ll bet you’ll find it interesting.

Clearly the afterburner put off a fair bit of heat.

The J58 is a hybrid turbojet and ramjet engine. Basically, it is two engines in one; three, if you count the afterburner. And in a sense, you should count it, since the J58 was the first engine designed to run almost full-time on its afterburners.

Basically, a turbojet engine becomes inefficient at a certain speed; a conventional ramjet can’t operate below a certain speed; and an afterburner uses an enormous amount of fuel. Pratt & Whitney found ways around each of these problems with a level of elegance that rivals the Bugatti Veyron. And, in fact, they could be said to be closely related, because like the Veyron, the J58 engine changes shape and flow dynamics at different speeds. Two special fuels were required for the massive jet engine to operate, with one being so volatile that flame-suits were required just to be in the vicinity of it, and the other so safe that technicians could continue welding on the aircraft while it was being refueled.

The engines were used in the SR-71 Blackbird and its siblings, and remain one of the very few engines certified by the USAF for continued flight at speeds above Mach 3. A very exclusive club indeed.

  • I will be the first to say it: that shit is hot.

  • Lotte

    Now I'm wondering what to swap this engine into onto…a pair of these bad boys would definitely help takeoff here and look awesome at the same time (like the 777ER with the huge GEs…huge engines on passenger jets look awesome.)

    <img src="http://farm4.static.flickr.com/3328/3194317553_80687b8009.jpg&quot; width="400">

  • I got to see shock diamonds from an early F-18 up VERY close and personal. Beautiful and freaky.

    Middle of the night, in the middle of the Indian ocean, shortly after Desert Shield/Storm, on an aircraft carrier now enjoying a life as a museum in Southern California. I was doing the nightly cal checks for one of the shipboard landing Radars and headed out to the rear of the flightdeck to raise the "ram-pole" which was a large 6"~ish diameter pole with an airplane beacon transceiver and corner reflector mounted on top. The pole was about 30 feet tall and was raised with an air-assisted hand-crank motor, simulating a target at an exact known location to calibrate the Radar.

    In order to do that you had to walk to the very rear corner of the flightdeck and climb over the side into the "pit" which was a small box hung off the port-side several stories above the water. In the dark, which always freaked me out because it looked exactly like the ocean below it at night.

    The usual order of business was to check and make sure the pole would not hit the wings of any jets that may be parked overhead (they weren't supposed to spot the planes there, but they always did). Then you turned on the beacon, raised the pole, and if there were two techs working that night you waited for the red signal light mounted next to the controls that indicated the tests were complete. If you were working alone you had to haul your ass all the way back to the radar transmitter room, do the checks and come back to lower the pole.

    This particular night there were two of us, so after making sure the box just missed the tail of the F-18 "illegally" parked above us I sat there and waited for the red light, while looking out at the black infinity of the Indian ocean.

    A short while later I heard a bunch of voices approach, which turned out to be the plane crew. So I popped up and waved at them, in a "Thanks for parking on our head again, ya jerks" manner. They looked at me, at the pole, and then went about their business and I went about mine.

    Suddenly they started the @#$% motors up!! For reference, they usually spot (park) the planes with the tails hanging slightly out over the side, which put the exhaust of this plane directly overhead, about 10 feet above.

    I started waving frantically and yelling (completely futile) "STOP! STOP! @#$%& STOP!!" And I realized they hadn't actually seen me, nor did they bother to check. (It WAS pretty dark, but still). All I could do was hunker down in the corner as far from the heat as possible, cover my mouth (freaking stinks!) and close my eyes (it burns, it burns) and wait it out. Even wearing a cranial head and ear protection it was deafeningly loud. And hot.

    Our red signal light blinked. Then a while later blinked again. Then blinked repeatedly "shave & a haircut" trying to tell me they were done. But I was trapped. Sorry. I'm. Not. Moving.

    Then it got even louder and hotter as the flight crew did throttle and afterburner tests. In the middle of this hell I chanced a look up and saw those beautiful shockwave diamonds in a pair of blue flames. Right above me.

    IT WAS THE SINGLE MOST AWESOME THING I HAVE EVER SEEN. Then my eyes welled up with tears (fumes, heat, beauty or fear, your pick) and I went back into the fetal position.

    When it was all over with they shut the plane down and I climbed the ladder and popped up out of the pit screaming all kinds of profanities and threatening to skin them all alive. They all looked at me with HUGE eyes and said "things". I'm not sure exactly what they said because there was no sound, just flapping lips.

    That was about 20 years ago, and sometimes I still can't hear a damn thing.

    • Deartháir

      Why the fuck didn't you do that as a POST?? That was awesome!

  • Alan

    I don't think anyone's ever described the Bugatti Veyron as "elegant" before.

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