OT - flying the SR71

Might be fiction - but a damn good read .........

formatting link
Regards,

Kim Siddorn,

Reply to
Kim Siddorn
Loading thread data ...

Thanks, Kim. Enjoyable link.

Gyppo

Reply to
J D Craggs

Gentlemen,

At the tender age of thirteen years and up until I was twenty one I belonged to 301 squadron ATC Bury St Edmunds and I also belonged to a Local Aviation Group. Through both I was fortunate to get up close to the SR 71 Blackbird at its base at Mildenhall Air Base. as the piece says when on the ground it leaks like a sieve and on one occasion the Base Fire Crew demonstrated the special properties of the Fuel, when a blow lamp was played onto normal Jet fuel it ignited very quickly but if the same thing was done to the SR 71 fuel it proved very difficult to ignite. The ground crew had to wear special heat proof suits when the aircraft returned from a Mission because of the heat it gave off. I used to spend hours at the fence watching the planes and it was always easy to spot when an SR 71 was about to take off because half an hour before a launch a KC 135, military Boeing 707, would take off, nothing unusual you might think as the base had at least 40 of them but this one was special and only there for the two SR 71's. The F111 he referred to was most likely from Upper Heyford as they had Photo Reconnaissance/ Electronic countermeasures F111 called Ravens. The Aviation Club even managed to have a pilot and RSO give us a talk on the SR 71. Did you also know that the original designation was RS 71 but at its launch President Kennedy got it wrong so it stuck.

Martin P

Reply to
campingstoveman

We had a really close "hands-on" look at one on Monday, plus an engine was out on display at the Pima Air & Space Museun, Tucson, Arizona.

Unusual to see such a beast with no "Keep Off" signs or ropes, but the whole place is like that, and a great bunch of people running it. 156acres, 250 planes plus engines on display, inside and out.

Picked up a B-17 piston at another site, and could have had the master rod plus other conrods or a complete S/H barrel and head, just to bring it back On Topic.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

formatting link

Reply to
Peter A Forbes

Gentlemen, I forgot to mention that like all jet engines there is a little to how much air can be rammed in the front so there is a speed limit, to overcome this, the Concorde suffered from the same problem, the intakes become more restricted as the aircraft gets faster to reduce the volume, we were always led to believe by the Americans that at high Mach No's the SR 71 engines became sophisticated Ram Jets which could cope with the air speed.

Reply to
campingstoveman

Close but no coconut. Jet engines need the intake air to be subsonic so supersonic aircraft need to restrict the intake and then expand the air in a plenum chamber to reduce velocity before it hits the first stage of the compressor. It is also normal to add an afterburner to improve peak power availability for takeoff and sonic transition.

Reply to
crn

It was flying secretly for 2 years before the public announcement and the name change, and by then Kennedy was dead. It was Johnson who made the announcement (although probably Curtis LeMay who'd written the change).

Reply to
Andy Dingley

Not the J58 though. It's a unique design and really is a hybrid of variable bypass turbofan and a ramjet (a turbofan is a turbojet with cold air bypass, where the first fan stages are only used to deliver throust and don't pass their airflow through the hot core of the turbojet). At speed, 80% of the thrust is from the ramjet. The engine doesn't really work alone, but as part of a complex inlet system and nacelle with a movable inlet spike and reversible-flow doors. Concorde, Tornado, F-15 etc. have a complex two-dimensional moving ramp system (the characteristic square inlets), but that's nothing on the J58.

The predecessor of the SR-71, the A-12 first flew on the relatively simple J75 engine (turbojet with afterburner) and could only achieve Mach 2. With the new J58 engine, it achieved Mach 3.2 Apart from sheer speed, the fuel economy and heat loading of the J75 wouldn't have allowed the sustained high speed cruise of the J58. Unlike an afterburner, the airflow feeding the ramjet section of the J58 has been passed through the cold air bypass system, not through the engine core, so permitting more thrust and better cooling of the burners. Designing afterburning engines was always a compromise: choosing a pressure ratio for efficient dry operation limits thrust under wet (afterburner) operation. Military jets are usually limited in afterburner duration, so they're optimised for maximum wet thrust. The long SR-71 duration required efficiency in both, hence choosing the complexity of this variable cycle operation.

The bypass ratio varies in flight as the various doors and bleeds open and close. The inlet has something like 6 separate sets of inlets and doors, 3 of which actually reverse their flow direction as speed increases. From a standstill everything is an inlet to flow sufficient air mass at low speed, but the extra doors gradually close as speed increases. When supersonic, the inlet system must also act to correctly generate a shock wave that permits subsonic flow speed into the turbofan compressor (turbojets can't run on supersonic inlet air). Stabilising this shockwave requires the inlet spike to retract backwards and some of the forward doors (previously inlets) now open to dump waste airflow through the (hollow) centrebody spike and overboard.

Reply to
Andy Dingley

This list seems to have become the "I remember when" for aeronuts ... but as a registered anorak who qualifies I can live with that whilst engines are quiet .....

When I lived in the US I ran a software company. We were actively working with a bunch of aerospace companies on supply chain s/w, & I recruited a senior consultant who had good industry credentials & could open doors in Washington.

Only later, whilst sinking many beers with him, did I find out he was a former Blackbird pilot. We also had en ex-spook who had broken his back twice crashing Phantoms in Vietnam, & I'd been senior in British Airways. We had a good team ......

The Blackbird guy opened up a bit, but was still conscious that much of the performance data is still classified, as are many of the missions. He was proud that he belonged to a smaller club than astronauts...

For those interested, a must-read is Skunk Works -- the story of the Lockheed development facility -- one of the most interesting books I've read on aviation, & I own a few hundred!

Colin

Reply to
Colin

Read that on the way back from the USA, Ben Rich writes a good book.

Tim had a spare copy so I didn't have to buy it!

The co-author of the book, Leo Janos, was also co-author of "Yeager", no prizes for guessing whom that was about, and it is another very good read.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

formatting link

Reply to
Peter A Forbes

I've wandered around under two SR71's. One (s/n 06930 - NASA) out front at the Huntsville Aerospace Center in Alabama and the other is on the deck (of all places) of the USS "Intrepid", a WW2 aircraft carrier on permanent mooring in Manhattan.

formatting link
Currently closed for renovation I see...........

Regards,

J. Kim Siddorn, Regia Anglorum

This e-mail and attachments are intended for the named addressee only and the information in this message and/or attachments may contain protected health, legally privileged, or otherwise confidential information. If you, the reader of this message, are not the intended recipient, you are hereby notified that you may not further disseminate, distribute, disclose, copy or forward this message or any of the content herein. If you have received this E-mail in error, please notify the sender immediately and delete the original.

Any views expressed in this message are those of the individual sender and may or may not indicate the established policy of Regia Anglorum. It is the society's principal to rely solely upon hard copy communications in dealing with contractual matters.

This computer is protected with daily updated anti-viral software, but it is the responsibility of the recipient to ensure their incoming mail is virus-free.

Reply to
Kim Siddorn

Fascinating aircraft, we got a shot of the foward undercarriage bay, there's a lot of stuff in there!

One at Duxford One at Castle AFB (Ex SAC Base, now a museum) One at USAF Museum, Dayton OH One at Pima Air & Space Museum

I think there were about 20 or so at the end of flying.

Only at the Pima one are you allowed to poke around underneath and around the aircraft.

Petr

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

formatting link

Reply to
Peter A Forbes

I remember attending the Farnborough airshow, as a boy, in the early 70's (IIRC). An SR71 flew in, having departed from the States about 3 hours ago The flying display finished with the BBMF, that was the first time I had ever heard big piston engines working hard. I'm certain that it was this sight and sound got me hooked on engines and all things mechanical.

(winter project a Chrysler 440cid engine rebuild with 500cid forged stroker crank)

Julian.

Reply to
Julian

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.