Yep!
The finish on these is amazing.

The SR71 nose must be shaped like that to deal with the shockwave somehow.. but far beyond me to visualise how it might behave. Can anybody explain?

Good question. I was wondering the same thing!
In this shot you can just make out the 'divots' spoiling the nice curve.


Sorry for the poor photo quality (it was the special paint)

THE SR-71 Blackbird? You got to see on in real life? Oh. My. God.

I didn't know people were allowed to do that.

I read that the panels were so loose at room temp that the thing leaked fuel like crazy. Once it got in the air, the pilot took it up and back at supersonic speeds to heat up the skin so it would actually hold fuel. Then they would air-to-air fuel it up for the actual mission.

I heard the SR-71 is the king of all in aerodynamics, maybe its design can be implemented on more conventional aeroplanes unless of course, its a supersonic only design. Pictures are amazing.

Mmm, not really. The U2 was more impressive in some ways. For various reasons the performance envelope for the SR71 was a bit broader than the U2, that is, it was less finely tuned.

Not a bad aircraft by any means, but it didn't really pave the way very much, or establish a useful baseline for next generation a/c. Concorde (for example) was a much cleverer design.

Yeah but the thing was bloody fast!

Is there even now an "official" plane that can go faster?

You should be asking us Comrade.

Greg, you could be talking about Formula One!

By the way, those 'divots' were caused by the SR71 ramming the refuelling tanker.

There is also this detail on the wing , taken from the time I went to Duxford too

I think there are more amazing facts about this plane than any other.
Being able to get up close and pick at its titanium skin with your fingers is a real joy.



32,000 lb thrust. 450kg fuel per minute. Engine increases efficiency as speed increases!

Divots? IR sensors.

I think that deserves a 'why' too. Where are all the supersonic aerodynamicists on this F1 forum?

Excuse my poor terminology, I was referring to the two 'dents' in the bodywork.
I like Tony's reasoning best so far

The efficiency of any normal jet engine increases with speed (up to a point) . It's all to do with the relationship between thrust and horsepower.... As we all know hp is more important.

There is something that was unique to the SR71's engines at that time, possibly standard now, in that they acted more like ram-jets at very high speed, and the central cones were hydraulicly moved fore and aft as the speed changed to control the shock-waves entering the intake. I think Concord had a similar system using ramps inside the intake. I have always had admiration for the US aeronautical industry, especially at the cutting edge, not that we couldn't have done the same or better with sufficient funding and the political will, but it puzzles me that the automobile industry has not follwed suite, if they had perhaps they would be real contenders in F1.

The world is a less exciting and awe-inspiring place without the SR71 and Concord.

thats a beautiful picture. i REALLY need to get myself to duxford soon!

On the topic of wing twist. The primary reason for having a twisted wing is to ensure that the tips are at a lower angle of attack than the rest of the wing, and so at high angles of attack the root will stall first and then the tip. thats pretty useful if you want to ensure you have control authority to recover from the stall.

In subsonic planes, an elliptical lift distribution minimises induced drag, and this can be achieved by either have an elliptical wing like the spitfire, or a wing with different planform geometry with varying levels of twist.

The design of the nose has me a bit puzzled but i suspect it might have a subsonic motivation rather than a supersonic one. in any case i will ask my aerodynamics professor about this, im sure he'll know! Some Sr-71's/A-12's had a smoother nose:

http://www.sr-71.org/photogallery/blackbir...961-2003-01.jpg

As Tony Matthews mentioned, a lot of supersonic aircraft have/had ramps and cones to ensure that the shockwaves created at the tip of the ramp/cone coincide with the entry to the engine nacelle/housing. the reflection of shock waves continues down the intake, compressing the air all the way. This compression is so much that at about Mach 3, your engine no longer needs a traditional compressor and so the idea of the ramjet came about..

Well, now you've got me thinking, when did variable geometry intakes get introduced? B70 had them so they must have tried in them in the 50s. Su7 (Fitter)had them in 55.

Have you seen the Bristol 188? The RAF base where it is held (near Telford) has a brilliant museum, full of oddball stuff like a collection of German WW2 SAMs and suchlike.

I've only just started getting into your posts TM, and all I can say is,

where have you been my whole life?

LOL! Quick I'll say something absurd! Erm ... Montoya needs to get the hell out of NASCAR and get his ass back to the more worth pursuit of F1!

Phew!

The intakes are what impressed me most. The cones slow the air down and 'screw' in and out by 66cm to direct the airflow. Mind-boggling to think that they worked it all out on models and them sent some plucky chap up at 1500mph to make sure it works!
Apparently on an early mission the pilots had to increase cruising speed to avoid a touch of trouble which is when they found out they used less fuel than expected.

Unfortunately the U2 was hanging from the top of the hanger so I couldn't get any close ups. Its shape and form is very pleasing to the eye though!
I will have to check out RAF Cosford(?) next time I'm up there.

I don't know about "official" but I believe that's public knowledge.

I always thought the fuel used in the Blackbird was interesting... PWA 535 aka JP-7. Extremely low volatility and high oxidation stability, not distillate-based but a selection of blend stocks with very low impurities. Almost no oxygen, toluene, nitrogen, etc. Unbelievably expensive, boutique fuel. Also contained cesium to reduce the exhaust radar signature. Very slippery, considerable perflourocarbon content to improve lubricity as the fuel is also the working fluid in cooling and lubrication circuits.

The volatility being so low, an injector system was required for startup or lighting the afterburner... squirted in about 50cc of triethylborane which is *extremely* pyrophoric. The aircraft was a logistical nightmare on multiple levels, a real PITA operationally and thus not the most flexible of tools, an important factor in reconnaissance... no doubt contributing to the regular program cancellations.

BTW, the SR-71/A12/M21 starter carts were constructed by Frank Kurtis, the Indy car builder. Used a pair of 425 ci Buick V8 engines with automatic transmissions, later updated to LS6 BBC. So in a Blackbird group the start cart was known as a Buick, as in "okay, bring the Buick over here." Open exhaust headers, spun the turbine up to 3200 rpm to light the firecracker. Kurtis also supplied the start carts for the F-100 Super Sabre (which also carried a cartridge system) and built the Rocketdyne sled for North American, one of the fastest land vehicles ever built... though it never carried a passenger.

On reflection - and all my comments are made without reference to google, as I keep forgetting it's there - variable geometry intakes are probably well-used from quite early, I just mentioned the ones I knew about. The SR71 cone is, for some reason, particularly interesting to me.

the Bristol 188 doesn't ring any bells, Greg, I will check it out. I may even have seen it, as my father took me to Farnborough regularly in the '50's, when it was an annual event and showcased so many fascinating new and experimental aircraft - so many memories! My early interest was always more 'plane oriented than cars, it's just that cars seemed to get more interesting and 'planes less as the years passed. The Telford museum sounds very interesting, I will check that too.

I live only 40 minutes drive from Duxford, and the USAF section is something else, a great piece of architecture crammed full of wonderful exhibits, I must go again soon!

OfficeLinebacker, thank you for what I take to be flattery, even if it's not it sounds nice!

Yes, crammed is the operative word.

Here's the 188, as you can see a (big) generation earlier than the A12/SR71

http://www.rpec.co.uk/engineerswalk/pics/26ResearchT188.jpg

There are a couple of dozen SR-71/A12/M21 on display in various collections around the USA, so you shouldn't have too much trouble finding one if you are interested. (I think just about everyone but Walt Soplata got one.) Wright-Patterson in Dayton has all three variants. Also has the remaining XB-70 and lots of other cool stuff.

Btw Robroy, do you have any pictures of the TSR-2 that is apparently based in Duxford?

I should add, getting back to this thread's topic , the 188 is bright stainless steel.

LOL think of the fuel they WERE going to use--coal slurry!

Oh, BTW--this is my desktop, has been for months:

I did read once that at Mach 3 cruise a large proportion (50+%) of the thrust of the engine came from the suction at the intake nozzles! I don't know how accurate that claim is.

Went to Dayton in 2006. Had the interesting experience of having a security check to go to the experimental hangar.



That is the Piper Enforcer (a turbine powered Mustang) with the SR-71 in the background.

Also went to Duxford in 2007, but to an airshow amd not the museum.

The thrust from the intake thing is one of those chicken and egg factoids that always gets thrown around. kinda sorta, in my opinion. When you are at Duxford make sure you visit all the hangars, the maintenance workshop is very interesting (obviously you take pot luck as to what they are working on).

OLB - do you know what those circles are in that exhaust?

Shock Diamonds <- (link)

Great photo OLB! It just became my desktop wallpaper too.

Yep the pic is actually captioned. Neat link from gg though.

Sorry! No. My old digital camera can only hold 30 photos!!!!!!! I really need to get a new one soon.

I didn't realise there were so many different shaped noses on the SR71's, but I'm really interested by the shape of the Duxford one. Let us know what your professor says regarding the shape of this!

I remember the Bristol 188 now, the photo seemed very familiar! Never saw it fly though. Stainless steel? Fairey Delta 2, one-time Woprld Airspeed Record Holder, I think, piloted by Peter Twiss, 1,300-odd mph, and a droop-snoot precurser to Concord. Remember the time when test pilots were heroes, and their names known in every house-hold?

I trust youall took a moment to remember our veterans on Monday. I think veterans day is held on a different day in England or Europe. My dad, 90, and two brother's, Army, and me flew to Mc Dill AFB for a really great time on Monday. I flew back today in really shit weather.
The shape of the nose was part of a laser air-data collection system. It uses laser light instead of air pressure to produce airspeed and attitude reference data such as angle of attack and sideslip (normally obtained with small pitot tubes and vanes extending into the air stream or from tubes with flush openings on an aircraft's outer skin.) These notches and other detection sensors locations provided information for the systems that are now installed on current hypersonic manned spy planes that we know nothing about which tell of the presence of atmospheric particles at altitudes of 80,000 feet and above where the 'new' planes are operating continuously and sometimes generating Mach 8 signatures. The system uses six sheets of laser light projected from under the surface. As microscopic-size atmospheric particles passed between the two beams, direction and speed were measured and processed into standard speed and attitude references. An earlier laser air data collection system was successfully tested at Dryden on a F-l04 testbed.

It did so. Kelly Johnson's finest. Research information from the YF-12 program was used to validate analytical theories and wind-tunnel test techniques to help improve the design and performance of future military and civil aircraft. The American supersonic transport project of the late 1960s and early 1970s benefited greatly from YF-12 research data.
From February 1972 until July 1973, a YF-12A was used for heat loads testing in Dryden's High Temperature Loads Laboratory (now the Thermostructures Research Facility). The data helped improve theoretical prediction methods and computer models of that era dealing with structural loads, materials and heat distribution at up to 800'f, the same surface temperatures reached during sustained speeds of Mach 3.
When you first saw the SR 71, it was obsolete. About 1985 or so. They first flew when I was in high school way back in 64. The Blackbird's performance is still classified. There are things flying out there with Mach 8 signatures and the SR 71 was a test bed for systems found on these new spy planes. See my other post.

The SR-71 was used as a science camera platform for NASA's Jet Propulsion Laboratory, Pasadena, Calif., was flown in March 1993. From the nosebay of the aircraft, an upward-looking ultraviolet video camera studied a variety of celestial objects in wavelengths that are blocked to ground-based astronomers.
In addition to observing celestial objects in the various wavelengths, missions included "downward" looking instruments to study rocket engine exhaust plumes, volcano plumes and the Earth's atmosphere.

The SR-71, operating as a testbed, also has been used to assist in the development of a commercial satellite-based, instant wireless personal comunications network, called the IRIDIUM system, under NASA's commercialization assistance program. The IRIDIUM system is being developed by Motorola's Satellite Communications Division. During the development tests, the SR-71 acted as a "surrogate satellite" for transmitters and receivers on the ground.

The SR-71 was used in a program to study ways of reducing sonic boom overpressures that are heard on the ground much like sharp thunderclaps when an aircraft exceeds the speed of sound. Data from the study led to aircraft designs that reduced the "peak" of sonic booms and minimize the startle affect they produce on the ground.

Instruments at precise locations on the ground record the sonic booms as the aircraft passes overhead at known altitudes and speeds. An F-16XL aircraft (Another story)was also used in the study. It was flown behind the SR-71, probing the near-field shockwave while instrumentation recorded the pressures and other atmospheric parameters.

yes. Much faster.

The Lockheed F80 Shooting Star was first built around the British Halford H.1 Goblin engine which was developed during WWII. This turbojet had the first variable inlet and was further developed by Allison with their 1946 J33 supersonic engine. We stole everybody's technology after the war and our German scientist were better than your German scientist, so there. The British Bolshevik government gave their Commie allies in the USSR all of the latest jet engine technology directly after the war. Our commie president at the time gave the Ruskies our A and H bomb technology in real time. Our present communist government is transferring our classified technology to the Chicoms at an alarming rate as did comrade Clinton. Man, do I hate the left. We all stand by while they destroy our western civilization. Anyway, where was I? Oh yeah, somewhere in this BB, some real aero guys discussed the F4 vari-ramp bleed air inlets. I wish I knew that much about them before I flew the dam things.
.

Way back when, the big lasers were gas dynamics, basically a rocket engine with mirrors. The laser group was in the Rocket Support building, which was about a mile further out in the swamp from the jet engine test stands. When the J58 was tested, as we drove to work we could see a second jet engine sticking out of the test stand, apparently this was needed to run some sort of air pump to move enough air to get the J58 to run like it was at altitude. My coffee cup would vibrate on my desk when they throttled it up, you had to wear Mickey Mouse ear protectors if you were going to drive past the test area on the way to lunch.

All the SR 71s and YF-12s and the XP 70 I've seen leaked fuel even after being in museums for years.

The SR-71 Blackbird's Pratt & Whitney J58 engines were in that they could convert in flight from being a turbojet to being a compressor-assisted ramjet. At high speeds (above Mach 2.4), the engine used variable geometry vanes to direct excess air through 6 bypass pipes from downstream of the fourth compressor stage into the afterburner. 80% of the SR-71's thrust at high speed was generated in this way, giving much higher thrust, improving specific impulse by 10-15%, and permitting continuous operation at Mach 3.2. The name coined for this setup is turbo-ramjet.



http://en.wikipedia.org/wiki/J-58

http://en.wikipedia.org/wiki/Rolls-Royce_Olympus

Fed on air compressed by supersonic waves, wow. That has to be the mother of all air intake.

No unfortunately there's not.
There's the myth of the Aurora, but it's just a myth. The only engines capable of going much faster than the SR-71 could are scramjets, and they are still just test models - of which Australia is leading the way. There's also ramjets, but they need a fair bit of speed before they can start to work. There's also no real airframe technology that can take the sustained heat.

The SR-71 was an utterly amazing project though, to think that in the late 50's such a machine could be made!

I'd be quite happy if it were maximized.

I didn't think the technical forum was the place for a political rant, but it must be a pretty dumb sort of US Commie government that allows itself to get re-elected every 4 years, and puts a lethal weapon in the hands of someone with apparently no knowledge or experience of geopolitics.
Come on Phantom II, I was in Czechoslovakia in 1968 when the Prague Spring was crushed by a Soviet invasion, so I saw what real communism is like.

Didn't you know that everything to the left of Adolf Hitler is a communist.

Who you going to believe? When you knew about the SR71, it had already been flying for 20 years. 3 of the SR71s that flew in the late 80s and early 90s were test beds for the systems that are used on the new spy planes.