Secret Aircraft

[Sub_Umbra]

jtr-- Thanks for posting that. Years and years ago I had a great documentary on Project Pluto. I got rid of it a long time ago when I dumped my VHS tapes. I wanted to see it again a couple years ago but I couldn't remember the project's name.

IMO Project Pluto is one of the weirdest aviation stories of all time.

 

[moldyoldy]

Given the technology that was available at the the time the SR-71 in my book is an astounding example of what good engineers can come up given solid direction and resources. Kelly Johnson an Co built one helluva aircraft that looks faster standing still in a hangar than most aircraft at Mach 1.2 I remember when I was a kid watching the nightly news and seeing reports of the mysterious sonic booms off the East Coast as SR-71's headed over to Asia for recon flights. More than a few transcripts out there from air traffic controllers monitoring SR-71's that were coming in from their retirement flights and flying faster than their scopes could register over the Western US.

I've known a few people that worked out at Area 51 and related facilities. They laugh when they hear the UFO stuff and say "If you knew what really goes on out there and what we do, you'd be really, really bored".

Rather that put a tarp over secret U.S. test aircraft the DoD should just straddle them with a mannequin of Vladimir Putin

Ref the Kelly Johnson and Co quote above: When an SR-71 came in to Washington area for a flyby before landing and being trucked off to the museum, it came in relatively low over the crowd, then the pilot lit the burners, stood it on it's tail and left. After the noise subsided, one of the design engineers on the ground pulled out his slide-rule and said something to the effect of "and we designed that with these". The SR-71 certainly could be noisy, but even the U-2 was rather noisy at takeoff over my head as compared with the usual fighters.

 

[moldyoldy]

While on the subject of the SR-71, its maximum sustained speed is Mach 3.2, but the maximum speed is still classified (and rumored to be well in excess of Mach 5). I would imagine heating of the fuselage would be the biggest issue keeping the plane from maintaining >Mach 3.2, but it wouldn't prevent brief forays to Mach 4 or perhaps even Mach 5.

Somewhat related to this was Project Pluto. Although intended for cruise missiles, a nuclear-powered ramjet would probably have found its way into the SR-71 had Project Pluto succeeded. In fact, there were rumors that Project Pluto was merely a cover to develop nuclear-powered ramjets for the SR-71.

The problem with the SR-71 was not necessarily the possible speed, but if the pilot performed a zoom-climb. the SR-71 was capable of going sub-orbital, but would not have sufficient control or control surfaces for the re-entry. Even the F-15 has performed a zoom climb and hit a satellite with a missile. The preferred method is to launch a missile from a Navy ship, and was once shown on the Military Channel.

 

[moldyoldy]

imagine the sound of that? two stealth fighters flew over me once, and it has been the loudest thing I have ever heard.

I was going to say photoshopped but I guess the shadows are ok...

I saw the auroras, two flying together flanked by jets...when they landed them at edwards, in 95 or 6 or there abouts..looked something like these, but were perfect isosceles triangles..

once upon a time in a place far far away, a B52 flew over me on takeoff with full water injection. It seemingly covered the sky and I had to cover my ears, or rather, squeeze my muffs tighter against my ears. The only noisier aircraft was a C-130 with JATO assist. The high-pitched exhaust from the JATO units was really penetrating! However standing behind a pair of large fighters as their full afterburners kick in really squeezes/thumps a persons chest cavity, the noise is almost unnecessary.

 

[moldyoldy]

perhaps an fyi would help out CPF members as to some of the nuances of speeds at an altitude, especially when discussing fast aircraft such as the SR-71, Aurora, and beyond.

Using a Mach number to describe a flight speed is deceptive, and valid only for that aircraft at that altitude nominally as determined inside the aircraft. For most of the ground-based purposes, speeds are cited in a distance covered in a short period of time, such as 1.6 miles per sec (SR-71), or a named ground speed in conventional units which can be used for speed record purposes. Nevertheless, a Mach number is dependent on the altitude, temperature, density of the air, etc. Here are some links to help out the discovery process:

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http://www.aerospaceweb.org/question/atmosphere/q0112.shtml

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There is a calculator in the following link that is quite useful.

http://www.grc.nasa.gov/WWW/k-12/airplane/mach.html

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Flying supersonic at low level is a feat of power. The B-58 Hustler was designed to fly supersonic at low level (over Moscow) and was equipped with 4 after-burning engines. At higher altitudes, the B-58 Hustler at Mach 2 was a challenge to the fighters of it's time and set many records! The F4 Phantom could achieve Mach 2.2 and was considered a good example of if you mounted big enough engines on a rock, it would fly. The SR-71 is listed only as Mach 3+. Modern A-A missiles fly around Mach 5. The US Space Shuttle re-enters the atmosphere at about Mach 25 and comes out of the ionization layers at about Mach 23.

Flying supersonic at high altitude requires less power as compared with low level supersonic flight from an air-breathing engine. However, how that air-breathing engine is designed varies widely between nominally supersonic aircraft.

The SR71 uses turbo-ramjets with an inlet cone or spike that moves back in the housing with increasing speed. The MiG-21 has an inlet cone that moves forward with increasing speed. The MiG-25 Foxbat was supposed to be a competitor to the SR-71 and uses a totally different type of air intake. For the English speakers:

http://en.wikipedia.org/wiki/Inlet_cone

In all cases, the engine design controls the airflow in to the engine such that a supersonic shock wave does not reach (too far) into the air-breathing engine where the goal is to avoid supersonic flow inside the engine such as a scramjet. ie: The SR-71 engines are mounted farther out on the wings to avoid the shockwave from the nose. A more critical factor in the SR-71 is that the shock wave from the inlet spike nominally ends at the outer shroud and should not penetrate (too far) in to the engine. At max speeds, the inlet is fully back against the stop. Those shock waves vary with the various altitude related factors. Which means that a "max" speed at one altitude is not the same "max" speed at another altitude. Which is one of the reasons why the MiG-25 and the SR-71 traded off setting speed records....

Here is a link to the SR-71 manual opened to the engine page showing the air flow and shock waves. Notice that the bottom image stops at Mach 3.2 with a fully retracted inlet cone. That means a specific Mach number at flight altitude - leaving some wiggle room for the many rumors of how fast the SR-71 could fly

http://www.sr-71.org/blackbird/manual/1/1-33.php

In my mind, the SR-71 is truly the last of it's kind, meaning very fast with air-breathing engines, no matter at low or very high altitudes. Beyond the SR-71 are other interesting aircraft with a ramjet/scramjet, or the rumoured Aurora with maybe a pulse-jet,..... At my former work, I had a full-screen photo of the SR-71 in flight on my home screen. The SR-71 was truly impressive in so many ways!

 

[Flying Turtle]

Interesting stuff. Thanks for the education.

Geoff

 

[StarHalo]

My favorite part of the SR-71 - who can name this device?

 

[moldyoldy]

Is that the rear view periscope, handle included? With the rear-view periscope the pilots could visually check on the engines, etc.

 

[StarHalo]

rolling bump

 

[Pinetreebbs]

My favorite part of the SR-71 - who can name this device?

Titanium O hammer?

 

[firelord777]

Nope, it's the DINGHY STABBER - one of the early SR-71s had an incident where the emergency survival raft inflated itself in the cockpit mid-flight, so after that, all SR-71s came with an icepick-type weapon that would allow the crew to frantically stab the sh*t out of a wayward dinghy if it were to happen again, then carry on their mission unabated. Some quality Soviet-style engineering thinking :thumbsup:

LOL!!! Imagine a pilot and his boat inflates! He'll be like "who put this piece of fart here!"

 

[StarHalo]

Is that the rear view periscope, handle included? With the rear-view periscope the pilots could visually check on the engines, etc.

Titanium O hammer?

Nope, it's the DINGHY STABBER - one of the early SR-71s had an incident where the emergency survival raft inflated itself in the cockpit mid-flight, so after that, all SR-71s came with an icepick-type weapon that would allow the crew to frantically stab the sh*t out of a wayward dinghy if it were to happen again, then carry on their mission unabated. Some quality Soviet-style engineering thinking :thumbsup:

 

[moldyoldy]

Nope, it's the DINGHY STABBER - one of the early SR-71s had an incident where the emergency survival raft inflated itself in the cockpit mid-flight, so after that, all SR-71s came with an icepick-type weapon that would allow the crew to frantically stab the sh*t out of a wayward dinghy if it were to happen again, then carry on their mission unabated. Some quality Soviet-style engineering thinking :thumbsup:

chuckle! No report I ever read mentioned that little piece of equipment! did the SR-71s ever have another inflating raft incident?

 

[StarHalo]

chuckle! No report I ever read mentioned that little piece of equipment! did the SR-71s ever have another inflating raft incident?

Only happened the one time. As far as I know, the Blackbird was the only military aircraft that had an edged weapon as standard interior equipment.

 

[AnAppleSnail]

Only happened the one time. As far as I know, the Blackbird was the only military aircraft that had an edged weapon as standard interior equipment.

I would insist on training day that this icepick is strictly for repelling boarders in flight.

 

[moldyoldy]

I would insist on training day that this icepick is strictly for repelling boarders in flight.

and the rear view periscope is to check 6 - where are those fighters getting on our tail...

 

[StarHalo]

Say hello to the Boeing CHAMP - Counter-electronics High-powered Microwave Advanced Missile Project, better known as the "Flying Blackout"; this EMP-generating guided cruise missile was successfully tested last week when it flew a predetermined route over a Utah desert testing area and shut down all the computers located at seven target areas - it also inadvertently killed the cameras at those sites that were meant to monitor the event.

 

[moldyoldy]

heheh, lots of publicity... but, anything that is goes public already existed in various forms for quite some time before this particular test. Not far from where we tested our howitzers in the desert SW, there is an EMP test facility. What impresses me is that the power generation to penetrate buildings was shrunk to a missile size. One of the reasons that the Soviets still designed A/C electronics with electron tubes in some of their advanced fighters is because electron tubes are very resistant to EMP or the very strong radars as found on some other aircraft. meaning that a fighter pilot really should not want to fly in front of some theoretically unarmed aircraft. In any case, rad-hard chips are difficult to design and build with a very low yield. read: expensive! nuff said.

 

[AnAppleSnail]

What impresses me is that the power generation to penetrate buildings was shrunk to a missile size.

Doing it once is easy. You move something through a high-voltage coil with explosives. Doing it multiple times, though...that's impressive.

 

[Steve K]

Was there someplace authoritative that said that the CHAMP generated an EMP? The two Boeing press releases that I checked just said it used microwaves to take out specific targets. In that way, it remind me of most ECM (electronics countermeasures) aircraft, such as the EA-6B Prowler or EA-18 Growler.

There is one site that specifically indicates that it is not an EMP type device:
http://www.theregister.co.uk/2012/10/25/boeing_champ_missile_microwave_attacks/

"Boeing announced the plans for CHAMP back in 2009, as part of the US Army's continuing quest for a weapon that can knock out electronics easily. You can do this with the electromagnetic pulse (EMP) produced by a nuclear explosion, but those tend to be somewhat messy as they produce rather too much "collateral damage." "

As a guy who does EMC work, I'd be interested in hearing about the power generated, the fields produced, etc. In general, commercial electronics is not designed to tolerate much of an electromagnetic field. Automotive stuff is generally around 30v/m, I think, and mil-spec aircraft is in the range of 200v/m. The stuff I work with is more in the 100v/m range.