Science question of the day: Why was the SR-71 Blackbird painted black?

03Sssnake

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It has to do with the base used. Light colors use a white or light base which has more titanium dioxide in it which makes it more opaque. Darker colors have a more clear base that has little to no titanium dioxide.

:D

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Machdup1

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It seems clear that they science’d the shit out of it and decided of all of the technical solutions, black looks sinister as ****, which will make the Soviets our bitches. Sonic boom, decision made.
 

CV355

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Answer is already in this thread. My question is, if they wanted to eliminate the 1100 pounds paint would add, why didn't they explore other methods of coatings/treatments? It's not like they didn't have the budget for it.. :)

Aww hell, tear off every exterior panel and send it out for PVD nitride.
 

Silverstrike

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The Mig 31 could only briefly maintain mach 3 on those intercepts...However they got their timing down and that along with the AA-9 scared us enough to start keeping our distance and eventually end the flights into Soviet airspace.


No the MiG 31 could never achieve Mach 3 it is only capable of doing a Mach 2.8 dash of about 5 minutes, unless you don't throttle back then engine damage would occure past that time, the Recon MiG-25 though could do sustained Mach 3 and 3.2 in brief dashes, the Interceptor MiG 25 though could never do it as it was specifically red lined at Mach 2.8. Belenko (which defected to Japan in 1976 with his MiG-25) stated when the CIA told him of Israeli F-4's trying to intercept MiG-25's over the Goland Hts on how the MiG's would always throttle up and go past Mach 3 every time their RWR's went off when a Phantom achieved a lock. He flat out stated that those engines would of been junk and would need a total overhaul, it also explained why his unit started to have supply of engine problems as they was being diverted to a Middle East nation, at the time there was only 3 MiG-25 operators outside of the USSR, that being Libya, Algeria, and Syria. And Syria never had any recon 25's in their fleet until the Bekka Valley incident in 1982 so all of those run ins was with the interceptor MiG-25's between Israel and Syria in the late 70's.

But what made the MiG-31 a real terror was the data link system it employed. Where a 4 ship formation of MiG-31's going against 8 air targets would communicate electronically between themselves. Where the flight lead would pick 2 targets and it would be sent to the other three then his wingman would pick another 2 that wasn't picked out by the lead and it would continue to the other element and his wingman to where all 8 would be locked up and engaged and fired on without breaking radio silence! NATO did not find this ability out until a Soviet spy defected to the west in the spring of 1988.
 

James Snover

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GNBRETT and a couple others got it right: heat reduction via radiation. Everybody thinks black is the worst color for keeping cool because you put your hand on a black car, it burns. The trick is: that is heat that was absorbed, and now being re-radiated back out. The secret is that black both gains and loses heat faster than any other color. So if you are going to be picking up a lot of heat, say from air friction of half-a-psi at 80,000 feet at Mach 3.2, black is the best way to get rid of it.

It was a few months later they figured out they could add stuff to the paint for radar absorption.


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James Snover

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I forgot to say why they needed an efficient way to get rid of the heat. Here’s why:

The temperatures at the hottest part of the airframe were getting within 100F degrees of the temp at which Titanium begins to lose strength. Most metals will lose strength way before they begin to melt, and the Blackbird needed the strength of the Titanium and it’s light weight. One without the other was no good.

In aerospace engineering, a margin of a hundred degrees is not acceptable. So Ben Rich, the guy who designed the inlets and all of the Blackbird’s critical thermodynamic issues, suggested painting it black because he remembered his high school physics.

The story goes that Johnson blew a gasket. Here he is trying to save every pound he could, and here is his right hand man suggesting adding 1,100 pounds for a gimmick he didn’t even think would work.

But he thought about it overnight, and in the group meeting the next morning, Johnson told everyone he was wrong, Rich was right, and then he gave Rich a one-dollar bill.

BenRixh said he, and the two or three other guys who proved Johnson wrong, never spent those dollars. They framed them. Because Johnson was almost never wrong.


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James Snover

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Answer is already in this thread. My question is, if they wanted to eliminate the 1100 pounds paint would add, why didn't they explore other methods of coatings/treatments? It's not like they didn't have the budget for it.. :)

Aww hell, tear off every exterior panel and send it out for PVD nitride.
They didn't have them in the late fifties/early sixties. Everything about the Blackbird was special, and all of it was designed to manage heat, and they had to invent at least 75% of what went into the old girl.

The oil for the engines is one example: it was solid below 750F. It had to be preheated with torches before flight to get it into a liquid state. No gaskets sealing the fuel tanks. Nobody had any material that could take the range of temps. So she leaked, on the ground. The fuel: highly uninflammable. It had to be preheated before being fed into the combustion chamber to ensure ignition. So ... they also used it as coolant throughout the leading edge surfaces of the wings, and bingo: 2-for-1. Cooling the airframe, pre-heating the fuel.
 

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Thanks for going thru this exercise. You never know when you need to think outside the box, and lots of time its already been done, just with a different box.
 

James Snover

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Thanks for going thru this exercise. You never know when you need to think outside the box, and lots of time its already been done, just with a different box.
It's an easy subject for me to get carried away on. One of the all-time great engineering feats humanity has managed to come up with (so far), and then there's the Skunkworks, and how Johnson managed it, and then there's the sheer size of the program when you add in the tankers, maintenance, special supplies, different variants. One of my favorite subjects.
 

598

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I understand the supply side logistics just to keep it in the air, and the covert ops to service it overseas were huge.
 

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It's an easy subject for me to get carried away on. One of the all-time great engineering feats humanity has managed to come up with (so far), and then there's the Skunkworks, and how Johnson managed it, and then there's the sheer size of the program when you add in the tankers, maintenance, special supplies, different variants. One of my favorite subjects.


The only thing I think was never cross tried was between KC-135's and KC-10 on keeping the Blackbird fleet fueled on missions, as I have never seen a Blackbird in photos or video's behind a KC-10 only the KC-135's.


I have seen the lone YF-12A, the SR-71A both at the USAF museum then the SR-71B at Kalamazoo Air Zoo. I would love to see the SR-71C or the bastard bird as it was known by the crews, what made it special was that it was the only hybrid SR ever made, what made it a hybrid, simple Lockheed took the rear remains of the crashed 2nd YF-12A and grafted a SR-71B nose to it. The real story behind the derogitory name was that it had a nasty tendency to yaw out of control if you wasn't on top of your game. The C is on permanent display at Hill AFB in Utah which is a little out of the way from Ohio to go see.

Then you have the model that started it all the A-12 I would of loved to seen the lone trainer that Lockheed built of the 12 but that is never going to happen as it is on display in California.
 
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ViperRed91GT

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The only thing I think was never cross tried was between KC-135's and KC-10 on keeping the Blackbird fleet fueled on missions, as I have never seen a Blackbird in photos or video's behind a KC-10 only the KC-135's.

Because the 71 used JP-7, so they modified some of the 135’s (designated the Q model) to carry this fuel. Cost prohibitive and unneeded capacity to modify any of the KC-10’s, coupled with the fact that it didn’t exist during the creation and first half of the operational time of the 71.
 

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