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97 votes
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Why does it take so long to develop modern military jets?

First of all, it took at least five years even back then, but your observation is absolutely correct. You would need to go back one more decade to find a frontline fighter that was designed within ...
Peter Kämpf's user avatar
90 votes

Why does it take so long to develop modern military jets?

There are quite a few reasons for this- technically speaking, the primary one is that the system complexity has increased tremendously. More systems mean more interfaces, more redundancies, meaning ...
aeroalias's user avatar
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65 votes
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Why was the production of the Lockheed SR-71 Blackbird halted?

Why did they stop building it? Because they built 32, and that was as many as was needed at the time. 32 spy planes was plenty for the USAF/CIA to use, so building more would have been a waste. By ...
Jon Story's user avatar
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44 votes

Why does the SR-71 Blackbird sometimes have dents in the nose?

The SR-71 had a detachable nose (photo #2), and could change between three different nose cones depending on the mission. I haven't found a lot of information on the three, other than what this site ...
bjelleklang's user avatar
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43 votes

Why does it take so long to develop modern military jets?

UPDATE: I want to clarify/emphasize a few things in my answer. #1: Ultimately, the core driver of development time is growing complexity. More advanced threats means more advanced systems, which ...
Hephaestus Aetnaean's user avatar
43 votes
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Why was the SR-71 made of titanium?

Because the specific strength of titanium at higher temperatures is better than that of steel (both are much better than that of aluminium). Specific strength vs. temperature is shown on the above ...
Koyovis's user avatar
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42 votes
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Could the SR-71 Blackbird be used for nearspace tourism?

Significant issues with the concept: the SR-71 lacks RCS, so you'd lose attitude control if you got significantly above normal operating height. I originally wrote that it doesn't handle in-flight ...
Zeiss Ikon's user avatar
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39 votes
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The SR-71 flew at 2193 mph. Mathematically, how can this be Mach 3.3?

The SR-71 was only capable of Mach 3.3 flight at altitude. You can see the limitations in the pilot's operating handbook(POH) for the aircraft: At higher altitudes the relative speed of sound is ...
Dave's user avatar
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35 votes
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Why did the SR-71 Blackbird have a light on its top?

That is an anti-collision light as described in the flight manual: Anti-Collision/Fuselage Lights and Switch Two combination retractable anti-collision and fuselage lights are located at the top and ...
Bianfable's user avatar
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27 votes

Heating of XB-70 vs. SR-71

While black surfaces emit heat more efficiently than lighter colours, this was not the only reason for the colour of the Blackbirds. Earlier iterations of the A-12, the predecessor of the SR-71, were ...
Jpe61's user avatar
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23 votes

Could the SR-71 Blackbird be used for nearspace tourism?

I work and have worked with several SR-71 crew members. In the past, they have pointed out two principle impediments: Crew workload Cost Crew workload is shared between both crewmembers, and the ...
mongo's user avatar
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21 votes
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How long did the SR-71 take to get to cruising altitude?

According to the performance data in the manual it takes 19.9 minutes to get to 70,600 feet. Refueling time will depend on how much fuel is needed for the mission as well as how long it takes to ...
Dave's user avatar
  • 101k
21 votes

Why did the SR-71 Blackbird have a light on its top?

During missions the SR-71 had to be refuelled air to air many times. These missions took place also at night, so visual cues were absolutely necessary. Also the mission obviously were often flown ...
Jpe61's user avatar
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21 votes

Why was the SR-71 made of titanium?

There is a great article here that breaks it down in depth but its combination of factors made it the best choice, not a single factor (i.e. heat resistance). But, in reality, the strongest titanium ...
Dave's user avatar
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19 votes
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What are the limiting factors for high altitude planes (e.g: U2 or SR71) preventing them from going higher?

The limiting factor for subsonic aircraft, including the U-2, is well explained here. For supersonic aircraft this answer simply says the limit is "a combination of wing loading and maximum speed". ...
Peter Kämpf's user avatar
17 votes
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Why was the U-2 so different from the SR-71?

Because the requirements were different. When U-2 was developed, the requirement was for an aircraft which would fly high at 70,000' due to the (mistaken) belief that the Soviets would be able to ...
aeroalias's user avatar
  • 100k
17 votes

Why does it take so long to develop modern military jets?

In the age of computerized design, drafting, testing and milling, we can develop products faster than ever before. It's definitely not technology slowing down development. When we develop a plane for ...
gwally's user avatar
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16 votes
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Why does the J58 engine of the SR-71 have a diffuser after the inlet spike?

Generally, a compressor cannot work efficiently at supersonic speed due to the shockwaves, the role of the inlet cone and diffuser is to slow the air below Mach 1. There is a similar need for a ramjet,...
mins's user avatar
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16 votes

Could the SR-71 Blackbird be used for nearspace tourism?

Typical SR-71 missions proceeded as follows: Fill tanks on ground. Tanks leaking fuel like crazy, by design. Plane takes off, with fuel leaking everywhere. Plane gets to altitude, and flies very fast ...
John's user avatar
  • 269
15 votes

Why does it take so long to develop modern military jets?

This is just an additional point, but a bit more than a comment. In the late 60s there was still a cohort of design/test personnel whose skills and attitudes were formed during WWII and the early ...
Chris H's user avatar
  • 1,157
14 votes

Heating of XB-70 vs. SR-71

The color of the aircraft was decided primarily based on the military mission, not for temperature. Black helped the SR-71 blend in better at night and high altitudes, and the paint was also designed ...
fooot's user avatar
  • 73.4k
13 votes

Why was the production of the Lockheed SR-71 Blackbird halted?

For several reasons: First off, the SR-71 was a plane which was never intended. An earlier Blackbird incarnation, the single seat A-12 had been in service for several years with the CIA under the ...
Romeo_4808N's user avatar
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12 votes
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Can stainless steel replace titanium for Mach 3+ speeds?

Both the MiG-25 and MiG-31 designs had engines that would overheat and be damaged an anything past Mach 2.83, so both planes were limited by this. Typical speeds were closer to Mach 2.5 to extend the ...
fooot's user avatar
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11 votes
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Is there currently any heat shielding and paint for speeds of up to Mach 6?

I'm reasonably certain the speed limit (so to speak) on the SR-71 wasn't to prevent its skin from melting. The hottest the skin got during flight was less than 600 C. That's definitely hot--but it's ...
Jerry Coffin's user avatar
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11 votes
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Is it possible to use refrigeration technology to cool the skin of supersonic aircraft?

Is it possible to use refrigeration technology to cool down the aircraft's skin so it can reach much higher speeds? Fundamentally: no. Refrigeration technology moves heat energy around, it doesn't ...
vidarlo's user avatar
  • 1,526
10 votes

What are these SR-71 "Ports" for?

According to the SR-71 handbook section 6-11, these are fuel dump vents (outer) and fuel tank pressure relief vent (center). Since this is copyrighted material, I will not include a screenshot of the ...
Jpe61's user avatar
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10 votes
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Heating of XB-70 vs. SR-71

So how it is possible that these two planes... are so differently handling with the heating? Different materials built in different ways. The only materials able to sustain high temperature without ...
sophit's user avatar
  • 13k
9 votes
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What is the true top speed of the SR-71?

Based on the SR-71A operational envelope, the top Mach number was Mach 3.3 when authorized by the commander and Mach 3.2 otherwise. The top airspeed was 400 kts equivalent airspeed when supersonic and ...
Cpt Reynolds's user avatar
  • 4,807
8 votes

Can stainless steel replace titanium for Mach 3+ speeds?

Let's note some properties of steel and titanium. For steel, we choose 4340 alloy (oil-quenched and tempered); for titanium, we use the Ti-6Al-4V alloy (solution heat-treated and aged). These are not ...
Sanchises's user avatar
  • 13.4k

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