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Seems to be the most efficient aiframe for a lot of reasons, yet they were two of a kind.
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Seems to be the most efficient aiframe for a lot of reasons, yet they were two of a kind.
Because radar? Where would the radar gear go if not in the nose of the plane?
Because supersonics require a much pointier nose to reduce shockwave, and the air intakes are oversized for later engine developments and added lots o' drag.
It started going downhill with the F-86D.
What Duke said.
Take a look at an F4 Phantom some time. Those pieces on the fuselage just ahead of the jet intakes actually limit how much air comes into the engine at higher speeds.
I recently watched an old BBC show on Youtube called When Britain Ruled the Skies. They had all kinds of wild futuristic looking jet fighter designs in the 1950s and 1960s, it's worth viewing if you're into old jet planes.
Supersonic flight is the big one.
From a visual and design philosophy standpoint, I think that airframe type is easily the ugliest post-WW1 design. It's the awkward pubescent stage between a WW2 fighter plane and a modern F15-style supersonic jet fighter.
KyAllroad wrote: What Duke said. Take a look at an F4 Phantom some time. Those pieces on the fuselage just ahead of the jet intakes actually limit how much air comes into the engine at higher speeds.
Does it reduce the air, or INCREASE the pressure of said air (therefore getting more air in). I know the cones on the front of the SR-71 were developed to do just that, even though most people look at them and see them as deflecting air.
(BTW, I'm just finishing up reading the book skunk works by Ben Rich the guy who ran the place during the stealth fighter development, it is an AWESOME read and I really recommend it).
It reduces it. At supersonic speeds the airflow is too much for a conventional jet engine.
The SR.-71 is a special case because it goes into ram-jet more at higher speeds. Whole different design parameters.
Also consider how much weight and space it costs to have a duct running through the entire plane.
Actually, the Soviets stuck with it for a while. The Mig 17 and 19 shared the same basic airframe design, as well as some of the SU's.
EDIT: Another factor that lead to the basic design being abandoned is the fact that it basically only leaves the exterior of the plane for all of the electronics, life support, weapons control, etc.
In reply to tuna55:
Because speed.....
KyAllroad wrote: It reduces it. At supersonic speeds the airflow is too much for a conventional jet engine. The SR.-71 is a special case because it goes into ram-jet more at higher speeds. Whole different design parameters.
More importantly, it makes the incoming air subsonic. Turbines can't deal with supersonic flow, so when going supersonic, there's a venturi in the air intake to reduce the flow to sub-sonic.
Also, supersonic aerodynamics are very different than subsonic- where the total cross section area is as or more important than how smooth a surface is. So where the wing area is greatest, the fuselage is narrowest.
alfadriver wrote: Also, supersonic aerodynamics are very different than subsonic- where the total cross section area is as or more important than how smooth a surface is. So where the wing area is greatest, the fuselage is narrowest.
Yes, this is called an "area-ruled fuselage". IIRC, the F-102 was built before that particular technique was invented and would barely break mach 1, the F-106 was basically a redesign of the same plane to use the area rule and would do mach 2.5.
Bascially we know a whole lot more about aerodynamics now than we did in the 50s, and all of that is incorporated into newer aircraft.
The sound barrier. Got it.
Too bad. It's a pretty thing.
In reply to tuna55:
Considering the sabre barely had adequate armament(let's face it, the 50's were good on prop driven aircraft, but inferior on the stronger jets), they did do great work in Korea.
The J-58 of the A12/SR-71 was still a turbo jet, thus requiring subsonic airflow. The genius of the Blackbird is Ben Rich's nacelles. The inlet cone slowed down air for the J-58s, and diverts air around the jet exiting in the afterburner, creating a rudementary ram jet. Rich's inlets alone contribute 55% of the total thrust. The J-58 is the only jet rated for continuous, full, afterburner.
Early jets looked like that because designers didn't know better. They were still learning and willing to try different designs to try to get the most out of first generation, low thrust, turbo jets.
The real question to ask is: why don't all pre-supersonic jets look like them (and many do). One of the prime reasons for this is that the F86 & Mig both use then then somewhat new axial flow engine design. Earlier jets used the original (Whipple designed) radial flow layout which are much shorter and fatter. Examples of that style are the Vampire and the P80 / T33:
Fun fact: You know how you can build a jet engine from a turbocharger, by feeding the compressor output into the turbine inlet? The radial flow jets in early jet aircraft were basically just a giant version of that.
GameboyRMH wrote: Fun fact: You know how you can build a jet engine from a turbocharger, by feeding the compressor output into the turbine inlet? The radial flow jets in early jet aircraft were basically just a giant version of that.
Yes!
https://grassrootsmotorsports.com/forum/build-threads-and-project-cars/the-next-project-gas-turbine-content/48381/page1/
Appleseed wrote: The J-58 is the only jet rated for continuous, full, afterburner.
I'll be that nerd-- so were the Olympus engines on the Concorde.
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