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Newbie questions Rail / Ejector launchers
Hi,
Here is a newbie question. What are the merits and the pitfalls of rail vs ejector launchers for guided missiles? I suppose bombs have to be ejector launched and rockets rail. Whenever I visit an airshow, I ended up scratching my head. -- AL New anti-terrorism tool, "Fly naked" http://www.alfredivy.per.sg |
#2
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AL wrote in message ...
Hi, Here is a newbie question. What are the merits and the pitfalls of rail vs ejector launchers for guided missiles? I suppose bombs have to be ejector launched and rockets rail. Whenever I visit an airshow, I ended up scratching my head. Ejectors are used to place a missile or bomb far enough away from the aircraft so that they are in relatively undisturbed airflow. This has been required on every fighter that carries missiles in an internal weapons bay, such as the F-102, F-106, YF-12, and the new FA-22. Ejectors are also often useful for external stores to get the weapon clear of the complex flow field near the aircraft. Extensive tests are carried out for any new aircraft or new store to determine the separation behavior and what type of ejector is required for it. I have a vague memory that the F-14 required especially powerful ejectors to ensure clean separation of bombs carried under the fuselage, as the fuselage of that aircraft is a lifting body and stores are subjected to aerodynamic forces that tend to push them up against the aircraft. I think it was also an F-14 that shot itself down when the ejector for a Sparrow missile failed and the missile lit off while still held in its recess. Hope this helps, Peter Wezeman anti-social Darwinist |
#3
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peter wezeman wrote:
I think it was also an F-14 that shot itself down when the ejector for a Sparrow missile failed and the missile lit off while still held in its recess. Dunno about the above, but a Tomcat shot itself down when a (properly functioning) Sparrow fired from one of the after recesses pitched up while still under the aircraft, and struck the underside of the big Grumman bird. This led to the development of a new mark of Sparrow (AIM-7P?) which further delayed pitchup to allow more runout. Jeff |
#4
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"AL" wrote in message ... Hi, Here is a newbie question. What are the merits and the pitfalls of rail vs ejector launchers for guided missiles? I suppose bombs have to be ejector launched and rockets rail. Whenever I visit an airshow, I ended up scratching my head. A general rule for missiles might be: Ejector racks next/on the fuselage Rails away from the fuselage. underwing and wingtip. Ejector racks kick the missile out from the fuselage to get out of the airflow, to clear other protuberances (other missiles, etc) and also to limit the burn effects from the missile motor. Consider if the F-4/Sparrow were on rails. The front missile can't launch without burning the aft missile, and the aft missile can't launch because the front missile is in the way. (Not counting the fact that two of the fins are recessed into the fuselage, and the missile body itself is in a slight recess) Pete |
#5
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Consider if the F-4/Sparrow were on rails. The front missile can't launch
without burning the aft missile, and the aft missile can't launch because the front missile is in the way. (Not counting the fact that two of the fins are recessed into the fuselage, and the missile body itself is in a slight recess) Originally the plan was to use rails that swing down... the front missiles were on a trapeze system, and the aft ones were on arms that swung down from an inboard hinge (parallel to roll axis). That got scrapped halfway through the design process. |
#6
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F102 had rails for missiles and tubes for rockets. 3 each RX tubes
were in each of the center four doors. MX rails were pneumatically extended and retracted. The firing cycle was thus: Doors snapped open, rear (3) rails extended, 3 missiles fired, front rails snapped down as rears retracted, front 3 missiles fired, front rails came up, doors snapped closed - all in 3 seconds flat. Everybody was extremely respectful of extended doors on the ground especially with HP pneumatic (3000PSI) system charged. Special clamps held doors extended when working around the Deuce in this condition. Walt BJ |
#7
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"WaltBJ" wrote in message om... F102 had rails for missiles and tubes for rockets. 3 each RX tubes were in each of the center four doors. MX rails were pneumatically extended and retracted. The firing cycle was thus: Doors snapped open, rear (3) rails extended, 3 missiles fired, front rails snapped down as rears retracted, front 3 missiles fired, front rails came up, doors snapped closed - all in 3 seconds flat. Everybody was extremely respectful of extended doors on the ground especially with HP pneumatic (3000PSI) system charged. Special clamps held doors extended when working around the Deuce in this condition. Walt BJ Right. Rails for missiles held internally. Same as the -106. IIRC, a guy at Loring lost part of his arm putting the downlocks on a bird coming back from an alert mission. You had to put the locks on prior to shutdown, and with the doors open. Fault in the system caused a door-close just as he was putting on one of the locks. There is no possible way to move fast enough to avoid the doors snapping shut. Pete |
#8
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peter wezeman wrote: AL wrote in message ... Hi, Here is a newbie question. What are the merits and the pitfalls of rail vs ejector launchers for guided missiles? I suppose bombs have to be ejector launched and rockets rail. Whenever I visit an airshow, I ended up scratching my head. Ejectors are used to place a missile or bomb far enough away from the aircraft so that they are in relatively undisturbed airflow. This has been required on every fighter that carries missiles in an internal weapons bay, such as the F-102, F-106, YF-12, and the new FA-22. Ejectors are also often useful for external stores to get the weapon clear of the complex flow field near the aircraft. Extensive tests are carried out for any new aircraft or new store to determine the separation behavior and what type of ejector is required for it. I have a vague memory that the F-14 required especially powerful ejectors to ensure clean separation of bombs carried under the fuselage, as the fuselage of that aircraft is a lifting body and stores are subjected to aerodynamic forces that tend to push them up against the aircraft. I think it was also an F-14 that shot itself down when the ejector for a Sparrow missile failed and the missile lit off while still held in its recess. Hope this helps, Peter Wezeman anti-social Darwinist The F-106 and F-102 used rails, not ejectors for the AIM-4. Only the AIR-2A was "ejected" from the bay. Vygg |
#9
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Pete wrote: "AL" wrote in message ... Hi, Here is a newbie question. What are the merits and the pitfalls of rail vs ejector launchers for guided missiles? I suppose bombs have to be ejector launched and rockets rail. Whenever I visit an airshow, I ended up scratching my head. A general rule for missiles might be: Ejector racks next/on the fuselage Rails away from the fuselage. underwing and wingtip. Ejector racks kick the missile out from the fuselage to get out of the airflow, to clear other protuberances (other missiles, etc) and also to limit the burn effects from the missile motor. Consider if the F-4/Sparrow were on rails. The front missile can't launch without burning the aft missile, and the aft missile can't launch because the front missile is in the way. (Not counting the fact that two of the fins are recessed into the fuselage, and the missile body itself is in a slight recess) Pete So a AIM-9 when mounted on the fuselage willl be ejector launched or are they limited by design? -- AL New anti-terrorism tool, "Fly naked" http://www.alfredivy.per.sg |
#10
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So a AIM-9 when mounted on the fuselage willl be ejector launched or are
they limited by design? All AIM-9's are rail launched. Fuselage mounting of one would require a short pylon and a rail attached to it. |
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