Do fighter jets have a Vne?

beasly

beasly

Well-Known Member
Or do you reach a point where the airframe can withstand any aerodynamic force the Earth can throw its way?
 
well, in my drunken stupor, i think Vne is just another way of saying load factor, and i imagine load factor would be way more than what the body can withstand in a fighter plane. Sooo yes, in my non professional opinion, i would think there is a Vne, but its so fast that it doesnt matter.
 
Many of the restrictions on speed are based on external stores being carried....drop tanks, some munitions, etc.
 
Old Dominion Flyer said:
So if one were to exceed "drop tank Vne", the drop tank would depart the aircraft? Interesting. Got any accident reports about it?
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Moreso likely to have damage to the mounting equipment, etc. Or, might cause undesirable aerodynamic actions. The bigger limitation with external stores is G onset/loading, and speed range for employment of weapons stores.
 
cmill said:
well, in my drunken stupor, i think Vne is just another way of saying load factor, and i imagine load factor would be way more than what the body can withstand in a fighter plane. Sooo yes, in my non professional opinion, i would think there is a Vne, but its so fast that it doesnt matter.
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Where the hell have you been!?
 
cmill said:
well, in my drunken stupor, i think Vne is just another way of saying load factor, and i imagine load factor would be way more than what the body can withstand in a fighter plane. Sooo yes, in my non professional opinion, i would think there is a Vne, but its so fast that it doesnt matter.
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A number of years ago there was a F-15 at Eglin that was on a flight test mission. The pilot was in a high speed dive when a wing separated from the aircraft. The pilot ejected but was killed in the ejection. If I remember correctly the plane was travelling over 2.0M at the time of the separation.

Edit: good to see you around cmill!
 
Technically, because we're talking about a jet here, wouldn't it be Vmo/Mmo, and not Vne? Principle is pretty much the same, but still. Also, I'm fairly certain (though I've never flown such an aircraft before) that there is a speed in which aerodynamic forces would be sufficient to cause structural damage.
 
Some other considerations would also be thermodynamic; compression/expansion; metallurgical, etc

Lot's of good info on the SR-71 and many problems (i.e. extremely shallow bank angle limitations at high speed)
 
I don't know about other fighter type jets, but mine has very little chance of exceeding the upper mach limit in the book. Like Mike said, the real limitations are generally carriage/release limits for external stores. For us, double bubble, or a drop tank on each wing, imposes the biggest limitation, which is kind of laughable because you could never hope to see said limit with two drops. Other limits imposed are based on fuzes for weapons, which can be damaged by excessive speed and/or have difficulty arming as advertised in such cases.
 
The F-15E has both max Mach and max indicated speeds...neither of which I ever came close to hitting despite several attempts. They weren't hard and fast numbers, and differed based on altitude and configuration. Have to get into the charts to know what they are for your given conditions, so not at all numbers that were memorized ops limits for pilots.

Any of you who flew the T-38A remember the pre-flight mantra "red at 710", which referred to checking the red marker on the airspeed indicator which showed the max KCAS at 710.
 
MikeD said:
Moreso likely to have damage to the mounting equipment, etc. Or, might cause undesirable aerodynamic actions. The bigger limitation with external stores is G onset/loading, and speed range for employment of weapons stores.
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So are you able to bug the VNE for a given configuration, or just brief and be aware of the a/s and G limits?
Does aerodynamics affect which pylons you can put a given device on?
 
ryan1234 said:
Some other considerations would also be thermodynamic; compression/expansion; metallurgical, etc

Lot's of good info on the SR-71 and many problems (i.e. extremely shallow bank angle limitations at high speed)
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"Cleveland Center, NASA nine-oh-one, level, flight level six five zero, and ma'am, we don't do turns!"

Yeah, well I made some pretty awesome copies at work today. So there.
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And I took off in under 1000'.
 
XLR99 said:
So are you able to bug the VNE for a given configuration, or just brief and be aware of the a/s and G limits?
Does aerodynamics affect which pylons you can put a given device on?
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Nope. Just know what you're carrying and what the most limiting item is. Keep in mind too that in the A-10, this was rarely ever something I needed to keep in mind. In the F-117, definitely.
 
Apophis said:
Technically, because we're talking about a jet here, wouldn't it be Vmo/Mmo, and not Vne? Principle is pretty much the same, but still. Also, I'm fairly certain (though I've never flown such an aircraft before) that there is a speed in which aerodynamic forces would be sufficient to cause structural damage.
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You are pretty much correct. Military aircraft do not need to comply with FAA regulations on speeds (regarding certification of aircraft), but it would make no sense at all to establish "Vne" for any jet. Vne actually only applies to Title 14 CFR PART 23 aircraft, which are AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES. Transport aircraft are certificated under Part 25, which utilizes Vmo and Mmo.
 
seagull said:
You are pretty much correct. Military aircraft do not need to comply with FAA regulations on speeds (regarding certification of aircraft), but it would make no sense at all to establish "Vne" for any jet. Vne actually only applies to Title 14 CFR PART 23 aircraft, which are AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES. Transport aircraft are certificated under Part 25, which utilizes Vmo and Mmo.
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Just because it's not regulatory doesn't mean it doesn't exist ;P
 
I'm vaguely remembering a story about some sort of g limit horn on maybe an F15? Guys would just pull until they heard the horn maybe? And some incident involving entering the wrong exterior load into the computer to processes load limits for the flight controls?

Stories from long ago for sure.
 
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