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Author Topic: Unusual, almost absurd question.  (Read 1051 times)

Offline VooDoo

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Unusual, almost absurd question.
« on: May 07, 2004, 11:40:32 AM »
But, as usual, very simple ;).

G-limits of the F-4J and later Phantom II. Max. service etc.

PS Yes, I know that this thing doesnt have even a single prop :D.
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Online Guppy35

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Unusual, almost absurd question.
« Reply #1 on: May 07, 2004, 03:24:49 PM »
My understanding is 9Gs was the limit although pilots pulled more in it.

Randy Cunningham in an F4J on his second Mig kill, says he pulled 12 Gs, breaking panals in the aircraft.  Since I believe they had a G-meter to record this stuff, I would imagine he wasn't making it up

Dan/Slack
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Offline VooDoo

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Unusual, almost absurd question.
« Reply #2 on: May 07, 2004, 03:48:56 PM »
Usualy it is said that F-4E have max. expluatational g-limit of 6. I can give a link but its in russian. So I want to know something  about other modification - maybe after some bugfixing g-limit was moved in higher g-numbers. And... 12G clearly not an expluatational g-limit - plane started to brake apart. Max. expl. means no residual deformation after maneuver ended.
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Offline GScholz

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Unusual, almost absurd question.
« Reply #3 on: May 07, 2004, 06:10:58 PM »
IIRC the early models had a 3G limit because the radar would suffer damage at higher G. The mid-late Vietnam era F-4s had a 6G limit, and the late models were limited at 8G.


... IIRC.
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Offline VooDoo

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Unusual, almost absurd question.
« Reply #4 on: May 08, 2004, 12:06:50 AM »
Late means F-4J ? And source please ?
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Offline hogenbor

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Unusual, almost absurd question.
« Reply #5 on: May 08, 2004, 08:17:14 AM »
Considering the limits, how did Cunningham and his F4 survive 12G? Considering 9G is the death limit in AH and so on...
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Offline VooDoo

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Unusual, almost absurd question.
« Reply #6 on: May 08, 2004, 12:17:47 PM »
3-6-8 G are expluatational limits. This means that ac will not be damaged until those limits are exceeded. If they will be exceeded ac can sustain some permanent damage. And if you pull out more than max. allowed G's your ac will be destroyed.
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Online Guppy35

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Unusual, almost absurd question.
« Reply #7 on: May 08, 2004, 12:38:11 PM »
Quote
Originally posted by hogenbor
Considering the limits, how did Cunningham and his F4 survive 12G? Considering 9G is the death limit in AH and so on...


He was being shot at by a Mig17 and he says it was purely a reaction.  I imagine the adrenilin was pumping bigtime when he pulled into that Mig.  The quote says he broke "wing panals, flap panals, everything!"

Quoting from a story by an Air Force F4E pilot describing a dog fight with a Mig in Vietnam (Hard wing not slatted in this cas):
"This time I pull six an a half Gs.  I don't have any qualms about pulling more.  I've never heard of a wing coming off an F4.  Three of my buddies have pulled 12 Gs and brought the  bird home."

Apparently they did the 12 G bit on more then one occasion.

Dan/Slack
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Offline VooDoo

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Unusual, almost absurd question.
« Reply #8 on: May 09, 2004, 06:44:07 AM »
And one more question - initial climb rate of the F-4E ?

http://home.att.net/~jbaugher1/f4_11.html
gives 61,400 feet per minute. Looks like misprint. And absolutely no info about ac load in tests.
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Offline GScholz

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Unusual, almost absurd question.
« Reply #9 on: May 09, 2004, 05:51:04 PM »
No that sounds correct for the F-4E. The F-4E had better engines than the earlier models. The load during the test would be clean with only light fuel ... just like any other performance test. With a war load the climb rate would be significantly less.
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Offline VooDoo

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Unusual, almost absurd question.
« Reply #10 on: May 10, 2004, 01:33:34 AM »
All other F-4s has less climb. Smth like 40-48 KF. Even RF.
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Offline Ghosth

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Unusual, almost absurd question.
« Reply #11 on: May 10, 2004, 07:57:21 AM »
Probably they were not useing sustained gee's, but a quick 1 or 2 sec max pull back.

Which while it could have damaged the plane might well have left the pilot pretty much in control.

The guy who tested the rocket sled hit many times that.  History channel said when he hit the brakeing he was doing neg 40 gee's.
 
(yes he did have some detached retina problems)

So very possible to pull a quick 12 trying to get a plane around.

And if you don't believe me we'll put a mig on YOUR 6 and see what happens!  :)
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Offline Rino

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Unusual, almost absurd question.
« Reply #12 on: May 10, 2004, 06:49:58 PM »
Quote
Originally posted by Guppy35
My understanding is 9Gs was the limit although pilots pulled more in it.

Randy Cunningham in an F4J on his second Mig kill, says he pulled 12 Gs, breaking panals in the aircraft.  Since I believe they had a G-meter to record this stuff, I would imagine he wasn't making it up

Dan/Slack


     In 1983 I personally witnessed the G-meter of an F-4E that
had the carats at +10 and -8 on the same flight.  It had incurred
these forces during a mock dogfight at Tyndall AFB.

     The aircraft "lost" an AIM-7 sparrow launcher that completely
departed the aircraft.  Also all the engine mount bolts had
"broken" and the engines were resting on the gear doors.

     Needless to say this was one crazy SOB, but the F-5 that was
chasing him didn't catch him ;)
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Offline Citabria

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Unusual, almost absurd question.
« Reply #13 on: May 14, 2004, 02:39:22 AM »
Ive heard that before about the engine mountings breaking on phantoms that were over G'd
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