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#542
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Peter Stickney wrote: In article , "Terrell Miller" writes: "Pat Flannery" wrote in message ... Peter Stickney wrote: The airplane was also rather dangerous to fly, as well, and losses were high. - by 1960, when it had been in service for 5 years, more than 500 had been totally destroyed in flying accidents. I knew about the roll coupling problem due to the undersized vertical fin, but didn't know the attrition rate was quite that appalling. this may be urban myth, but a long time ago I read that part of the "Saber Dance" thing was because a specific old-timer at the McDonnell plant was supposed to be installing nuts upside down for some reason, but he'd been there twenty years and he knew damn well you don't install nuts back'ards. So under certain flight profiles an aileron would get hung up on the "properly" installed nut. Apparently they never told the poor schlub how many pilots he'd killed. It sounds like the conflation of two stories. The Sabre Dance (the film of one appears in the movie "X-15", with Charles Bronson as a steely-eyed Test Pilot) occurred when you got an F-100 way on the backside of the Thrust/Drag Curve, where Induced Drag is incredibly high, and the airplane's going too slow for the controls to have much effect. At that high an AoA, you can be well below the power-off stall speed - you've got the engine's thrust helping fight gravity, you see, and there's not enough oompth to accelerate to a reasonable flying speed. That's one of the most chilling pieces of film I've ever seen. You know the guy's had it, there's no way out, he's too low & slow to eject, even if he could take his hand off hte stick to reach for the handle, you just don't know when. The other problem offurred with F-86Fs and F-86Hs built, I believe, at North American's Inglewood plant. There was a connection in the aileron linkage that, because of the danger of the linkage binding when the wing flexed at high speeds, needed to be assembled in an unusual, non-standard manner. (This fault, BTW, is what killed Joe MacConnel, the #1 USAF/UN Ace from the Korean War, while testing the F-86H) Some guy on the line figured that the drawings were wrong, 'cause you just don't put a bolt in that way, and did the hookup the way he thought it should be done. Reminds me of one of Bob Hoover's test flights in the F-86. They had just installed a new hydraulic system for the control surfaces and Hoover made the first test flight. He taxied out to the runway, pushed the throttle forward, and when the plane reached flying speed he pulled the stick back, lifted off the runway, and retracted the gear. He heard the gear thump into the wheel wells - and immediately lost all control of the airplane! The elevator was frozen into a nose up attitude, so the plane entered an ever steeper climb, came to a dead stop with the nose vertical, swapped ends, and dove straight toward the ground. The plane pulled out of the dive a few feet above the runway and repeated the process. The ground was screaming "Eject!, Eject!, Eject!" at him, but he knew he was too low. The plane went through several of those wild gyrations when a new problem developed: Hoover saw that he was headed straight for a hanger. Fortunately, with each gyration the plane gained a little bit of altitude and JUST cleared the hanger. Once out over the ocean Hoover began to work the problem and discovered that by manipulating the trim control he could dampen out the oscillation and set up a reasonably stable climb. "OK, you have enough altitude, now Eject!" the ground told him, but he refused. He wanted to save the airplane so they could determine what went wrong. He also discovered that he had a little bit of aileron control with the stick, so he got the plane turned to the north and headed for the dry lake bed at what is now Edwards AFB. He carefully got the plane set up on a long final approach, dropped the gear, and again went through another series of oscillations until he could get the plane re-trimmed for the new configuration. Again the ground told him "Eject! You have no way to do a proper flare, so when you touch down, you'll lose control and crash!" Again he refused. Once the plane got down into ground effect, the nose came up and the plane greased itself onto the dry lakebed so smoothly that the only way that Hoover could tell he was on the ground was a slight vibration from the gear. He said later that it was the smoothest landing he ever made. Thanks to Hoover's remarkable feat it didn't take long to figure out what the problem was. The new hydraulic system controls were wired to a new ground stud in a wheel well. They neglected to check for clearance, so when the gear came up, it knocked off the stud, and the redundant hydraulic systems, which had ALL been wired to that one ground stud, failed, freezing the control surfaces. They discovered another minor detail too: Someone had forgotten to remove the safety pin from the ejection seat! Hoover couldn't have ejected if he had wanted to! He said that had he tried to eject, and discovered that he was trapped, he might have panicked and lost it. Had Hoover not decided to try to save the airplane, some other pilot might have died too before they found the problem. The roll-yaw coupling is something that really started appearing when airplanes began getting very long, woth their mass distributed along their length. Since the datum line of teh aircraft is almost always at some angle to the flight path, a fast roll will tend to make thos masses want to moge away from teh axis of the roll. This makes the fuselage yaw. The magnitude and rate of onset of that yaw can be high enough to be completely out of control, and may lead to structural failure. The early short-tailed F-100As, and the X-3 research aircraft were the first serious cases of this problem. -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
#543
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In article , Derek Lyons wrote:
(George William Herbert) wrote: There are several ex-nukes who have contributed to alt.war.nuclear over the years... At least over here on the seaborne side of the house 'nukes' are the guys who operate the reactor. 'Weaponeers' work the missile launch and fire control systems. Now there's a job title that sounds like you should get a jumpsuit and a cape. -- -Andrew Gray |
#544
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In article , George William Herbert wrote:
Peter Stickney wrote: The First Rule of Nuke Stuff. Those who know don't post. Those who post don't know. That has been grossly exaggerated. Those who know often post; so far, nobody who knows has posted inappropriate material which was not either otherwise declassified or rendered non-sensitive by the passage of time. ....that anyone noticed. -- -Andrew Gray |
#545
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Andrew Gray wrote:
In article , Derek Lyons wrote: (George William Herbert) wrote: There are several ex-nukes who have contributed to alt.war.nuclear over the years... At least over here on the seaborne side of the house 'nukes' are the guys who operate the reactor. 'Weaponeers' work the missile launch and fire control systems. Now there's a job title that sounds like you should get a jumpsuit and a cape. In the USAF, the officers in the silos are called Missile Launch Officers (or they were back in the day when that was to have been my MOS . . . long story . . .); they were often referred to as "missileers" informally. -- Herb Schaltegger, B.S., J.D. Reformed Aerospace Engineer Remove invalid nonsense for email. |
#546
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On Wed, 18 Feb 2004 14:52:27 +0000, Henry Spencer wrote:
Kevin Willoughby lid Imagine that, a FROG ON-OFF switch, hardly the work for test pilots. -- Mike Collins Collins would be on stronger ground there if astronauts weren't notorious for a significant error rate on switch-flipping for experiments... :-) One could argue that astronauts/test pilots error rate for switch flipping actually strengthens Collin's ground, since it raises the concern that test pilots shouldn't be entrusted with such tasks, maybe the frog itself would do better. G |
#547
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In article ,
(Derek Lyons) writes: (Peter Stickney) wrote: The First Rule of Nuke Stuff. Those who know don't post. Those who post don't know. Second Rule of Nuke Stuff: Those who cite the first rule really don't know. I kept going. didn't I? that should have been clue enough. (Didn't the Navy have their Regulus subs in the Pacific until the mid-late '60s, too?) The Regulus patrols ended in 1964. (I knew a guy who made some patrols on Tunny and Growler. Scary stuff.) IIRC SSBN's began making patrols in the Pacific shortly thereafter. Ah, O.K. I know that the big subsonic cruise missiles stayed in service for longer than anywone would have expected. -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
#548
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#549
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On Wed, 18 Feb 2004 05:46:04 GMT, LooseChanj
wrote: I saw one of those Gulfstreams obviously doing a simulated shuttle landing from the parking lot of the KSC headquarters building. Nothing quite prepares you for the sight of an airplane headed almost straight *down*. It's really not straight down at all. It's about 30 deg. (A normal airliner glide slope is 3 deg, just for a reference.) It sure does look like it's straight down, though, particularly if you're looking at it head-on. Mary -- Mary Shafer Retired aerospace research engineer |
#550
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On Wed, 18 Feb 2004 17:57:15 -0500, Rick DeNatale
wrote: On Wed, 18 Feb 2004 14:52:27 +0000, Henry Spencer wrote: Kevin Willoughby lid Imagine that, a FROG ON-OFF switch, hardly the work for test pilots. -- Mike Collins Collins would be on stronger ground there if astronauts weren't notorious for a significant error rate on switch-flipping for experiments... :-) One could argue that astronauts/test pilots error rate for switch flipping actually strengthens Collin's ground, since it raises the concern that test pilots shouldn't be entrusted with such tasks, maybe the frog itself would do better. G You do both know, don't you, that the latest test crew comprises one test pilot and one dog? The dog is there to bite the test pilot if the pilot even touches the switches and the test pilot is there to feed the dog. Mary -- Mary Shafer Retired aerospace research engineer |
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