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#111
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
On May 11, 11:30 am, "Keith Willshaw"
wrote: "Ken S. Tucker" wrote in ... On May 10, 8:37 pm, Bill Shatzer wrote: Ken S. Tucker wrote: On May 10, 4:24 pm, "Keith Willshaw" wrote: "Ken S. Tucker" wrote in ... On May 10, 12:23 pm, "Keith Willshaw" Name one missile that does so and the mechanism it uses for braking. Sputnik, returned dogs safely in the 50's. They used speed brakes, then parachutes. No it didnt, Sputnik was not recoverable and the dog Laika died in space And the other 24 dog missions ? Please aquaint and get back to us. Ken [...] Dunno, but the first Soviet canine passengers successfully returned from orbit weren't in the 1950s. The discussion involves sub-orbital, (IRBM's or MRBM's), http://en.wikipedia.org/wiki/Soviet_space_dogs to prove sub-orbital re-entry capability, see it in 1951. (Keith went off track with Laika). Ken Actually the person who raised the issue of dogs in Sputnik was you. Laika was the ONLY dog to fly in a sputnik in the 1950's. Keith I'm sorry Keith, the ref disagrees with you. But I'll agree node my head. Good Bye. Ken |
#112
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
Ken S. Tucker wrote:
[snip] For instance using ADC (Analog to Digital) and DAC (Digital to Analog) converters going into an Elektronic Brain....was nearly sci-fi. It still is sci-fi. Although nowdays it is the analog side they do not know about. Andrew Swallow |
#113
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
On May 12, 5:13*pm, Andrew Swallow wrote:
Ken S. Tucker wrote: [snip] For instance using ADC (Analog to Digital) and DAC (Digital to Analog) converters going into an Elektronic Brain....was nearly sci-fi. It still is sci-fi. Although nowdays it is the analog side they do not know about. Andrew Swallow Not really. We were collecting analog data as late as early 90s. Some were doing digital , most data was analog. Had to do conversions, did that on tape systems, read analog tape, created digital tape, ran digital tape as input to computer systems. I don't know if they do digital data recordings directly, now, would make sense but there are reasons not to do it. you can get higher frequency of data with analog data. highest was FM, could get 1000 samples / sec. Real interesting looking at realtime data. Usually wouldn't print it until right at where you needed data. Recorders spit out tons of thermal paper. Fun to watch. Vast majority was 20 samples / sec at most, which was fine for analog. I had some data requirements at 10000 cycles / sec, what they did was run it at 10th of the speed it was recorded at. For some reason, analog to digital was a 1:1 time write to tape. One hour of data took one hour to convert to digital record. Then we had to run the digital tape through some other programs to make sense of it all. Usually was just a voltage point. Conversion created say acft, tail, flight #, date, time, mach #, alt and whatnot. Lots of the conversion literally was a patch board hookup. Flight data reels in raw format were probably an inch, inch and a half wide, weighed about 50 lbs. One wasn't bad, two were real strain to carry. Most fighters had one tape recorder. Easier to do analog data right off of transducers. |
#114
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
On May 13, 1:03 am, frank wrote:
On May 12, 5:13 pm, Andrew Swallow wrote: Ken S. Tucker wrote: [snip] For instance using ADC (Analog to Digital) and DAC (Digital to Analog) converters going into an Elektronic Brain....was nearly sci-fi. It still is sci-fi. Although nowdays it is the analog side they do not know about. Andrew Swallow Not really. We were collecting analog data as late as early 90s. Some were doing digital , most data was analog. Had to do conversions, did that on tape systems, read analog tape, created digital tape, ran digital tape as input to computer systems. I don't know if they do digital data recordings directly, now, would make sense but there are reasons not to do it. you can get higher frequency of data with analog data. highest was FM, could get 1000 samples / sec. Real interesting looking at realtime data. Usually wouldn't print it until right at where you needed data. Recorders spit out tons of thermal paper. Fun to watch. Vast majority was 20 samples / sec at most, which was fine for analog. I had some data requirements at 10000 cycles / sec, what they did was run it at 10th of the speed it was recorded at. For some reason, analog to digital was a 1:1 time write to tape. One hour of data took one hour to convert to digital record. Then we had to run the digital tape through some other programs to make sense of it all. Usually was just a voltage point. Conversion created say acft, tail, flight #, date, time, mach #, alt and whatnot. Lots of the conversion literally was a patch board hookup. Flight data reels in raw format were probably an inch, inch and a half wide, weighed about 50 lbs. One wasn't bad, two were real strain to carry. Most fighters had one tape recorder. Easier to do analog data right off of transducers. Let me guess, corrections invited. Today, software and computer enhanced flying is well known to a military pilot. (The rumor that the F-22's crossing the International dateline caused the computer - via software glitch - to crash is a typical example). In a sense, software removes pilots burden. When was software first used? I'm guessing it was 1st used to automatically control the F-111 wing sweep. Ken |
#115
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
In article
, "Ken S. Tucker" wrote: On May 13, 1:03 am, frank wrote: On May 12, 5:13 pm, Andrew Swallow wrote: Let me guess, corrections invited. Today, software and computer enhanced flying is well known to a military pilot. (The rumor that the F-22's crossing the International dateline caused the computer - via software glitch - to crash is a typical example). In a sense, software removes pilots burden. When was software first used? I'm guessing it was 1st used to automatically control the F-111 wing sweep. Ken Ken, The pilot commanded the F-111 wing sweep position via a lever that was mounted underneath the left canopy rail. It hung underneath the rail and was hinged to flip up (outboard) to stay out of the way. The pilot would move his left hand from the throttles up to the handle, grab it and rotate it down, then push it forward or pull it back. Forward equals wings move forward, back equals wings move back. When the handle was stowed in the outboard spring loaded position, it was friction locked from moving forward or back. The wing sweep control handle was connected via manual cable (not electrical cable) to the high-lift control system, which in turn controlled the wing sweep position. Wing sweep position was directly proportional to wing sweep handle position. The two hydraulic systems provided control power to move the wings. The wing sweep actuator was a non-reversible system that prevented the wing sweep position from being affected by airloads. The forward position was 16 degrees leading edge sweep. The aft position was 72.5 degrees leading edge sweep. The wings moved at 3.8 degrees per second. The aircraft placard G limits were -3.0 to +7.33 symmetric when the wings were stationary. This were later changed to -1.5 to +7.33. During wing sweep, the placard G limits were 0 to +4.0 symmetrical. Assymmetric G during wing sweep was prohibited. The F-14 Tomcat used a more sophisticated wing sweep system. The pilot's right throttle contained a five position thumb switch (button) on the inboard side which was very similar to the trim button on the stick except that unlike the trim button which was spring loaded to the center position, the pilot could place the wing sweep button in any of the five positions. The positions we Forward: Sweep wings forward Aft: Sweep wings aft Down: Sweep wings to sixty degrees (I think) Up: Autosweep Center: No command In the Autosweep mode, the Central Air Data Computer (an analog device) commanded the wing sweep position according to Mach number, using a pressure altitude bias. Furthermore, regardless of wing sweep mode, the CADC would not allow the wings to be over-sped. If the pilot manually commanded the wings forward, the CADC would stop the wing sweep movement when they reached the computed Maximum Safe Mach value. If the pilot left the wing sweep control in the center (no command) at takeoff instead of up (Auto) then the CADC would start to sweep the wings aft during aircraft acceleration to prevent overspeeding the them. The forward position was 20 degrees leading edge sweep. The aft position was 68 degrees leading edge sweep. The wings moved at 15 degrees per second. The aircraft placard G limits were -1.5 to +6.5 symmetric even during wing sweep. Grumman improved on the F-111's wing box to gain this capability, unfortunately at the expense of a substantial amount of extra weight. Variable geometry wings proved to be a great asset to the F-111 in the interdiction/strike role. In my opinion it provided no benefit to the F-14 in the A/A role. The F-15A empty weight was 28,500 pounds. The F-14A empty weight was 40,000 pounds. Most of this was due to the VG component of the aircraft. These two aircraft are nearly the same length. The F-14 used a simple fly-by-wire throttle. The interconnect between the throttles and the engine fuel controls was electrical. The F-16 uses a similar FBW throttle system, that compliments its FBW flight control system which which GD borrowed from the F-111. GD used the Vark's triple channel FBW flight control system, added a fourth channel, and added a few more features (ie. limiters, some of which were eventually added to the Vark's FBW FCS) and then used it in the F-16. -- Kurt Todoroff Markets, not mandates and mob rule. Consent, not coercion. |
#116
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
Kurt R. Todoroff wrote:
Variable geometry wings proved to be a great asset to the F-111 in the interdiction/strike role. In my opinion it provided no benefit to the F-14 in the A/A role. The F-15A empty weight was 28,500 pounds. The F-14A empty weight was 40,000 pounds. A couple of comments: VG helped the Tomcat in the A/A role by extending loiter time, and in the Fleet Air Defense role they spent a lot of time at max conserve. And, once the F-14 got decent engines it was a pretty good dogfighter, some of that because the wing optimized as you went along. One disadvantage was that, if your opponent knew what he was doing he could look at you and deduce your energy state from your wing position. Whether he was able to do anything about depended on what he flew--for example, the MiG-23, also VG, could not sweep his wings at more than 2.5G, so if you kept the pressure on he was pretty well stuck in a non-optimal configuration regardless. Jeff -- Love stinks. J. Geils |
#117
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
In article ,
Jeff Crowell wrote: Kurt R. Todoroff wrote: Variable geometry wings proved to be a great asset to the F-111 in the interdiction/strike role. In my opinion it provided no benefit to the F-14 in the A/A role. The F-15A empty weight was 28,500 pounds. The F-14A empty weight was 40,000 pounds. A couple of comments: VG helped the Tomcat in the A/A role by extending loiter time, and in the Fleet Air Defense role they spent a lot of time at max conserve. And, once the F-14 got decent engines it was a pretty good dogfighter, some of that because the wing optimized as you went along. One disadvantage was that, if your opponent knew what he was doing he could look at you and deduce your energy state from your wing position. Whether he was able to do anything about depended on what he flew--for example, the MiG-23, also VG, could not sweep his wings at more than 2.5G, so if you kept the pressure on he was pretty well stuck in a non-optimal configuration regardless. Jeff Hi Jeff, Crediting VG with extending the Tomcat's loiter time is using circular reasoning. You don't increase loiter performance by making the aircraft heavier. A simpler, less costly, method would have been to use a fixed wing and then regain those eleven thousand pounds and reduce the wing loading, thus reducing the associated induced drag and the loiter fuel requirements. The drawback would have been reduced supersonic range which, prior to the F-22, was overrated by the USAF and USN. I'm not convinced that the VG wing contributed to the Tomcat's close in fighting capability over a fixed wing. I would argue the opposite. The CADC scheduled the wing position according to Mach number, not how hard the pilot was pulling on the pole, and not according to G loading. The C_L versus AOA curve on all VG aircraft becomes flatter with progressively greater wing sweep angle. For pure maneuverability and/or loiter, the unswept wing provides the greatest benefit of high C_L and low induced drag. For pure speed, the highly swept wing is the choice. I would be curious to know how the F-15 carrying six AIM-54s would fare in the Tomcat's loiter environment. I would like to hear John Carrier's take on this. You are correct about the engines. The Tomcat (and the Vark) both suffered from poor P_s due to their underpowered TF-30 engines. I read in AW&ST a version of the test report on the flight test program of the F-14 with the GE F110-GE-400 engines. The Tomcat realized very significant performance increases in all flight regimes with the GE engines. The most notable improvements were in engine reliability during hostile flight environments. During the flight testing, the crew took the F-14 to FL600, slowed to approach speed, and then cycled one engine throttle back and forth between Idle and Max AB. Except for one minor self-correcting hickup, the engines responded and performed superbly in this environment. Afterburner lightoff and termination were flawless. -- Kurt Todoroff Markets, not mandates and mob rule. Consent, not coercion. |
#118
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
"Ken S. Tucker" wrote in message ... In a sense, software removes pilots burden. When was software first used? I'm guessing it was 1st used to automatically control the F-111 wing sweep. Ken AFAIK the first aircraft to use a digital flight control system was a modified F-8C with the F-16 being the first aircraft fitted with the system on the production line. Keith |
#119
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
On May 13, 12:27*pm, "Keith Willshaw"
wrote: "Ken S. Tucker" wrote in ... In a sense, software removes pilots burden. When was software first used? I'm guessing it was 1st used to automatically control the F-111 wing sweep. Ken AFAIK the first aircraft to use a digital flight control system was a modified F-8C with the F-16 being the first aircraft fitted with the system on the production line. Keith Yep, that was the original NASA prototype. Fun fact, related to how I originally came across it: the control unit for the computer system used in the first phase of testing was a surplus Apollo DSKY unit. Imagine trying to punch in "nouns" and "verbs" at Mach 2, backed up by a few KB of ferrite-core memory... -JTD |
#120
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"PENTAGON WORKING TO GIVE F-35 JSF NUCLEAR-STRIKE CAPABILITY"
Kurt R. Todoroff wrote:
Variable geometry wings proved to be a great asset to the F-111 in the interdiction/strike role. In my opinion it provided no benefit to the F-14 in the A/A role. The F-15A empty weight was 28,500 pounds. The F-14A empty weight was 40,000 pounds. Jeff Crowell wrote: A couple of comments: VG helped the Tomcat in the A/A role by extending loiter time, and in the Fleet Air Defense role they spent a lot of time at max conserve. And, once the F-14 got decent engines it was a pretty good dogfighter, some of that because the wing optimized as you went along. One disadvantage was that, if your opponent knew what he was doing he could look at you and deduce your energy state from your wing position. Whether he was able to do anything about depended on what he flew--for example, the MiG-23, also VG, could not sweep his wings at more than 2.5G, so if you kept the pressure on he was pretty well stuck in a non-optimal configuration regardless. Kurt R. Todoroff wrote: Crediting VG with extending the Tomcat's loiter time is using circular reasoning. You don't increase loiter performance by making the aircraft heavier. A simpler, less costly, method would have been to use a fixed wing and then regain those eleven thousand pounds and reduce the wing loading, thus reducing the associated induced drag and the loiter fuel requirements. The drawback would have been reduced supersonic range which, prior to the F-22, was overrated by the USAF and USN. You make an excellent point--I wonder what the Turkey's approach speed would have been with fixed geometry wings which would have also permitted the sprint speed. I completely agree with your comments regarding the overemphasis on sprint speed, at least as regards the top end Mach number of that sprint BUT... Part of the stated need for the sprint speed was for a late-launching (or out of position) interceptor to get into position to kill the archer instead of shooting at arrows. The Backfire and Blackjack were seen as pretty fearsome opponents. ISTR that the Phantom came aboard at about 135 knots, there was value seen in reducing that number with the F-14; again, a lighter aircraft would have done that, all else equal. The swing mechanism was a reliability risk, too, though I don't know how that compared to other maintenance items on the bird. I'm not convinced that the VG wing contributed to the Tomcat's close in fighting capability over a fixed wing. I would argue the opposite. The CADC scheduled the wing position according to Mach number, not how hard the pilot was pulling on the pole, and not according to G loading. The C_L versus AOA curve on all VG aircraft becomes flatter with progressively greater wing sweep angle. For pure maneuverability and/or loiter, the unswept wing provides the greatest benefit of high C_L and low induced drag. For pure speed, the highly swept wing is the choice. Well, probably the correct argument to have is how badly do you need the turning performance of the unswept configuration in a modern (even modern as-of then) fight. ROE and training to fight the previous war versus Speed Is Life! I would be curious to know how the F-15 carrying six AIM-54s would fare in the Tomcat's loiter environment. I would like to hear John Carrier's take on this. Someone with access to an Eagle Dash 1 could probably dope out a similar drag index and make a stab at it. You are correct about the engines. The Tomcat (and the Vark) both suffered from poor P_s due to their underpowered TF-30 engines. I read in AW&ST a version of the test report on the flight test program of the F-14 with the GE F110-GE-400 engines. The Tomcat realized very significant performance increases in all flight regimes with the GE engines. The most notable improvements were in engine reliability during hostile flight environments. During the flight testing, the crew took the F-14 to FL600, slowed to approach speed, and then cycled one engine throttle back and forth between Idle and Max AB. Except for one minor self-correcting hickup, the engines responded and performed superbly in this environment. Afterburner lightoff and termination were flawless. Pretty bloody impressive! Jeff -- Murphy's Laws of the gunfight: Always assume there is one more, somewhere. |
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