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InterceptorV8 posted:I can't be the only person here who thinks the first time someone beats the SR-71's speed record, they'll take one out of storage, dust it off, hammer down, take the record back, put it back into storage and be all I've always got the feeling that the SR-71s published top speed was sort of a "wink nudge" sort of thing, anyway. At the same time, the speed record has probably been beaten many times since then and we don't know about it. 
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Apr 20, 2010 03:16
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Previa_fun posted:I've always got the feeling that the SR-71s published top speed was sort of a "wink nudge" sort of thing, anyway. The SR-71's published top speed and altitude (the Mach 3.2 and 80,000ft seen in many sources) weren't actually limitations on the airframe. The SR-71 was restricted more by temperature limits than engine power, so on cold days, it was very capable of exceeding the published numbers. According to the SR-71 pilots manual, Mach 3.3 was allowed as long as the compressor temperature stayed below 427C. On the same page as that limit however, a performance chart indicates that on a cold enough day at altitude, an SR-71 could hit about Mach 3.5 without exceeding the compressor temp limitation. As for the altitude, the pilots handbook says "The maximum altitude limitation is 85,000ft unless higher altitude is specifically authorized", so it's a good bet that altitude "limit" was pretty commonly broken, especially when SR-71's were fired upon.
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Apr 20, 2010 06:19
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azflyboy posted:The SR-71's published top speed and altitude (the Mach 3.2 and 80,000ft seen in many sources) weren't actually limitations on the airframe. The SR-71 was restricted more by temperature limits than engine power, so on cold days, it was very capable of exceeding the published numbers. The sled driver story specifically describes exceeding Mach 3.5 when under fire from SAMs over libya, so it's basically confirmed by the pilots themselves.
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Apr 20, 2010 06:35
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InterceptorV8 posted:They built that plane with loving SLIDE RULERS, how many of you fuckers have ever handled one? I actually used the slide rule on my watch while taking pictures of the Hornet -- somebody asked how much gas it carried, pilot gave a figure in pounds (because that's what they use in the military), I did the math and told the kid what it was in gallons. 
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Apr 20, 2010 06:57
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Bad Angus! Bad!
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Delivery McGee posted:I own three, and I was born well after the advent of the electronic calculator. A 10" Pickett, a 6" pocket Sun Hemmi, and an E6B on the bezel of my Seiko. 
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Apr 20, 2010 07:11
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I own a slide ruler that was a going away present from my old company...they where weird.
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Apr 20, 2010 13:37
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Delivery McGee posted:I actually used the slide rule on my watch while taking pictures of the Hornet -- somebody asked how much gas it carried, pilot gave a figure in pounds (because that's what they use in the military), I did the math and told the kid what it was in gallons. Rule of thumb so you can do it in your head next time, 150 gallons for every 1000 lbs. They're rounding the pounds figure anyway, so the inaccuracy doesn't matter.
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Apr 20, 2010 17:27
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InterceptorV8 posted:They built that plane with loving SLIDE RULERS, how many of you fuckers have ever handled one? I saw a slide rule one once. They appear to be a weird relic from some ancient alien civilization, covered with cryptic writing and ratios. I quickly shielded my eyes with my TI-83 and continued playing Dope Wars. The trouble with the SR-71, of course, is that what it CAN do is greatly in excess of what it SHOULD do. It's the quintessential "big motor in a light body" hotrod -- fast as gently caress, right up until the moment that it self destructs. Also keep in mind that ground speed for a given Mach number decreases as altitude increases, so Mach 3.5 at altitude is slower than Mach 3.5 at sea level. I'd be hugely surprised if the Sled couldn't punk the poo poo out of Mach 4 with a little oxidizer tank to help it breathe at 100k+ ft.
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Apr 20, 2010 17:53
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oxbrain posted:Rule of thumb so you can do it in your head next time, 150 gallons for every 1000 lbs. They're rounding the pounds figure anyway, so the inaccuracy doesn't matter. I've always figured 7 pounds per gallon with #2 when scaling out.
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Apr 20, 2010 18:12
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InterceptorV8 posted:I've always figured 7 pounds per gallon with #2 when scaling out. Dividing by 7 in your head is more difficult. Say the plane takes 12,000 gallons. Divide by 10 for 1,200, divide by 2 for 600, add back to the 1,200 for 1800 gallons. JetA is 6.79-6.84 lbs per gallon, which would be 1,754-1,767. It's not a perfect number, but it's good enough.
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Apr 20, 2010 18:49
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Sterndotstern posted:Also keep in mind that ground speed for a given Mach number decreases as altitude increases, so Mach 3.5 at altitude is slower than Mach 3.5 at sea level. I'd be hugely surprised if the Sled couldn't punk the poo poo out of Mach 4 with a little oxidizer tank to help it breathe at 100k+ ft. Might not even need one. At the plane's marked top speed, the engines have transitioned almost entirely to ramjets (I believe only 20% of the air goes through the compressor), which can work just fine up to Mach 5. Higher speed just means more air rammed into the engine.
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Apr 20, 2010 20:41
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orange lime posted:Might not even need one. At the plane's marked top speed, the engines have transitioned almost entirely to ramjets (I believe only 20% of the air goes through the compressor), which can work just fine up to Mach 5. Higher speed just means more air rammed into the engine. This isn't necessarily true. You can design a ramjet that works up to Mach 5, but not every ramjet will work at that speed. A ramjet relies on being able to slow the airflow down to under Mach 1 (and drat near to zero compared to the intake velocity) so that the ignitors can actually get the fuel-air mix burning. If you can't slow it down enough, it'll just blow out like a match in the wind. And that's a bit difficult unless you have systems that allow the ramjet to change shape. Mach 5 is the "limit" because around there the area ratios between intake and choking point start to get impractical. On top of that, your stagnation (ram) pressure is getting high enough that the drat flow just re-accelerates after the choking point instead of slowing down further. That's where SCRamjets come in. The SC stands for supersonic combustion, as in being able to set the fuel-air mix on fire while the flow is still supersonic past the ignitors.
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Apr 20, 2010 22:21
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It's kind of a shame that nobody really built a scramjet. Impracticality be dammed, it would be awesome!
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Apr 20, 2010 22:48
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I think I'm partial to the Orion project propulsion. We have all these nukes, might as well use them for something.
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Apr 20, 2010 22:49
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ApathyGifted posted:Mach 5 is the "limit" because around there the area ratios between intake and choking point start to get impractical. On top of that, your stagnation (ram) pressure is getting high enough that the drat flow just re-accelerates after the choking point instead of slowing down further. That's where SCRamjets come in. The SC stands for supersonic combustion, as in being able to set the fuel-air mix on fire while the flow is still supersonic past the ignitors. Crikey, you seem to know something. How do you keep the mix alight in a supersonic breeze?
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Apr 20, 2010 22:52
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jandrese posted:It's kind of a shame that nobody really built a scramjet. Impracticality be dammed, it would be awesome! They have, actually. It's just really really hard to do. http://en.wikipedia.org/wiki/X-43 "Fuel was flowing to the engine for eleven seconds, a time in which the aircraft traveled more than 24 km." Also, more research needs to be put into the linear aerospike engine, because it looks so drat cool:  The fuel burns on the outside, with the expanding shockwave forming one half of the combustion chamber. VVVVV You only said "it's a shame that nobody really built one." A number have been constructed and run in ground tests, and two have flown. orange lime fucked around with this message at 23:16 on Apr 20, 2010 |
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Apr 20, 2010 23:02
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A single experimental aircraft does not make something "in use". I was hoping more for a followup to the SR-71. Too bad satellites pretty much killed off manned recon even though they don't do as good of a job in many cases. They're a lot cheaper than some brand new scramjet equipped aircraft though.
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Apr 20, 2010 23:08
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orange lime posted:Also, more research needs to be put into the linear aerospike engine, because it looks so drat cool: It looks like a loving spaceship landing thruster.
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Apr 20, 2010 23:20
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Godholio posted:It looks like a loving spaceship landing thruster. I seem to remember there was a linear aerospike in contention for the Apollo/Saturn program that didn't get built in favor of the gimbaled bell design that you think when you think Space Rocket. [edit] Wiki remembers it better than I do. http://en.wikipedia.org/wiki/Aerospike_engine meltie posted:Crikey, you seem to know something. How do you keep the mix alight in a supersonic breeze? Slo-Tek fucked around with this message at 23:37 on Apr 20, 2010 |
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Apr 20, 2010 23:33
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VikingSkull posted:I think I'm partial to the Orion project propulsion. We have all these nukes, might as well use them for something. The above comment is not complete without the below link. http://www.ted.com/talks/george_dyson_on_project_orion.html Also, all this talk about aerospikes brings back bad memories of the X-33. They might as well have cancelled Christmas. 
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Apr 21, 2010 02:12
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jandrese posted:A single experimental aircraft does not make something "in use". I was hoping more for a followup to the SR-71. Too bad satellites pretty much killed off manned recon even though they don't do as good of a job in many cases. They're a lot cheaper than some brand new scramjet equipped aircraft though. If satellites killed off the SR-71, then loitering HALE (high altitude, long endurance) UAVs like Global Hawk made damned sure that it would never be revived. With near real-time satellite datalinks, speed to and from the target is of little importance. The ability to loiter for hours on end is what really sets apart Global Hawk from anything before it.
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Apr 21, 2010 04:22
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Sterndotstern posted:I saw a slide rule one once. They appear to be a weird relic from some ancient alien civilization, covered with cryptic writing and ratios. I quickly shielded my eyes with my TI-83 and continued playing Dope Wars.  I stole this for a FB status.
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Apr 21, 2010 04:25
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Boomerjinks posted:The above comment is not complete without the below link. My bad, I usually add it. I figured everyone in this thread knew what I was talking about though.
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Apr 21, 2010 21:20
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MrChips posted:If satellites killed off the SR-71, then loitering HALE (high altitude, long endurance) UAVs like Global Hawk made damned sure that it would never be revived. With near real-time satellite datalinks, speed to and from the target is of little importance. The ability to loiter for hours on end is what really sets apart Global Hawk from anything before it. Well, that and that fact that we're not fighting the Soviets in Russia. Slow moving UAVs probably wouldn't last long against a first world nation's anti-air defenses, but since we're fighting small groups of people hiding in dirty third world nations these days it does a great job.
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Apr 21, 2010 21:38
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jandrese posted:Well, that and that fact that we're not fighting the Soviets in Russia. Slow moving UAVs probably wouldn't last long against a first world nation's anti-air defenses, but since we're fighting small groups of people hiding in dirty third world nations these days it does a great job. You can put up a whole lot of stealthy UAVs for the cost of a single SR-71. The concept is pretty well obsolete.
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Apr 21, 2010 22:00
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Sterndotstern posted:I saw a slide rule one once. They appear to be a weird relic from some ancient alien civilization, covered with cryptic writing and ratios. I quickly shielded my eyes with my TI-83 and continued playing Dope Wars. I'm one-upping the other guy a few posts up and using this as that thing Facebook likes to put just under your profile picture.
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Apr 22, 2010 00:41
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KYOON GRIFFEY JR posted:You can put up a whole lot of stealthy UAVs for the cost of a single SR-71. The concept is pretty well obsolete. Yeah  Even if we made a UAV with super-cruise and top notch stealth, it would probably be a lot cheaper and smaller than an SR-71.
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Apr 22, 2010 01:13
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Fire Storm posted:Yeah
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Apr 22, 2010 01:51
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emf posted:Something like a modern, less killy version of the D-21? I would be very, very surprised if there weren't such a UAV currently in service. Someone at DARPA was thinking along your lines, but taking it one step further. Behold, the Rapid Eye UAV concept: https://www.youtube.com/watch?v=jkrcTz4bQbo Rapid Eye would fill this need nicely, were it not for the inability of the Chinese and Russians to tell if it's WWIII or not.
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Apr 22, 2010 02:56
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Fire Storm posted:Yeah Even if you just rebuilt something to SR-71 performance targets without a pilot I bet it would be cheaper to operate and it would probably be cheaper to build as well.
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Apr 22, 2010 14:34
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They're doing an airshow on our base this weekend, so I've gotten to see some neat stuff. Saw 2 Super-Hornets and 2 Hornets alongside eachother for the first time .. definitely did not realize that the Super-Hornet was that much bigger. They had the SH's painted up like Migs (white nose w/ sky blue camo). If I go to the full show tomorrow, I'll try and get some nice pics. I saw a couple A-10s on the other side as well but haven't gotten to check the full line-up.
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Apr 23, 2010 21:32
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Firefighter training in the middle of a huge thunderstorm!
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Apr 24, 2010 00:25
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InterceptorV8 posted:They built that plane with loving SLIDE RULERS, how many of you fuckers have ever handled one? I learned how to use one as a kid, but would probably suck horribly if I tried it now, although I still have a couple I got at Goodwill. My dad's a loving whiz at slide rules, he's a retired tool-and-die maker. Funfact: When the first pocket calculators got cheap enough for machinists and toolmakers to own them, in the early Seventies - the young guys used them all the time but double-checked themselves with a sliderule, while the old dudes continued to use sliderules but doublechecked with newfangled calculators.
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Apr 24, 2010 03:09
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MrChips posted:Someone at DARPA was thinking along your lines, but taking it one step further. Behold, the Rapid Eye UAV concept:
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Apr 24, 2010 06:14
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Nait Sirhc posted:Firefighter training in the middle of a huge thunderstorm!
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Apr 24, 2010 09:08
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Nostalgia4Infinity posted:Hells yeah, I'm famous Do you have a high res of this? I'd love it for a wallpaper.
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Apr 24, 2010 09:14
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Nait Sirhc posted:Firefighter training in the middle of a huge thunderstorm! Curious...do they just light up old airframes from boneyards for training, or is there just a designated skeleton they light up every single time (placing the crew dummies in, then lighting that fucker on fire)?
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Apr 24, 2010 18:14
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movax posted:Curious...do they just light up old airframes from boneyards for training, or is there just a designated skeleton they light up every single time (placing the crew dummies in, then lighting that fucker on fire)? It's a purpose built skeleton made from steel.
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Apr 24, 2010 18:27
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It's also natural gas piping, too, right? That's not an oil fire.
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Apr 24, 2010 19:22
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azflyboy posted:
My dad's a former fighter pilot, so he has some awesome stories. Recently (as a result of this thread) we were talking about the SR-71 and I mentioned 85,000 ft. He said all of the published specs and limits were low, and they actually flew quite a bit higher than that.
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Apr 24, 2010 20:08
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