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I was considering posting something like this, but looks like you beat me to it. I'm a pilot and flight instructor myself (as well as a huge airplane and history nerd), so I'd be happy to answer any questions, especially about smaller aircraft. To contribute:  Click here for the full 1280x1020 image.  Click here for the full 1900x1492 image. The SR-71 Blackbird is quite possibly the most amazing aircraft ever to take to the skies. Developed in the 1950's in complete secrecy, the SR-71 still holds several speed records and achieved a level of performance that hasn't been seen since. Most modern fighters can reach speeds of Mach 2 (twice the speed of sound) over a short dash, and the F-22 can cruise at slightly over Mach 1, but the SR-71 spent most of it's life cruising in excess Mach 3 above 80,000ft. The SR-71 was powered by a pair of Pratt & Whitney J58-P4 engines, which produced 32,500lbs of thrust each, and were designed to spend most of their time running on afterburner. When running at Mach 3, the actual turbine blades of the engine produced very little power, with the engine intakes producing most of the thrust by manipulating a trapped shockwave to function like a ramjet. Since navigating at 2,500MPH and 80,000ft is a bit tricky, the SR-71 also featured an ingenious navigation system that used the stars for navigation. Once told it's starting location, date, and time, the system used a telescope run by an analog computer to search the sky for one of 56 stars in a database, which it then used to figure out where the aircraft was. Well before GPS was invented, this system could keep the aircraft within 300ft of a straight line course, and within .2 miles of a course while turning, even on 12 hour missions spanning half the globe. Despite carrying over 80,000lbs of fuel, the SR-71 consumed it at such a prodigious rate that refueling was required about every 90 minutes on a mission, and there was a fleet of KC-135 tankers dedicated to supporting SR-71 operations. The SR-71 operated from 1964 to 1989, when it was killed by political infighting over the massively over-budget B-1 and B-2 projects. However, three SR-71's were reactivated from 1994 to 1997, with the last SR-71's (two NASA operated examples) ceasing flight operations in 1999. Edit: fixed table breakage. azflyboy fucked around with this message at 02:05 on Mar 8, 2010 |
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Mar 8, 2010 02:02
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Advent Horizon posted:I like the SR-71 and all, but there's nothing like the sound of a four-engined Douglas. Big piston engines (especially radials) are some of the best sounding things on earth. A couple of years ago, I had the chance to see something like a dozen Spitfires flying together, and the sound of 144 Merlin and Griffon cylinders doing past is almost indescribable.
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Mar 8, 2010 02:25
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Needs more videos... Perfect emergency landing, except for the cow... http://www.youtube.com/watch?v=1pfZiTDchH0 We've got this runway, so we're going to use all of it http://www.youtube.com/watch?v=aWtdtuspnoM&feature=related Crosswind testing for a 777 and 747, these guys are good http://www.youtube.com/watch?v=ljOxo0s33sI A 747 making the infamous "checkerboard approach" at the old Kai Tak airport in Hong Kong with a hefty crosswind. The approach required a 47 degree turn less than two miles from the runway and well below 1000ft, and whacking an engine on the asphalt was a distinct possibility if the rollout was mistimed. http://www.youtube.com/watch?v=OtnL4KYVtDE Some very impressive low level flying by Mirage pilots, set to surprisingly good music. http://www.youtube.com/watch?v=v9T51UsuaPU&feature=related Zero G dog! http://www.youtube.com/watch?v=jU9USxJ9vPs Zero G Vomit! http://www.youtube.com/watch?v=p8gPRgw5_y8 EDIT: fixed broken links azflyboy fucked around with this message at 05:15 on Mar 8, 2010 |
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Mar 8, 2010 02:39
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MrChips posted:To experience the ultimate in pistons and propellers, you guys need to take a week off work in September and go to the Reno National Air Races. There are several classes of aircraft racing, but the headliners are in the Unlimited category, populated with highly modified WWII-vintage aircraft, such as these: There was an article in Air and Space a couple of years ago that mentioned the Reno teams are running into trouble finding replacement engines because of how fast they destroy them. Since Merlin parts haven't been manufactured for 60 years, parts are getting rare, and there are only a few people that supply spares for those engines still flying. Several of those individuals simply won't sell to Reno teams, since racing destroys in about 30 minutes an engine that would last decades on a stock P-51 or Spitfire. As impressive as the Reno Unlimiteds are, I'd really like to see the class evolve into something that didn't destroy increasingly rare engines for one race per year.
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Mar 8, 2010 03:32
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Blue Footed Booby posted:Then why don't you post one? It's a Saab Draken, a Swedish interceptor used from 1960's through the 1990's, with the last examples (flown by Austria) being retired in 2005. Unlike American interceptors, the Draken was intended to operate from reinforced public roads during wartime, and could be rearmed and refueled in about 10 minutes by conscripts with only basic training.
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Mar 8, 2010 04:54
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FullMetalJacket posted:i'm doing this while it's still the first page: While the F-14 did have a bunch of problems with the early production models, the fact that it could (theoretically) hit another aircraft with a missile from 100 miles away is pretty cool.
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Mar 8, 2010 05:44
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Maker Of Shoes posted:Sweet mother of God! What is that thing?! It's an Eraknoplan. Eraknoplans use a phenomena known as ground effect (where a wing near the ground forms a cushion of air underneath it) to skim just over the ground or water surface at high speeds. In theory, this would allow a large military force to be deployed beneath enemy radar coverage, but the Soviets never really solved some stability and navigation issues, so only a few were ever built. Here's a video of the vehicle in the pictures (dubbed the "Caspian Sea Monster") in use. http://www.youtube.com/watch?v=YSYmSnpQ360
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Mar 8, 2010 22:02
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Throatwarbler posted:I thought they worked well enough, except the only problem was that they couldn't really handle rough seas that you might encounter on the open ocean, so other than the Caspian Sea and a few other inland bodies of water it wasn't really usable anywhere else. They did work, but keeping something that size in ground effect at high speed would require a very good pilot (and smooth water), so something like large hovercraft were a better solution to the problem.
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Mar 8, 2010 22:19
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MrChips posted:With performance almost unmatched by the fighters of its day (remember, this aircraft first flew in 1947) and the looks to go with it, aircrews often gave into the temptation to beat the everlasting poo poo out of their B-47s. Combined with the high-speed, low-level flying that often comprised the missions assigned to the B-47, many of these aircraft succumbed to airframe fatigue. Part of that low level flying also involved one of the more impressive methods of delivering a nuclear bomb ever devised for an aircraft. When the B-47's mission was changed from high altitude bombing to low altitude penetration and bombing, it was realized that the aircraft wouldn't have the time to escape the blast if it dropped a nuclear weapon at low altitude. To solve this problem, the LABS (low level bombing system) technique was devised, which was a combination of specialized bombsight and some pretty impressive maneuvering to make low altitude nuclear weapon delivery survivable. Flying at low level and high speed, the B-47 would pull up as though performing a loop, with the bomb being released just before the aircraft reached the vertical. This served to "toss" the bomb at the target, and the B-47 would continue the pullup until it was flying inverted, at which point the pilot would roll the aircraft back to level flight and dive back towards the ground heading away from the mushroom cloud they'd just caused. Performing the LABS maneuver imposed massive stresses on the airframe (even more so than low level flying), and after it became clear that metal fatigue was becoming a serious issue, the maneuver was stopped. Here's a video giving a pretty good idea what the maneuver looked like. http://www.youtube.com/watch?v=mqIJL8lx00o
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Mar 9, 2010 07:03
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VikingSkull posted:
I remember reading that the Nighthawk was retired simply because the aircraft were getting old (and therefore more costly to keep flying) and the USAF wanted more F-22's, so they canned the F-117. The F-117 was also designed using the very best of 1970's technology, and the role it served (penetration and surgical strike) could be performed by the B-2, F-22 or a JASSM (a stealthy cruise missile), so it wasn't terribly useful to keep around in the future.
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Mar 11, 2010 06:20
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VikingSkull posted:
I'm not sure how useful the F-117 would have been for the "dirty little wars" that have cropped up since the 1990's, especially the war on terror. The Nighthawk was designed to penetrate heavily defended airspace, drop two guided bombs on something important, and then get away undetected, which isn't terribly relevant right now. Cruise missiles have improved since Desert Storm to the point where they're great at precision strikes, and if it's absolutely necessary to use a manned aircraft to drop something, a B-2 can carry more weapons over a longer range, and is likely harder to see on radar than it's older brother. Most of the post Gulf War conflicts have seen bombers being used primarily for ground support, with B-52's and B-2's alike orbiting until needed, dropping a couple of guided weapons on something, and going back to orbiting, which the F-117 simply couldn't do.
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Mar 12, 2010 00:57
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Advent Horizon posted:If they're thinking about using Caravans, what about the Twin Otter? Seems like that might be a better idea. If an engine goes out you've got a spare, and you can haul more weaponry around (or more fuel for more loiter time). De Havilland Canada stopped building Twin Otters in 1988, so I doubt the USAF would have been interested in buying aircraft that aren't made anymore. Since the aircraft is so popular ,a company called Viking Air bought the manufacturing rights in 2004, and starts delivery of new aircraft later this year. Given how versatile the Twin Otter is, I wouldn't be surprised if the US military ends up buying a few for various purposes.
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Mar 12, 2010 07:09
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Autism Sundae posted:How is it a really ingenious idea? Some dude basically said "hey check this out, you know tanks have like turrets on top? Let's do this poo poo on a plane". Nobody else did it because in every other air force there was another dude that took about ten seconds to think about it and said "no, that poo poo's retarded". For example, the original idea behind the B-17 was that it would be used to destroy fleets of enemy ships with high altitude bombing, which proved to be almost impossible due to the relatively small size of ships and the fact that they could maneuver. During the early part of the Pacific campaign (up to 1943), several attempts were made to attack Japanese shipping with B-17's, but the bombing accuracy was so abysmal (around 1%) that the USAAF eventually gave up and switched to skip-bombing with smaller aircraft. Even when B-17's were used against stationary land targets with the Norden bombsight, bombing accuracy from high altitudes was still poor, with the USAAF finding that it took 108 B-17's dropping 648 bombs to ensure that only two bombs hit within a 400x500ft area. Prior to the Battle of Britain, RAF fighter tactics were based on very strict, squadron sized formations that were designed to attack waves of enemy bombers, but gave no consideration to the fact that said bombers might have fighter escorts. As a result, the Luftwaffe (which used much looser, two plane elements) absolutely decimated RAF fighters until the British changed their tactics to closely mirror what the Germans were using. azflyboy fucked around with this message at 22:14 on Mar 12, 2010 |
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Mar 12, 2010 22:09
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EDIT isn't quote!
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Mar 12, 2010 22:14
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VikingSkull posted:Isn't the A-10 basically the Skyraider with a bigger gun and jets? The F-4 was also used by all three branches, and it's the only aircraft to be flown by both the Blue Angels and Thunderbirds simultaneously.
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Mar 12, 2010 22:49
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jandrese posted:Caveat: I got this information from a movie*, so the accuracy may not be perfect. That's basically correct. The HK-1 was supposed to be finished by 1944, but it wasn't completed until 1947, allegedly because Hughes was insisting on "perfection". Hughes was pretty well known for defrauding the government, (a Hughes payoff to Nixon likely triggered the Watergate break-in, and he basically owned the state of Nevada) and it's likely he assumed the HK-1 contract wouldn't have any serious repercussions.
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Mar 12, 2010 23:17
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ApathyGifted posted:
The problems with the engine on the Thunderscreech mostly came from the fact that it was too complex. Allison created the T40 by taking two of their T38 turboprops, bolting them together and adding a hellishly complex clutched gearbox and propeller control system (which required 25 vacuum tubes to operate). The idea was that one of the power sections could be shut down in flight to improve range, but the idea never worked that well, and the tendency for the gearboxes to fail spectacularly and the unreliability of the vacuum tubes in the prop control system doomed the engine. Allison did make up for the J40 fiasco in the form of the T56, which has been reliably powering the C-130 fleet (among others) since 1954, with over 18,000 of the engines being delivered to date.
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Mar 16, 2010 19:23
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Nebakenezzer posted:
That fabric is insulation blankets. Aircraft skin is incredibly thin (under 1/2 inch thick), and the temperature at 30,000ft is normally in the -40/-50C range, so the insulation reduces the amount of bleed air required to keep the aircraft warm and makes the interior quieter as well. The insulation also keeps the fuselage skin from getting damaged if something bumps into it. As for the fans, they're something the Soviets used in pretty much all of their aircraft since the 1940's. The blades are made out of rubber or plastic, so that's why there isn't a guard around them. The AN-124 is pressurized and therefore air conditioned (engine bleed air has to be cooled before it can be used to pressurize the cabin), but the fans help keep the crew from roasting on the ground when the engines aren't running. azflyboy fucked around with this message at 22:19 on Mar 16, 2010 |
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Mar 16, 2010 22:15
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OptimusMatrix posted:I've always liked these SR71 stories. There are some interesting stories involving operating the SR-71 over the lower 48 as well. Early in the program, an SR-71 was hit with a series of problems that resulted in an engine failure over the southwestern US. Since the SR-71 couldn't stay at speed and altitude on one engine, the crew was forced to make a supersonic descent somewhere over Utah while trying to get the engine running again. Eventually, they got the engine restarted, just in time to sonic-boom the Mormon Tabernacle in Salt Lake City. On another occasion, an SR-71 overflew Lyndon Johnson's Texas ranch and blew out his picture windows with the sonic boom, which resulted in the training routes being altered to avoid pissing LBJ off. During another training mission, an SR-71 experienced an autopilot and navigation failure over the US southwest. The pilot decided to try and hand-fly the flight plan at Mach 3, but mistimed a turn over Arizona by a few seconds, which resulted in the aircraft ending up somewhere over Mexico by the time the turn finished up. As the pilot later remarked, "You haven't been lost 'till you've been lost at Mach 3."
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Mar 17, 2010 18:22
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ab0z posted:"The SR-71 had a turning radius of about 100 mi. at that speed and altitude, so I wasn't even sure what state we were going to land in." The SR-71's pilot manual actually included charts for turn time/distance at various groundspeeds due to the amount of real estate the aircraft chewed up doing anything at cruise speed. For example, it says that a 180 degree turn at Mach 3 (flown at a 30 degree bank angle) would require just over 8 minutes to complete, and the aircraft would cover 235 miles while doing so. Also, the pilots manual for the SR-71 is available for free online here, and it's pretty interesting. http://www.sr-71.org/blackbird/manual/ There's some redacted sections pertaining to the cameras and radar systems (although that information is now publicly available), but otherwise there's everything you'd ever want to know about an SR-71 in there. azflyboy fucked around with this message at 19:26 on Mar 17, 2010 |
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Mar 17, 2010 19:21
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Nebakenezzer posted:Holy cow! The second wing adds quite a bit of lift, and the aircraft is also fitted with large flaps and drooping ailerons (which droop down when flaps are extended) as well as slats that automatically pop out from the leading edge of the wing at low speeds to add even more lift.
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Mar 17, 2010 21:05
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MrChips posted:You might be able to find a couple of used earlier editions on Amazon or eBay, but they'll still be at least a hundred bucks or so. If you've got the scratch, this book is well worth the money. Also, I'd recommend "The Untouchables" by the same author, Brian Shul. I do use that address, but I don't know if the email function on SA is working. My email address is dsflyboy AT earthlink.net
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Mar 18, 2010 08:58
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Sterndotstern posted:
A lot of recent developments in aviation are aimed at improving existing aircraft to keep them flying rather than spending tens of billions on a new design that's going to go massively over budget and behind schedule. As an example, look at the C-130J and A-400 programs. By modernizing a 50 year old aircraft, Lockheed was able to gain significant improvements in speed, fuel economy and takeoff/landing performance, all while developing the aircraft roughly within time and budget constraints. The A-400 (a completely new design) is currently four years behind schedule, something like 25% over budget (Airbus is expected to lose around $10 billion on the whole program), and Airbus is threatening to cancel the program if they don't get thrown more money. As a result of the delays, several A-400 customers have cancelled their orders and bought C-130J's and C-17's instead. The USAF is also following a similar "if it ain't broke, just update it" strategy. Both the C-5 and KC-135 fleets have had substantial amounts of money thrown at them to upgrade things like engines and avionics and replace aging structural components to increase the performance of the aircraft and get more value out of the initial investments. Ironically, the B-52 seems to be doing slightly better than the aircraft that was supposed to replace it. In 2003, the USAF decided to retire about 30 B-1's (reducing the fleet to 67) meaning there were more B-52's flying than the aircraft that was supposed to replace it. Despite being well over 40 at this point, the B-52 fleet still manages to have a far higher availability rate than either the B-1 or B-2 that were intended to replace it. Currently, the B-52 is supposed to be in service until at least 2040 (making the youngest flying aircraft about 80 years old), with the B-1 fleet being retired at about the same time.
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Mar 19, 2010 06:02
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jandrese posted:IMHO, the Concorde was a failure in the end because regular Joes couldn't afford to fly on it, and the ticket prices were high enough that most businesses would only let executives fly on it. What actually killed the Concorde was 9/11 and the resulting economic downturn. After Air France 4590 crashed in July of 2000, the entire Concorde fleet was grounded for some costly upgrades to the fuel tanks to prevent another tire blowout from rupturing a tank. In addition to those repairs, the Concorde fleet was simply getting old, and the surviving aircraft were getting close to needing some incredibly costly updates to their avionics and systems within the next few years to keep the aircraft airworthy and compliant with new rules and regulations. Aside from the upgrade costs, the basic maintenance on the fleet was also getting more expensive, since making spare parts for a fleet of 14 aircraft worldwide is going to be more costly than spares for a design with several hundred aircraft in service. Despite those costs, the Concorde was still considered viable, until 9/11 happened. When the World Trade Center towers fell, the people killed included many of the executives who either routinely flew on Concordes or had the power to authorize others to do so. The loss of a core customer base and the resulting downturn in the airline industry made it impossible for the aircraft to turn a profit in the face of increasing operating costs and looming upgrade costs, so Air France and British Airways made the logical choice to retire the Concorde fleet. In an odd twist of fate, the first BA Concorde to fly after the accident did so on 9/11/2001, making a quick "out and back" flight from Heathrow with BA employees on board. EDIT: Since I've got nothing better to do, here's a comparison between the 767 and Concorde to show just how expensive they were to operate. For reference, the Paris-New York route (the longest Concorde route in normal service) is just shy of 3,200 nautical miles. A 767-200 carries just under 24,000 gallons of fuel, allowing it to carry (for a 3-class setup) 181 passengers just short of 6,400 nautical miles. That works out to about 48 miles/gallon per passenger, and on a New York to Paris or London flight, that number would likely be higher as a result of the aircraft not carrying full fuel. A Concorde carried about 26,400 gallons of fuel, which allowed it to carry 92 or 100 passengers (depending on the airline) a maximum of only 3,900 nautical miles. This works out to about 14.8 mpg/passenger (with 100 seats) or 13.5 with 92 seats. Even without taking other operating costs into effect, it's pretty obvious why the Concorde wasn't able to survive the post 9/11 recession. azflyboy fucked around with this message at 21:00 on Mar 19, 2010 |
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Mar 19, 2010 20:36
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And now for something a bit less exciting... basic trainers. I work as a flight instructor, so these are where I get to spend my day, assuming the weather cooperates. The oldest aircraft I fly are Piper Warriors (the oldest in the fleet was delivered in 2005).  Click here for the full 1024x694 image.  Click here for the full 1280x972 image. First designed in 1960, the basic design of the Warrior has changed little in the intervening 50 years, and the design is now aging badly, despite getting a glass cockpit in 2005. The biggest problems with the Warrior are mostly ergonomic. For some reason, Piper only puts a door on the right side of the aircraft, and the seats become distinctly uncomfortable after fairly short flights. The ventilation does an amazing job of freezing ankles (that's where the vents are) without actually cooling the cabin down, and the heater is equally worthless when it gets cold outside. Adding to the fun, Piper stuck the fuel selector where there's no chance the flight instructor could reach it (it's in the lower left of the cockpit photo), and they also put the transponder and carb heat controls in locations where they're really awkward for the student to reach. Because the glass cockpit system was basically thrown into the airplane, it's not very user-friendly and still requires two separate GPS units (the two small screens in the center of the panel) to work. The standby instruments are also placed in a horrible location, making them incredibly awkward to use if the glass system actually fails. That said, the Warrior is still great for student pilots due to it's landing behavior. The landing gear appears to be indestructible, and even with the "interesting" landings students tend to make, it's hard to get more than a single bounce out of the gear before the airplane decides to stay on the ground. Even if a student lands nosewheel first (which occasionally happens), the nosegear assembly is bolted to the engine mounts and takes an astonishing amount of abuse without getting damages. The other airplane I fly is the Cessna 172, which is slowly replacing the Warrior fleet where I work. First built in 1955 and still in production, the Cessna 172 is the most produced aircraft in history, and has aged much better than it's Piper competition.  Click here for the full 1200x687 image.  Click here for the full 1196x811 image. Thanks to fuel injection, the 172 delivers 20 more horsepower than the Warrior (180 vs 160), which results in a higher climb rate while only burning slightly more fuel than the Warrior. Cessna chose to use the Garmin G1000 glass cockpit system, which delivers a truly staggering amount of information and navigation capability with a very common-sense interface and controls. If the screen on either side fails, the pilot can simply push a button to tell the remaining screen to display a mix of flight instruments, navigation and engine instrument information, which is a great "peace of mind" feature. Aside from the G1000, Cessna also stuck a very nice interior in the 172, with very comfortable leather seats, large, tinted plexiglass sun visors, and even an ipod jack. Cessna also decided to add shoulder and head level vents to the cockpit (which do a great job of cooling the cabin), and having doors on both sides of the cockpit is amazingly useful. Cessna also added airbags to the 172, and they're attached to the lap belts, inflating up at the occupants to prevent them from smashing their heads on the glareshield or yoke. Unfortunately, the newer 172's seem to have a bit of a "glass jaw" in the nosewheel design. Whereas Piper bolts the Warrior's noswheel to the engine mounts, Cessna bolts theirs to the firewall, which is only .16 inches thick. If a student lands a 172 nosewheel-first fairly hard, there's a good chance the impact will result in a wrinkled firewall and/or floorboards, which results in about $50,000 in repairs (on a $300k airplane), the flight instructor getting a 709 ride from the FAA (a checkride to make sure you're competent to be an instructor), as well as a butt chewing from various supervisors. The spring-steel design of the main gear also results in a tendency for the aircraft to impersonate a deranged kangaroo on really hard landings, but even with those foibles, the 172 still makes a great trainer, albiet one that requires the instructor to watch students a bit closer on landings.
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Mar 20, 2010 05:04
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Maker Of Shoes posted:For anyone not familiar with AMARC here's a satalite shot of the "bone yard". It's unreal. There are also several F-16's sitting out there that were supposed to be sold to Iran before the Shah was overthrown. Apparently the aircraft are technically the property of the Iranian government and so can't be sold off or scrapped, but because of the arms embargo they can't be delivered, so they've been sitting in shrink-wrap for the last 30 years or so.
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Mar 22, 2010 06:30
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Nebakenezzer posted:
Mostly, it's because the B-52's are paid for, they're reliable, and the airframes can be adapted to do basically anything. The B-52 is apparently more reliable than the B-1 or B-2. As of 2001, the B-52 fleet averaged an 80% readiness rate, versus 53% for the B-1 and only 26% for the B-2. For conflicts like Afghanistan (and Iraq after the initial invasion), heavy bombers get used mostly in an "on call" role, which they weren't really designed for. Normally, the bomber will simply orbit at high altitude until given a target, at which point they'll release one or two precision guided bombs onto whatever needs to disappear, after which point the aircraft goes back to orbiting until given other targets or going home. During the 1960's, SAC B-52's maintained a 24 hour airborne alert at various points near the USSR, and the qualities that made the B-52 suitable for that mission happen to dovetail with the smaller conflicts the US gets involved in now. In areas where there's no real anti-air threat, the B-52's ability to loiter at altitude makes it a more economical choice than something originally designed for high-speed penetration at low altitude. The fact that the B-52 has a longer range than the B-1 means it can loiter longer without refueling, and on missions where the bombers probably won't engage many targets, the B-1's larger bombload doesn't really matter much.
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Mar 23, 2010 02:39
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Nebakenezzer posted:
It's an Armstrong Whitworth Argosy, which was a 1960's RAF cargo carrier that was also sold to some civilian operators.
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Mar 24, 2010 23:36
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decahedron posted:Probably the same reason that cars are now more difficult to maintain - increased technological sophistication. There was also a lot of "trial and error" fixes to older aircraft (due to more of them being built) during their production runs that modern designs usually don't go through. In the case of the B-52, the current USAF fleet is comprised entirely of "H" models, which were the last of 744 total B-52's manufactured. Each successive B-52 variant was built to improve the capabilities of the aircraft as well as solve any design problems from earlier models, and most B-52 variants underwent at least one modification in service to correct things like fuel leaks or unreliable engines. When the B-52H was built, it incorporated the lessons learned from all the earlier B-52 models, which means that the USAF has mostly needed to replace outdated electronics to keep the aircraft viable as technology changes. Because of that evolution, the B-52 fleet started with a proven airframe, and every time it gets upgraded, the technology added has already been proven, which removes the teething problems any new electronic system is going to run into.
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Mar 25, 2010 18:59
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Boomerjinks posted:The best part of the Tu-4 story was the part where Russian scientists visited the engine factory in the US wearing specially-designed soft sole shoes, which they used to collect metal shavings around the different lathes. SNEAKY FUCKERS! The Russians also bought TU-4 tires from the US. When the TU-4 was built, Soviet industry couldn't produce tires of that size, so they simply had people in the US purchase a bunch of surplus B-29 tires to last until Soviet versions could be produced.
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Mar 26, 2010 02:28
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Nebakenezzer posted:
Chemically, diesel and jet fuel are really similar, but there are a couple of minor differences between the two fuels. First of all, Jet-A (and Kerosene) are lighter fuels than diesel, and lack some of diesel's lubricating properties. Jet fuel normally has an anti-bacterial agent mixed in, as well as an anti-icing additive to keep the water in the fuel from freezing and clogging fuel lines and filters. Since those additives aren't normally present in diesel, high altitude operations using it can become problematic, since any water in the fuel will freeze when cold-soaked to -30C. Some turboprop aircraft actually have the capability to burn 100LL Avgas in an emergency, although doing so imposes all kinds of limitations on the engines, and the lead content of Avgas normally requires a teardown of the engine to inspect for lead deposits or other damage. azflyboy fucked around with this message at 22:43 on Mar 28, 2010 |
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Mar 28, 2010 22:38
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ApathyGifted posted:
Flaps actually serve two purposes. As you mentioned, they alter the shape of the wing to reduce stall speeds and increase lift, but they serve a second purpose as well. When flaps are extended past a certain point, they allow a steeper decent angle to be flown on approach without the airspeed increasing. This steeper glidepath gives the pilot a better view of the runway through most of the approach, which useful for U-2 pilots. On the subject of strange landings, the B-52 has a pretty interesting way of dealing with crosswinds. Normally, large aircraft are landed in a crosswind by pointing the nose into the wind through most of the approach, followed by using rudder to swing the nose of the aircraft to point down the runway just as the wheels touch down during the flare. Here's some footage of the "crab method" being used by a 747 and 777 in some really heavy crosswinds. http://www.youtube.com/watch?v=ljOxo0s33sI Because of how the B-52 is landed (the aircraft approaches with the nose low and is basically flown onto the runway), the crab method wouldn't be feasible, so Boeing came up with a pretty clever solution to the problem. The four main gear trucks on the B-52 can be deflected up to 20 degrees either side of center during approaches, which allows the aircraft to land with the nose deflected into the wind, while the landing gear are pointed straight down the runway. This leads to the aircraft trundling down the runway sideways, which is incredibly bizarre to see. I couldn't find a video of a crosswind landing in a B-52, so here's a couple separate ones to demonstrate the point. A normal B-52 landing, complete with braking parachute. http://www.youtube.com/watch?v=4JxFMIGRNb4 A B-52 demonstrating the crosswind landing gear on the ground (and taking out some runway lights in the process). http://www.flightlevel350.com/Aircraft_Boeing_B-52_Stratofortress-Airline_USA_-_Air_Force_Aviation_Video-4875.html
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Apr 2, 2010 21:46
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VikingSkull posted:Basically, yeah. If it's military, it probably is capable of mid-air refueling. About the only military aircraft I can think of without mid-air refueling capability is the U-2/TR-1. The CIA experimented with fitting a few U-2's with refueling capability in the early 1960's, and although the aircraft could stay aloft in excess of 14 hours, pilots became dangerously fatigued under those conditions and the idea was eventually scrapped.
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Apr 3, 2010 01:12
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Frank Dillinger posted:isn't something like this kind of an environmental hazard? I mean, dumping that much hydrocarbon fuel can't be good, can it? Most large aircraft are capable of taking off at weights far in excess of their maximum landing weights, so fuel dumps are common on most large airliners and military aircraft to allow rapid weight loss in the event of an emergency. As an example, the 747-400 has a maximum takeoff weight around 875,000lbs, but a maximum landing weight in the 650,000lb range. Even at low altitudes where turbine engines use a lot of fuel, it would still take hours consume that much gas, so the ability to get rid of fuel in a hurry is a pretty handy safety feature. Most fuel dump sites are located over either uninhabited areas or over water, and the fuel is dumped at a high enough altitude and airspeed that it is dispersed over a huge area to reduce any possible hazard to people on the ground. In the event of a major emergency (a severe birdstrike for example), pilots will dump fuel regardless of where they are, but for emergencies that aren't as critical (shutting down one engine on a 747), the normal procedure is for the crew to fly to a designated point, dump the fuel there, and then return to land.
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Apr 5, 2010 02:32
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Minto Took posted:There was an incident a few years back with an Airbus and a birdstrike where the plane had to loiter for some time before landing since it didn't have the ability to dump fuel. Most short and medium-haul airliners lack the ability to jettison fuel, since they can land at their takeoff weight in an emergency. Since an overweight landing does risk structural damage and can collapse the landing gear, most pilots will elect to burn off the excess fuel in an emergency unless the situation requires an immediate landing for some reason.
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Apr 5, 2010 05:04
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Minto Took posted:Is the service ceiling on the WB variant any different from the initial airframe? Yep. The B-57 models (both the British and Martin built versions) had a service ceiling around 48,000ft, whereas the RB-57 could operate around 65,000ft.
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Apr 6, 2010 23:11
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Mobius1B7R posted:Wow a double post, I am an idiot. Well lets make something fun out of this, what is the best engine noise to your ears? I personally love the howl of the RBs on the 757. Anything with an obscenely large piston engine. I had the chance to see about a dozen Spitfires flying in formation a couple of years ago, and the sound of that many Merlins and Griffons running simultaneously was absolutely breathtaking.
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Apr 9, 2010 06:02
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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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Sterndotstern posted:High bypass means you can present a large fan dangling off the front of the turbine which performs most of the useful thrusting, while a smaller and more efficient turbine jet drives it. Another large part of the efficiency of turbofans has to do with the fact that they have relatively low exhaust velocities compared to turbojets. For jet engines at subsonic speeds, moving a large volume of air at a lower velocity is much more fuel efficient than accelerating a small volume of air to a high velocity, and it also drastically reduces the amount of noise from the engine. At higher speeds (above about Mach 1.6), the lower exhaust velocity of a turbofan becomes a bit of a disadvantage compared to turbojets, but using a lower bypass turbofan allows for a good mix of subsonic turbofan efficiency and turbojet performance at high speeds.
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Apr 29, 2010 19:42
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MrChips posted:
Even on racers, auto engines don't have a great track record. In the late 1980's, Burt Rutan and Bob Pond designed an aircraft intended to compete in Reno class against the WW2 warbirds that dominated the Unlimited class. The resulting aircraft (dubbed Pond Racer) bore a passing resemblance to a P-38, but was an entirely new design that was constructed of lightweight composite materials and used a pair of highly modified Nissan VG30 engines, intended to produce about 1,000hp each.  Click here for the full 800x543 image. In order to do away with intercoolers for the turbocharged engines, Pond Racer was designed to run on methanol, and the engines required a massive preheat before starting (due to extremely tight tolerances), and needed external cooling upon landing to avoid heat-soaking the composite engine cowlings. Pond Racer first flew at Reno in 1991, and qualified at a respectable 400mph, but didn't fly in the actual race. Shortly after takeoff for the main race, Pond Racer suffered a mechanical failure when the left engine threw a rod out of the block, but the pilot was able to land safely. During development of the engines, Pond Racer suffered a string of oil related issues, with the engines tending to "puke" oil overboard at an appalling rate, usually resulting in bearing and connecting rod failures due to oil starvation. Eventually it was discovered that the engine problems were caused by undersized oil passages in the rocker heads, which was due to the fact that the car-sourced engines weren't designed for sustained running at high RPM, but not before the aircraft went through quite a few engines. After a second place finish in 1992 (albeit in the Bronze class), Pond Racer returned to Reno in '93. During qualifying, Pond Racer abruptly pulled up off the course, with pilot Bob Pond telling the ground crew that there was a problem with the right engine, and a controller advised Pond that the aircraft was trailing smoke. As Pond Racer turned back for landing, a puff of smoke was seen from the right engine, followed quickly by the right propeller seizing in position without the blades feathering to reduce drag. Shortly after the engine failure, Pond Racer impacted the ground, killing the pilot and bringing an end to the program. After the accident, it was discovered that the right engine had experienced two connecting rod failures due to oil loss (the oil loss was the cause of the initial smoke), which lead to the rods punching holes in the oil pan, crankcase and water jackets of the engine, causing the seizure.
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May 12, 2010 06:15
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