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CharlesM posted:Oh nice. I saw an ANA 787 taxiing on Thursday. I'm looking forward to the day I get to ride on one. SJC? I've seen them lining up for takeoff while driving on 880 a couple times now. Very noticeable due to plane's sheer size, most things taking off from SJC aren't clearly visible from the freeway what with the blast fences, but the 787 really stands tall. One time I saw the taxi while on 880N, then turned onto 101N because that's where I was going and saw the climbout as I got near the end of the runway.
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# ¿ Nov 18, 2013 09:42 |
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# ¿ May 5, 2024 00:59 |
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One approach to wires that I've heard of is a form of lidar. Uses rotating mirrors to scan a laser rangefinder beam and image the environment close to the aircraft, plus some post processing to pick out likely lines, provide collision warnings, and so forth. If you design the receiver correctly this can be a much more effective machine vision system for reliably detecting thin wires in poor ambient lighting than any pixel array imaging system. As far as I know this technology has not yet been perfected or fielded, but it struck me as having a lot of potential when I first heard of it. Has obvious military applications so it might even get funded and eventually trickle down to civilian helicopters.
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# ¿ Jan 16, 2014 04:59 |
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Terrible Robot posted:GIS-ing "flying wing concept" is a loving goldmine Hah, I remember seeing that thing in Popular Mechanics (*), decades ago. If I remember right it was supposed to be a supersonic flying wing. The fins and engine pods are supposed to swivel so it can take off and land with the wing leading edge roughly normal to airflow, and transition to the depicted swept configuration for supersonic flight. (edit: or maybe it was just high subsonic? don't remember honestly) Insane. I also recognized your first image, which was a NASA funded engineering study conducted by MIT. Probably had some real engineering rigor behind it, though as the MIT PR makes clear, it isn't supposed to be a blueprint of something anyone should build just yet. * AKA the preferred pre-Internet method for distributing dumb tech "concepts" dreamed up by design students BobHoward fucked around with this message at 07:06 on Jan 24, 2014 |
# ¿ Jan 24, 2014 06:59 |
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Captain Postal posted:Of course I do. You realize that the cabin fixtures of airbus aircraft actually do move more than boeing? Citation needed. You do realize that your trolling is incredibly transparent right? Let's do a recap of a few of the ways you've been super dumb. I've seen overhead bins sway side to side alarming (till I thought about it) distances in a Boeing, which you started out claiming as a uniquely Airbus thing. If Airbus planes fell apart after five years, airlines and leasing agencies and so forth would never buy them. And for gently caress's sake, PLASTIC WEAK METAL STRONG HURR when the only actual "plastic" passenger airplane making revenue flights today is a Boeing? Dumbass.
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# ¿ Jan 28, 2014 04:31 |
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Fun F-16 / SHSC crossover fact: it was the first use of MIL-STD-1553, which has since been used as a digital communications backbone in all kinds of military vehicles (not just aircraft, it's used in tanks and APCs among other things).
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# ¿ Feb 9, 2014 09:39 |
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The recently declassified CIA U-2 / OXCART (A-12) history touches on F-104 / U-2 crossover several times. Page 45 states that only the wings and tail were unique to the U-2, and the rest of the aircraft was made with F-104 tooling.
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# ¿ Feb 24, 2014 20:21 |
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VikingSkull posted:I tried Google image search to see if I could find a picture of it and came up with this instead. The SNORT test track at China Lake. Click for a PDF with a couple more pics of tests and some history.
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# ¿ Mar 14, 2014 12:37 |
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Looks like blisks have already been in service on smaller engines like turbofans for quite a while now.
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# ¿ Mar 22, 2014 01:54 |
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Linedance posted:normally I'd say it were one of them youfoes, but since it's the Daily Mail, if it is, it's no doubt full of illegal aliens come to scrounge off benefits. And probably spy on your innocent white daughters. If you read the article (do not read the article), the Mail is true to form. They're prominently featuring some random moron's theory that it's a SR-72 (Lockheed's paper proposal for a hypersonic SR-71 successor), even though it obviously cannot be a hypersonic aircraft. But hey, the moron is an ex-Marine so clearly he is an authority worth quoting
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# ¿ Apr 20, 2014 10:52 |
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I'm partial to N318SL
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# ¿ Jun 1, 2014 05:44 |
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Anybody know why the 787 has an oval divot and triangular fairing where the horizontal stabilizer attaches to the fuselage?
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# ¿ Jun 2, 2014 08:46 |
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Brovine posted:I would guess that's the trim system - elevator trim is usually done by tilting the entire horizontal stabiliser. The triangular bit is probably the arc of movement and the accompanying mechanism, and the oval is probably a flattened section to allow for that movement. Ah, makes sense now. I was confused because a deflected elevator control surface is clearly visible in Mobius1B7R's picture, and assumed that if you had elevators you wouldn't bother with an all-moving tailplane (and vice versa). I guess it's a limited-range all-moving system for trim so that the airplane can be very aerodynamically clean when trimmed for level cruise, and less-clean elevators for full control authority.
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# ¿ Jun 2, 2014 10:14 |
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Mahmoud Ahmadinejad posted:Every so often I am reminded that there's a crazy dude in Portland living in a 727 http://www.airplanehome.com/ quote:"Humanity's current challenge is to devise efficient means and methods to economically site essentially complete retired jetliners as homes, making them much more commonly available. An elegantly executed project using an intact jetliner (except sans engines) is urgently needed to provide a compelling model which can be easily emulated. My dream is to accomplish this with the Airplane Home V2.0 project, ideally using a Boeing 747-400ER, hopefully starting in earnest within less than one year. Skimming the giant wall of text which follows, he appears to be serious about this. 747 hulks will save glorious Nippon from future tsunamis because what could be a better lifeboat than an airliner, and he shall be so famous and desired that he'll be able to have his fantasy waifu dance for him on their wings. Hope he's getting some mental health care, 'cause he's deep in some kind of delusional belief system.
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# ¿ Jun 10, 2014 12:50 |
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Fucknag posted:Which brings to question why they're developing it for Navy vessels. Are those electrical? Lasers powered by chemical reactions are a thing.
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# ¿ Jun 16, 2014 22:04 |
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Some of the youtube commenters are claiming the A340 pilots should've looked before crossing the runway. Would they actually have visibility out of the cockpit in that direction? Seems possible that they wouldn't.
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# ¿ Jul 6, 2014 21:44 |
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Vessbot, you should check this out: Blackbird (land yacht) Running a wind powered vehicle direct downwind faster than the wind spawned a billion internet flame wars back in the day, until the guys who created Blackbird shut most detractors up. They and others had built small models, and made YouTube videos of them, but lots of people refused to believe fakery wasn't involved until the certified, instrumented Blackbird record runs. (Some, of course, kept screaming about fraud anyways.) There's lots of material out there which will help you to understand how it works. It's mindbending even if you've decided to suppress the usual intense skepticism people have when they first encounter the idea. Point is, intuition can be very misleading. I suspect this question is a similar issue where your intuition tells you it can't possibly be true, but it is bog standard physics. If it's real (and I think it probably is) I'd guess it's something to do with jet engines burning an awful lot of fuel. I dunno what percentage of the mass airflow coming out the tailpipe is (ex-)fuel, but all the fuel mass is being accelerated backwards with respect to the airplane regardless of its velocity relative to the airstream. Another source of jet engine power is thermal expansion of intake air and combustion products, and it doesn't seem necessary for exhaust gasses to be moving the intuitively "right" way relative to the atmosphere in order to extract power from this expansion.
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# ¿ Aug 1, 2014 03:24 |
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Snowdens Secret posted:I'm curious how well an early-rev Sidewinder would resolve a Zero. For what it's worth I've personally witnessed an airshow demo where a bench-mounted Sidewinder seeker head (I think this would've been 1980s vintage) enthusiastically tracked a smoldering cigarette. That little robot really wanted to help eradicate lung cancer. Locking onto piston engine exhaust against a background of sea (relatively cool) and sky (ditto) seems reasonably plausible to me.
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# ¿ Aug 9, 2014 08:11 |
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Sir Cornelius posted:
Question for anyone who might know: It strikes me, looking at this picture, that there must be a tremendous amount of extra mechanical complexity putting the engines out in the rotating pods. During the long history of Osprey development, did they ever look at configurations with roof mounted turbines ala conventional helos? Seems like it would potentially be better. The Osprey we got has power shafts to cross couple the engines anyways, so there shouldn't be any weight gain from moving the engines inboard. Might even save some weight, and more importantly two large heavy objects would be very close to the center of mass, which seems desirable. I also remember reading news stories years ago about Osprey prototypes having persistent issues with all the plumbing in the rotating engine pods. Fuel or oil lines abrading as the pods rotated, leading to eventual puncture and engine fire, fun stuff like that. (Were there compelling reasons to put the engines out in the pods? Guess what I'm curious about is if anyone knows what the trade studies looked like.)
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# ¿ Aug 24, 2014 22:15 |
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YF19pilot posted:I think BobHoward was getting at using a traditional pair of turboshafts positioned high on the fuselage, with the actual tilt-rotors where they currently are positioned. Main issue with that I can see, BobHoward, is the configuration might interfere with the fuselage itself in terms of cargo and crew capacity, or you'll end up with one ugly duckling (basically "configuration issues"). Also, the crew chief ain't going to be a very happy man having to crawl up on that wing to fix the engines, not to mention other complexities which wouldn't normally be there on a normal fixed wing or normal rotary wing aircraft. Yeah that's basically what I was asking. Thanks for the answers everyone, and sorry if I use terminology like turbines vs turboshafts poorly, I are a dumb computer engineer. Just curious about design tradeoffs like these, aerospace engineering is cool.
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# ¿ Aug 25, 2014 04:14 |
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Isn't SpaceX the one that's all ~*~silicon valley tech startup culture, but with ROCKETS~*~, which translates to 80 hour work weeks without overtime and rapid burnout? You probably dodged a bullet.
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# ¿ Oct 11, 2014 01:45 |
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Inacio posted:Can we post insane (but seriously proposed) concepts here? I dunno if I'd call that "seriously proposed". It's just the pretentious wanking of a self-promoting "designer", not anything anybody capable of real aeronautical engineering ever took even slightly seriously. Google the dude's name (Luigi Colani) and you'll find all kinds of ridiculous poo poo. It's vaguely plane-shaped sculpture, not serious engineering. This is a man who does not understand how jet engines work. (Or why large airplanes which aren't also flying wings need large horizontal tail surfaces, for that matter. Apparently pitch stability isn't necessary. But that would interfere with making his cool "heh heh this plane looks like a shark guys" design. Or, in the case of the 2000 passenger "design", a goose.)
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# ¿ Oct 18, 2014 21:17 |
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Godholio posted:Yeah his design is going to sink right through any tarmac in the world. The more you look at them the more fractally wrong his designs get. Inacio posted:The problem with Colani is that it's not just pretentious wanking or self-promotion. Gotcha, and I believe the answer is yes. Boeing once did a design study for a truly ginormous aerial bulk cargo tanker; if they thought that was possible to build I don't see why a 2000 passenger aircraft would be out of the question. In practice, it won't ever get built because the real-world practical problems with a passenger aircraft of such size are daunting.
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# ¿ Oct 19, 2014 11:19 |
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The guy who tweeted about seeing the SS2 crash unfold over his head does independent reporting on the private space race. He's been pessimistic about SS2 for a while and posted this rather eerily prescient article... on Thursday. http://www.parabolicarc.com/2014/10/30/apollo-ansari-hobbling-effects-giant-leaps/ I skimmed over his posts over the last couple years and found a lot of interesting stuff reported in earlier articles. Branson has relatively little of his own money in Virgin Galactic, it's mostly bankrolled by Abu Dhabi oil money. VG has burned something like $400M over 10 years (and another $200+M on the "spaceport" in New Mexico, which sounds like it was a horrible boondoggle in its own right) to produce one spacecraft which (prior to the crash) had fired its rocket motor in flight just three times, and made it to space zero times. Earlier this year, Branson made a big public show of promising that he (and his children!) would fly a mission to space in SS2 this year, which was either suicidally foolhardy or an attempt to preserve the illusion that things were going great. There's some hints that corners were cut to return to powered flight this year. Assuming this guy's reporting is reasonably close to the truth (he does seem to have had some run-ins with Virgin Galactic PR, it's not a very amicable relationship), I don't see much future for SS2. If I was in charge of the oil money I'd pull out.
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# ¿ Nov 1, 2014 11:15 |
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MrChips posted:Linedance I just saw some up-close pictures of GGBF...holy poo poo I can't believe someone didn't die in those seats by the prop. I found some pics and yeah, Perhaps the flight crew evacuated those seats prior to landing? Logical step if you're worried about gear problems in that aircraft.
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# ¿ Nov 9, 2014 06:08 |
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Ola posted:One of them is the most successful of its kind with an unprecedented victory ratio, the other is a clunker which has only served as an instrument of provocation from a nation run by jerks and assholes. Ignoring the question of how it has been used, it seems a bit of a stretch to call that airplane a "clunker". You don't plan to keep flying a strategic bomber design for 80+ years if it's a total POS. (Same goes for its counterpart, the B-52.)
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# ¿ Nov 22, 2014 00:44 |
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I'm new to the Jerry thing. What are the greatest hits?
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# ¿ Jun 11, 2020 20:36 |
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e.pilot posted:My favorite thing about this video is that he’s so completely self unaware he reposted it as a point of pride. I made the mistake of reading the comments. Unfortunately it sounds like he's got groupies, possibly including student pilots. Also, those landing approaches . I'm not even a flight simulator pilot, but I've watched enough What You Haven't Seen vids to know those are not safe maneuvers on final, jesus christ how has he not stalled a wing and packed it in by now
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# ¿ Jun 11, 2020 22:35 |
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Applebees Appetizer posted:Interesting article about a cool jet An okay article, but I thought it spent way too much time on "it was too expensive for Canada," and not enough on the reason why the expenses became unacceptable. After all, Canada afforded it long enough to produce several flying airplanes. The Arrow was revealed to the public on the same day Sputnik launched. That was an omen: it was already obsolete. As it became clear that ICBMs were going to be a thing, it became equally clear that a pure interceptor aircraft like the Arrow wasn't going to be needed in huge quantities. The primary first-strike threat had ceased to be fleets of long-range Soviet bombers coming in over the north pole. (And, as an aside, the fear of a giant arctic bomber attack was abating for other reasons. That was largely USAF-stoked paranoia about the "bomber gap", in which the USAF got handed a shitload of money by convincing US congressmen that the Soviets were way ahead in long range jet bombers. Such fears were deflating a bit as intelligence built up to show that (a) the Soviets weren't actually building thousands of bombers and (b) the bombers they did have probably weren't capable of such long-range missions.) Furthermore, policymakers in many Western nations had begun to think that bomber interception was a role best served by long range ground-launched missiles, rather than launching a manned aircraft to bring air-to-air missiles to incoming bombers. So, the Arrow had become an extremely expensive, state-of-the-art white elephant. It was never going to see high volume production. As unpopular as the decision was in , I think you can make a solid argument that cancellation was correct. Canada wasn't alone: around the same time, the US cancelled its own high performance interceptor, the XF-108. It wasn't nearly as far along in its development as the CF-105 (nothing but a mockup was ever built), but on paper it would've been an even more capable interceptor. It, too, was already obsolete. After roughly 1960, nobody but the Soviets kept designing and building dedicated interceptors. The Soviets only did so because the US was the only power to keep a large strategic bomber fleet.
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# ¿ Jun 21, 2020 20:12 |
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priznat posted:It still was a pretty nifty plane and the development was interesting but get the wrong people talking about it and it becomes like a UFO that could fly rings around anything the Soviets or Americans could put in the sky even decades after the fact. Speaking of, while googling to check information for my effortpost I encountered this bonkers proposal that Canada should have saved money by reviving the Arrow program rather than buying F-35s. Which is, just, uh, I don't even. Yes, the F-35 program is a slow motion trainwreck, but you don't solve a problematic aircraft by replacing it with a thoroughly obsolete aircraft designed 60 years ago for a completely different role. But, as you say, there's this jingoistic cult belief system around it being the perfect airplane.
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# ¿ Jun 21, 2020 22:48 |
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Applebees Appetizer posted:Oh I love the Draken too, I just love the Viggen dual (canard?) delta wing . The F-106 is my favorite "classic" delta. The Hustler was pretty rad too. If you like delta wings with sections at different angles, look up the one I mentioned which was never actually built, the XF-108. It looked pretty cool.
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# ¿ Jun 21, 2020 22:59 |
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Nebakenezzer posted:Here's a question: was the design of the A-4 Skyhawk taken out of design studies to create a submarine launched jet fighter? No, "Heinemann's Hot Rod" was a carrier aircraft from the start. In 1952 the Navy asked Douglas to design a jet replacement for the piston engined A-1 Skyraider. Heinemann and co. met or exceeded the required specs, in part by deliberately choosing to make it very compact and focusing on light weight and efficiency rather than building a big lumbering monster. https://www.historynet.com/heinemanns-hot-rod.htm (Note that they saved weight by using a small delta wing that could fit on a carrier elevator without needing a folding mechanism. Not a design you'd choose for a submarine! A sub launched aircraft would probably want to have a long skinny detachable wing, not a stubby fixed delta.)
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# ¿ Jun 24, 2020 03:25 |
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Spaced God posted:Aircraft down in Accomack County, VA. They're saying all 4 people parachuted out. If it's military, the gently caress airplane has 4 seats you can chute out of? If it's not, how often do people actually chute out of civvie aircraft? Parachute jump flights? I've heard of the pilots of same wearing their own chute.
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# ¿ Aug 31, 2020 21:25 |
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Spaced God posted:God I have that loving gopro video of the two jump planes mid-airing and everyone getting out in my head and now I'm That incident was exactly what was on my mind when I read your post. Amazing that the worst injuries in that one were some minor cuts suffered by the pilot who had to bail out, and he didn't get them during the midair accident sequence, only upon landing his parachute. https://wcfcourier.com/news/local/w...1a7c7ace17.html
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# ¿ Aug 31, 2020 23:11 |
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Pretty sure this video was linked in the thread before, but it's relevant again, has all sorts of stuff about the drop systems in the Global Supertanker https://www.youtube.com/watch?v=D-pC7XYHV7s
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# ¿ Sep 29, 2020 23:21 |
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ImplicitAssembler posted:I've been following this project for about 2 years or so. He's always been engaging with the comments and people have offered solutions, constructive criticism, etc...except over the last 6 months, it's turned into the usual youtube comment poo poo and I think that, along with the stress and frustration with the project has him reacting in this manner. Dude's reaction to terrifying levels of pitch oscillation, roll instability, needing to take off at very high speed, and inadequate power is basically "this will all be fine if I raise the landing gear, I'll just fix the overheating issues and raise the gear next time". He's probably going to kill himself.
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# ¿ Oct 13, 2020 07:24 |
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charliemonster42 posted:I've been following this now that you guys brought it back to my attention, and the dude is concerning. My father-in-law mentioned this plane to me a while back but I never looked into it too closely as it just seemed like a Velocity ripoff. Man, you sent me back down this rabbit hole, and what a ride it was. As you say it appears to be a mod of the Velocity XL, down to reusing parts as-is. https://www.velocityaircraft.com/xl https://www.youtube.com/watch?v=QF024xnfzAU So all that stuff where he was declaring the instability was just turbulence in the giant empty wheel wells when the gear is down? The Velocity XL has the same gear and same wheel well, but doesn't wobble around the pattern. Based on pictures of the Velocity XL and Raptor, he's tweaked the aerodynamic configuration of airfoils, control surfaces, and body shape. With it being overweight, there's probably also weight and balance issues. So he's ripped off a working design and made it look cooler and redesigned it around a theoretically cheaper engine, but it's not stable because he's not an aeronautical engineer and apparently canard configurations are always a bit tricky. Also sounds like he had some of the same issues with the scale RC model. Instead of fixing and testing in a cycle until everything was resolved, he just kind of guessed what was happening and made changes to the full size aircraft without doing enough work to validate them on the scale model. But that's just the first few feet of the hole... He had THESE FUCKIN' GUYS running his flight test program https://www.wasabiaero.com/contact-us-ii Literal (ex-)Scaled Composites motherfuckers. Steely eyed test pilot / engineer types. Flew cross country several times to help him make the Raptor into a real airplane. https://www.youtube.com/watch?v=5gnEknj242M He fired them shortly after the session documented in that video, then took the airplane up without resolving all the things they identified. It seems clear they got the boot because they were telling him things he didn't want to hear. They're being very restrained about criticizing him, because they had to walk on eggshells just to get him to fix the issues they identified in inspection and test. I think they don't want to burn all bridges and cut off any chance of changing his mind, since it's clear he's a super high risk to kill himself and others. But god drat, that video is just a nonstop whirlwind tour of red flags. (I recommend watching it all the way through. It's a little rough in parts because they had a technical issue with wifi interference causing mic clicks, but it's so fascinating and information dense.) Apparently Wasabi is the second set of real test pilots he's fired from the project. I haven't gone that far down the hole, would love it if someone who has can give any pointers.
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# ¿ Oct 21, 2020 22:34 |
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I'm rewatching the Wasabi vid and there's just so much - Peter (the builder) resists a recommendation to set a brake restrictor valve to allow the test pilot access to max possible braking force during taxi tests because the manufacturer recommended some lower limit and they must have some reason for it. Justin (test pilot) responds "I guess it comes down to whether you want to save the brakes or save the plane at the end of the runway" - in response to their request to fix wing skin that had disbonded from a rib due to his own design or build error, "I see what you're saying, but don't know how that is any sort of thing which needs to be addressed right away, there's no chance in hell that can keep separating all the way down". (this was Wasabi applying their policy of not testing with damaged primary structure, which, you know, is reasonable.) The comments are actually worth going through. I think this one about sums it up. quote:Flyby Wire
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# ¿ Oct 22, 2020 02:30 |
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Humphreys posted:Dammit, I was kinda hoping they were going to restore it to operational or use it to rebuild. It's been sitting in salt water for 30 years with little or no maintenance. Just looked it up and the Caspian Sea isn't nearly as high salinity as the open ocean, but still, there has got to be a lot of corrosion in that thing by now.
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# ¿ Oct 23, 2020 12:06 |
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Sagebrush posted:Oh boy...he's really going forwards with "the oscillations are caused by turbulence in the wheel wells" I kept digging by reading a bunch of this thread: https://www.homebuiltairplanes.com/forums/threads/raptor-composite-aircraft.24721/ and I completely lack surprise. The pattern of him briefly, grudgingly accepting help from people who know what they're doing only to turn on them as soon as they say things he doesn't want to hear (or begin to threaten his image with his mini-cult) is quite old. ImplicitAssembler posted:I think they totally blew the relationship by posting that video. Airport issue should have been sorted by the first visit, not the third. Sure, it was the right decision, but by that point the relationship had clearly broken down. So from the wasabi video and that giant thread I've learned that yes, the airport issue should've been sorted early, but not for the reason you think. (a) Wasabi raised the issue with him possibly even prior to the first visit, and he wouldn't listen (b) The final trip was the first time they scouted the surrounding terrain with a low level flight, because the first two visits they flew commercial into a different airport. (Why didn't they hire a local plane during one of the first two trips? Probably because inspection and ground test were revealing way too many problems to even attempt a first flight, so no need to spend Peter's money on that until it was time.) (c) prior to scouting, they thought the highway and possibly some parts of the terrain might be marginal places to land, but seeing things from the air revealed zero viable options for a forced off-field landing immediately after takeoff (d) during that third trip, the builder's lovely amateur ECU tune (he watched some webinar and decided he was an expert tuner afterwards, LOL) caused an engine shutdown during taxi tests, a failure mode which the builder knew about, but thought was no big deal (e) they also were not feeling super confident about the prop speed reduction unit, turbos, or cooling (f) due to all the above and countless other non-powertrain things, their evaluation of the airport progressed from 'marginal, keep prodding Peter about it' to 'hard no' Fortunately, Peter at least listened to that part of their advice. Which makes it a little weird that he also fired them for it.
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# ¿ Oct 25, 2020 10:29 |
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# ¿ May 5, 2024 00:59 |
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Source4Leko posted:The Finnish guy seems to know what he has (which is awesome) while this guy thinks he's Burt Rutan and designs planes in real life the same way I do in KSP while putting less effort into his build and repairs than I do when I fix my lawnmower. I would say he actually puts an immense amount of effort into his build and repairs. It's his full time job, and he clearly gets a lot of work done on the airplane-shaped object, particularly for someone who's doing so much of the work solo. The problem is that his hard labor isn't producing much of value because he's a Dunning-Kruger posterchild. He's designing and building planes like he's playing KSP, but isn't aware that there's more to it than KSP, and resists being told so. Just look at this majestic reply to one of the many who've told him his compound turbo design is all hosed up. (Short version of the correct idea for a compound turbo: think about how a multi-spool turbojet or turbofan engine works. Cold gas flows through the largest compressor stage first, then through progressively smaller compressor stages as it's compressed further. Hot gas flows through the smallest turbine first, and then through progressively larger turbines as it expands. Anything else doesn't make sense.) Peter Muller posted:I took the advice of several different outfits on how to configure the compound turbos. Perhaps no one knew what they were suggesting and it's set up incorrectly. Either way, the hot side housings are identical in size so the order on that side should not really make a difference, they are both moving the same amount of exhaust. On the cold side I'm feeding small into big. 2867 into 2871. At max power the small one boosts about 6psi, the big one about 21psi. Now I don't really want to run much more than the 43psi total pressure that I'm running now. If I inject more fuel I get a lambda below 1 and black smoke. The setup is generating a measured 1000lbs of thrust. The aircraft accelerates well enough to move the mass as quick as most other GA aircraft. I've measured that as well. So, with enough thrust and not overheating and not running the turbine inlet temp over 1500f I'm quite happy that the powerplant is dialed in as much as it can be without a Dyno. I don't need to go to the trouble of putting it on a Dyno just to get a number. Anyway, that's my take on it. Your mileage may vary. I guarantee that if he's not just outright lying about getting advice from several different "outfits", he didn't listen to it. They'd never have approved his idiotic equal size turbines, nor would they recommend small-to-large on the cold side. They'd also have told him that no matter what he did, he'd need to dyno it to develop the ECU map. (He's consistently refused to put his engine on the dyno.) I wish the bolded was short enough to be a thread title. It's so good.
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# ¿ Oct 25, 2020 23:10 |