|
standard.deviant posted:Marine KC-130s have external light strips for night ops. You can see them at 0:38 in this video. North Korea took it a little bit further.
|
#
?
Oct 11, 2020 22:18
|
|
|
|
| # ? Jun 2, 2024 08:02 |
|
|
Nebakenezzer posted:Move "guy in the tail" to "guy in a cockpit with a bespoke 3d computer miracle visual system" may be the single worst political pork barrel in the past...20 years? Airbus has had exactly zero problem with that move in the A330 MRTT. They had a couple of teething issues elsewhere (I think the boom fell off, once?) but all things considered it's been a remarkably successful program, much better managed than its rival KC-46, or Airbus' own A400M. So Boeing took a while to realize sun glare on the optics could be a problem. But that's not a flaw of the concept, it's a flaw of the implementation. The Pegasus was IMO badly rushed. Boeing tried to make a frankenplane (or frankentanker) thinking it'd reduce development costs and time, and the result was a lot of problems.  Same basic story as the 737MAX in a way. Boeing needs to rush a product in a niche where the competition has a superior offer, and makes a proper mess of it.
|
|
#
?
Oct 11, 2020 22:26
|
|
|
It takes 25+ years of gross mismanagement to end up in a situation like this.
|
|
#
?
Oct 12, 2020 00:18
|
|
|
Godholio posted:It takes 25+ years of gross mismanagement to end up in a situation like this. Agreed. I'd say the "like sears" comment is going to be eerily apt as this dumpster fire continues
|
|
#
?
Oct 12, 2020 00:42
|
|
|
Godholio posted:It takes 25+ years of gross mismanagement to end up in a situation like this. Thread title if it weren't too long
|
|
#
?
Oct 12, 2020 03:53
|
|
|
Kilonum posted:Thread title if it weren't too long nah it’s perfect
|
|
#
?
Oct 12, 2020 03:54
|
|
|
i own every Bionicle posted:Apologies if this is the wrong thread or has been discussed before but I couldn’t find it. The guy who started the Raptor aircraft company finally test flew his plane after an insane design and build cycle and a bunch of test pilots walked away from it. The video is absolutely terrifying and has the plane going through some pretty wild oscillations and the engine nearly overheating for the entire ~2 minute flight. That's one hell of an oscillation. It's non-damping, like a phugoid, but the period is like 3 seconds instead of a minute or two? Bad. Scary. Points to clear problems in the aerodynamic design or at least in the weight and balance. Also that landing was drat close to a propstrike. A gust at the wrong moment in the flare and you'd definitely scrape it. Yeeesh. I admire the guy for trying something new -- lord knows general aviation needs some new blood -- but it looks like he's got some back-to-the-drawing board level aerodynamic questions. And that isn't even starting in on why his engine might have started overheating after 2 minutes in the pattern on a standard day e: yeah, the comment that his canards are stalling sounds plausible. In a canard design the canards provide lift and keep the nose up, so if they stall the nose will drop, immediately putting the canards back below their critical angle, bringing back the lift, raising the nose again, and so on. lomarf if he literally just has them installed at the wrong angle of incidence; you'd think that would be day 1 clean-sheet aerodynamic design Sagebrush fucked around with this message at 04:16 on Oct 12, 2020 |
|
#
?
Oct 12, 2020 04:12
|
|
|
Sagebrush posted:e: yeah, the comment that his canards are stalling sounds plausible. In a canard design the canards provide lift and keep the nose up, so if they stall the nose will drop, immediately putting the canards back below their critical angle, bringing back the lift, raising the nose again, and so on. lomarf if he literally just has them installed at the wrong angle of incidence; you'd think that would be day 1 clean-sheet aerodynamic design Well, he had to return his
|
|
#
?
Oct 12, 2020 04:19
|
|
|
Sagebrush posted:
Would that be what's causing the oscillation? The canard stalls, the nose drops, the canard gets lift again, which lifts the nose, which causes the canard to stall again.
|
|
#
?
Oct 12, 2020 04:31
|
|
|
I am not an aeronautical engineer but a canard stall certainly sounds plausible to me. You also can get oscillations like that if your plane is loaded with the CG too far aft. A stable airplane has its center of gravity in front of its center of lift, meaning that if you removed the horizontal stabilizer it would assume a nose-down attitude. In a conventional plane, the rear stabilizer generates downforce, which pushes the tail down and brings the nose up to level; in a canard design the canards produce lift, raising the nose*. In both cases, having the CG too far aft means that the stabilizer loses its effectiveness, and the plane tends to oscillate in pitch as if it's suspended right on its balance point (which it is -- the suspension point being the geometric sum of the lift vectors). If the oscillations in this case were being caused by a simple loading problem, that's even dumber than a canard stall because weight and balance calculations are literally just arithmetic. No fancy equations whatsoever. *Incidentally, this is why canard designs are a little more efficient; the conventional plane has to produce more total lift (and hence more induced drag) for a given weight because it needs to compensate for the stabilizer's downforce. The canard design adds the lift from the stabilizer and wing instead. Canard designs are also more unstable, though, because having the stabilizer in front of the CG will cause continued divergence if the plane is pointed away from the relative wind, while the conventional design will tend to weathervane the plane back into stable flight when disturbed. Consider throwing a dart with fins on the back versus fins on the front.
|
|
#
?
Oct 12, 2020 05:09
|
|
|
It's cool it's just running the latest patch for FS2020, gotta wait 2 weeks for the next one and hope something else doesn't break.
|
|
#
?
Oct 12, 2020 05:54
|
|
|
e.pilot posted:nah it’s perfect Aeronautical Insanity: It takes 25+ years of gross mismanagement to end up ...checks out
|
|
#
?
Oct 12, 2020 06:02
|
|
|
Sagebrush posted:
He seems very ok with trial-and-erroring his way into a good airplane. His lack of concern over anything is what makes ME concerned. "Well we'll just add another oil cooler and see what happens!" No dude, do a little math and see what you actually need, and start from there.
|
|
#
?
Oct 12, 2020 06:37
|
|
|
On thinking about it some more, idk if it could be a canard stall because it was doing it in a gentle climb and even in the descent. If the surfaces were stalling in those circumstances, he shouldn't have had the control authority to perform the landing flare. Maybe it is literally just that he eyeballed the CG and all that engine weight in the back is putting him in a bog standard short period oscillation like what kills dozens of people a year when they try to put too many grown-ups in the back seats of a Saratoga.
|
|
#
?
Oct 12, 2020 07:01
|
|
|
That's a pretty cool project, it's good that it didn't kill him.
|
|
#
?
Oct 12, 2020 08:12
|
|
|
EvenWorseOpinions posted:That's a pretty cool project, it's good that it didn't kill him. Yet. He sure acts like a manbaby about negative comments though.
|
|
#
?
Oct 12, 2020 10:55
|
|
|
Humphreys posted:Yet. "feel free to comment unless you're going to criticize me in any way shape or form" lol
|
|
#
?
Oct 12, 2020 13:19
|
|
|
I think it’s a lack of yaw stability partially due to wing-fuselage interactions inducing Dutch roll, which he has attempted to fix by having the CG too far forward, leading to canard stall.Humphreys posted:Yet. If you go back and skim through the old videos his attitude and approach hasn’t really changed. He appears to do a lot of design and building before /concurrently with any calculations or analysis. The scaled RC model looked like it flew a lot like this prototype, but was tested after most of the full scale molds were cut, so the changes they could make based on that testing were pretty minimal. He has the designer of the Velocity begging him to let him help in the comments of all the videos but seems pretty adamant about doing it all himself. My favorite comment of his is that the instability is caused by the landing gear bays, and the next test flight will be much better because he will put the gear up 
|
|
#
?
Oct 12, 2020 13:23
|
|
|
i own every Bionicle posted:My favorite comment of his is that the instability is caused by the landing gear bays, and the next test flight will be much better because he will put the gear up Gonna get that prop-strike on landing that way! Sure is thinking outside the box.
|
|
#
?
Oct 12, 2020 13:30
|
|
|
it gets worse:quote:Hi Peter! quote:I first advised Peter to do this a year ago. My comment and subsequent ones by several other knowledgeable people were not just ignored, many were deleted. Peter is sure he has designed the turbos correctly and will not be swayed. Even by people who have been there and got the t-shirt.
|
|
#
?
Oct 12, 2020 13:36
|
|
|
Godholio posted:That's not the big problem though...Boeing is failing at the basics of building airplanes. Moving the boom operator up front should be trivial, we did it with tail gunners decades ago. But loving up fuel tank seals, leaving ladders in compartments...this is more than just overselling "advanced" tech. Turns out when you trim headcount on the line including QA, people have to rush to finish things, stuff gets missed and quality goes down, who woulda guessed??? Fact remains that Charleston has an objectively worse quality problem and it's so well known that some airlines won't even accept deliveries from that plant, which is probably not a good position to be in when it's already hard to sell airplanes e: I think we're all in agreement that Boeing is turbo hosed at this point rscott fucked around with this message at 13:47 on Oct 12, 2020 |
|
#
?
Oct 12, 2020 13:43
|
|
|
Gonna give Raptor guy about two years to live.
|
|
#
?
Oct 12, 2020 14:02
|
|
|
Ola posted:Gonna give Raptor guy about two years to live. That's pretty good for a turn-of-the-century aeronautical pioneer after his first flight.
|
|
#
?
Oct 12, 2020 14:12
|
|
|
It’s possible that the canard is over loaded and stalling, but it seems just as likely to me that it’s simple poor static stability from a bad placement of the CG relative to the aerodynamic center. Some things need CFD or experimentation to figure out, but in this case, it’s fairly easy to predict what should happen with good enough accuracy using a vortex lattice method or even just a hand calculation. These days anyone can download decent tools like AVL, XFLR5, or OpenVSP and, with some study, figure them out well enough to get decent stability results. Like, it will take some effort to learn on your own, but a small amount compared to building a clear-sheet airplane! That the aircraft has this problem in the year 2020—and that the designer seems to think retracting the gear will fix it—does not bode well for future “envelope expansion” of the vehicle.
|
|
#
?
Oct 12, 2020 14:32
|
|
|
Ola posted:Gonna give Raptor guy about two years to live. I’d give him 2 weeks if he’s going to keep flying that thing.
|
|
#
?
Oct 12, 2020 15:20
|
|
|
Tetraptous posted:It’s possible that the canard is over loaded and stalling, but it seems just as likely to me that it’s simple poor static stability from a bad placement of the CG relative to the aerodynamic center. Some things need CFD or experimentation to figure out, but in this case, it’s fairly easy to predict what should happen with good enough accuracy using a vortex lattice method or even just a hand calculation. These days anyone can download decent tools like AVL, XFLR5, or OpenVSP and, with some study, figure them out well enough to get decent stability results. Like, it will take some effort to learn on your own, but a small amount compared to building a clear-sheet airplane! He does some CFD with Solidworks. It’s...something. https://www.youtube.com/watch?v=m7eiWD9OTxI
|
|
#
?
Oct 12, 2020 15:41
|
|
|
Wild. I remember seeing alleged specs on the raptor before and thinking it looked good. Pity, bc pusher canards satisfy some inexplicable attraction I have to bizarre designs. For all it’s faults a Long-EZ looks like a hell of a good time.
|
|
#
?
Oct 12, 2020 16:19
|
|
|
Humphreys posted:Gonna get that prop-strike on landing that way! Sure is thinking outside the box. It looks like the prop could strike on almost every take off or landing. 
|
|
#
?
Oct 12, 2020 16:50
|
|
|
i own every Bionicle posted:He does some CFD with Solidworks. It’s...something. I didn’t take the time to watch all of that nonsense, but it’s telling that the final reduced result is a plot of increasing lift and drag versus airspeed (for presumably a constant angle of attack). What, is the aircraft going to gain weight as it goes faster? Instead of varying airspeed (i.e. Reynolds number, which won’t really have a huge impact in the “high” Reynolds number range), he might have actually learned something if he varied angle of attack. For instance, is the change in pitching moment going to bring the nose up or down if the angle of attack increases? And how bad is the trim drag going to be during cruise? Like, your average aeromodeler designing a new RC airplane knows this stuff better than this guy.
|
|
#
?
Oct 12, 2020 17:31
|
|
|
When the Raptor inevitably crashes in the desert, hopefully one of his passengers is an RC airplane designer who can help him cobble the remaining canards together into a makeshift plane.
|
|
#
?
Oct 12, 2020 18:17
|
|
|
Love to oscillate wildly in the flare, it's just  .
|
|
#
?
Oct 12, 2020 18:24
|
|
|
Humphreys posted:Yet. 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. I also think y'all selling him short 
|
|
#
?
Oct 12, 2020 18:34
|
|
|
To be sure, he has gotten a plane airborne from a clean sheet, which is not trivial.
|
|
#
?
Oct 12, 2020 19:40
|
|
|
ArcMage posted:To be sure, he has gotten a plane airborne from a clean sheet, which is not trivial. I don't think it's an entirely clean sheet. It seems to be based on the Velocity kit https://www.velocityaircraft.com/ There have been many canard vaporware planes over the years, most of them based on popular kits, making bold claims and end up with the founder dead or sued. e: I need to moderate that claim a lot. There have been some vaporware planes and some deaths. Ola fucked around with this message at 20:26 on Oct 12, 2020 |
|
#
?
Oct 12, 2020 19:54
|
|
|
ImplicitAssembler posted:I also think y'all selling him short We'll see.
|
|
#
?
Oct 12, 2020 19:56
|
|
|
rscott posted:
It won't stop them from getting a gigantic government bailout at some point though. There's literally no way the U.S's last major aerospace manufacturer would be allowed to shut its doors, gross mismanagement or not.
|
|
#
?
Oct 12, 2020 20:15
|
|
|
Arson Daily posted:It won't stop them from getting a gigantic government bailout at some point though. There's literally no way the U.S's last major aerospace manufacturer would be allowed to shut its doors, gross mismanagement or not. buyout or fail they've bought back stock with public funds before, gently caress 'em if they refuse a public stakeholder again
|
|
#
?
Oct 12, 2020 20:28
|
|
|
Potato Salad posted:buyout or fail Buyout and fire everyone that works in Chicago for starters.
|
|
#
?
Oct 12, 2020 20:34
|
|
|
Midjack posted:Buyout and fire everyone that works in Chicago for starters. The Chicago move was the most baffling loving thing from the outside.
|
|
#
?
Oct 12, 2020 21:24
|
|
|
|
| # ? Jun 2, 2024 08:02 |
|
|
Loucks posted:Pity, bc pusher canards satisfy some inexplicable attraction I have to bizarre designs.   https://www.youtube.com/watch?v=xV2Z2g-q3X8
|
|
#
?
Oct 12, 2020 22:06
|
|
