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jandrese posted:~9g is right on the edge of what the human body can take with a g-suit. 13g is defiantly pushing it, although if the maneuver is short enough you can probably get away with it. Pretty much this. Human beings (and any animal our size and smaller) can take shitloads of G for short periods of time. You've got that colonel who rode that rocket sled way back then who was pulling in the neighborhood of 40 g's for periods shorter than a second. And my old-rear end copy of Guinness says that the world record for survived G's was 231 by a race car driver hitting a wall, sustained for just a few thousandths of a second. As for the plane itself, yeah, it's pretty much a matter of wing loading, which is just a product of size and weight. For instance, the Extra EA-300 is stressed for +-10G with one person on board, and only +-8G with two people. That's because if you assume an average weight of ~150 pounds per person (which is lowballing quite a bit for the average man, I think.), you're adding 10% more weight compared to the empty aircraft. There's also the whole square/cube problem going on. The amount of G's you can pull is aerodynamically limited by how much lift you can get out of the wing and how much mass the aircraft has. Lift is dominated by the wing area, which increases with the square of a reference dimension as you increase the size of the aircraft. The general rule of thumb is that weight increases in proportion to the cube of the reference dimension. Of course, there are other factors going on (materials used being the biggest), but it's enough for guesswork. You can take it to an even greater extreme by looking at unmanned aircraft. If you took the pilot out of an F-16 and flew it with a computer, it would still be limited to about 9G's. But the AIM-9X it fires can pull something like 60 G's. And it has no wings, just little control vanes. (And vectored thrust) That square/cube thing is also why ants can lift 100 times there own weight and elephants can die just dropping a few inches- mass increases by the third power as an animal gets bigger, but strength is determined by the cross sectional area of the muscle, which only increases by the square.
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Apr 9, 2010 19:27
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Slo-Tek posted:There are some middling strange airplane pictures here: This one in particular caught my eye: 
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Apr 9, 2010 19:32
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Manny posted:This one in particular caught my eye: I think that is the USS Los Angeles. Second best airship ever built. It was smaller and didn't have a hangar or retrieval gear for fixedwing aircraft like the Akron and Macon did.
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Apr 9, 2010 19:57
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Discussion about G-forces tend to include some misunderstandings and some facts taken as absolutes, here's a little low-down: The G-limit of a plane is the strength of the structure. Just about any plane is capable of overstressing itself. In general aviation it's called Vma, or maneuvering speed. Below that (not counting mixed inputs) you can move the controls to their limits without causing damage. Above you cannot. There's one case of an F-15 in an inadvertent dive pulling nearly 30 G as the pilot discovered his mistake, breaking the wing spar and crashing. Fly-by-wire uses all kinds of wizardy like measuring the onset of G and pitch rate to keep the plane within its limits, yet it can still break those limits in certain situations. Over-G is a regular occurrence in military aviation (perhaps less now) and requires costly downtime for inspection and repair. Over-G in a civil aircraft can be very dramatic indeed: https://www.youtube.com/watch?v=LPbhQS6IljU Aerobatics planes are very light, very simple and can be built very strong, so they have higher G-limits. But an Extra 300 at 12 G bleeds off its speed awfully fast so they don't sustain those forces for long, even if they want to. Fighter planes could easily be built to withstand 15 G but it would be very heavy and since the driver can't take 15 Gs in the Z-axis for much time, there's no point. (I mentioned mixed inputs. Say you are pulling 9 G and curving through the sky just fine. Then while in the turn, you move the stick to the lower corner so it barrel rolls. By mixing pitch and roll, you have overstressed the outboard wing which moved up in addition to the 9 G it already had.) The G-limit of a human being tends to be quoted at 9, also when talking about Formula 1 drivers. But they don't pull much sustained G in the Z-axis (head to toe), but X (accel/brake) and Y (cornering). The most often mentioned limit refers to blacking out when you pull G in the Z axis and prevent blood from getting to your brain. The early astronauts were pulling 8-10 G on launch and 12-14 G on reentry, sustained for several minutes. They were awake and talking all the time because - in addition to being fantastically well trained - they were on their backs and taking the forces in the X axis. I suppose the limit of 9 (many fighters are 7.5 or 8) is chosen by design at some point. What's the maximum G we can limit a reasonable (weight/complexity) fighter design to? And what's the maximum G we can reasonably expect well trained pilots to sustain on a regular basis? The limit of injury tend to be quoted around the experience of that rocket guy ApathyGifted posted. Obviously less time of force applied means less work done on your poor cells, but given enough time of repeated strains even within those limits you can develop injuries . Detached retina is a work hazard of drag racers. And apparently, so the rumor has it, G-straining in fighter planes causes huge hemhorroids. Think about that the next time you see a fighter pilot walking with a broad legged swagger.
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Apr 9, 2010 21:53
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OptimusMatrix posted:I read the whole thread but I'm not sure if this story was posted. It's an article from Gizmodo about a Sled Driver on a mission over Libya. It's a heart racing read. I had the theme from The Right Stuff going in my head while I read this.
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Apr 9, 2010 22:07
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Ola posted:Discussion about G-forces From one of the links Slo-Tek posted:  Click here for the full 1002x606 image.
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Apr 9, 2010 22:16
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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. An F-14D Upgrade at zone five burner sitting on the waist cats of a carrier, full war load of fuel and ammo getting shot off. At night.
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Apr 9, 2010 22:35
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Used Sunlight sales posted:An F-14D Upgrade at zone five burner sitting on the waist cats of a carrier, full war load of fuel and ammo getting shot off. My crotch would have literally exploded.
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Apr 9, 2010 22:55
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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. P-47 start and when it passes over. C-141 landing for some reason. My dad flew these, mom and I would watch them land and call out the aircraft as they landed. C-130 Everything about this aircraft. Dad flew this as well, friends thought it was an ugly aircraft but I fell in love with it the second I saw it. Up close it's an amazing looking aircraft. I've got a shirt somewhere that has a small Cessna caricature looking all pleased with himself on a runway, behind him a C-130 looking smug, and behind him a C-5 Galaxy looking like he just poo poo his pants and his tires are on fire. F-15 on take off going into a vertical climb full afterburner with more then half the runway left. Rhien Main AFB was awesome for having all kinds of aircraft taking off and landing. Tornadoes as they pass over head. Chinooks also sound amazing. Living in Germany when my dad was an Airforce pilot was amazing.
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Apr 9, 2010 23:20
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Ola posted:Discussion about G-forces tend to include some misunderstandings and some facts taken as absolutes, here's a little low-down: For the record, I only brought up that aerodynamic limit thing because I wanted to talk about the square-cube law. It still applies to the structural mechanics you were discussing, but I sort of went off on a tangent and never got back.
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Apr 9, 2010 23:32
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fromoutofnowhere posted:C-130 Everything about this aircraft. Dad flew this as well, friends thought it was an ugly aircraft but I fell in love with it the second I saw it. Up close it's an amazing looking aircraft. I've got a shirt somewhere that has a small Cessna caricature looking all pleased with himself on a runway, behind him a C-130 looking smug, and behind him a C-5 Galaxy looking like he just poo poo his pants and his tires are on fire. Thanks to growing up next to a CFB I find the sound of planes landing at night, but particularly the C130, soothing.
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Apr 10, 2010 00:41
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This was a cute C-130 thing I saw the other year. A C-130 in 357th Fighter Group livery, complete with Invasion stripes. A bit anachronistic, but the 357th squadron ended up becoming a Ohio National Guard squadron post war, and many years and several reorganizations later ended up as a C-130 squadron based out of Mansfield Ohio.
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Apr 10, 2010 01:00
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ApathyGifted posted:For the record, I only brought up that aerodynamic limit thing because I wanted to talk about the square-cube law. It still applies to the structural mechanics you were discussing, but I sort of went off on a tangent and never got back. It wasn't meant to prove anyone wrong, just an excuse to go off on my tangent. 
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Apr 10, 2010 01:17
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Lest we forget, the prettiest thing to slip the surly bonds of earth, and accelerate champagne and caviar past mach 2, Concorde: http://www.youtube.com/watch?v=uu21rM9ahkY&feature=fvw Four Rolls Royce Olympus engines, roaring over London, with the world's greatest aerobatic team as an escort. The Royal Air Force Aerobatic Display Team - The Red Arrows http://www.youtube.com/watch?v=qIv7MK2gtN4&feature=related 
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Apr 10, 2010 01:34
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dangerz posted:When the F35 AA1 took off, it had this really ghostly howl to it when they first launched. The current 35s also have it somewhat, but they redid part of the air intake so you dont hear it as much. The 22s also kind of have it. The 22 does have a very distinctive sound. I can hear 15's on approach every time, we had one come in recently passing through cross-country. I heard the noise of a jet fly over and clear as day, I high pitched 'weeeee' noise as the pilot eased off the throttles for approach and the nozzles opened. Also my absolute favorite sound in the world has to be a jet engine lighting off during a start. The low rumble you hear and feel in your chest never fails to make me grin like a little kid. This video really doesn't do it justice: http://www.youtube.com/watch#!v=un0a0DBxX5A Edit: Oh we had a restored P-51 drop by for a ceremony today and I got to poke around at it a bit. drat that is one sexy aircraft. Nostalgia4Infinity fucked around with this message at 04:39 on Apr 10, 2010 |
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Apr 10, 2010 04:30
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Early production Hind(A variant) Click here for the full 980x675 image. I'm not sure if it was a prototype or if it was put into service. Note the lack of the distinctive Double-Bubble Canopy.
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Apr 10, 2010 12:00
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jandrese posted:~9g is right on the edge of what the human body can take with a g-suit. 13g is defiantly pushing it, although if the maneuver is short enough you can probably get away with it. You're talking Jerk force (g/s) not g. 13g is nothing in e.g. a collision. For a very brief moment the human body can easily handle 50g and +100 survivors aren't totally unheard of.
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Apr 10, 2010 14:46
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TimingBelt posted:Early production Hind(A variant) Wow, that really looks terrible.
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Apr 11, 2010 15:28
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TimingBelt posted:Early production Hind(A variant)  ATE Superhind Mk.V  Click here for the full 1504x1000 image. ATE Superhind Mk.III e:  Click here for the full 864x576 image. Atlas CSH-2 Rooivalk  Click here for the full 1024x682 image. Atlas Oryx ming-the-mazdaless fucked around with this message at 16:26 on Apr 11, 2010 |
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Apr 11, 2010 16:06
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Blaster of Justice posted:You're talking Jerk force (g/s) not g. 13g is nothing in e.g. a collision. For a very brief moment the human body can easily handle 50g and +100 survivors aren't totally unheard of. Richard Hammond experienced 100 gs briefly during his crash, for example.
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Apr 11, 2010 21:22
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Nebakenezzer posted:Richard Hammond experienced 100 gs briefly during his crash, for example.
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Apr 11, 2010 22:31
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InitialDave posted:Some say he used to be as tall as Clarkson...  Hot drat that was fast.
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Apr 11, 2010 22:47
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Looking through some footage and thought this would fit in, a couple radials on an old warbird. That's me coming out the bomb bay...
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Apr 12, 2010 02:38
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The Electronaut posted:Looking through some footage and thought this would fit in, a couple radials on an old warbird. That's me coming out the bomb bay... That is badass as gently caress.
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Apr 12, 2010 03:19
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Fucknag posted:Wait... so you went skydiving out of the bomb bay of a B-17? That's the new #1 thing on my "list to do before death." loving awesome.
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Apr 12, 2010 05:30
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The Electronaut posted:Looking through some footage and thought this would fit in, a couple radials on an old warbird. That's me coming out the bomb bay... "Your honor, I present exhibit A. as proof that I am indeed, the bomb."
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Apr 12, 2010 06:50
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ab0z posted:"Your honor, I present exhibit A. as proof that I am indeed, the bomb." Should be his new avatar / title combo...
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Apr 12, 2010 13:01
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My favourite (fictional) aircraft, and its accompanying howl. The Lady vs Redwolf: http://www.youtube.com/watch?v=slL7Y2-sCgQ
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Apr 12, 2010 18:50
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Fucknag posted:Wait... so you went skydiving out of the bomb bay of a B-17? Indeed I did. Thanks! I posted pictures of the aircraft I got to see back in Feb in the TFR. Copy and paste from that post: P-51C, the only remaining two person/trainer P-51 left.  TBM, carrier based, torpedo bomber.  B-24.  B-17.  B-17 interior, behind the radio room.  B-17 bomb bay.  B-17 waist gunner position.  B-17 tail from the radio room.  B-17 view of the Florida/Georgia coastline at 3,000 feet or so. 
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Apr 13, 2010 02:04
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Any of you going to Sun n Fun in Lakeland, FL this week? Plenty of pretty planes to gawk at there..
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Apr 13, 2010 02:38
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Sterndotstern posted:(Northrop flying wings) The B-2 team went to great lengths to let Jack Northrop know that finally, his ideas were going to take flight. "The team designing the B-2 Spirit obtained special security clearance to show their design to Jack Northrop, the man who had essentially invented the big-bomber flying wing. He was brought to the plant in 1980, and shown drawings and a scale model of what they proposed to build. It was apparently a very emotional moment for all concerned, and Northrop quipped that this must be why God had kept him alive for the past twenty years!"
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Apr 13, 2010 06:36
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silversiren posted:Any of you going to Sun n Fun in Lakeland, FL this week? Plenty of pretty planes to gawk at there.. Going on Saturday. Can't wait. Missed Airfest at MacDill this year so I need my airshow fix.
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Apr 13, 2010 07:15
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The Electronaut posted:Indeed I did. Thanks! I posted pictures of the aircraft I got to see back in Feb in the TFR. Copy and paste from that post: Holy poo poo! I saw these planes when they were at Mountain View, CA last year, and got a ticket for the Nine-O-Nine as a graduation gift. They left a panel above the radio room off, and I was able to look over the wing at the B-25 flying next to us. It made the 12 year old history nerd in me very happy.
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Apr 13, 2010 22:56
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Mobius1B7R posted:Going on Saturday. Can't wait. Missed Airfest at MacDill this year so I need my airshow fix. Definitely worth going. Also try to check out the new restaurant that opened at the end of runway 5, Earhart's Runway Grill. The food isn't all that great but it gives a spectacular view of the whole airfield and they broadcast the tower transmissions over headsets that are set up in each booth.
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Apr 14, 2010 02:42
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norton I posted:Holy poo poo! I saw these planes when they were at Mountain View, CA last year, and got a ticket for the Nine-O-Nine as a graduation gift. They left a panel above the radio room off, and I was able to look over the wing at the B-25 flying next to us. The Nine-O-Nine  I love that plane.
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Apr 14, 2010 03:10
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The Electronaut posted:Indeed I did. Thanks! I posted pictures of the aircraft I got to see back in Feb in the TFR. Copy and paste from that post: Heavy metal was accurate about the interior, hah.
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Apr 14, 2010 03:27
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I'd like to give a shout-out to the best fighter that almost was: The Northrop F-20 Tigershark. Based on the F-5 airframe, the Tigershark was updated with cutting edge avionics, a slightly different design for better aerodynamics, and a MUCH more powerful engine. If the F-5 is the Miata of jet aircraft, the F-20 is the Miata with a LSx swap. http://www.youtube.com/watch?v=kw9nlgnPq3E I'd have loved to see these flown by a military demonstration team. Would have been perfect for, say, the Thunderbirds, but instead they fly the incredibly overrated F-16. 
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Apr 14, 2010 04:24
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If the F-20 had been offered instead of the F-5E, it would've had a chance. But being a maxed-out airframe vs a new design with tons of upgrade potential...Northrop brought it into the game too late to make a difference. Edit: Yeah, it would've been sick in a demo team though.
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Apr 14, 2010 05:15
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Previa_fun posted:I'd like to give a shout-out to the best fighter that almost was: The Northrop F-20 Tigershark. Holy poo poo it had a 70% thrust increase over the F-5... didn't know that.
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Apr 14, 2010 05:22
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talk show ghost posted:Heavy metal was accurate about the interior, hah. Pretty much every bomber from that war had an absurdly cramped interior. I have no idea how crews got out when the things were hit, because there is hardly enough room to turn around. The nose position in a B-25 pretty much consists of being crammed into a 3 foot high cabinet.
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Apr 14, 2010 05:24
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