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Posted: 12/22/2013 2:55:20 PM EDT
[#1]
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Sweep increases lateral directional stability, so sometimes anhedral is used to reduce the effect. The high location is a contributor but not as strong as sweep. Anhedral in low wings may cause the engines to drag. These airplanes are not rigid, so deflection is taken into account, too. Quote HistoryQuoted:
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What about anhedral versus dihedral? A C-17 or C-5 looks like it has anhedral, while all the commercial planes have significant amounts of dihedral. It seems like it would be difficult to have anhedral on a low wing. Are the military transports designed for less lateral stability, or is there something else at play? ETA I guess having a high wing let's you get away with less dihedral, but there seems to be a pretty big difference... maybe more than enough to be explained by that. The anhedral/dihedral decision is strongly based on the wing sweep, not on the "logical" pendulum effect of a high wing. Modern stability aids allow overcoming weak lateral directional stability, so one configuration might rely on less dihedral or anhedral for some other reason, knowing it can be made up electronically. I was under the impression that high wing was inherently more stable, hence the anhedral to balance high wing stability with the anhedral's increased maneuverability. Sweep increases lateral directional stability, so sometimes anhedral is used to reduce the effect. The high location is a contributor but not as strong as sweep. Anhedral in low wings may cause the engines to drag. These airplanes are not rigid, so deflection is taken into account, too. That's a bad thing, right? 
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Posted: 12/22/2013 2:56:49 PM EDT
[#2]
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I have a lot of good things to say about it...where are your friends stationed? Quote HistoryQuoted:
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Lockheed's been lying to the bill payer for a loooooooong time about reliability. 
My friends that fly C-5s have almost nothing good to say about that plane, ESPECIALLY in the reliability dept. But it's plausible deniability when the plane "breaks down" in Germany, and you can spend a few days at the biergarten while they fix it.  I have a lot of good things to say about it...where are your friends stationed? I enjoyed watching them taxi, take off and all that jazz... but according to the crew chiefs on a good day only about 50% of them on the line were flyable. |
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Posted: 12/22/2013 3:01:13 PM EDT
[#3]
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That's a bad thing, right? Quote HistoryQuoted:
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What about anhedral versus dihedral? A C-17 or C-5 looks like it has anhedral, while all the commercial planes have significant amounts of dihedral. It seems like it would be difficult to have anhedral on a low wing. Are the military transports designed for less lateral stability, or is there something else at play? ETA I guess having a high wing let's you get away with less dihedral, but there seems to be a pretty big difference... maybe more than enough to be explained by that. The anhedral/dihedral decision is strongly based on the wing sweep, not on the "logical" pendulum effect of a high wing. Modern stability aids allow overcoming weak lateral directional stability, so one configuration might rely on less dihedral or anhedral for some other reason, knowing it can be made up electronically. I was under the impression that high wing was inherently more stable, hence the anhedral to balance high wing stability with the anhedral's increased maneuverability. Sweep increases lateral directional stability, so sometimes anhedral is used to reduce the effect. The high location is a contributor but not as strong as sweep. Anhedral in low wings may cause the engines to drag. These airplanes are not rigid, so deflection is taken into account, too. That's a bad thing, right? Poor form, just like running into the committee boat in a sailboat race. |
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Posted: 12/22/2013 3:02:55 PM EDT
[#4]
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If you think something is wrong with the plane, Germany is a good place to get it checked out. 
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Lockheed's been lying to the bill payer for a loooooooong time about reliability.
My friends that fly C-5s have almost nothing good to say about that plane, ESPECIALLY in the reliability dept. But it's plausible deniability when the plane "breaks down" in Germany, and you can spend a few days at the biergarten while they fix it. serial lying about maintenance while collecting TDY and avoiding missions is a matter of pride in airlift units it appears. If you think something is wrong with the plane, Germany is a good place to get it checked out.
Even you don't think something is wrong with the plane, Germany is a good place to get it checked out. Hawaii, too. I hear Rota is popular. |
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Posted: 12/22/2013 3:06:23 PM EDT
[#5]
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Even you don't think something is wrong with the plane, Germany is a good place to get it checked out. Hawaii, too. I hear Rota is popular. Quote HistoryQuoted:
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Lockheed's been lying to the bill payer for a loooooooong time about reliability.
My friends that fly C-5s have almost nothing good to say about that plane, ESPECIALLY in the reliability dept. But it's plausible deniability when the plane "breaks down" in Germany, and you can spend a few days at the biergarten while they fix it. serial lying about maintenance while collecting TDY and avoiding missions is a matter of pride in airlift units it appears. If you think something is wrong with the plane, Germany is a good place to get it checked out.
Even you don't think something is wrong with the plane, Germany is a good place to get it checked out. Hawaii, too. I hear Rota is popular. Rota and Germany have MX support available there. Other places... not so much. Plus, the beer is tasty in Germany and the wine is great in Spain. |
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Posted: 12/22/2013 3:11:07 PM EDT
[#6]
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Prop driven aircraft with wing mounted engines need a high wing mount for obvious reasons. Look at how tall the landing gear is on the Connie. http://cdn-www.airliners.net/aviation-photos/photos/8/2/1/0095128.jpg Quote HistoryQuoted:
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I will have to ask my BIL this question since he works on the C130 line and see if he can get an answer about this. Prop driven aircraft with wing mounted engines need a high wing mount for obvious reasons. Look at how tall the landing gear is on the Connie. http://cdn-www.airliners.net/aviation-photos/photos/8/2/1/0095128.jpg Could have had shorter gear had they spread that HP out over a four-bladed prop but long, three-bladed props are quieter and a little more fuel-efficient. Another civie vs. .mil aircraft difference. |
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Posted: 12/22/2013 3:41:59 PM EDT
[#8]
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Dirt. Mil aircraft have to be able to land gear up and take off again. Look up pics, they used to test them at Sicily DZ, pretty cool shit. And Mil don't care if the cargo aka passengers are sitting right next to a loud engine. Also requires less caution when operating GSE and other equipment vehicles in close proximity. This? http://www.youtube.com/watch?v=XKeCVYTiIWg Not really "landing" is it? Nah. Guess memory failed me, could have sworn I'd seen a pic of a gear up landing on one of the Bragg DZs captioned that it was a test to meet a requirement, not to develop SOP or anything. Can't find anything on it, sorry for the mis information. |
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Posted: 12/22/2013 4:29:08 PM EDT
[#9]
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Even you don't think something is wrong with the plane, Germany is a good place to get it checked out. Hawaii, too. I hear Rota is popular. I was never fortunate enough to score either one...  it was always Germany going into/out-of the SWA AOR.
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Posted: 12/22/2013 4:29:57 PM EDT
[#10]
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Dirt. Mil aircraft have to be able to land gear up and take off again. Look up pics, they used to test them at Sicily DZ, pretty cool shit. And Mil don't care if the cargo aka passengers are sitting right next to a loud engine. Also requires less caution when operating GSE and other equipment vehicles in close proximity. Guess you've never flown as a passenger on a Boeing 727, at least not in the rear seats...... |
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Posted: 12/22/2013 4:34:02 PM EDT
[#11]
may of already been touched on, but a coworker said maybe it's for the sound... less sound for the passengers. Whiny little bitches.
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Posted: 12/22/2013 4:42:53 PM EDT
[#12]
Podded engines on the -47 and 707 were designed to facilitate maintenance, esp. In the days of low TBOs of early jet engines.
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Posted: 12/22/2013 5:20:35 PM EDT
[#13]
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Nah. Guess memory failed me, could have sworn I'd seen a pic of a gear up landing on one of the Bragg DZs captioned that it was a test to meet a requirement, not to develop SOP or anything. Can't find anything on it, sorry for the mis information. Quote HistoryQuoted:
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Dirt. Mil aircraft have to be able to land gear up and take off again. Look up pics, they used to test them at Sicily DZ, pretty cool shit. And Mil don't care if the cargo aka passengers are sitting right next to a loud engine. Also requires less caution when operating GSE and other equipment vehicles in close proximity. This? http://www.youtube.com/watch?v=XKeCVYTiIWg Not really "landing" is it? Nah. Guess memory failed me, could have sworn I'd seen a pic of a gear up landing on one of the Bragg DZs captioned that it was a test to meet a requirement, not to develop SOP or anything. Can't find anything on it, sorry for the mis information. may have been LAPES |
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Posted: 12/22/2013 5:36:28 PM EDT
[#14]
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... military utilize unimproved runways and adverse landing condition, commercial no This. Generally want to keep rocks and other shit OUT of the engines. 
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Posted: 12/22/2013 10:22:38 PM EDT
[#15]
Why was the P2 Neptune Mid Wing, it ran through the middle of the fuselage? It was a pain to traverse from front to rear as you had to climb over the wing inside.
Why was it's replacement, low wing? Wouldn't the low wing hinder looking down for submarines? |
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Posted: 12/22/2013 10:25:42 PM EDT
[#16]
Northwest used to fly some of those high wing mount planes into Dallas. I don't remember the models.
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Posted: 12/22/2013 10:47:57 PM EDT
[#17]
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Engines need to be higher so you don't suck a goat with an afghan attached to its ass through it. 
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Posted: 12/22/2013 10:49:47 PM EDT
[#18]
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Yes... *laughing*... that's kind of what I was getting at... Quote HistoryQuoted:
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Engines need to be higher so you don't suck a goat with an afghan attached to its ass through it.
Yes... *laughing*... that's kind of what I was getting at... I lost. 
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Posted: 12/22/2013 11:04:14 PM EDT
[#19]
Airliners have a floor near the mid line of the fuselage, passenger seats are above the floor and cargo space is below the floor and so is the wing spar. These planes can't carry tall things like tanks and other tall .mil stuff.
Military cargo planes need to be able to carry tall things, so the floor is very low in the fuselage and the wing spar is near the top of the fuselage. Then there is the unimproved runway/foreign object debris thing and the short field/short runway thing. Finally, in a .mil cargo plane it is good for the fuselage to be low to the ground for ease of loading and unloading via a ramp that is carried on the plane. Cargo airliners don't accommodate drive on and drive off stuff, or parachute drop stuff. Side note: low mounted wings have some dihedral and high wing planes have some anhedral. |
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Posted: 12/22/2013 11:09:12 PM EDT
[#20]
You won't see a low wing with anhedral wings.
Anhedral wings reduce stability (adding maneuverability), swept wings increase stability (to a point, critical mach). Part of why the F-16 had to be fly by wire. It's a tradeoff for a low cargo entry/exit point. |
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Posted: 12/22/2013 11:21:27 PM EDT
[#21]
Military cargo planes are usually designed to be able to easily get cargo into and out of the plane. The ground level ramp allows that, and there is no need to lift cargo 15 feet in the air to get it in the plane. Look at a 747 cargo vs a C-5/17/130/119/123/141. Which design will allow loading large heavy cargo in the most efficient manner?
How would a Stryker fit in a 747? |
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Posted: 12/22/2013 11:30:19 PM EDT
[#22]
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Engines need to be higher so you don't suck a goat with an afghan attached to its ass through it.
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Posted: 12/22/2013 11:54:40 PM EDT
[#23]
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You need to check the take off weights again. People weigh less than tanks. Max take off weight of a C-5M is 675,000 pounds. Max take off weight of an A380 passenger flight is 1,275,000 pounds. Tanks weigh a lot, but 500+ self loading freight weighs more. |
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Posted: 12/23/2013 12:08:05 AM EDT
[#24]
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Max take off weight of a C-5M is 675,000 pounds. Max take off weight of an A380 passenger flight is 1,275,000 pounds. Tanks weigh a lot, but 500+ self loading freight weighs more. Quote HistoryQuoted:
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You need to check the take off weights again. People weigh less than tanks. Max take off weight of a C-5M is 675,000 pounds. Max take off weight of an A380 passenger flight is 1,275,000 pounds. Tanks weigh a lot, but 500+ self loading freight weighs more. that max takeoff weight seemed a bit low and is. Max takeoff weight (2.2 g) 840,000 lb from this page http://www.lockheedmartin.com/us/products/c5/c-5-specifications.html maybe the TOW is limited for other reasons. |
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Posted: 12/23/2013 1:36:23 AM EDT
[#25]
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Even you don't think something is wrong with the plane, Germany is a good place to get it checked out. Hawaii, too. I hear Rota is popular. I don't know about now, but twenty years ago Shepard AFB was real popular when a new MIMSO class arrived. The ENJJPT boys loved it too. My honey and I used to sit at the Club and watch the feeding frenzy; it was a spectacle. |
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Posted: 12/23/2013 5:04:51 AM EDT
[#26]
Quote HistoryQuoted: Dakota had low wings. And high landing gear (it was a tail-dragger). |
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Posted: 12/23/2013 5:11:49 AM EDT
[#27]
Quote HistoryQuoted: Nope, the original design was to incorporate an all passenger, all freight or combi freight plus passenger missions. All three were considered from the start, not just one. Boeing was putting the company at risk and so they went all in. The 747-8 was designed to intrude into the A-380 cargo mission with an airplane that can carry lots of weight in a compact efficient package. The A-380 can carry lots of feathers. I've watched a couple of AN-124 airplanes with loads that were just plain amazing. One was the guts of a bottling plant from Italy. Part was unloaded out the rear ramp, part was unloaded out the front. The airplane had to be stabilized so it couldn't squat on the ramp, and the front required erection of a bridge crane that to move the load onto a custom and extremely long trailer that looked like a bridge on wheels that was carefully lined up in front of the nose. And the USAF has specialized cargo handling equipment (K-loaders, etc.) to do what civilians have to customize, because civilians don't normally move cargo using these procedures. |
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Posted: 12/23/2013 5:12:41 AM EDT
[#28]
Quote HistoryQuote HistoryQuoted: Quoted: Dirt. Mil aircraft have to be able to land gear up and take off again. Look up pics, they used to test them at Sicily DZ, pretty cool shit. And Mil don't care if the cargo aka passengers are sitting right next to a loud engine. Also requires less caution when operating GSE and other equipment vehicles in close proximity. This? http://www.youtube.com/watch?v=XKeCVYTiIWg Not really "landing" is it? LAPES. If he lands it, he's doing it wrong. |
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Posted: 12/23/2013 5:15:54 AM EDT
[#29]
Quote HistoryQuoted: My friends that fly C-5s have almost nothing good to say about that plane, ESPECIALLY in the reliability dept. But it's plausible deniability when the plane "breaks down" in Germany, and you can spend a few days at the biergarten while they fix it. Quote HistoryQuoted: Quoted: Lockheed's been lying to the bill payer for a loooooooong time about reliability. My friends that fly C-5s have almost nothing good to say about that plane, ESPECIALLY in the reliability dept. But it's plausible deniability when the plane "breaks down" in Germany, and you can spend a few days at the biergarten while they fix it. You know it's really a maintenance issue when the plane breaks in a shithole. I flew from place to place several times o C-5s. Never broke. One brought me 'home' (to CONUS) from DESERT STORM - and it could have broken in Rota, but didn't. |
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Posted: 12/23/2013 5:16:18 AM EDT
[#30]
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unimproved airfields. Zackly. High wings keep intakes and parts away from shit on ground. Nearly the ultimate in that attempt: 
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Posted: 12/23/2013 5:20:37 AM EDT
[#31]
The high wing aircraft have lower fuselages for driving vehicles/tanks onto.
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Posted: 12/23/2013 5:21:52 AM EDT
[#32]
Quote HistoryQuoted: Even you don't think something is wrong with the plane, Germany is a good place to get it checked out. Hawaii, too. I hear Rota is popular. But not Tinker. I knew the plane was really broke when we landed at Tinker. Bangkok, Kinshasa (back in the day there were awesome buys on jewelry and flight crew stayed free in the InterCon where the SAS and Lufthansa stews stayed), etc. - it's usually a fault the MRT can't duplicate when they show up. Had a C141 on final approach to Dakar break and turn around and fly 4 hours back to Kinshasa because that deal was sweeter than Dakar's. |
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Posted: 12/23/2013 5:23:12 AM EDT
[#33]
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My friends that fly C-5s have almost nothing good to say about that plane, ESPECIALLY in the reliability dept. But it's plausible deniability when the plane "breaks down" in Germany, and you can spend a few days at the biergarten while they fix it. Quote HistoryQuoted:
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Lockheed's been lying to the bill payer for a loooooooong time about reliability.
My friends that fly C-5s have almost nothing good to say about that plane, ESPECIALLY in the reliability dept. But it's plausible deniability when the plane "breaks down" in Germany, and you can spend a few days at the biergarten while they fix it. My friend flew right seat in C-5s. He has lots of pictures from exotic places, while the flying repair bill was downed for work. |
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Posted: 12/23/2013 5:31:57 AM EDT
[#34]
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High wing aircraft can get lower to the ground for drive-on/drive-off capabilities. You would have to worry about high-centering long cargo (i.e. Helicopters, trailers, etc.) if you had an abrupt slope both from the cargo floor to the ramp and from the ramp to the ground. In the C-5 we can "forward kneel" to nearly eliminate this factor. Even with this ability, some cargo still needs shoring. http://sci2.esa.int/hubble/webcam/images/Dcp_1071.jpg We has to make looooong ramps to get our boat trailers up in a C17.ill see if I can't find the pictures |
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Posted: 12/23/2013 5:35:47 AM EDT
[#35]
Stability
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Posted: 12/23/2013 5:42:54 AM EDT
[#36]
So, lots of good reasons for high wing military aircraft have been provided. Not so much justification for low-wing commercial aircraft other than the advantage of stacking the cargo and passenger compartments. Does the low-wing design offer greater passenger comfort. Better visibility? Does one design inherently offer a calmer/smoother flight experience? Or is it just a case that the top deck design of the standard commercial jet is conducive to moving passengers on and off the aircraft?
BTW, I don't know these things. I'm just asking. |
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Posted: 12/23/2013 6:00:08 AM EDT
[#37]
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Stability Quote HistoryQuoted:
Stability Stability of what? It's obvious that successful high wing and low wing airplanes are stable. They're also stable while sitting on the ground, and while taxiing, and during take off and landings. So tell us your thoughts. Quoted:
So, lots of good reasons for high wing military aircraft have been provided. Not so much justification for low-wing commercial aircraft other than the advantage of stacking the cargo and passenger compartments. Does the low-wing design offer greater passenger comfort. Better visibility? Does one design inherently offer a calmer/smoother flight experience? Or is it just a case that the top deck design of the standard commercial jet is conducive to moving passengers on and off the aircraft? BTW, I don't know these things. I'm just asking. This has already been covered. Locating the engines close to the ground for access and keeping the wing carry through stucture out of the passenger cabin have about equal weight in the decision. An overhead wing has to be located high enough to keep all of the structure out of the cabin, so that means structure has to be provided outside of the basic circular formers, and that adds weight. Then all that structure has to be faired to and bottom, so that adds more weight. A low wing located below the cabin floor has less constraint on its exact vertical location so carry through structure is more straight forward, hence lighter, and fairings are smaller, simpler, and lighter. There are also aerodynamic drag benefits by putting the wing closer to the fuselage mid line, and although that is hard to argue on most airplanes, it's critical to sweep up and eliminate all the drag possible on these types. Quoted:
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unimproved airfields. Zackly. High wings keep intakes and parts away from shit on ground. Nearly the ultimate in that attempt: http://airpigz.squarespace.com/storage/hi-res/Boeing_YC-14.jpg The YC-14, YC-15, and C-17 all exhibit configurations designed to generate very high maximum lift coefficients for short takeoff and landing performance by either upper surface blowing in conjunction with the flaps, or large span slotted Fowler flaps. There are probably some good drawings on the net that illustrate the difference in how each type works and it's interesting for those that are interested in V/STOL or STOL airplanes. NASA's QRSA will be another airplane to study. |
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