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Posted: 4/9/2010 4:50:39 PM EDT
[#1]
Quoted:
By which standards do you judge it? Well, it can't have a ton of aerodynamic lift from the engine pylo...er, I mean "wings". The flat underside of the fuselage will generate some lift but I tend to agree with the "one engine will get you to the crash site" school. But, the AV-8A killed a lot of people too. The "B" was much better. I'm guessing that 20 years down the road, the Osprey will be a decent aircraft. TC |
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Posted: 4/9/2010 4:52:52 PM EDT
[#2]
Quoted:
Loose both engines with no auto rotation capability...forget it. Well sure, if they come loose and fall off, I'm sure there will be major structural damage, and it'll crash. Not so sure about simply losing the use of an engine, though. |
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Posted: 4/9/2010 4:53:46 PM EDT
[#3]
Quoted:
What always got me is this isn't a "pure" design. It's not an airplane and it's not a helicopter. But it does both... By which standards do you judge it? Powered Lift. 
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Posted: 4/9/2010 4:58:51 PM EDT
[#4]
Osprey
Smokin' hole looking for a location. |
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Posted: 4/9/2010 5:00:33 PM EDT
[#5]
Quoted:
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Loose both engines with no auto rotation capability...forget it. Well sure, if they come loose and fall off, I'm sure there will be major structural damage, and it'll crash. Not so sure about simply losing the use of an engine, though. I'm talking about dual engine failure at any altitude or speed other than a hover. |
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Posted: 4/9/2010 5:04:23 PM EDT
[#6]
68-19583––What aircraft is your sig line?
TC |
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Posted: 4/9/2010 5:08:25 PM EDT
[#7]
Quoted:
68-19583––What aircraft is your sig line? TC UH-1H, like a dumb ass I didn't put any thought in to decent screen name and this was the first military thing that popped in to my head. 
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Posted: 4/9/2010 5:09:17 PM EDT
[#8]
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Loose both engines with no auto rotation capability...forget it. Well sure, if they come loose and fall off, I'm sure there will be major structural damage, and it'll crash. Not so sure about simply losing the use of an engine, though. I'm talking about dual engine failure at any altitude or speed other than a hover. From what I have heard, in regards to the Osprey and the BA-609 (it's civilian sibling), that it's possible to do an auto, but nobody is allowed to practice them, except in a simulator. 
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Posted: 4/9/2010 5:10:04 PM EDT
[#9]
What about on a treadmill?
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Posted: 4/9/2010 5:11:39 PM EDT
[#10]
Quoted:
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Loose both engines with no auto rotation capability...forget it. Well sure, if they come loose and fall off, I'm sure there will be major structural damage, and it'll crash. Not so sure about simply losing the use of an engine, though. I'm talking about dual engine failure at any altitude or speed other than a hover. From what I have heard, in regards to the Osprey and the BA-609 (it's civilian sibling), that it's possible to do an auto, but nobody is allowed to practice them, except in a simulator.
That's good to hear for the crew's sake. I know very little about the 22 and I'll admit, it scares the hell out of me. |
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Posted: 4/9/2010 5:22:39 PM EDT
[#11]
Quoted: Quoted: By which standards do you judge it? Well, it can't have a ton of aerodynamic lift from the engine pylo...er, I mean "wings". The flat underside of the fuselage will generate some lift but I tend to agree with the "one engine will get you to the crash site" school. But, the AV-8A killed a lot of people too. The "B" was much better. I'm guessing that 20 years down the road, the Osprey will be a decent aircraft. TC there is enough lift for level flight with the rotors horizontal. if there is one engine out, it will have enough thrust at intermediate rotor angle for a running landing. the problem with autorotate is pitch angle and very limited energy storage in the rotors. |
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Posted: 4/9/2010 5:31:19 PM EDT
[#12]
It is supposed to be able to land, vertically, OEI. I don't know if that is configuration dependent and what kind of margins there are.
Quoted: Quoted: By which standards do you judge it? Well, it can't have a ton of aerodynamic lift from the engine pylo...er, I mean "wings". The flat underside of the fuselage will generate some lift but I tend to agree with the "one engine will get you to the crash site" school. TC Actually the airfoil of the wing is very thick, and it has those huge flaps(although I'm not sure how the flaps would be positioned - I know they are straight down in hover for efficiency reasons). I would bet you can get quite a bit of lift from that wing even at (relatively) lower speeds. Combine that with some lift from the rotors in an intermediate position, and a run-on landing with no engines isn't as impossible as it sounds... assuming you aren't starting from the wrong side of the H-V curve to begin with. I'd like to see that page in the book too. So it can do a landing sort of like an airplane - which brings us back to GeorgiaBII's question. OEI ETA: Next, Gaillard says that the V-22 has never been tested to take off or land with one engine shut down during 17 years of evaluation. However, during the last four years flying on the MV-22, I have been single-engine two times; on both occasions, the aircraft responded as if nothing had happened. The aircraft’s ability to provide lift comes from its torque available vs. torque required — simply put, if you limit the amount of torque that a student pilot can use during takeoff or landing training events, which we do, you in turn simulate a single-engine profile. I can tell you that there is no difference between actual and simulated single-engine performance. |
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Posted: 4/9/2010 5:32:14 PM EDT
[#13]
The drawing also shows "Allison Engine"..
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Posted: 4/9/2010 5:33:41 PM EDT
[#14]
Quoted:
Gravity wins?  Gravity always wins. 
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Posted: 4/9/2010 6:41:56 PM EDT
[#15]
Quoted:
The drawing also shows "Allison Engine".. That's because the Osprey engine comes from the Allison T56 turboshaft engine. Rolls-Royce bought Allison in 1994, well after the Allison T406/AE 1107C-Liberty turboshaft engine was designed and built. All that means is that the drawing was done before 1994. |
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Posted: 4/9/2010 6:57:17 PM EDT
[#16]
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Does it use a Sprag clutch like the Phrog? I know that is what allows the 46 to auto rotate. Been 11 years since I flew on the Phrog but still remember natops and the limits for her. No auto rotation. I've been told that the Osprey has "some" autorotation. Don't know if it was true (or perhaps my leg was being pulled), but it was a pretty credible source. No autorotation capability from anything I've heard. |
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Posted: 4/9/2010 7:10:17 PM EDT
[#17]
I've been on quite a few test flights in Chinooks and Blackhawks and taking one engine to flight idle while in cruise flight one cannot tell the difference. I'm pretty sure this is how it is suppose to be.
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Posted: 4/9/2010 7:28:24 PM EDT
[#18]
Both survived this crash. |
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Posted: 4/9/2010 7:30:00 PM EDT
[#19]
And if I only knew how to embed a video ... this is cool!
V22 Roll |
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Posted: 4/9/2010 7:34:15 PM EDT
[#20]
Quoted:
Is anyone else alarmed by the apparent age of that drawing? It looks Nam era. Glad I'm not the only one thinking that. 
Program started in '81. |
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Posted: 4/10/2010 5:33:45 PM EDT
[#21]
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Posted: 4/10/2010 5:45:17 PM EDT
[#22]
Quoted:
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68-19583––What aircraft is your sig line? TC UH-1H, like a dumb ass I didn't put any thought in to decent screen name and this was the first military thing that popped in to my head. Naw. I just thought you were being cagey and cryptic with your screen name. 
Keith J––That makes sense about the "props" not retaining enough energy to autorotate. I'm obviously not a rotorwing guy and I'm afraid to ask my friends who are. They're a little twitchy... 
TC |
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Posted: 4/10/2010 5:51:00 PM EDT
[#23]
My guess is it doesn't autorotate. All you could do is keep it in airplane mode and do what you would do in any other fixed wing aircraft.........belly landing in the best available location within your glide slope.
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Posted: 4/10/2010 5:58:51 PM EDT
[#24]
Quoted: Quoted: Quoted: 68-19583––What aircraft is your sig line? TC UH-1H, like a dumb ass I didn't put any thought in to decent screen name and this was the first military thing that popped in to my head. Naw. I just thought you were being cagey and cryptic with your screen name. Keith J––That makes sense about the "props" not retaining enough energy to autorotate. I'm obviously not a rotorwing guy and I'm afraid to ask my friends who are. They're a little twitchy... TC and there is the problem of flow reversal through the rotors. in all autorotations, the pitch of the aircraft increases while the airflow through the rotor must change direction, always with a good bit of lost altitude. then there is the collective which also reverses, usually dropping the collective to the floor. this trades potential energy of the aircraft to both rotational energy in the rotor and usually a good amount of translational energy. in the osprey, getting as much lift means translational energy or forward speed. since the rotors won't pitch back far enough, auto rotation isn't possible. |
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Posted: 4/10/2010 6:01:37 PM EDT
[#25]
Quoted: My guess is it doesn't autorotate. All you could do is keep it in airplane mode and do what you would do in any other fixed wing aircraft.........belly landing in the best available location within your glide slope. the space shuttle has a pretty poor glide ratio. but since it comes in way hot, ground effect or flare is considerable. with all that energy, just pull some elevator right before flare and float in. that poor glide ratio also means considerable drag when the elevator pitch up is commanded. |
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Posted: 4/11/2010 11:41:58 AM EDT
[#26]
Nobdy died in that crash. As I recall, that was first attempt to get one off the ground. Something was miswired in the controls or somesuch. I'll try to remember to ask about autorotation next time I work out there. |
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Posted: 4/19/2010 9:28:34 PM EDT
[#27]
Okay, I caught a crew chief to talk to today.
The Osprey CAN auto-rotate, IF it has the altitude. "Not from 30 feet." One engine operation is not a problem if the engines are tilted. It cannot VTOL one engine, and hovering one engine would be "very difficult." "Maybe with half a fuel load." It was busy, and I didn't have the tiime to ask more detailed questions, but maybe this will answer some of the previously posted inquiries. |
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Posted: 4/19/2010 9:44:55 PM EDT
[#28]
Quoted:
http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. |
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Posted: 4/19/2010 9:49:12 PM EDT
[#29]
Quoted:
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http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) |
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Posted: 4/19/2010 9:52:18 PM EDT
[#30]
Quoted: 1. Can the Osprey vertically land with only one engine? Or is this a situation for an airplane type of crash landing? 2. Can the osprey auto rotate once it loses engine power if already in vertical decent? I am curious since the engines are on the opposite edges of the airframe and that looks like an awfully large amount of weight to conteract with pure thrust. It looks like it would flip over if one engine died when it was vertical. Same way a CH47 or CH46 does - there's a shaft/transmissions connecting everything. In fact, all multiengine rotorcraft use a similar layout... The CH-47/46 are the best 'comparison' because they are dual-rotor, no-tail-rotor configs.... |
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Posted: 4/19/2010 9:54:28 PM EDT
[#31]
Quoted:
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http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? |
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Posted: 4/19/2010 9:56:48 PM EDT
[#32]
Quoted: Quoted: What always got me is this isn't a "pure" design. It's not an airplane and it's not a helicopter. But it does both... By which standards do you judge it? Powered Lift. Was going to say 'FAA calls it powered lift - it's own separate classification'.... |
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Posted: 4/19/2010 9:59:31 PM EDT
[#33]
Quoted:
1. Can the Osprey vertically land with only one engine? Or is this a situation for an airplane type of crash landing? 2. Can the osprey auto rotate once it loses engine power if already in vertical decent? I am curious since the engines are on the opposite edges of the airframe and that looks like an awfully large amount of weight to conteract with pure thrust. It looks like it would flip over if one engine died when it was vertical. 1. The Osprey can land on one engine, if the engines are tilted. STOL. No VTOL. 2. Auto rotation is possible. Can a helicopter auto rotate in a verticle decent? Same same. |
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Posted: 4/19/2010 10:02:28 PM EDT
[#34]
Quoted:
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http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? Yes, the Chinook has "drag issues" compared to the Osprey. |
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Posted: 4/19/2010 10:07:44 PM EDT
[#35]
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http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? Yes, the Chinook has "drag issues" compared to the Osprey. Let me rephrase my question. Instead of mounting the engines on the end of the wings they could have mounted them on fuselage hard-points with nacelles or used a configuration like a CH-46 . Either way you would still have the same functionality with the same number of combining transmissions without the funky tilting engine design issues. |
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Posted: 4/19/2010 10:09:58 PM EDT
[#36]
Quoted:
Quoted:
Is anyone else alarmed by the apparent age of that drawing? It looks Nam era. Glad I'm not the only one thinking that.
Program started in '81. Eagle Claw was the inspiration for the Osprey program. |
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Posted: 4/19/2010 10:16:50 PM EDT
[#37]
Quoted: Drag. The hub of the rotor already produces a good deal of drag, hiding the nacelles behind the hubs of the rotor reduces the profile area drag of the engine/transmission. Quoted: Quoted: Quoted: Quoted: Quoted: http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? Yes, the Chinook has "drag issues" compared to the Osprey. Let me rephrase my question. Instead of mounting the engines on the end of the wings they could have mounted them on fuselage hard-points with nacelles or used a configuration like a CH-46 . Either way you would still have the same functionality with the same number of combining transmissions without the funky tilting engine design issues. |
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Posted: 4/19/2010 10:19:18 PM EDT
[#38]
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Drag. The hub of the rotor already produces a good deal of drag, hiding the nacelles behind the hubs of the rotor reduces the profile area drag of the engine/transmission.
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http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? Yes, the Chinook has "drag issues" compared to the Osprey. Let me rephrase my question. Instead of mounting the engines on the end of the wings they could have mounted them on fuselage hard-points with nacelles or used a configuration like a CH-46 . Either way you would still have the same functionality with the same number of combining transmissions without the funky tilting engine design issues. That makes sense. 
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Posted: 4/19/2010 10:29:30 PM EDT
[#39]
Quoted: The other engine carries the aircraft all the way to the scene of the crash. This. |
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Posted: 4/19/2010 10:30:56 PM EDT
[#40]
Quoted:
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Drag. The hub of the rotor already produces a good deal of drag, hiding the nacelles behind the hubs of the rotor reduces the profile area drag of the engine/transmission.
Quoted:
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http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? Yes, the Chinook has "drag issues" compared to the Osprey. Let me rephrase my question. Instead of mounting the engines on the end of the wings they could have mounted them on fuselage hard-points with nacelles or used a configuration like a CH-46 . Either way you would still have the same functionality with the same number of combining transmissions without the funky tilting engine design issues. That makes sense.
Fuselage mounted, the rotors would be horizontal, or close to it. Just like a helicopter. Wing end mounted, the motors can tilt the rotors to vertical. It's that simple. Horizontal=helicopter. Vertical=airplane. Militarily, which is faster? The Osprey can do both. |
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Posted: 4/19/2010 10:44:07 PM EDT
[#41]
Quoted: Quoted: If an osprey loses an engine the other engine spins both propellers. So they claim… No, there's no "claim" about it... If engine 1 fails, engine 2, assuming it's running, will power both props. The only thing that could prevent this would be the failure of the drive shaft (unlikely, it's a huge friggin' piece of metal) or the complete loss of a/both props function (also unlikely, they can take a lot of abuse and still get at least some functional thrust). The question isn't will the remaining engine power both props... It will... The question is, will that be enough power to allow a sufficiently soft landing as to prevent vehicle or crew loss? Probably is the answer... Remember, it has the option of landing vertically, or horizontally, or something inbetween... It takes a tiny amount of thrust to keep the plane airborne in forward flight, whereas it takes a shit-ton to keep it airborne in hover mode... The crews best bet is to throw it into forward flight (thus also unassing any threats that may have caused the problem), pick the closest flat spot of ground, and make a non-vertical landing... The higher velocity/lift they can safely maintain on their emergency approach, the better, provided there's enough rolling distance for them to come to a stop. Over the ocean is where the V-22 really gets interesting... It's layout should allow it, if it has sufficient altitude at the time of failure, to transition to forward flight mode. It can thus stay in the air and head for land (preferably an airfield), and even if it's at sea a considerable distance, using tanker support one should be able to nurse it home, provided it isn't a progressive systems failure. |
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Posted: 4/19/2010 10:46:34 PM EDT
[#42]
Quoted:
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Drag. The hub of the rotor already produces a good deal of drag, hiding the nacelles behind the hubs of the rotor reduces the profile area drag of the engine/transmission.
Quoted:
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http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? Yes, the Chinook has "drag issues" compared to the Osprey. Let me rephrase my question. Instead of mounting the engines on the end of the wings they could have mounted them on fuselage hard-points with nacelles or used a configuration like a CH-46 . Either way you would still have the same functionality with the same number of combining transmissions without the funky tilting engine design issues. That makes sense.
Fuselage mounted, the rotors would be horizontal, or close to it. Just like a helicopter. Wing end mounted, the motors can tilt the rotors to vertical. It's that simple. Horizontal=helicopter. Vertical=airplane. Militarily, which is faster? The Osprey can do both.
I don't think you understand. I was an aircraft mechanic. I worked on Chinooks. You take a V-22. Keep the same configuration. Move the engines to the fuselage. You have Hard-point like a CH-47. Gear train goes like this. Engine - combining transmission - drive shaft - C Box - reduction gearing to wing mounted props. 
Like this: 
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Posted: 4/19/2010 10:48:51 PM EDT
[#43]
I'm not an aviation expert, but I believe they fucking crash and explode.
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Posted: 4/19/2010 10:55:22 PM EDT
[#44]
Quoted: Quoted: Quoted: Quoted: Quoted: Drag. The hub of the rotor already produces a good deal of drag, hiding the nacelles behind the hubs of the rotor reduces the profile area drag of the engine/transmission. Quoted: Quoted: Quoted: Quoted: Quoted: http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? Yes, the Chinook has "drag issues" compared to the Osprey. Let me rephrase my question. Instead of mounting the engines on the end of the wings they could have mounted them on fuselage hard-points with nacelles or used a configuration like a CH-46 . Either way you would still have the same functionality with the same number of combining transmissions without the funky tilting engine design issues. That makes sense. Fuselage mounted, the rotors would be horizontal, or close to it. Just like a helicopter. Wing end mounted, the motors can tilt the rotors to vertical. It's that simple. Horizontal=helicopter. Vertical=airplane. Militarily, which is faster? The Osprey can do both. I don't think you understand. I was an aircraft mechanic. I worked on Chinooks. You take a V-22. Keep the same configuration. Move the engines to the fuselage. You have Hard-point like a CH-47. Gear train goes like this. Engine - combining transmission - drive shaft - C Box - reduction gearing to wing mounted props. http://madmikey.mu.nu/archives/Tiltrotor.jpg http://www.chinook-helicopter.com/standards/images/drivetrain.jpg One reason is IR guided missiles. Do you want them hitting an engine nacel forty-five feet from the other engine and twenty feet from the fuselage, with a driveshaft that might keep you in powered and controlled flight... Or do you want it hitting an engine mounted on top of the fusalage, four feet from the other engine, probably resulting in both failing and being pretty much fucked? Fuselage mounted "twins" was the main reason the the Russian hinds got themselves fucking slaughtered over Afghanistan... One stinger goes up the tailpipe of engine 1, and blows both engines the fuck up, and on a heavy bitch like that, you're all gonna die at the point. Also, a lack of good launch warning equipment, flares and proper IR reduction and misdirection in the design didn't help that any. |
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Posted: 4/19/2010 10:58:13 PM EDT
[#45]
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Drag. The hub of the rotor already produces a good deal of drag, hiding the nacelles behind the hubs of the rotor reduces the profile area drag of the engine/transmission.
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http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? Yes, the Chinook has "drag issues" compared to the Osprey. Let me rephrase my question. Instead of mounting the engines on the end of the wings they could have mounted them on fuselage hard-points with nacelles or used a configuration like a CH-46 . Either way you would still have the same functionality with the same number of combining transmissions without the funky tilting engine design issues. That makes sense.
Fuselage mounted, the rotors would be horizontal, or close to it. Just like a helicopter. Wing end mounted, the motors can tilt the rotors to vertical. It's that simple. Horizontal=helicopter. Vertical=airplane. Militarily, which is faster? The Osprey can do both.
I don't think you understand. I was an aircraft mechanic. I worked on Chinooks. You take a V-22. Keep the same configuration. Move the engines to the fuselage. You have Hard-point like a CH-47. Gear train goes like this. Engine - combining transmission - drive shaft - C Box - reduction gearing to wing mounted props. http://madmikey.mu.nu/archives/Tiltrotor.jpg http://www.chinook-helicopter.com/standards/images/drivetrain.jpg One reason is IR guided missiles. Do you want them hitting an engine nacel forty-five feet from the other engine and twenty feet from the fuselage, with a driveshaft that might keep you in powered and controlled flight... Or do you want it hitting an engine mounted on top of the fusalage, four feet from the other engine, probably resulting in both failing and being pretty much fucked?
Name a twin helicopter that does not have this configuration...or for that matter the A-10 I think a missile hit would blow the assembly off of the ac. |
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Posted: 4/19/2010 11:01:32 PM EDT
[#46]
Quoted: Name a combat rifle that does not have a piston in it...Name a twin helicopter that does not have this configuration...or for that matter the A-10 Just because the V-22 is the first to use this, or the only one, does not prove it to be a bad idea. The M-16 and its children are proof of that. It is done because it has its advantages. Quoted: I think a missile hit would blow the assembly off of the ac. Then you watch too many movies. Sure, if you hit it with a fucking SA-5, you're going to blow the entire fucking craft into confetti. But your average MANPAD (the primary threat to such an aircraft) has a warhead that isn't much bigger than a hand grenade. And anyone who has actually seen what those do knows that, while lethal as fuck and quite damaging to equipment, they will hardly blow the nacel off of a V-22. The lesson the Soviets learned on the Hind in Afghanistan against MANPADs was that you want your engines as far apart as possible, as much IR concealment and redirection as practical, good flares, good launch warning and as much mechanical redundancy in prop/rotor power as possible. The V-22 is designed around these lessons. It is the hardest chopper-ish-thing to kill with MANPADs on Earth. |
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Posted: 4/19/2010 11:04:42 PM EDT
[#47]
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I'm not an aviation expert, but I believe they fucking crash and explode. Yes, they "explode" when they crash, as do most military planes, and many civilian planes. They do not ordinarily "crash," however. Neither do other military or civilian planes. But it does happen. Fuck. Read the definition of "explode" and "explosion.." Then look up "crash and burn." "Combustion" vs. "detonation." Get some science before you open your gaping maw. |
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Posted: 4/19/2010 11:08:25 PM EDT
[#48]
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[Sure, if you hit it with a fucking SA-5, you're going to blow the entire fucking craft into confetti. But your average MANPAD (the primary threat to such an aircraft) has a warhead that isn't much bigger than a hand grenade. And anyone who has actually seen what those do knows that, while lethal as fuck and quite damaging to equipment, they will hardly blow the nacel off of a V-22. The aerodynamic instability and the turbine coming apart would take care of that. |
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Posted: 4/19/2010 11:11:31 PM EDT
[#49]
Science H. Logic, the answer why the engines are placed where they are is aerodynamics, namely reduction of profile area drag. The nacelles, the technical term for the "pods" which contain engine and transmission, are riding in the wind shadow of the rotor hub.
If the engines were mounted on the fuselage, this would increase the profile area and resulting drag. Since the CH46/47 don't have tilt rotors and placing the engines aligned axially with the rotor axis (or at least parallel) would result in loss of cargo space. Turboshaft engines are highly compact, the transmissions comprise the majority of weight and volume in the power plant. |
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Posted: 4/19/2010 11:11:47 PM EDT
[#50]
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Drag. The hub of the rotor already produces a good deal of drag, hiding the nacelles behind the hubs of the rotor reduces the profile area drag of the engine/transmission.
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http://www.chinook-helicopter.com/standards/images/drivetrain.jpg Interconnected drive shafts for rotor craft work pretty well.... I always wondered why thy did not place the engines on the fuselage like a Chinook. It seams like it would have been a cleaner design. 250 MPH is the answer. (or close to it) Drag issue? Yes, the Chinook has "drag issues" compared to the Osprey. Let me rephrase my question. Instead of mounting the engines on the end of the wings they could have mounted them on fuselage hard-points with nacelles or used a configuration like a CH-46 . Either way you would still have the same functionality with the same number of combining transmissions without the funky tilting engine design issues. That makes sense.
Fuselage mounted, the rotors would be horizontal, or close to it. Just like a helicopter. Wing end mounted, the motors can tilt the rotors to vertical. It's that simple. Horizontal=helicopter. Vertical=airplane. Militarily, which is faster? The Osprey can do both.
I don't think you understand. I was an aircraft mechanic. I worked on Chinooks. You take a V-22. Keep the same configuration. Move the engines to the fuselage. You have Hard-point like a CH-47. Gear train goes like this. Engine - combining transmission - drive shaft - C Box - reduction gearing to wing mounted props. http://madmikey.mu.nu/archives/Tiltrotor.jpg http://www.chinook-helicopter.com/standards/images/drivetrain.jpg One reason is IR guided missiles. Do you want them hitting an engine nacel forty-five feet from the other engine and twenty feet from the fuselage, with a driveshaft that might keep you in powered and controlled flight... Or do you want it hitting an engine mounted on top of the fusalage, four feet from the other engine, probably resulting in both failing and being pretty much fucked?
Name a twin helicopter that does not have this configuration...or for that matter the A-10 I think a missile hit would blow the assembly off of the ac. This is a very old argument. Indeed, how many helicopters would survive a "missile blow?" Gee whiz guys, it's an airplane. Nothing magical about it, it's all science and mathematics. It can take off like a chopper, and convert to flight like an airplane. It'll get shot down with a missile, just like a UH1, CH-47 or an F-16 or F-117. If you fuck up what makes it fly, it'll crash. |
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