Responce to Dave that Yahoo bounced for no reason
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Responce to Dave that Yahoo bounced for no reason
 
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Date: Wed, 25 Jun 2003 13:13:26 -0700 (PDT) From: "Robert Thomas" <[hidden email] Subject: Response to Dave To:[hidden email] Sorry it took me so long to respond to your message, but I wanted to try and think things through before I responded. I also wanted to see if anyone would jump on your comments so that I could build off of them as you have done so well with my contributions. To:[hidden email] From: "davrecon" [hidden email] Date: Sat, 21 Jun 2003 04:03:02 -0400 Subject: Re: [SHADO] SkyDiver Design Overboard? Enjoy ----- Original Message ----- From: "Robert Thomas" <[hidden email]> To: <[hidden email]> Sent: Wednesday, June 18, 2003 5:01 PM Subject: Re: [SHADO] SkyDiver Design Overboard? Enjoy One of my friends is currently at sea aboard a boomer operating God Only knows where. He once told me that they had to account for the weight of everything on the boat and how it changed when they were balancing the ballast tanks, because any shifting of weight would lead to the Center Of Gravity changing, and thus rearranging the mass needed to balance the boat. > ......... and I can't see SkyDiver being any different. The computers would have to begin shifting ballast before Sky launched, and there would still be a minute or two before the pumps could catch up with the new Weight Distribution. > > -------------------------------------------------------- Agreed about the crew and stuff moving about the interior of the boat that would have to be compensated for by an active system, as it would be quite random. Indeed, every time somebody flushed a toilet, a few pounds would move from here to there. However, compared to the overall weight of the submarine, these weight shifts would be relatively "unsevere" you might say, andeasily compensated for. The reactor core, however, is fixed in position, and the rest of the boat could be built in balance around it. Also, the Sky plane at the front of the boat is fixed in position, And of constant weight. Proactive balancing could be accomplished during fueling tokeep it neutral. Refueling could be done immediately after termination of the previous flight, or any time at their digression. This would keep the plane neutral at all times, totally independent of the boat, mind you. Possibly the weight transfer of the pilot upon his moving from the sub to the cockpit (that's very small) could effect trim, but I'd suspect that to be trivial. How would you Trim Sky? Are you suggesting that Sky has its own ballast tanks, as well as pumps to move the water in and out of the system? Where are these tanks located, and what do you do if you cant trim the planeto neutral? I dont see how, or why for that matter, you would want to put ballast tanks in Sky. You suggested earlier that there were Simple chambers in Sky (June 7th, 03, 1941 Hours), but I dont see how this would help things. Unless we take the ideal of Flooding all areas of Sky that are not electrical or the cockpit to equalize the water pressure, then Sky wwould have to be built like a submarine with a pressure hull to match that of Diver. I dont think you would impair the flight characteristics of Sky (such asthey are) by designing the aircraft in this fashion. It might be interesting to run a program to simulate different Sky designs in a Real Worldsetting, but even if I had the programming skill to write one from scratch, (Which I dont, since I have failed every time I try it on CADS) I dont have enough details of the craft to make a computer model. I am not aware of anybody who has enoughdata to build such a model, or a powerful enough computer network to run it on. Even if we used a 3_D Scanner to scan in one of the many SkyDiver models available, you would still need to know what the scale was, the weight of theaircraft and a dozen and one other things that we just dont know for sure The launch of the plane could be affected AFTER the computerized Weight balancing took place for the fueling operation. Thus, the plane is effectivelyweightless, and has no ill effect upon separation. I dont see how you could make it Weightless, and besides that, thevery presence of Sky affects how Diver operates. Diver is designed to be part of a whole, even though it can work independently at reduced efficiency. Diver loses whatever streamlining it had when Sky separates, as well as a major (Possible) source of control surfaces. (See below) Even if Sky was weightless, its being there, as well as its absence would affect the operations of Diver in a number of various ways. Speed would be reduced from the increased drag, even as the ship noise level would double or triple due to the increased drag, as well as the increased power needed to compensate for that drag. The boat & plane would both be trimmed during fueling and completed before the launch. Trim them both, independently, to be neutral. Fueling would most likely be a slower process, requiring less powerful ballast pumping. It would just make good engineering sense to ballast the plane for Neutral buoyancy at all times on the cruise. Simplicity makes for better design. Less severe demands on the pumps. Less chance for foul ups. You would have to constantly monitor and fine trim the boat for Crew activities during cruise as you said, but it removes the need for that "slam balance" at plane launch! You also eliminate the need for those Nose thrusters on the sub.... Considering that there are only five or six people on board Diver at any one time, I dont think you need to worry about their activities. Fuel for Sky, on the other hand, is a whole new ball game. Just where doe Sky carry its fuel? Are the fuel cells in the main body or the wings? Or maybe even both of them. Just how much fuel does it need for aStandard mission? How much extra fuel is carried on board? Where arethe tanks located in Diver? Just as you have to allow for the changes caused by the movement of weight,your CG is changed when you remove weight as well. Diver would have one set of Habits or Quirks when Sky is attached and would handle totally different when Sky is away. The entire cross section of Diver changes,plus you lose whatever lift you were getting from Skys wings. Seeing as how Diver has no forward bow planes, if they were using Skys wing elevators as planes (Doubtful as that would be just one more thing thatneeded a computer linkage, as well as one more thing to go wrong.) then all of Divers vertical movement would be controlled from the stern rudders and diving planes. Considering the drag Diver has in the front, they seem very inadequate for the job of moving the ship at any rate of speed. Perhaps this is another job for those small impellors that are hidden in the sub superstructure. They could be used to give a little push to the rudder commands as well as speed up the rate in which turns or other movements are accomplished.[i] Ask your friends how the missiles are arranged around the sub. I'll bet youthey tell you they're arranged around the CG for good balance. I'll even bet their launch sequence is planned to maintain it that way, to minimize reballasting in case they have to let a lot fly.... In that case, they can't ballast each individual missile for Neutral buoyancy, because they are INSIDE the sub. Or... Is the weight of a missile the same as the weight of the water that floods into its silo on launch? How about a torpedo? What's your boomer friend sayabout that? Dave H [i] I had better watch myself or this will end up as long as the original article that I wrote about SkyDiver. --------------------------------- Do you Yahoo!? SBC Yahoo! DSL - Now only $29.95 per month! [Non-text portions of this message have been removed] |
Re: Responce to Dave that Yahoo bounced for no reason
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----- Original Message ----- From: "Robert Thomas" <[hidden email]> To: <[hidden email]> Sent: Thursday, June 26, 2003 2:54 PM Subject: [SHADO] Responce to Dave that Yahoo bounced for no reason >>>>>>>>>>> > > > How would you "Trim" Sky? Are you suggesting that Sky has its own ballast tanks, as well as pumps to move the water in and out of the system? Where are these tanks located, and what do you do if you can't trim the plane to "neutral"? -------------------------------------------------- As I said, the same way you trim the sub. And no, you don't need much, or any really, of the mechanisms inside the plane itself. To save flight weight, you simply run lines from the sub's ballasting managment plumbing through a disconnector to the air chambers within Sky. Simple chambers inside the body of Sky can be anything from using already existing voids formed by structural members, like wing boxes, spaces between the stringers and longerons in the wings and body, honeycombed structures etc, to simple plastic bladders attatched to available interior spaces at appropriate locations near the CG. Bladders can contain air, need not be pressure resistant, plastic is salt water immune, and can weigh very little. I doubt there would be any reason you could not ballast Sky to be neutral. You can ballast ships to float, cars to sink, and huge submarines to do anything you want them to....you can ballast Sky to be neutral. Whenever an airplane or a helicopter ditches in the ocean, or a car goes off a bridge, it first floats until the air leaks out enough for it to sink. I would expect Sky to be no different, you're just managing the bouyancy. --------------------------------------------- > > I don't see how, or why for that matter, you would want to put ballast tanks in Sky. You suggested earlier that there were "Simple chambers in Sky" (June 7th, 03, 1941 Hours), but I don't see how this would help things. > > > I don't see how you could make it "Weightless", and besides that, the very presence of Sky affects how Diver operates. Diver is designed to be part of a whole, even though it can work independently at reduced efficiency. > ------------------------------------------------- If you can make a submarine weightless, there is no reason you cannot make an airplane weightless underwater. They are both just hunks of metal in the final analysis. It is simple physics. ------------------------------------------------- > Diver loses whatever streamlining it had when Sky separates, as well as a major (Possible) source of control surfaces. (See below) -------------------------------------------------- True, SkyDiver's handling characteristics would change as a result of losing the shaped nose of the plane, but I'd assume the ship's designers would have accounted for all that. That has no effect on the neutral bouyancy thing however. Intersting point about the tail and wings of the plane effecting the subs motion underwater. The wings would tend to apply a nose-up moment to the sub when in motion. Just like anything else, I would suspect the designers would incorporate that, or nullify it when attached to the sub. -------------------------------------------- > > Even if Sky was weightless, its being there, as well as its absence would affect the operations of Diver in a number of various ways. Speed would be reduced from the increased drag, even as the ship noise level would double or triple due to the increased drag, as well as the increased power needed to compensate for that drag. > > --------------------------------------------- Yeah, well life's a bitch! Thats why engineers get paid the big bucks to deal with stuff like that .... :-) Perhaps some low profile leading edge devices could be employed on the front of the sub to smooth things out while the plane is away. Perhaps small dive planes could counter wing lift when the plane IS there. Maybe Skydiver cruises with a small negative angle of attack due to the wings, which the designers simply consider too trivial and unimportant to design away. Look at the way ordinance and drop tanks are mounted on fighterplanes, especially some swing wing types. Some minor things can just be ignored under some circumstances. --------------------------------------------- > > > Considering that there are only five or six people on board Diver at any one time, I don't think you need to worry about their activities. Fuel for Sky, on the other hand, is a whole new ball game. -------------------------------------------- Personally, I've always liked to think of Skydiver as being a large craft, with perhaps 30 crew on board. This allows for two 12 hour crew shifts, medical officers and other specialists, & two shift pilots, for extended duration deployments.... but that's just me.... -------------------------------------------- > > Just where doe Sky carry its fuel? Are the fuel cells in the main body or the wings? Or maybe even both of them. Just how much fuel does it need for a "Standard" mission? How much extra fuel is carried on board? Where are the tanks located in Diver? > --------------------------------------------- Grab a CAD and decide for yourself! Typical design philosophy makes use of all of those options. My design of fuel tanks on a plane meant to descent to the depths of the ocean would be opened ended chute boxes, opened to the sea water. Inside these are held long sausage shaped flexible fuel bladders. That way the sea pressure doesn't stress your fuel tanks. The fuel itself maintains equilibrium with the suurounding sea pressure, much like a diver's body fluid balances out the pressure on a scuba dive. The long narrow chutes prevent fuel lateral weight transfer from sloshing and flight attitude changes. As for how much fuel in a typical mission, You'd have to do an analysis for that one - do an aircraft sizing and a weight determination, aerodynamic analysis, get all your performance and drag data together, determine a typical mission profile, and crunch the numbers. Typically this takes a lot of time and money. Dave H. ---------------------------------------- |
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