Franklin
07-01-2005, 11:15 AM
http://www.hydrofoil.com/whyhydrofoil.htm
http://www.hydrofoil.com/reference.htm
http://www.hydrofoil.com/gallery.htm
http://www.hydrofoil.com/reference.htm
http://www.hydrofoil.com/gallery.htm
View Full Version : Is a supersonic boat possible?
Sketch
07-01-2005, 03:32 PM
How low can you safely fly a plane?
The speed of sound at sea level is 340.29 m/s. That is about eight times faster than the fastest hydrofoil. Supersonic flight is an engineering marvel, a topic on which other members can speak much more knowledgeably than me. Considering that that water is 784 times more dense than air, why would you want to dip an appendage into such a medium if the goal is speed? For stability perhaps? Look what happens when you go to the rolling heap for stability at 60 mph (see above websites).
Is it possible? I am always the optimist, but why? The forces acting on such an appendage(s) at supersonic speed would be huge, with resultant drag penalties. Of course there is also cavitation to consider. I'm curious, what happens if any solid is moved through water at supersonic speed? How long will it take to dissolve :D ?
The speed of sound at sea level is 340.29 m/s. That is about eight times faster than the fastest hydrofoil. Supersonic flight is an engineering marvel, a topic on which other members can speak much more knowledgeably than me. Considering that that water is 784 times more dense than air, why would you want to dip an appendage into such a medium if the goal is speed? For stability perhaps? Look what happens when you go to the rolling heap for stability at 60 mph (see above websites).
Is it possible? I am always the optimist, but why? The forces acting on such an appendage(s) at supersonic speed would be huge, with resultant drag penalties. Of course there is also cavitation to consider. I'm curious, what happens if any solid is moved through water at supersonic speed? How long will it take to dissolve :D ?
RANCHI OTTO
07-01-2005, 05:58 PM
Yes...but only if God will permit it.....!
Ranchi Otto
Ranchi Otto
markdrela
07-01-2005, 06:16 PM
Is a supersonic boat possible?
To allow a meaningful answer, you will first have to define what constitutes a "boat". How about if I take an F-15, and fly very low while dangling a piece of wire in the water? Is that a boat?
This is not a silly question. This very issue came up when Doug Milliken was commissioned to write the rules for the DuPont Human-Powered Watercraft Speed Prize, in the late 1980's. It was pretty clear that the fastest way to traverse the speed course would be in a human-powered airplane. To rule this out, he considered all sorts of "boat" definitions. Merely requiring contact with the water was not sufficient, because of the airplane with trailing wire solution. In the end he decided that the boat had to derive a majority of its lift and control forces from the water. Propulsion was left unspecified.
This definition worked well for a human-powered boat, but it probably wouldn't be an enforcable for an extremely fast boat. Saying "no air lift" would probably disqualify most current hydroplane boats. How can you prove that air isn't providing a significant amount of lift to the vehicle? Ditto with air fins providing stability and control.
To allow a meaningful answer, you will first have to define what constitutes a "boat". How about if I take an F-15, and fly very low while dangling a piece of wire in the water? Is that a boat?
This is not a silly question. This very issue came up when Doug Milliken was commissioned to write the rules for the DuPont Human-Powered Watercraft Speed Prize, in the late 1980's. It was pretty clear that the fastest way to traverse the speed course would be in a human-powered airplane. To rule this out, he considered all sorts of "boat" definitions. Merely requiring contact with the water was not sufficient, because of the airplane with trailing wire solution. In the end he decided that the boat had to derive a majority of its lift and control forces from the water. Propulsion was left unspecified.
This definition worked well for a human-powered boat, but it probably wouldn't be an enforcable for an extremely fast boat. Saying "no air lift" would probably disqualify most current hydroplane boats. How can you prove that air isn't providing a significant amount of lift to the vehicle? Ditto with air fins providing stability and control.
Franklin
07-02-2005, 10:28 AM
To allow a meaningful answer, you will first have to define what constitutes a "boat". How about if I take an F-15, and fly very low while dangling a piece of wire in the water? Is that a boat?
This is not a silly question. This very issue came up when Doug Milliken was commissioned to write the rules for the DuPont Human-Powered Watercraft Speed Prize, in the late 1980's. It was pretty clear that the fastest way to traverse the speed course would be in a human-powered airplane. To rule this out, he considered all sorts of "boat" definitions. Merely requiring contact with the water was not sufficient, because of the airplane with trailing wire solution. In the end he decided that the boat had to derive a majority of its lift and control forces from the water. Propulsion was left unspecified.
This definition worked well for a human-powered boat, but it probably wouldn't be an enforcable for an extremely fast boat. Saying "no air lift" would probably disqualify most current hydroplane boats. How can you prove that air isn't providing a significant amount of lift to the vehicle? Ditto with air fins providing stability and control.
http://www.lesliefield.com/other_history/alexander_graham_bell_and_the_hydrofoils.htm
http://www.lesliefield.com/images/alexander_graham_bell_hd4_1919.jpg
Hydrofoil boats have been around for something close to 100 years.
Casey Baldwin (working with Alexander Graham Bell) set a World Water Speed Record of 70 mph with one in 1918.
http://www.foils.org/racers.htm
http://www.foils.org/US-3%20Hydrofoil.jpg
This is not a silly question. This very issue came up when Doug Milliken was commissioned to write the rules for the DuPont Human-Powered Watercraft Speed Prize, in the late 1980's. It was pretty clear that the fastest way to traverse the speed course would be in a human-powered airplane. To rule this out, he considered all sorts of "boat" definitions. Merely requiring contact with the water was not sufficient, because of the airplane with trailing wire solution. In the end he decided that the boat had to derive a majority of its lift and control forces from the water. Propulsion was left unspecified.
This definition worked well for a human-powered boat, but it probably wouldn't be an enforcable for an extremely fast boat. Saying "no air lift" would probably disqualify most current hydroplane boats. How can you prove that air isn't providing a significant amount of lift to the vehicle? Ditto with air fins providing stability and control.
http://www.lesliefield.com/other_history/alexander_graham_bell_and_the_hydrofoils.htm
http://www.lesliefield.com/images/alexander_graham_bell_hd4_1919.jpg
Hydrofoil boats have been around for something close to 100 years.
Casey Baldwin (working with Alexander Graham Bell) set a World Water Speed Record of 70 mph with one in 1918.
http://www.foils.org/racers.htm
http://www.foils.org/US-3%20Hydrofoil.jpg
Franklin
07-02-2005, 10:29 AM
How low can you safely fly a plane?
The speed of sound at sea level is 340.29 m/s. That is about eight times faster than the fastest hydrofoil. Supersonic flight is an engineering marvel, a topic on which other members can speak much more knowledgeably than me. Considering that that water is 784 times more dense than air, why would you want to dip an appendage into such a medium if the goal is speed? For stability perhaps? Look what happens when you go to the rolling heap for stability at 60 mph (see above websites).
Is it possible? I am always the optimist, but why? The forces acting on such an appendage(s) at supersonic speed would be huge, with resultant drag penalties. Of course there is also cavitation to consider. I'm curious, what happens if any solid is moved through water at supersonic speed? How long will it take to dissolve :D ?
The goal would be a World WATER Speed Record.
The speed of sound at sea level is 340.29 m/s. That is about eight times faster than the fastest hydrofoil. Supersonic flight is an engineering marvel, a topic on which other members can speak much more knowledgeably than me. Considering that that water is 784 times more dense than air, why would you want to dip an appendage into such a medium if the goal is speed? For stability perhaps? Look what happens when you go to the rolling heap for stability at 60 mph (see above websites).
Is it possible? I am always the optimist, but why? The forces acting on such an appendage(s) at supersonic speed would be huge, with resultant drag penalties. Of course there is also cavitation to consider. I'm curious, what happens if any solid is moved through water at supersonic speed? How long will it take to dissolve :D ?
The goal would be a World WATER Speed Record.
BillyDoc
07-02-2005, 01:47 PM
The speed of sound in sea water is 1,531 meters/sec. So there's lots of "room" between current records and "supersonic."
Didn't Russia develop some very fast torpedoes? How fast are they?
Didn't Russia develop some very fast torpedoes? How fast are they?
gonzo
07-02-2005, 06:23 PM
The problem is wave making resistance plus the compression of the sound waves the vessel would be overcoming. On the land speed record, a supersonic car went out of control because the shock wave was making holes in the track and violently shaking it.
mackid068
07-02-2005, 09:28 PM
Silly question, but it is possible, perhaps a WIG (wing in ground vehicle?) http://www.4p8.com/eric.brasseur/swlbi.html (This website's writer says that it is possible to avoid shockwaves!)
Sean Herron
07-03-2005, 07:02 PM
Hello...
I have a supersonic boat in my garage just now...
Come on over - and I will show it to you and my vodka still as well...
If I like you - we can get into the sauce and talk about our Martian brothers who await the day that we choose to plug ourselves back into the grid...
Sure.... :)
SH.
I have a supersonic boat in my garage just now...
Come on over - and I will show it to you and my vodka still as well...
If I like you - we can get into the sauce and talk about our Martian brothers who await the day that we choose to plug ourselves back into the grid...
Sure.... :)
SH.
tspeer
07-03-2005, 09:08 PM
Silly question, but it is possible, perhaps a WIG (wing in ground vehicle?) http://www.4p8.com/eric.brasseur/swlbi.html (This website's writer says that it is possible to avoid shockwaves!)
What he's described is essentially the Buseman biplane. Unfortunately, he forgot about wave drag due to lift and only considered the effects of thickness.
The USAF Flight Dynamics Laboratory (now a division of Wright Laboratories) did some work on a supersonic parasol design in which the wing was mounted on a tall strut from the fuselage and wraped down and back in a continuous curve toward the tips. It was designed to intercept the bow shock from the fuselage.
Wave riders are another type of design that use these effects. The original waverider concept had a cross section like an inverted chevron and wedge-shaped buttlines. It traps a shock wave underneath between its highly swept leading edges. The top surface was designed to allow the flow to go straight past. The simplest way to design a waverider is to compute the theoretical flowfield for a virtual wedge or axisymmetric shape, and then trace out the streamlines for the flow that intercepts a portion of the resulting shock wave. Hypersonic vehicles like the X-43 (http://www.nasa.gov/centers/dryden/research/X43/) also use a similar concept, with the whole underside of the forebody forming the compression ramp for the inlet and the underside of the aft fuselage being the exhaust nozzle.
The XB-70 had outer wing panels that drooped down for high speed flight to turn it into a waverider-like configuration. They called the effect "compression lift".
I think the most likely design for a supersonic watercraft would be something like a waverider with very narrow sidewalls in contact with the water. The acceleration from any kind of waves would be very high if it had much waterplane area at all. To have stable pitch-heave coupling, the waterplane area would have to be ahead of the center of gravity and the aft end would be supported aerodynamically. The problem isn't providing enough lift, of course, it's avoiding having too much. It may be designed to actually provide a steady down-force to maintain contact with the water under the expected dynamic variations.
What he's described is essentially the Buseman biplane. Unfortunately, he forgot about wave drag due to lift and only considered the effects of thickness.
The USAF Flight Dynamics Laboratory (now a division of Wright Laboratories) did some work on a supersonic parasol design in which the wing was mounted on a tall strut from the fuselage and wraped down and back in a continuous curve toward the tips. It was designed to intercept the bow shock from the fuselage.
Wave riders are another type of design that use these effects. The original waverider concept had a cross section like an inverted chevron and wedge-shaped buttlines. It traps a shock wave underneath between its highly swept leading edges. The top surface was designed to allow the flow to go straight past. The simplest way to design a waverider is to compute the theoretical flowfield for a virtual wedge or axisymmetric shape, and then trace out the streamlines for the flow that intercepts a portion of the resulting shock wave. Hypersonic vehicles like the X-43 (http://www.nasa.gov/centers/dryden/research/X43/) also use a similar concept, with the whole underside of the forebody forming the compression ramp for the inlet and the underside of the aft fuselage being the exhaust nozzle.
The XB-70 had outer wing panels that drooped down for high speed flight to turn it into a waverider-like configuration. They called the effect "compression lift".
I think the most likely design for a supersonic watercraft would be something like a waverider with very narrow sidewalls in contact with the water. The acceleration from any kind of waves would be very high if it had much waterplane area at all. To have stable pitch-heave coupling, the waterplane area would have to be ahead of the center of gravity and the aft end would be supported aerodynamically. The problem isn't providing enough lift, of course, it's avoiding having too much. It may be designed to actually provide a steady down-force to maintain contact with the water under the expected dynamic variations.
mackid068
07-03-2005, 10:22 PM
I had absolutely no idea, I just posted some website that I didn't even read :D But anyway, let's just say that, for now, it's impossible. Perfect conditions with a flat bottom boat powered by a few jet engines, maybe.
Sketch
07-04-2005, 07:31 AM
The speed of sound in sea water is 1,531 meters/sec. So there's lots of "room" between current records and "supersonic."
The speed of sound in air at sea level is 340.29 m/s or 761 mph. I thought this would be a more appropriate measure for a supersonic boat as most of it will be above water - a supersonic submarine is a whole 'nother can of worms ;) (1531 m/s is over 3000 mph!)
And yes, I was thinking of a water speed record - "How low can you safely fly a plane" was a facetious remark. I'll use more smilies next time :rolleyes:
Kevin Barry
The speed of sound in air at sea level is 340.29 m/s or 761 mph. I thought this would be a more appropriate measure for a supersonic boat as most of it will be above water - a supersonic submarine is a whole 'nother can of worms ;) (1531 m/s is over 3000 mph!)
And yes, I was thinking of a water speed record - "How low can you safely fly a plane" was a facetious remark. I'll use more smilies next time :rolleyes:
Kevin Barry
mackid068
07-04-2005, 06:58 PM
An unmanned submarine is possible, a high-output nuclear reactor powering a vessel using jet drive, no radiation shielding or weapons, just a computer, reactor and drive.
gonzo
07-05-2005, 02:39 AM
However, a submarine is not a boat so it doesn't qualify.
Franklin
07-05-2005, 10:40 AM
The problem is wave making resistance plus the compression of the sound waves the vessel would be overcoming. On the land speed record, a supersonic car went out of control because the shock wave was making holes in the track and violently shaking it.
Didn't happen.
The only car to go supersonic made four successful supersonic runs.
Didn't happen.
The only car to go supersonic made four successful supersonic runs.
Franklin
07-05-2005, 10:49 AM
What he's described is essentially the Buseman biplane. Unfortunately, he forgot about wave drag due to lift and only considered the effects of thickness.
The USAF Flight Dynamics Laboratory (now a division of Wright Laboratories) did some work on a supersonic parasol design in which the wing was mounted on a tall strut from the fuselage and wraped down and back in a continuous curve toward the tips. It was designed to intercept the bow shock from the fuselage.
Wave riders are another type of design that use these effects. The original waverider concept had a cross section like an inverted chevron and wedge-shaped buttlines. It traps a shock wave underneath between its highly swept leading edges. The top surface was designed to allow the flow to go straight past. The simplest way to design a waverider is to compute the theoretical flowfield for a virtual wedge or axisymmetric shape, and then trace out the streamlines for the flow that intercepts a portion of the resulting shock wave. Hypersonic vehicles like the X-43 (http://www.nasa.gov/centers/dryden/research/X43/) also use a similar concept, with the whole underside of the forebody forming the compression ramp for the inlet and the underside of the aft fuselage being the exhaust nozzle.
The XB-70 had outer wing panels that drooped down for high speed flight to turn it into a waverider-like configuration. They called the effect "compression lift".
I think the most likely design for a supersonic watercraft would be something like a waverider with very narrow sidewalls in contact with the water. The acceleration from any kind of waves would be very high if it had much waterplane area at all. To have stable pitch-heave coupling, the waterplane area would have to be ahead of the center of gravity and the aft end would be supported aerodynamically. The problem isn't providing enough lift, of course, it's avoiding having too much. It may be designed to actually provide a steady down-force to maintain contact with the water under the expected dynamic variations.
A WIG/Waverider using supercavitating appendages to augment control and stability could be worth considering.
http://www.deepangel.com/html/the_squall.html
The USAF Flight Dynamics Laboratory (now a division of Wright Laboratories) did some work on a supersonic parasol design in which the wing was mounted on a tall strut from the fuselage and wraped down and back in a continuous curve toward the tips. It was designed to intercept the bow shock from the fuselage.
Wave riders are another type of design that use these effects. The original waverider concept had a cross section like an inverted chevron and wedge-shaped buttlines. It traps a shock wave underneath between its highly swept leading edges. The top surface was designed to allow the flow to go straight past. The simplest way to design a waverider is to compute the theoretical flowfield for a virtual wedge or axisymmetric shape, and then trace out the streamlines for the flow that intercepts a portion of the resulting shock wave. Hypersonic vehicles like the X-43 (http://www.nasa.gov/centers/dryden/research/X43/) also use a similar concept, with the whole underside of the forebody forming the compression ramp for the inlet and the underside of the aft fuselage being the exhaust nozzle.
The XB-70 had outer wing panels that drooped down for high speed flight to turn it into a waverider-like configuration. They called the effect "compression lift".
I think the most likely design for a supersonic watercraft would be something like a waverider with very narrow sidewalls in contact with the water. The acceleration from any kind of waves would be very high if it had much waterplane area at all. To have stable pitch-heave coupling, the waterplane area would have to be ahead of the center of gravity and the aft end would be supported aerodynamically. The problem isn't providing enough lift, of course, it's avoiding having too much. It may be designed to actually provide a steady down-force to maintain contact with the water under the expected dynamic variations.
A WIG/Waverider using supercavitating appendages to augment control and stability could be worth considering.
http://www.deepangel.com/html/the_squall.html
dougfrolich
07-05-2005, 11:42 AM
The major problem using supercavitating appendages on a surface craft is the penetration of the gas envelope made by the conection between the apendage and the craft on or near the surface. The whole idea of a supercavitating "torpedo" is that it envelops itself in a self made vapour "bubble". If vapour envelope is penetrated I think that it would probably collapse, or never develop, causing a "sticky" situation.
Franklin
07-05-2005, 11:46 AM
The major problem using supercavitating appendages on a surface craft is the penetration of the gas envelope made by the conection between the apendage and the craft on or near the surface. The whole idea of a supercavitating "torpedo" is that it envelops itself in a self made vapour "bubble". If vapour envelope is penetrated I think that it would probably collapse, or never develop, causing a "sticky" situation.
http://www.ctechdefense.com/speed.html
2509 West 19th Street, Port Angeles, WA 98363
PHONE (360) 452-2275 * FAX (360) 452-2297 * info@ctech.esdcorp.com
Underwater Speed Limits
(Following is the full text submitted to Scientific American. The published version was shortened for editorial reasons.)
"There appear to be two conceptual ways of approaching supercavitation. The generally accepted one derives from propeller cavitation theory and holds that the water is essentially boiled by dropping its pressure via abrupt acceleration. This creates a source of gaseous water vapor which creates the cavitation bubble. It is generally assumed that the cavitation bubble is filled with this water vapor. Indeed, in low speed (say torpedoes) supercavitation applications the cavity size is usually enhanced with ventilation gases. This fits well with the understanding that gas creates the bubble in the first place and appears to work well within that context. It also fits comfortably in the general framework of marine engineering.
Last September, at an ONR sponsored Supercavitation Conference, Dr. Kirschner (of Anteon Corporation) and I were discussing the idea of a theoretical speed limit for supercavitating objects, assuming material strength issues could be overcome. As previously mentioned, conventional wisdom holds that the cavity is created by the water vapor and therefore, at some speed, the volumetric rate at which vapor can be generated will become insufficient to support the formation of a cavitation bubble which will clear the body. In other words, at some velocity the rate at which the water boils will become insufficient to fill the volume of the "hole" in the water created by the passage of the projectile and the cavity will collapse.
For whatever reason, I have a different mental picture of how the bubble is created, perhaps due to my background in hypersonics in graduate school. In that field discontinuities and rarified flows are encountered in the course of normal business. I do not know if anyone else shares this view but Dr. Kirschner and I have discussed it at some length. In any case, I believe the process is fundamentally one of momentum transfer. The cavitator, be it a disk or cone or whatever, imparts a significant radial velocity (relative to the axis of flight) to the water it comes in contact with. In effect the water is thrown violently to the side. It therefore has a high radial momentum that is resisted by the pressure of the water around it. This pressure serves to slow its radial velocity and will bring it to a stop over a finite time. The accepted definition of cavitation number is compatible with this idea. In the meantime, assuming a circularly symmetric cavitator, a round "hole" has been created in the water. What is in this hole, other than the projectile? I believe it is a vacuum, at least initially. Of course the water on the interior face of the bubble begins to boil, but it can only boil so fast, even in a hard vacuum. At slow velocities the rate of boiling can create a fairly decent partial pressure of water vapor in the cavity. In the limit case, as velocity increases, the pressure inside the cavity in the vicinity of the projectile will go to zero. Eventually the pressure acting on the water will reverse its radial velocity and cause the cavity to close. However, the projectile will be long gone by that point. If this approach is correct then, except for finding a material to withstand the steady state stagnation pressure, there may be no hydrodynamic upper limit to the velocity of a supercavitating body.
In any case, perhaps there is room for both viewpoints. In fact, they may very well be opposite sides of the same theoretical coin. I would certainly be interested to know what other people in the field thought of this approach. Perhaps it would provide an interesting topic of discussion within the article?"
http://www.ctechdefense.com/speed.html
2509 West 19th Street, Port Angeles, WA 98363
PHONE (360) 452-2275 * FAX (360) 452-2297 * info@ctech.esdcorp.com
Underwater Speed Limits
(Following is the full text submitted to Scientific American. The published version was shortened for editorial reasons.)
"There appear to be two conceptual ways of approaching supercavitation. The generally accepted one derives from propeller cavitation theory and holds that the water is essentially boiled by dropping its pressure via abrupt acceleration. This creates a source of gaseous water vapor which creates the cavitation bubble. It is generally assumed that the cavitation bubble is filled with this water vapor. Indeed, in low speed (say torpedoes) supercavitation applications the cavity size is usually enhanced with ventilation gases. This fits well with the understanding that gas creates the bubble in the first place and appears to work well within that context. It also fits comfortably in the general framework of marine engineering.
Last September, at an ONR sponsored Supercavitation Conference, Dr. Kirschner (of Anteon Corporation) and I were discussing the idea of a theoretical speed limit for supercavitating objects, assuming material strength issues could be overcome. As previously mentioned, conventional wisdom holds that the cavity is created by the water vapor and therefore, at some speed, the volumetric rate at which vapor can be generated will become insufficient to support the formation of a cavitation bubble which will clear the body. In other words, at some velocity the rate at which the water boils will become insufficient to fill the volume of the "hole" in the water created by the passage of the projectile and the cavity will collapse.
For whatever reason, I have a different mental picture of how the bubble is created, perhaps due to my background in hypersonics in graduate school. In that field discontinuities and rarified flows are encountered in the course of normal business. I do not know if anyone else shares this view but Dr. Kirschner and I have discussed it at some length. In any case, I believe the process is fundamentally one of momentum transfer. The cavitator, be it a disk or cone or whatever, imparts a significant radial velocity (relative to the axis of flight) to the water it comes in contact with. In effect the water is thrown violently to the side. It therefore has a high radial momentum that is resisted by the pressure of the water around it. This pressure serves to slow its radial velocity and will bring it to a stop over a finite time. The accepted definition of cavitation number is compatible with this idea. In the meantime, assuming a circularly symmetric cavitator, a round "hole" has been created in the water. What is in this hole, other than the projectile? I believe it is a vacuum, at least initially. Of course the water on the interior face of the bubble begins to boil, but it can only boil so fast, even in a hard vacuum. At slow velocities the rate of boiling can create a fairly decent partial pressure of water vapor in the cavity. In the limit case, as velocity increases, the pressure inside the cavity in the vicinity of the projectile will go to zero. Eventually the pressure acting on the water will reverse its radial velocity and cause the cavity to close. However, the projectile will be long gone by that point. If this approach is correct then, except for finding a material to withstand the steady state stagnation pressure, there may be no hydrodynamic upper limit to the velocity of a supercavitating body.
In any case, perhaps there is room for both viewpoints. In fact, they may very well be opposite sides of the same theoretical coin. I would certainly be interested to know what other people in the field thought of this approach. Perhaps it would provide an interesting topic of discussion within the article?"
dougfrolich
07-05-2005, 12:11 PM
These pics. show that is is possible to exceed the speed of sound underwater, The projectile is traveling at 1,549 m/s. I still have a problem understanding how a connection could be made to the "free surface" without creating a very unsteady mess.
Franklin
07-05-2005, 12:20 PM
These pics. show that is is possible to exceed the speed of sound underwater, The projectile is traveling at 1,549 m/s. I still have a problem understanding how a connection could be made to the "free surface" without creating a very unsteady mess.
For one thing, it's not like a balloon or soap bubble where if you pierce it it's going to pop.
For one thing, it's not like a balloon or soap bubble where if you pierce it it's going to pop.
gonzo
07-05-2005, 06:41 PM
Franklin: read the history of the supersonic car and the problems they had to deal with. The solution to the instability was a front spoiler.
chandler
07-05-2005, 07:06 PM
What's the point???
gonzo
07-05-2005, 07:22 PM
The point is to do your homework before critizicing others.
Franklin
07-06-2005, 10:29 AM
Franklin: read the history of the supersonic car and the problems they had to deal with. The solution to the instability was a front spoiler.
www.thrustssc.com
I was an acquaintance of Richard Noble's before he even set his 633 mph in 1983 and met him at the Bonneville salt flats in 1990 when he came to observe Art Arfons attempt on the land speed record. At that point, Noble was pursuing a boat for the transatlantic speed record and didn't even have firm plans for a supersonic car.
The key technology to making Thrust SSC work was an active suspension sytem that allowed the car's ground clearance and angle of attack to be changed on the fly.
www.thrustssc.com
I was an acquaintance of Richard Noble's before he even set his 633 mph in 1983 and met him at the Bonneville salt flats in 1990 when he came to observe Art Arfons attempt on the land speed record. At that point, Noble was pursuing a boat for the transatlantic speed record and didn't even have firm plans for a supersonic car.
The key technology to making Thrust SSC work was an active suspension sytem that allowed the car's ground clearance and angle of attack to be changed on the fly.
yipster
07-06-2005, 01:06 PM
the scientific american article above i seen before in another thread i replied on right?
The only car to go supersonic made four successful supersonic runs.
great to be acquainted with Richard Noble and have tasted the salt Franklin!
and without taking any credit from his fantastice achievement i do like to mention, who was it? Breedlove, Arfons, i dont recall, anyway that supersonic speed was run before by another / others, just not official or both ways in time or something...
are there any plans for a supersonic boat? than whats a boat dito and totally insane i call it ahead of hearing, but hey, someone is gonna do it sooner or later i guess ;)
The only car to go supersonic made four successful supersonic runs.
great to be acquainted with Richard Noble and have tasted the salt Franklin!
and without taking any credit from his fantastice achievement i do like to mention, who was it? Breedlove, Arfons, i dont recall, anyway that supersonic speed was run before by another / others, just not official or both ways in time or something...
are there any plans for a supersonic boat? than whats a boat dito and totally insane i call it ahead of hearing, but hey, someone is gonna do it sooner or later i guess ;)
Franklin
07-06-2005, 01:22 PM
the scientific american article above i seen before in another thread i replied on right?
great to be acquainted with Richard Noble and have tasted the salt Franklin!
and without taking any credit from his fantastice achievement i do like to mention, who was it? Breedlove, Arfons, i dont recall, anyway that supersonic speed was run before by another / others, just not official or both ways in time or something...
are there any plans for a supersonic boat? than whats a boat dito and totally insane i call it ahead of hearing, but hey, someone is gonna do it sooner or later i guess ;)
Nobody went supersonic before Andy Green in Noble's Thrust SSC car.
great to be acquainted with Richard Noble and have tasted the salt Franklin!
and without taking any credit from his fantastice achievement i do like to mention, who was it? Breedlove, Arfons, i dont recall, anyway that supersonic speed was run before by another / others, just not official or both ways in time or something...
are there any plans for a supersonic boat? than whats a boat dito and totally insane i call it ahead of hearing, but hey, someone is gonna do it sooner or later i guess ;)
Nobody went supersonic before Andy Green in Noble's Thrust SSC car.
glwanabe
07-06-2005, 03:14 PM
Somewhere in Louisiana, RIGHT NOW, there are a couple of Cajuns with a 14' johnboat, and there mounting a surplus f-4 phantom engine on it. Oh, and there are a lot of empty beer cans around. Last one still standing gets to ride it. That's all I got to say about that, gotta go, mama just put a fresh bowl of possum stew out.
Sean Herron
07-06-2005, 03:16 PM
Hello...
Here 'ya go...
But seriously - when my alien brothers were having a go at servicing my plugins - they mentioned something torpedo like - something like shark-skin scales - smallish blades on large diameter contra-rotating rings which ran along the length of the vehicle - something about operation within a non laminar layer...
Then I woke up with wet sheets and found this picture... :)
SH.
Here 'ya go...
But seriously - when my alien brothers were having a go at servicing my plugins - they mentioned something torpedo like - something like shark-skin scales - smallish blades on large diameter contra-rotating rings which ran along the length of the vehicle - something about operation within a non laminar layer...
Then I woke up with wet sheets and found this picture... :)
SH.
Sketch
07-06-2005, 03:35 PM
This discussion has made me laugh and smile more than once. Seriously though, a boat goes through air and water. While the definition of "boat" might be taxed, I'd be curious to see a vessle that can travel over the surface of the sea at supersonic speed. This inspiration is largely due to this discussion. Option 3 perhaps?
Kevin Barry
Kevin Barry
dougfrolich
07-06-2005, 03:51 PM
strap a russian supercavitating torpedo to one of these things, and bobs your uncle.
SailDesign
07-06-2005, 05:04 PM
How's about we define "boat" (for the purposes of this discussion) as a vehicle that moves over the surface of the water, with some fixed rigid part of it in contact with the surface, nocloser to the end of the body than 10% of LOA. i.e. the rigid, fixed part must be within the main body of the vehicle, not trailing behind it.
Steve
PS - the simple answer to the question originally posed must be "Yes". It is just that no-one has figured it out yet, but a s/s boat IS possible...
Steve
PS - the simple answer to the question originally posed must be "Yes". It is just that no-one has figured it out yet, but a s/s boat IS possible...
mackid068
07-06-2005, 07:09 PM
It's definately possible, eventually, at least.
dougfrolich
07-06-2005, 07:16 PM
Sean,
Perfect! I have an old 1.5Kw radar--now what did I do with those scram jets?...
Perfect! I have an old 1.5Kw radar--now what did I do with those scram jets?...
cyclops
07-06-2005, 09:37 PM
As I recall, Bluebirds last speed attempt was a crash because he probably crossed a small wavelet from his first run. Drives, controls, hull shape and power would have to look like a cross between the jet cars and jet fighters. Since the cars are not powered by the wheels, all water propulsion is off also. Lip Service as to calling it a boat.
marshmat
07-06-2005, 10:08 PM
I am aware of only one watercraft to ever exceed the speed of sound. Built by Convair and first flown on May 9, 1953, the XF2Y Sea Dart had a V-hull, delta wing, and twin waterski-like hydroplanes that extended from the bow/nose for takeoff and retracted once clear of the surface. Power was twin J46 turbojets (6000# each). The craft could reach 695mph at 8,000 feet altitude. On water, the beast was a pilot's hell to handle and vibrated like a jackhammer in waves higher than two inches. To the best of my knowledge, no other watercraft of any sort has approached this speed. (And yes, folks, the XF2Y is technically an airplane, although it behaves as a conventional boat below about 50 knots.)
Now, to reach that speed while in contact with the water....
Well, the obvious solution is to dangle a rope off the back of a Super Hornet or something like that. I think that counts as cheating. So we go with a boat shape for the bottom and airplane shape on top, but since only about 2" of hull could possibly touch the water at this speed, it's mostly about aerodynamics. And power. A helluva lot of power. Stick an afterburning M88 or F100 jet engine in it, either has enough power to toss a 9-ton boat directly upwards about 50,000 feet. We make the boat strong and rigid (read -> heavy) to take the incredibly huge loads, and shock-mount the cabin, 'cause this brute will vibrate like crazy upon hitting the wake of a muskrat. Now we add 40 bottles of Alberta Rye Whiskey, and have the crew draw straws. Short straw drives...
Oh, so you want to go supersonic in water? Now there's something. A kilometre-and-a-third per second. We can only just do that in air right now, and that's only with spacecraft and missiles, up at flight level 800 where there's almost no air anyway. So we fire a rocket-propelled missile straight into the lake from far enough back for it to accelerate up to speed.... oh, whoops, at velocities over a few hundred km/h, water is as rigid and unyielding as granite.
We routinely cut 2-inch steel plates with water jets at the speeds we're talking about here. For some reason, I don't think a supersonic boat will ever be practical. Possible, maybe- and some nutbar will try- but it's not something that is likely to work too well.
Now, to reach that speed while in contact with the water....
Well, the obvious solution is to dangle a rope off the back of a Super Hornet or something like that. I think that counts as cheating. So we go with a boat shape for the bottom and airplane shape on top, but since only about 2" of hull could possibly touch the water at this speed, it's mostly about aerodynamics. And power. A helluva lot of power. Stick an afterburning M88 or F100 jet engine in it, either has enough power to toss a 9-ton boat directly upwards about 50,000 feet. We make the boat strong and rigid (read -> heavy) to take the incredibly huge loads, and shock-mount the cabin, 'cause this brute will vibrate like crazy upon hitting the wake of a muskrat. Now we add 40 bottles of Alberta Rye Whiskey, and have the crew draw straws. Short straw drives...
Oh, so you want to go supersonic in water? Now there's something. A kilometre-and-a-third per second. We can only just do that in air right now, and that's only with spacecraft and missiles, up at flight level 800 where there's almost no air anyway. So we fire a rocket-propelled missile straight into the lake from far enough back for it to accelerate up to speed.... oh, whoops, at velocities over a few hundred km/h, water is as rigid and unyielding as granite.
We routinely cut 2-inch steel plates with water jets at the speeds we're talking about here. For some reason, I don't think a supersonic boat will ever be practical. Possible, maybe- and some nutbar will try- but it's not something that is likely to work too well.
Franklin
07-07-2005, 10:17 AM
As I recall, Bluebirds last speed attempt was a crash because he probably crossed a small wavelet from his first run. Drives, controls, hull shape and power would have to look like a cross between the jet cars and jet fighters. Since the cars are not powered by the wheels, all water propulsion is off also. Lip Service as to calling it a boat.
A LOT of factors were involved in the Bluebird crash.
http://www.users.myisp.co.uk/~climengs/bluebird/coniston.htm
A LOT of factors were involved in the Bluebird crash.
http://www.users.myisp.co.uk/~climengs/bluebird/coniston.htm
Franklin
07-07-2005, 10:20 AM
I am aware of only one watercraft to ever exceed the speed of sound. Built by Convair and first flown on May 9, 1953, the XF2Y Sea Dart had a V-hull, delta wing, and twin waterski-like hydroplanes that extended from the bow/nose for takeoff and retracted once clear of the surface. Power was twin J46 turbojets (6000# each). The craft could reach 695mph at 8,000 feet altitude. On water, the beast was a pilot's hell to handle and vibrated like a jackhammer in waves higher than two inches. To the best of my knowledge, no other watercraft of any sort has approached this speed. (And yes, folks, the XF2Y is technically an airplane, although it behaves as a conventional boat below about 50 knots.)
Now, to reach that speed while in contact with the water....
Well, the obvious solution is to dangle a rope off the back of a Super Hornet or something like that. I think that counts as cheating. So we go with a boat shape for the bottom and airplane shape on top, but since only about 2" of hull could possibly touch the water at this speed, it's mostly about aerodynamics. And power. A helluva lot of power. Stick an afterburning M88 or F100 jet engine in it, either has enough power to toss a 9-ton boat directly upwards about 50,000 feet. We make the boat strong and rigid (read -> heavy) to take the incredibly huge loads, and shock-mount the cabin, 'cause this brute will vibrate like crazy upon hitting the wake of a muskrat. Now we add 40 bottles of Alberta Rye Whiskey, and have the crew draw straws. Short straw drives...
Oh, so you want to go supersonic in water? Now there's something. A kilometre-and-a-third per second. We can only just do that in air right now, and that's only with spacecraft and missiles, up at flight level 800 where there's almost no air anyway. So we fire a rocket-propelled missile straight into the lake from far enough back for it to accelerate up to speed.... oh, whoops, at velocities over a few hundred km/h, water is as rigid and unyielding as granite.
We routinely cut 2-inch steel plates with water jets at the speeds we're talking about here. For some reason, I don't think a supersonic boat will ever be practical. Possible, maybe- and some nutbar will try- but it's not something that is likely to work too well.
Landing and takeoff speeds on the Sea Dart were about 120 knots. Don't big offshore boats run those same speeds NOW?
Now, to reach that speed while in contact with the water....
Well, the obvious solution is to dangle a rope off the back of a Super Hornet or something like that. I think that counts as cheating. So we go with a boat shape for the bottom and airplane shape on top, but since only about 2" of hull could possibly touch the water at this speed, it's mostly about aerodynamics. And power. A helluva lot of power. Stick an afterburning M88 or F100 jet engine in it, either has enough power to toss a 9-ton boat directly upwards about 50,000 feet. We make the boat strong and rigid (read -> heavy) to take the incredibly huge loads, and shock-mount the cabin, 'cause this brute will vibrate like crazy upon hitting the wake of a muskrat. Now we add 40 bottles of Alberta Rye Whiskey, and have the crew draw straws. Short straw drives...
Oh, so you want to go supersonic in water? Now there's something. A kilometre-and-a-third per second. We can only just do that in air right now, and that's only with spacecraft and missiles, up at flight level 800 where there's almost no air anyway. So we fire a rocket-propelled missile straight into the lake from far enough back for it to accelerate up to speed.... oh, whoops, at velocities over a few hundred km/h, water is as rigid and unyielding as granite.
We routinely cut 2-inch steel plates with water jets at the speeds we're talking about here. For some reason, I don't think a supersonic boat will ever be practical. Possible, maybe- and some nutbar will try- but it's not something that is likely to work too well.
Landing and takeoff speeds on the Sea Dart were about 120 knots. Don't big offshore boats run those same speeds NOW?
Franklin
07-07-2005, 10:57 AM
How's about we define "boat" (for the purposes of this discussion) as a vehicle that moves over the surface of the water, with some fixed rigid part of it in contact with the surface, nocloser to the end of the body than 10% of LOA. i.e. the rigid, fixed part must be within the main body of the vehicle, not trailing behind it.
Steve
PS - the simple answer to the question originally posed must be "Yes". It is just that no-one has figured it out yet, but a s/s boat IS possible...
A boat is something that MUST operate on the surface of the water because it's NOT an airplane.
For example, Donald Campbell's Bluebird? NOT an airplane.
Steve
PS - the simple answer to the question originally posed must be "Yes". It is just that no-one has figured it out yet, but a s/s boat IS possible...
A boat is something that MUST operate on the surface of the water because it's NOT an airplane.
For example, Donald Campbell's Bluebird? NOT an airplane.
yipster
07-07-2005, 03:54 PM
keep it coming, i rated this trhread 5 star :D
(have to run)
(have to run)
cyclops
07-07-2005, 03:55 PM
Is any one here versed on the instantanious energy a 2" wave will transfer to the keel and/or hull skin at 800 mph? Maybe a solid hull of Titanium would survive? No human will. - G force would probably shred the body from any harness.
Franklin
07-07-2005, 04:51 PM
Is any one here versed on the instantanious energy a 2" wave will transfer to the keel and/or hull skin at 800 mph? Maybe a solid hull of Titanium would survive? No human will. - G force would probably shred the body from any harness.
In case you hadn't noticed, none of the discussion from me about potential supersonic boat configurations has involved planing hulls, but instead considers hydrofoil boats (like the START of this thread) or supercavitation concepts.
In case you hadn't noticed, none of the discussion from me about potential supersonic boat configurations has involved planing hulls, but instead considers hydrofoil boats (like the START of this thread) or supercavitation concepts.
Sketch
07-07-2005, 08:21 PM
In case you hadn't noticed, none of the discussion from me about potential supersonic boat configurations has involved planing hulls, but instead considers hydrofoil boats (like the START of this thread) or supercavitation concepts.
Fair enough. Excellent thread by the way.
Much of this discussion has hinged on the definition of a boat. A jet dragging a wire does not a boat make. However, I don't suppose anyone will argue that a hydrofoiled moth - i.e. "flying moth" - is not a boat. Put some big jets on a hydrofoiled hull, that at speed (still crazy fast!), will lift the hull above the catastrophic chop.
If the jet and hull provide a stabilizing downward force that is countered by a lifting foil it becomes hard to argue that it is not a boat. That is, it can't fly. Ever. The vessel needs water to do what it does. It can be successful because the foil lifts the hull clear of the danger zone (relative danger :D ).
Look forward to reading more.
Kevin
Fair enough. Excellent thread by the way.
Much of this discussion has hinged on the definition of a boat. A jet dragging a wire does not a boat make. However, I don't suppose anyone will argue that a hydrofoiled moth - i.e. "flying moth" - is not a boat. Put some big jets on a hydrofoiled hull, that at speed (still crazy fast!), will lift the hull above the catastrophic chop.
If the jet and hull provide a stabilizing downward force that is countered by a lifting foil it becomes hard to argue that it is not a boat. That is, it can't fly. Ever. The vessel needs water to do what it does. It can be successful because the foil lifts the hull clear of the danger zone (relative danger :D ).
Look forward to reading more.
Kevin
Sketch
07-07-2005, 08:46 PM
if a foiled vessel is riding a couple feet above the mean surface of the water, how does the air flowing around the vessel deform the surface of the water? what kind of deformation would be beneficial to control?
Kevin
Kevin
Cary
07-07-2005, 10:44 PM
Surface effects would probably render the vessel out of the water making it an aircraft, if it did't, the water pressure would probably destroy it. Although the one I'm working on can get airborne at 0 kts, at about 60 kts it will become airborne anyway.
mackid068
07-07-2005, 11:15 PM
Well, a submerged "boat" WOULD certainly be able to reach supersonic speeds.
marshmat
07-07-2005, 11:15 PM
To have a hydrofoil in the water while the boat is going supersonic would put such horrendously huge loads on the foil and struts that they would collapse. Even titanium could not possibly hold up. Remember that the water brake on current jet hydrofoils is usually a 3x5cm steel pin on a big hydraulic ram- anything more would be snapped off by the 300mph water. A hydrofoil strut would either have to be so huge as to cause horrendous drag, or would snap off under the pressure. Recall water is about 600 times denser than air and thus exerts about 600 times as much force on a given structure.... and the wings of supersonic jets are already under horrendous stress.
Franklin
07-08-2005, 10:56 AM
Fair enough. Excellent thread by the way.
Much of this discussion has hinged on the definition of a boat. A jet dragging a wire does not a boat make. However, I don't suppose anyone will argue that a hydrofoiled moth - i.e. "flying moth" - is not a boat. Put some big jets on a hydrofoiled hull, that at speed (still crazy fast!), will lift the hull above the catastrophic chop.
If the jet and hull provide a stabilizing downward force that is countered by a lifting foil it becomes hard to argue that it is not a boat. That is, it can't fly. Ever. The vessel needs water to do what it does. It can be successful because the foil lifts the hull clear of the danger zone (relative danger :D ).
Look forward to reading more.
Kevin
A boat is something that MUST operate on the surface of the water because it's NOT an airplane.
Simply because a vehicle has a jet (or rocket) engine doesn't make it an airplane.
Ask any Florida cracker who has an airboat.
Much of this discussion has hinged on the definition of a boat. A jet dragging a wire does not a boat make. However, I don't suppose anyone will argue that a hydrofoiled moth - i.e. "flying moth" - is not a boat. Put some big jets on a hydrofoiled hull, that at speed (still crazy fast!), will lift the hull above the catastrophic chop.
If the jet and hull provide a stabilizing downward force that is countered by a lifting foil it becomes hard to argue that it is not a boat. That is, it can't fly. Ever. The vessel needs water to do what it does. It can be successful because the foil lifts the hull clear of the danger zone (relative danger :D ).
Look forward to reading more.
Kevin
A boat is something that MUST operate on the surface of the water because it's NOT an airplane.
Simply because a vehicle has a jet (or rocket) engine doesn't make it an airplane.
Ask any Florida cracker who has an airboat.
Franklin
07-08-2005, 10:58 AM
if a foiled vessel is riding a couple feet above the mean surface of the water, how does the air flowing around the vessel deform the surface of the water? what kind of deformation would be beneficial to control?
Kevin
Important question with no easy answer.
Kevin
Important question with no easy answer.
Franklin
07-08-2005, 11:06 AM
To have a hydrofoil in the water while the boat is going supersonic would put such horrendously huge loads on the foil and struts that they would collapse. Even titanium could not possibly hold up. Remember that the water brake on current jet hydrofoils is usually a 3x5cm steel pin on a big hydraulic ram- anything more would be snapped off by the 300mph water. A hydrofoil strut would either have to be so huge as to cause horrendous drag, or would snap off under the pressure. Recall water is about 600 times denser than air and thus exerts about 600 times as much force on a given structure.... and the wings of supersonic jets are already under horrendous stress.
http://www.users.myisp.co.uk/~climengs/bluebird/coniston.htm
Take a look at everything that was STILL ON Donald Campbell's Bluebird.
http://www.users.myisp.co.uk/~climengs/bluebird/coniston.htm
Take a look at everything that was STILL ON Donald Campbell's Bluebird.
mackid068
07-08-2005, 12:35 PM
Why try a hydrofoil? Let's skip straight to submarines!
Franklin
07-08-2005, 01:00 PM
Why try a hydrofoil? Let's skip straight to submarines!
http://www.deepangel.com/html/the_squall.html
Because that's been done, they're just not that interesting a challenge.
http://www.deepangel.com/html/the_squall.html
Because that's been done, they're just not that interesting a challenge.
asathor
07-09-2005, 08:52 PM
There are some basic advantages to boating over flying:
1. Load capacity
2. Start and stop any time / any port
3. Fuel economy
It seems that by the time you go supersonic you have lost 2 1/2 of them. Remember the Concorde? When the novelty died and now that working people (executives) have laptops and in-the-air telephones it is no loger a good use of resources and must be heavily subsidized.
1. Load capacity
2. Start and stop any time / any port
3. Fuel economy
It seems that by the time you go supersonic you have lost 2 1/2 of them. Remember the Concorde? When the novelty died and now that working people (executives) have laptops and in-the-air telephones it is no loger a good use of resources and must be heavily subsidized.
Sean Herron
07-09-2005, 09:24 PM
Hello...
The dirty sock trophy goes to the 'person' who realizes the folly in technology and it's obvious current replacement...
Slam a few sattelites into orbit and give your high paid executives a laptop and take away their expense accounts and what do you have...
Public dividends...
That and a bunch of flat assed typist nerd heads with a Fortune 500 subscription and a brief case filled with peanut butter sandwiches and a black umbrella...
I prefer the old 1970's vision of the world dashing CEO with a great idea that gets lost in the onboard complimentary drink bar, and sometimes literally in the Swiss flight attendant...
Where was I...
Oh yes - all of the above - plus - how do I mix my cocktail, and then set it down where it won't spill onto my silk socks - while I get my ship out of the way of the semi submerged Taiwanese container box full of toasters that is floating just ahead of me - me, going 800 mph or plus - whilst telling my wife, below, to hold onto the toilet grab bars, and the crew same, so we can all tack at more than subsonic speeds - ALL AT THE SAME TIME - hehehe.... :)
SH.
The dirty sock trophy goes to the 'person' who realizes the folly in technology and it's obvious current replacement...
Slam a few sattelites into orbit and give your high paid executives a laptop and take away their expense accounts and what do you have...
Public dividends...
That and a bunch of flat assed typist nerd heads with a Fortune 500 subscription and a brief case filled with peanut butter sandwiches and a black umbrella...
I prefer the old 1970's vision of the world dashing CEO with a great idea that gets lost in the onboard complimentary drink bar, and sometimes literally in the Swiss flight attendant...
Where was I...
Oh yes - all of the above - plus - how do I mix my cocktail, and then set it down where it won't spill onto my silk socks - while I get my ship out of the way of the semi submerged Taiwanese container box full of toasters that is floating just ahead of me - me, going 800 mph or plus - whilst telling my wife, below, to hold onto the toilet grab bars, and the crew same, so we can all tack at more than subsonic speeds - ALL AT THE SAME TIME - hehehe.... :)
SH.
marshmat
07-10-2005, 12:15 AM
Bluebird K7.
As I understand, the boat began skipping on its sponsons, then became airborne after the pilot applied the waterbrake and cut thrust. Upon hitting the water again, everything forward of the compressor fan was torn to shreds. The stern survived the impact because the front fifteen feet of boat had already absorbed most of the craft's kinetic energy by collapsing.
Bluebird was doing 320mph when she crashed. To go supersonic would require double that velocity; hence, the loads put on such a craft by wind and water would be four times what Bluebird had to handle.
Operating envelope tolerances would likely be tighter than a human pilot could manage. Think flying an F-18 on afterburner in severe turbulence at an altitude of six inches, and you'll have an idea how difficult a task it would be. The slightest ripple would require the exact and instantaneous adjustment of every control surface on the craft within milliseconds. Try driving a Corvette with the electromagnetic suspension- it updates each of four suspension units 1000 times per second. Now think how that ride would feel at ten times the speed, with each bump transferring a hundred times as much force to the vehicle. Computer controls faster than those of a modern fighter jet would be needed to keep this thing stable. It can be done, yes. But it will not be easy, cheap, or safe.
As I understand, the boat began skipping on its sponsons, then became airborne after the pilot applied the waterbrake and cut thrust. Upon hitting the water again, everything forward of the compressor fan was torn to shreds. The stern survived the impact because the front fifteen feet of boat had already absorbed most of the craft's kinetic energy by collapsing.
Bluebird was doing 320mph when she crashed. To go supersonic would require double that velocity; hence, the loads put on such a craft by wind and water would be four times what Bluebird had to handle.
Operating envelope tolerances would likely be tighter than a human pilot could manage. Think flying an F-18 on afterburner in severe turbulence at an altitude of six inches, and you'll have an idea how difficult a task it would be. The slightest ripple would require the exact and instantaneous adjustment of every control surface on the craft within milliseconds. Try driving a Corvette with the electromagnetic suspension- it updates each of four suspension units 1000 times per second. Now think how that ride would feel at ten times the speed, with each bump transferring a hundred times as much force to the vehicle. Computer controls faster than those of a modern fighter jet would be needed to keep this thing stable. It can be done, yes. But it will not be easy, cheap, or safe.
Franklin
07-11-2005, 10:45 AM
Bluebird K7.
As I understand, the boat began skipping on its sponsons, then became airborne after the pilot applied the waterbrake and cut thrust. Upon hitting the water again, everything forward of the compressor fan was torn to shreds. The stern survived the impact because the front fifteen feet of boat had already absorbed most of the craft's kinetic energy by collapsing.
Bluebird was doing 320mph when she crashed. To go supersonic would require double that velocity; hence, the loads put on such a craft by wind and water would be four times what Bluebird had to handle.
Operating envelope tolerances would likely be tighter than a human pilot could manage. Think flying an F-18 on afterburner in severe turbulence at an altitude of six inches, and you'll have an idea how difficult a task it would be. The slightest ripple would require the exact and instantaneous adjustment of every control surface on the craft within milliseconds. Try driving a Corvette with the electromagnetic suspension- it updates each of four suspension units 1000 times per second. Now think how that ride would feel at ten times the speed, with each bump transferring a hundred times as much force to the vehicle. Computer controls faster than those of a modern fighter jet would be needed to keep this thing stable. It can be done, yes. But it will not be easy, cheap, or safe.
How many times do I have to mention hydrofoils and supercavitation configurations before people stop thinking planing hulls are the only approach?
As I understand, the boat began skipping on its sponsons, then became airborne after the pilot applied the waterbrake and cut thrust. Upon hitting the water again, everything forward of the compressor fan was torn to shreds. The stern survived the impact because the front fifteen feet of boat had already absorbed most of the craft's kinetic energy by collapsing.
Bluebird was doing 320mph when she crashed. To go supersonic would require double that velocity; hence, the loads put on such a craft by wind and water would be four times what Bluebird had to handle.
Operating envelope tolerances would likely be tighter than a human pilot could manage. Think flying an F-18 on afterburner in severe turbulence at an altitude of six inches, and you'll have an idea how difficult a task it would be. The slightest ripple would require the exact and instantaneous adjustment of every control surface on the craft within milliseconds. Try driving a Corvette with the electromagnetic suspension- it updates each of four suspension units 1000 times per second. Now think how that ride would feel at ten times the speed, with each bump transferring a hundred times as much force to the vehicle. Computer controls faster than those of a modern fighter jet would be needed to keep this thing stable. It can be done, yes. But it will not be easy, cheap, or safe.
How many times do I have to mention hydrofoils and supercavitation configurations before people stop thinking planing hulls are the only approach?
mackid068
07-11-2005, 05:44 PM
Planing hulls are certainly NOT the only approach.
gonzo
07-11-2005, 05:48 PM
What is the waterline length for a displacement hull capable of supersonic speeds?
mackid068
07-11-2005, 05:55 PM
Very, very very long with huge amount of horsepower per ton, something like 50 hp ton or more? I don't know exactly, but just a lot of HP per ton.
marshmat
07-11-2005, 10:30 PM
Planing hulls are certainly NOT the only approach.
Very true. Very true indeed.
A note on supercavitation. The fastest current water-borne craft of any sort are supercavitating rocket-powered torpedoes. Problem: Here we are talking about supersonic. For a surface craft to go supersonic requires that it achieve 344 m/s or 1238 km/h (at sea level, 20 degrees Celsius). At this speed it is going supersonic in air. A submerged craft, like a supercavitating torpedo, must achieve 1531 m/s or 5512 km/h to exceed the speed of sound in sea water. Example: A torpedo going 1500 km/h, which would be Mach 1.2 in air, is only going Mach 0.27 in water. Sonic velocity is dependent on the medium and to be truthful in our claims we must measure it in the medium in which the vehicle is actually travelling.
(Note that to for a submerged torpedo to go supersonic would require it to reach what an aircraft pilot would consider Mach 4.4. At this speed, frictional heating at 80,000 feet altitude is sufficient to melt high-grade steel. I don't dare to imagine how much stress a vehicle at this speed would be under if it were touching water.)
Very true. Very true indeed.
A note on supercavitation. The fastest current water-borne craft of any sort are supercavitating rocket-powered torpedoes. Problem: Here we are talking about supersonic. For a surface craft to go supersonic requires that it achieve 344 m/s or 1238 km/h (at sea level, 20 degrees Celsius). At this speed it is going supersonic in air. A submerged craft, like a supercavitating torpedo, must achieve 1531 m/s or 5512 km/h to exceed the speed of sound in sea water. Example: A torpedo going 1500 km/h, which would be Mach 1.2 in air, is only going Mach 0.27 in water. Sonic velocity is dependent on the medium and to be truthful in our claims we must measure it in the medium in which the vehicle is actually travelling.
(Note that to for a submerged torpedo to go supersonic would require it to reach what an aircraft pilot would consider Mach 4.4. At this speed, frictional heating at 80,000 feet altitude is sufficient to melt high-grade steel. I don't dare to imagine how much stress a vehicle at this speed would be under if it were touching water.)
marshmat
07-11-2005, 10:36 PM
What is the waterline length for a displacement hull capable of supersonic speeds?
Assuming supersonic in air: 344 m/s or 669 kts is the target speed.
Assuming standard speed-length ratio of 1.34 in Old English units, and full displacement mode.
Solving for hull length gives 249,254 ft- meaning the hull is 75.97 kilometres long at the waterline.
The vessel's wake will travel about 1.2-1.5 times faster than a large open-ocean tsunami.
Assuming supersonic in air: 344 m/s or 669 kts is the target speed.
Assuming standard speed-length ratio of 1.34 in Old English units, and full displacement mode.
Solving for hull length gives 249,254 ft- meaning the hull is 75.97 kilometres long at the waterline.
The vessel's wake will travel about 1.2-1.5 times faster than a large open-ocean tsunami.
mackid068
07-11-2005, 10:55 PM
Holy crap! That's just not possible to use the disp hull then, right?
marshmat
07-11-2005, 11:16 PM
Well, going with a fastferry-like speed/length ratio of 2.0, we can shorten said boat to only 110,890 feet - a mere 33.79 km.
mackid068
07-11-2005, 11:29 PM
It CAN be done :D
Franklin
07-12-2005, 11:03 AM
Very true. Very true indeed.
A note on supercavitation. The fastest current water-borne craft of any sort are supercavitating rocket-powered torpedoes. Problem: Here we are talking about supersonic. For a surface craft to go supersonic requires that it achieve 344 m/s or 1238 km/h (at sea level, 20 degrees Celsius). At this speed it is going supersonic in air. A submerged craft, like a supercavitating torpedo, must achieve 1531 m/s or 5512 km/h to exceed the speed of sound in sea water. Example: A torpedo going 1500 km/h, which would be Mach 1.2 in air, is only going Mach 0.27 in water. Sonic velocity is dependent on the medium and to be truthful in our claims we must measure it in the medium in which the vehicle is actually travelling.
(Note that to for a submerged torpedo to go supersonic would require it to reach what an aircraft pilot would consider Mach 4.4. At this speed, frictional heating at 80,000 feet altitude is sufficient to melt high-grade steel. I don't dare to imagine how much stress a vehicle at this speed would be under if it were touching water.)
WHO CARES? The subject of this thread is Supersonic BOAT. It isn't SUBMARINE. It isn't TORPEDO. "The fastest current water-borne craft of any sort are supercavitating rocket-powered torpedoes" is why the subject is BOAT.
A note on supercavitation. The fastest current water-borne craft of any sort are supercavitating rocket-powered torpedoes. Problem: Here we are talking about supersonic. For a surface craft to go supersonic requires that it achieve 344 m/s or 1238 km/h (at sea level, 20 degrees Celsius). At this speed it is going supersonic in air. A submerged craft, like a supercavitating torpedo, must achieve 1531 m/s or 5512 km/h to exceed the speed of sound in sea water. Example: A torpedo going 1500 km/h, which would be Mach 1.2 in air, is only going Mach 0.27 in water. Sonic velocity is dependent on the medium and to be truthful in our claims we must measure it in the medium in which the vehicle is actually travelling.
(Note that to for a submerged torpedo to go supersonic would require it to reach what an aircraft pilot would consider Mach 4.4. At this speed, frictional heating at 80,000 feet altitude is sufficient to melt high-grade steel. I don't dare to imagine how much stress a vehicle at this speed would be under if it were touching water.)
WHO CARES? The subject of this thread is Supersonic BOAT. It isn't SUBMARINE. It isn't TORPEDO. "The fastest current water-borne craft of any sort are supercavitating rocket-powered torpedoes" is why the subject is BOAT.
asathor
07-12-2005, 01:33 PM
How do you get the passengers to the other end of the "boat" in time to get off?
MagLev trains?
MagLev trains?
yipster
07-12-2005, 01:45 PM
"The fastest current water-borne craft of any sort are supercavitating rocket-powered torpedoes"
i'm not so sure bout that, those russian torps do bout 400 km hr is said but hush hush, recently one sunk the koersk if i recall well. boat waterspeed record is and aims a little higher isnt it?
i'm not so sure bout that, those russian torps do bout 400 km hr is said but hush hush, recently one sunk the koersk if i recall well. boat waterspeed record is and aims a little higher isnt it?
mackid068
07-12-2005, 05:25 PM
The Kursk, you mean? It sunk due to an explosion related to the fuel for the torpedoes.
gonzo
07-12-2005, 06:49 PM
What would the compression of the shock wave do? My impression is that it would be another wave forming source.
asathor
07-12-2005, 10:31 PM
I don't know what the air to water sound wave refraction ratio is but it seems that while a large part of the energy in the lower 180 degree will be reflected back up a shockwave will form in the water. If the rings in the water are high enough they should be traveling faster that the boat which means that the two will meet somewhere. That could get bumpy.
(even hydrofoild would experience this in some form)
(even hydrofoild would experience this in some form)
chandler
07-14-2005, 05:02 PM
What I want to know is a supersonic rowboat feasible...imagine the weight savings in food and drinking water alone on a trans ocean attempt
mackid068
07-14-2005, 05:13 PM
Not really possible, nope :D
marshmat
10-29-2005, 04:23 PM
I think someone asked how much power it might take....
Spirit of Australia used about 1.88MW to reach 140 m/s, or so Warby's site claims. It weighed 1.6 tonnes. That translates to about 1575 hp/ton at that speed. Warby also claims his J34 can put out 9000hp on full afterburner, or about 5600hp/ton. These boats travel at roughly 0.5 Mach, so quadruple those power figures to get a rough estimate of what a supersonic craft might require. My bets would be on the 8000-12000 hp/ton range.
Spirit of Australia used about 1.88MW to reach 140 m/s, or so Warby's site claims. It weighed 1.6 tonnes. That translates to about 1575 hp/ton at that speed. Warby also claims his J34 can put out 9000hp on full afterburner, or about 5600hp/ton. These boats travel at roughly 0.5 Mach, so quadruple those power figures to get a rough estimate of what a supersonic craft might require. My bets would be on the 8000-12000 hp/ton range.
cyclops
10-29-2005, 06:46 PM
The British, Blue Bird almost made the return high speed run. Until he hit a tiny wave that was from his first pass. It bounched off a rock wall and the boat exploded so completly they never found any body parts. That was around 300 to 400 mph range. A bird farting 1/4 mile away is sure death!
marshmat
10-29-2005, 07:06 PM
The British, Blue Bird almost made the return high speed run.
Almost. There's an awful lot of "almost" in speed record attempts.
Hitting the water at 140 m/s is much like hitting concrete at 100 m/s. Ask any commercial airline pilot- their training is that if they have to ditch in water, come in as slow and as level as possible; full flap and slat if they can. Skimming the water at +5 degrees is something an airliner (or boat) can handle; impact at -20 degrees simply crushes the front of the vehicle flat in much the same manner as running a Ferrari into a wall at top speed. Kind of hard to manage this safely.
Almost. There's an awful lot of "almost" in speed record attempts.
Hitting the water at 140 m/s is much like hitting concrete at 100 m/s. Ask any commercial airline pilot- their training is that if they have to ditch in water, come in as slow and as level as possible; full flap and slat if they can. Skimming the water at +5 degrees is something an airliner (or boat) can handle; impact at -20 degrees simply crushes the front of the vehicle flat in much the same manner as running a Ferrari into a wall at top speed. Kind of hard to manage this safely.
cyclops
10-29-2005, 07:59 PM
BOATS to me have rudders, props and the hull in the water. Anyone of those missing is garbage. Hell, put your picture on 2 rockets, 1 for each way, and set a new record. No rules needed.
chandler
10-30-2005, 12:43 PM
What's the point? If you need to get there that fast book an airline ticket and keep the pollution and noise in the stratoshere.
Cary
10-31-2005, 11:32 AM
I wouldn't want to sanction stupidity as a national pastime, however, I recall water jets used to cut metal, and I think it is stupid, to try and get a boat to break a speed of sound record
cyclops
10-31-2005, 11:40 AM
I do not want to see people being killed in those "test" runs. Put a explosive computer in the boat. We know that humans are now worthless in reflex times above 300 mph. Jet jocks will confirm that in what is called a " departure ". Same thing as a non- recoverable spin. Save the people. Piss on the boats.
D'ARTOIS
10-31-2005, 06:19 PM
A boat is already barely controllable at speeds over 100 mph - for speeds closing on 140-150 mph one needs to have conditions that will play ball. Flat sea, no waves of some sort, you name it.
A supersonic boat should be either a WIGE or a Hydrofoil, and then, I give the best chance to a Hydrofoil.
Only a hydrofoil can operate under certain conditions - as long as the seastate permits.
Supersonic means over Mach 1 - e.g. about 1100 km/h or 594 knots/hr
people that never have driven or experienced speeds above 100 knots/hr may talk easily about this subject but the guys that do Off Shore Powerboating know that their lives can be stopped any moment if they go full throttle and something happens......
300, maybe 350 knots are feasible with an enormous gasturbine mounted in a Hydrofoil frame/body.
Then it might do a run under specific conditions - do we talk about a boat in this case and what will be the added value of the whole experience?
We are talking in this Forum about sailing yachts that - when they are fast - touch a mere 15 knots.
The guys that like fishing ( I hope I can experience it once) and that keep vessels that will go at 40-50 knots to their fishing spots, know how difficult it is to maintain that sort of speed when waves are building up.
What will be the next step? Boats at the speed of light?
A supersonic boat should be either a WIGE or a Hydrofoil, and then, I give the best chance to a Hydrofoil.
Only a hydrofoil can operate under certain conditions - as long as the seastate permits.
Supersonic means over Mach 1 - e.g. about 1100 km/h or 594 knots/hr
people that never have driven or experienced speeds above 100 knots/hr may talk easily about this subject but the guys that do Off Shore Powerboating know that their lives can be stopped any moment if they go full throttle and something happens......
300, maybe 350 knots are feasible with an enormous gasturbine mounted in a Hydrofoil frame/body.
Then it might do a run under specific conditions - do we talk about a boat in this case and what will be the added value of the whole experience?
We are talking in this Forum about sailing yachts that - when they are fast - touch a mere 15 knots.
The guys that like fishing ( I hope I can experience it once) and that keep vessels that will go at 40-50 knots to their fishing spots, know how difficult it is to maintain that sort of speed when waves are building up.
What will be the next step? Boats at the speed of light?
marshmat
10-31-2005, 06:38 PM
Boats at the speed of light?
Here to China in 0.065 seconds! Count me in!
Here to China in 0.065 seconds! Count me in!
cyclops
10-31-2005, 06:49 PM
Ok. How good are the best hull designs at reducing a bumpy ride. You should be able to hold a full Martini glass 1" from your lips with no spillage at 30 mph or so . By name, model and size, are there any boat under 25'-----35'-----or 45'. Speed is easy, comfort for all ages on 1 boat underway is far more difficult. Names, please.
marshmat
10-31-2005, 07:25 PM
Any boat can do that, Cyclops. Simply find a sheltered body of water, start measuring wave heights, and wait until there has been no wind at all for three hours. (In Canada, also wait until there have been no police for 3h, if there's going to be a martini around. Wouldn't want that, oh no.)
Oh, you meant in real conditions? (lol)
Oh, you meant in real conditions? (lol)
alexlebrit
09-28-2006, 08:37 AM
You see if this could all be solved if Concorde was still flying.
Simply make a One Sheet Skiff and buy two tickets.
Voila supersonic boat.
Simply make a One Sheet Skiff and buy two tickets.
Voila supersonic boat.
stonebreaker
09-28-2006, 12:03 PM
I wouldn't want to sanction stupidity as a national pastime, however, I recall water jets used to cut metal, and I think it is stupid, to try and get a boat to break a speed of sound record
Yeah, what's with all these stupid pioneers? It's not like mankind has ever benefitted from these dorks going faster, higher, farther... except for carbon fiber, fuel injection, aluminum, jet engines, turbochargers, communications satellites, solar power, hydrogen fuel cells, roller cams, iconel, and tang. Oh, and nozzles for industrial water cutting jets. But other than that, nothing.
Yeah, what's with all these stupid pioneers? It's not like mankind has ever benefitted from these dorks going faster, higher, farther... except for carbon fiber, fuel injection, aluminum, jet engines, turbochargers, communications satellites, solar power, hydrogen fuel cells, roller cams, iconel, and tang. Oh, and nozzles for industrial water cutting jets. But other than that, nothing.
Cary
09-28-2006, 12:44 PM
You wouldn't be able to keep it in the water, so it becomes an aircraft
SailDesign
09-28-2006, 05:44 PM
Of course a supersonic boat is possible.
No-one has yet discovered how to do it, but it will happen.... :)
Steve "anything is possible once you know how"
No-one has yet discovered how to do it, but it will happen.... :)
Steve "anything is possible once you know how"
granite
09-29-2006, 09:11 AM
I think it could be done, with a bit of creative thinking.
a planing or hydrofoil supersonic boat to be sucsesful would largely be skipping over the surface of the water if you go too deep the drag gets huge.
the problem is that water does not like to stay flat it keeps on getting kicked up into waves.
The solution is to cool the water to below 0 degrees C polish up a track plonk Thrust SST on and give it a shot
you have a speed record with the vehicle fully supported by water going supersonic.
a planing or hydrofoil supersonic boat to be sucsesful would largely be skipping over the surface of the water if you go too deep the drag gets huge.
the problem is that water does not like to stay flat it keeps on getting kicked up into waves.
The solution is to cool the water to below 0 degrees C polish up a track plonk Thrust SST on and give it a shot
you have a speed record with the vehicle fully supported by water going supersonic.
Crag Cay
09-29-2006, 09:52 AM
Granite - I like your logic! But you would only have a chance for one timed run, as the jet blast might 'impact' on the ice quality!
imagery1jw
09-29-2006, 04:04 PM
Hey BillyDoc,
Yes Russia did develope a highspeed torp years ago based off rocket drive and bubble enclosure so the torp never really touches water as it drives through it. Check Scientific America May of 00 or 01 for the artical. But the speed was around 230 knots.
Yes Russia did develope a highspeed torp years ago based off rocket drive and bubble enclosure so the torp never really touches water as it drives through it. Check Scientific America May of 00 or 01 for the artical. But the speed was around 230 knots.
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