United States Patent 5,886,284 Will , et al. March 23, 1999
Missile safety system for assuring minimum safe distance
Abstract
An arming and safing system for a missile having an acceleration responsive mechanism for actuating a timing device upon launching to insure arming only after the passage of a predetermined period of time, and an omnidirectional impact switch for activating a dudding switch in case of missile impact at a distance less than a minimum safe distance from the launching vehicle.
Inventors: Will; Albert S. (Bethesda, MD); Wilson; Robert R. (Chillum, MD) Assignee: The United States of America as represented by the Secretary of the Navy (Washington, DC)
Appl. No.: 423640
Filed: December 28, 1964
[snip]
The invention to which the present application is directed was developed as part of the SUBROC weapon system although it will be clear from the detailed description to follow that it may be employed with any ordinary missile using delay arming. The SUBROC missile is an antisubmarine weapon provided with a nuclear warhead and designed to be launched from a torpedo tube of an attack submarine, to thereafter emerge from the water and go through an air boost phase depending upon the selected range, during which it is directed to the target area by terminal guidance, and then to re-enter the water in the vicinity of the target.
Since such a warhead may have a lethal radius which is relatively close to the minimum operational range of the missile it is obvious that even slight missile malfunctions at any point in the trajectory, particularly in those cases when a short range is selected, could cause the re-entry body of the missile to enter the water at a location less than the minimum safe distance away from the launching submarine.
For this reason and in order to assure a high level of safety for the launching submarine, it became necessary to incorporate as one of the many safety features of the weapon a positive and reliable safety system for preventing arming of the missile, or for dudding the missile, if it should undergo erratic flight which causes it to impact the water at a distance less than the minimum safe distance for the launching submarine.
"thoms...@flash.net" <thoms...@flash.net> wrote: >The document also gives a little insight into how safety mechanisms >were implemented in those long-gone days.
Do note that mechanisms to prevent ownship kills go back well before SUBROC.
D. -- Touch-twice life. Eat. Drink. Laugh.
-Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL
Derek Lyons wrote: > "thoms...@flash.net" <thoms...@flash.net> wrote: > >The document also gives a little insight into how safety mechanisms > >were implemented in those long-gone days. > Do note that mechanisms to prevent ownship kills go back well before > SUBROC.
Yes, in ways that today's young'uns would find appallingly mechanical, I suspect. IIRC, the Mk-45 nuclear torpedo had a little gyro that would disarm(*) the warhead if it deviated more than a certain number of degrees (> 90 would be particularly bad) from the original course. One of the early nuclear naval SAMs -- I think it was Talos, but maybe not -- armed when a nut was released on launch and spun down a threaded shaft to close a switch after a suitable time. Very creative stuff.
It would be interesting to find out how far back such mechanisms go. Did WW II torpedos or other weapons have them?
(*) Now that I'm thinking of it, ISTR that the warhead was fuzed on propeller shaft turn count, with the hope that there was a more or less reliable relation between shaft turns and distance traveled. Very odometric.
> > "thoms...@flash.net" <thoms...@flash.net> wrote: > > >The document also gives a little insight into how safety mechanisms > > >were implemented in those long-gone days.
> > Do note that mechanisms to prevent ownship kills go back well before > > SUBROC.
> Yes, in ways that today's young'uns would find appallingly > mechanical, I suspect. IIRC, the Mk-45 nuclear torpedo had a little > gyro that would disarm(*) the warhead if it deviated more > than a certain number of degrees (> 90 would be particularly > bad) from the original course. One of the early nuclear > naval SAMs -- I think it was Talos, but maybe not -- armed > when a nut was released on launch and spun down a threaded > shaft to close a switch after a suitable time. Very creative > stuff.
But in firm keeping with the KISS rule, but after all way back then some designers probably still remembered all the things that can go wrong in combat use when you get too fancy.
> It would be interesting to find out how far back such mechanisms > go. Did WW II torpedos or other weapons have them?
> (*) Now that I'm thinking of it, ISTR that the warhead was > fuzed on propeller shaft turn count, with the hope that > there was a more or less reliable relation between shaft turns > and distance traveled. Very odometric.
Almost from the start Torpedoes were armed by a small propeler in the nose, so they had to run some distince before arming, for that matter the V-1 determined range by an air log. However in WWII Torpedoes did not have safty cutoffs if they turned off course, which lead to the odd embaressing insadent of ships torpedoing themselves when a fish went haywire, at least on US sub scored an own goal that way and a couple of others had near misses. An RN cruiser I think hit itself with a torpedo aimed at a German destroyer off North Cape, ironic considering all the torpedoes the Germans had fired at her and missed with.
> > > "thoms...@flash.net" <thoms...@flash.net> wrote: > > > >The document also gives a little insight into how safety mechanisms > > > >were implemented in those long-gone days.
> > > Do note that mechanisms to prevent ownship kills go back well before > > > SUBROC.
> > Yes, in ways that today's young'uns would find appallingly > > mechanical, I suspect. IIRC, the Mk-45 nuclear torpedo had a little > > gyro that would disarm(*) the warhead if it deviated more > > than a certain number of degrees (> 90 would be particularly > > bad) from the original course. One of the early nuclear > > naval SAMs -- I think it was Talos, but maybe not -- armed > > when a nut was released on launch and spun down a threaded > > shaft to close a switch after a suitable time. Very creative > > stuff.
> But in firm keeping with the KISS rule, but after all way back then some > designers probably still remembered all the things that can go wrong in > combat use when you get too fancy.
> > It would be interesting to find out how far back such mechanisms > > go. Did WW II torpedos or other weapons have them?
> > (*) Now that I'm thinking of it, ISTR that the warhead was > > fuzed on propeller shaft turn count, with the hope that > > there was a more or less reliable relation between shaft turns > > and distance traveled. Very odometric.
> Almost from the start Torpedoes were armed by a small propeler in the nose, > so they had to run some distince before arming, for that matter the V-1 > determined range by an air log. However in WWII Torpedoes did not have safty > cutoffs if they turned off course, which lead to the odd embaressing > insadent of ships torpedoing themselves when a fish went haywire, at least > on US sub scored an own goal that way and a couple of others had near > misses. An RN cruiser I think hit itself with a torpedo aimed at a German > destroyer off North Cape, ironic considering all the torpedoes the Germans > had fired at her and missed with.
The term used is "safe-and-arm". Almost all munitions use some form of safe-and-arm to prevent accidental operation or detonation. Most of these systems are simple mechanical systems as complicated systems and electronics have too many failure modes of both the safe and unsafe type. I am not sure about before W.W.II, but all explosive ordinance above 20 mm have some form of safe-and-arm.
>> > > "thoms...@flash.net" <thoms...@flash.net> wrote: >> > > >The document also gives a little insight into how safety mechanisms >> > > >were implemented in those long-gone days.
>> > > Do note that mechanisms to prevent ownship kills go back well before >> > > SUBROC.
>> > Yes, in ways that today's young'uns would find appallingly >> > mechanical, I suspect. IIRC, the Mk-45 nuclear torpedo had a little >> > gyro that would disarm(*) the warhead if it deviated more >> > than a certain number of degrees (> 90 would be particularly >> > bad) from the original course. One of the early nuclear >> > naval SAMs -- I think it was Talos, but maybe not -- armed >> > when a nut was released on launch and spun down a threaded >> > shaft to close a switch after a suitable time. Very creative >> > stuff.
>> But in firm keeping with the KISS rule, but after all way back then some >> designers probably still remembered all the things that can go wrong in >> combat use when you get too fancy.
>> > It would be interesting to find out how far back such mechanisms >> > go. Did WW II torpedos or other weapons have them?
>> > (*) Now that I'm thinking of it, ISTR that the warhead was >> > fuzed on propeller shaft turn count, with the hope that >> > there was a more or less reliable relation between shaft turns >> > and distance traveled. Very odometric.
>> Almost from the start Torpedoes were armed by a small propeler in the >> nose, >> so they had to run some distince before arming, for that matter the V-1 >> determined range by an air log. However in WWII Torpedoes did not have >> safty >> cutoffs if they turned off course, which lead to the odd embaressing >> insadent of ships torpedoing themselves when a fish went haywire, at >> least >> on US sub scored an own goal that way and a couple of others had near >> misses. An RN cruiser I think hit itself with a torpedo aimed at a German >> destroyer off North Cape, ironic considering all the torpedoes the >> Germans >> had fired at her and missed with.
TANG sank herself with the last torpedo in her inventory. There were a couple of other cases where a circular running torpedo was believed to be the cause of loss, but couldn't be definitely proven. The Mark 18 electric was particularly noted for this sort of behavior, generally blamed on corrosion caused by battery charging making the rudder pins bind. (Remember what used to happen to the battery tray in your car before they started making them out of plastic.)
The Mark 6 exploder, used in the Mark 14, 15 and 23 torpedoes, was armed by a waterwheel type impeller in a slot machined into the exploder baseplate. The impeller did three things. It raised the primers out of the safety chamber into the booster cavity, rotated an electrical safety switch that kept power grounded until the torpedo had travelled (officially) 480 yards, and it powered a small generator that charged the firing capacitor used to activate the solenoid that released the mechanical firing pin. -- Jack http://www.fleetsubmarine.com http://jtmcdaniel.com
> The term used is "safe-and-arm". Almost all munitions use some form of > safe-and-arm to prevent accidental operation or detonation. Most of > these systems are simple mechanical systems as complicated systems and > electronics have too many failure modes of both the safe and unsafe type. > I am not sure about before W.W.II, but all explosive ordinance above 20 > mm have some form of safe-and-arm.
> Mike
I wonder if Hedgehog rounds had these? I vaguely remember a story where the rounds were supposedly being loaded manually, and a crew member tripped and fell while carrying one - which landed on its nose and detonated. Now is that a true story?
>> The term used is "safe-and-arm". Almost all munitions use some form >> of safe-and-arm to prevent accidental operation or detonation. Most >> of these systems are simple mechanical systems as complicated systems >> and electronics have too many failure modes of both the safe and >> unsafe type. I am not sure about before W.W.II, but all explosive >> ordinance above 20 mm have some form of safe-and-arm.
>> Mike
> I wonder if Hedgehog rounds had these? I vaguely remember a story > where the rounds were supposedly being loaded manually, and a crew > member tripped and fell while carrying one - which landed on its nose > and detonated. Now is that a true story?
I believe there was one of those little prop things on the nose which armed the round in flight but thats from memory.
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On Fri, 21 Jan 2005 15:59:19 +1100, rb <snaf...@lycos.com> wrote: >I wonder if Hedgehog rounds had these?
I dimly recall something about this. Supposedly there's a flight-activated arming mechanism to the fuze. But the mechanical construction of the fuze body was weak and if you hit it hard enough, you simply crushed the thing and set it off anyway.
