Bad Navy I

Previous posts showed: the F-35 is obolete, electric highways can replace gasoline at less cost.

By 1975 the navy needed to completely redesign their torpedoes.  They did not and now have obsolete weapons systems.

   Torpedoes should not approach at shallow depths using only acoustic detection, they should approach at medium depth, 200-300 feet, using acoustic detection for proximity then using either laser scanning, ambient light detection or strobe lighting for terminal attack, a.  If the water is to shallow to allow for a deeper approach, the torpedo should deliberately porpoise, broach, to scan the ship at a distance of about 1/2 mile.
   In water, at a speed of 40 knots, 70 feet per second, the lifting force is 1/2 X density X velocity squared =
1/2 X 64 lbs per cubic foot (weight density of water) / 32 (acceleration of gravity) X 70 X 70 = 4900 lb/sq.ft.
That number is multiplied by the coefficient of lift and a second term to account for the winglets finite extent.  If the winglets are 2 feet squared, that is 9800 lbs times other factors.  The torpedo weighs maybe 3000 lbs.  It shoud be possible to ahve a turning rate of at least 1 g, 32 ft/second squared.  At 70 ft/sec, turning radius equals velocity squared divided by acceleration = 70 x 70 / 32 = 150 feet.  At a depth of 200 feet the torpedo can turn and attack the target upwards form underneath where it is more likely to destroy vital areas of the target ship.
   At 45 kts, 77 fps, 77 X 77 /32 = 190 ft radius, 200 feet would be deep enough.
   The chief advantage is that the torpedo cannot be spoofed. Acoustically a false target can be created, but the visual mass of the ship cannot be fooled.  The one option taht might exist is to paint the underside of the hull in a crackle pattern to simulate the uneven light from ocean waves, enabling the ship to blend in somewhat against the ocean surface.
    At a is shown a laser scan, but ambient light might be sufficient to create a shadow outlining the ship.  The other option is to use a strobe light similar to cruise missiles to illuminate the ship.  Water absorbs and diffuses light so a balance must be struck between adequate depth for torpedo operations and maximum depth at which the torpedo can visually resolve the ship.
    At b is shown the torpedo deliberately broaching to scan for the visual target of the ship in shallower water, again, this is to prevent acoustic spoofing.  At a range of 1/2 mile, a cannon shell fired form the ship to strike the torpedo would take 1 second at 2600 feet / second to arrive.  In addition, the cannon would have to slew into position before firing.  1/2 second to rise and 1/2 second to fall would mean the torpedo would exit the water at 16 feet per second upward velocity which would cause gravity to stop its upward velocity in 1/2 second.  For 70 ft/sec that would mean .23 radians or about 14 degrees exit angle.  If the wiglets produce 1 g, the downward velocity would stop after 4 feet of water depth, actually more allowing for angle of attack of the winglets, but still less than 10 feet.  Most ship hulls need more than 10 feet of draft so there should be plenty of water or torped operations whenever a target ship can operate.  The one difficulty is wave height, since the torpedo must rise high enough over wave crests to see the target ship.  This means the torpedo must rise at a sharper angle and spend more time exposed out of the water, but the waves will produce radar returns which will help to hide the torpedo and the waves themselves block radar until the torpedo rises above them.
   c and d show the winglets folded inside the torpedo body and opened for usage.
   e shows a rocket motor added to overcome the drag of the winglets and the net undisplaced weight of the torpedo.  The rocket motor would be integral with the propeller shaft and its nozzle would be in the propeller hub.  The spinning should have no significant effects on the rocket motor operation.  For a torpedo weighing 3000 lbs the negative buoyancy might be 300 lbs. another 300 lbs could account for the winglet drag for a total of 600 lbs.  At 200 feet depth the arc ditance would be 300 feet, at 70 ft/sec = 4.3 sec, say 5 sec.  600 lb X 5 sec = 3 000 lb-sec, solid fuel rockets have a specific impulse ( lbs of thrust X seconds of thrust / lbs of propellant) of 250 seconds.   3 000 lb-sec / 250 seconds = 12 lbs of propellant.  That amount of weight could be accommodated on the propellor shaft.  Owing to the back pressure of sea water at depth and some inefficiencies in the design shape of the motor, more fuel would be needed. But even 20-30 lbs would not be excessive.  Thermal coatings inside the propellor shaft would prevent it form softening during the five seconds of rocket burn.

   At right is a depiction of how the torpedo would look with the laser scanner stowed and recessed into the upper fore section of the torpedo and the wiglets stowed for the configuration of approach.  The winglets would be covered by a sleeve which would separate before the winglets open.
   The lower illustration shows the winglets deployed and the laser scanner rotated into its extended viewing position.  There is, by the way, a fish that has eyes that rotate like the laser scanner, normally they are rotated upwards to scan for prey but then they flip forward to enable the actual attack.

   The torpedo body would have to be structurally heavier than current designs and its form would reduce internal space, so:  the warhead would have to be smaller, the range would have to be reduced or the torpedo would have to be built physically larger and heavier.
   A wing-in-ground effect, stealth torpedo plane could be built.  It would fly 10-20 feet off the ocean surface so ship surveillance radars would look down at it against the ocean waves, obscuring its radar return.  The engine inlet would be located under the fuselage to hide it form radar.  The aircraft would be an unmanned drone.
   The aircraft would fly in pairs, a lead aircraft would scan for targets while the trailing aircraft would drop the torpedo for attack.  The trailing aircraft would be far enough away so it would be below the earth's curvature to hide the splash of the torpedo entering the water and preventing the ship form targeting the drones by revealing their location.  They would co-ordinate their movements through GPS or by inertial measurement.
They would be lethally effective at night but easily seen and militarily worthless in day-light.
   The torpedoes for such an aircraft would have to have a dunce cap over their front to prevent damage to the acoustic receiver form striking the water at 400 mph.
   I sent this to both DARPA aqnd the US Navy, neither was interested.