Screw Ballistics: An Essay





Edward E. Rochon




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Edward E. Rochon on Shakespir



Screw Ballistics : An Essay

Copyright © 2017 by Edward E. Rochon




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Some Other Works by the Author


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The State & Statecraft: An Essay
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U. S. Third Republic: An Essay
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Reading Material


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Table of Contents

Title Page


Chapter 1: Screws

Chapter 2: Spaceships, Moles & Drills

About the Author


We have smoothbore and rifled shells. The smoothbore is/was easier to conceive and manufacture, easier to clean, maintain, and generally with a higher muzzle velocity per charge of accelerant. Due to the need for accuracy in firing, a long process of squeezing out smoothbore guns of all sorts (cannon, rifles) occurred over half a millennium. In more recent times, the need for ever greater muzzle velocity to penetrate armor, coupled with improvements in precision manufacture of shells, led to a return of smoothbore weapons. Higher muzzle velocity also means longer range.

With better and stronger barrels, we see a return to cannon on ships in lieu of missiles due to the ability to project shells further at a lower cost and fundamentally simpler target acquisition. Shells also have enhanced range through rocket assisted shells. And since WWII, we have better detonation on target means through control mechanisms attached to the detonators (smart bullets, shells.) The ultimate consequence of this will be a diminution of air power as a prime factor in winning battles. These will be compelled to stay in the rear until the ground forces break up enemy anti-aircraft capabilities. Planes will still have great advantage in bringing air dropped artillery (bombs, airborne cannon) to a battlefield faster than land guns can get to the battlefront. Speed in war can be a critical component in victory.

So we have a trend towards smoothbore, long range field guns for all purposes. Viewing the trend, I began to think against the grain on smoothbore. Is it possible that greater rifling might have a niche in the complement of weapons available? The most extreme form of rifling would be a screw, a screw shell. Let us look at possible advantages and consequences of such a design: screw ballistics. Back to Table of Content



Chapter 1: Screws

Screws require threaded bores, self-bored or pre-bored. Screws are heliced shaped inclined planes. The planes must conform to threads in form and turn ratio. A screw projectile requires a clean bore, a means of timing the charge to take advantage of the faster turn rate, and a stronger barrel to deal with longer periods of pressure within the barrel. We then have to deal with trade offs in shell range, penetrating power and method of penetrating armor, velocity as a function of accelerant quantity, and how this affects the design of the fuse. A view of what the screw shell might look like and variations, its design parameters, are spelled out in the following word visualization:

Threads (male or female: outward or inward) w/ complementary barrel thread.
Strong thread material, symmetrical, smooth surfaces, hard.
Lubricated (self or applied) w/ graphite, coated soft metals, or other types of lubricant.
Self-propelled via inclined plane propulsion drawn from high spin velocity.
Balance Bias (optional) to give proper trajectory curve beyond standard curve.

COMMENTS ON SHELL: We generally engrave threads into the core or barrel that the screw enters. Because such a design is self-tapping, very useful with wood, this is the standard. It is possible to reverse the process, engraving the screw with threads and leaving the barrel with projected screw incline. This is probably a bad idea for our cannons as well, but in case some unanticipated consequences of screw shells arise, it is an outside the box variable. A great deal of pressure is placed on the inclined plane of the threaded material. Hard and strong for penetration is the norm for shells as well. Graphite is good for hot body lubrication. It could adhere to the shell on each firing, or be inserted as required externally. Soft metal to spare the hard surfaces should have a high enough melting point so as not to melt during ejection, but soft enough to effectively lubricate the shell in comparison to the hard surface of the shell. Other types of lubrication may be considered, from oils, to composite materials, self-adhering or applied. A screw shell, unlike a smooth shell, is a plane with an inclined plane propeller. The rapid spin will convert to forward motion, allowing a longer range and faster trajectory. The accelerant stores up energy in the spin. A smooth shell cannot take advantage of this spin, but a screw shell can. This brings up rudder control. Fins are possible as with mortar rounds or pop out fins on shells. However, a balance after the manner of balancing tires, can affect spin and so trajectory. This would allow firing at a curve that might dig out tanks behind berms or recessed in the ground.

Usually with a sharp point as w/ most screws.
A solid core option that rotates with the outer surface.
A non-rotating core w/ counteracting fins, gyros or jets.
Ball bearings or lubricant to stabilize non-rotating core.
Self-lubricated or externally lubricated coating in all cases.
Air-burst, anti-aircraft, anti-personnel, armor piercing, impact.
Drilling guns with self-destructing shells to clear drilling bore.

COMMENTS ON TYPES: Due to a generally slower penetration speed into armor, a characteristically sharper screw point might be advisable. We have the problem of deflection when hitting a slanted surface. And this is standard armor practice to keep surfaces on a slant to bounce off incoming fire. A sharp point would penetrate the armor initially by the pressure on small surface area factor. The inclined plane spin of a screw shell would tend to keep the shell stable while coring through armor. The sharp point allows penetration of slanted surfaces more effectively, providing penetration stabilization is maintained. This is probably new territory. Have screw shells been done before, as King Solomon implies? We see that screw shells penetrate armor more slowly and with a different technique, as it uses the spin to drill through as with a standard powered drill. More time for reactive armor to destroy the shell? We suppose so. Does the screw design deflect reactive armor energy more effectively than a smooth shell? I would think so (maybe not, or even increase it.) The planes would deflect energy but at cost of drill stabilization.

We might consider solid and independent cores. An independent core would be free of spin, allowing gyroscopes, lesser distorting forces on fuses, and possibly another stabilization factor during flight and penetration. We have the several means of doing this. We need to consider how to keep the spin surface away from the non-rotating core, bearings or lubricated surface.

I wonder if the slow penetrating speed of a screw shell might be adapted to drilling through rock under certain conditions. After each finishes its spin, it self-destructs, clearing the way for the next firing of a screw shell. Blowback of self-detonation may help clear the tunnel. Periodic clearing would help keep the drill tunnel clear for progressively deeper penetration. The gun itself would keep the required distance to be free of blowback shrapnel and exhaust.

The cannon is threaded to the required specifications.
The chamber depends on the accelerant charge, casing or not.
The chamber could be threaded or not, the tip of the shell engaging threading only.

COMMENTS ON CANNON: Completely threading a shell into the chamber might be time consuming and prone to cross threading. Placing only a few turns might be sufficient to start the process of spin. Because of the slow ejection and need to build spin speed in compensation for flight distance and speed, a prolonged accelerant firing time would be suitable.

Solid rocket fuel is an option for slow burn.
Layered caps is an option.
Fuel injection is an option due to long discharge time and spin acceleration.

We suppose the ideal use of screw shells would be for artillery, relatively short range defense and offensive cover fire. How efficiently the cannon and shell mitigated barrel friction, how fast the incline plane would keep the shell accelerated after ejection would be the factors affecting range of fire. Considerations of barrel cooling, rate of fire due to length of accelerant in the barrel burning are other factors.

Self-cleaning upon blowout.
Special dry ice shells that push forced air briskly through the barrel.
Special rotating wipe shells that eject the spinning swipe into and out of the barrel.
Hand tool cleaning with proper brushes

COMMENTS ON CLEANING: Cleaning as with any rifled or turned barrel is a potential problem. The deep grooves of screw cannons would seem to be a major factor. The tight fit of a screw shell may have some self-cleaning properties seen in rifled shells. The accelerant used certainly is a factor. Rapidly heating dry ice would make a great wind that could be partially held back by a blank wadding. A shell that runs a swab through the barrel would be quick. The usual special barrel tools would do the after combat cleaning to more exacting specifications. A camera might inspect the grooves during cleaning to ensure proper specifications and possible barrel failure. Back to Table of Content



Chapter 2: Spaceships, Moles & Drills

Screw projectiles bring up visions of the Late Doug McClure and other actors digging into the earth with mole type vehicles. We have Jules Verne and his big cannon sending men to the moon in a big projectile. In the last chapter, I mentioned the possibility of using screw projectiles as drilling devices. I will briefly go through potential uses for a screw projectile below.

SPACESHIPS: This is the Jules Verne earth to the moon scenario modified to deal with certain difficulties. I have dealt with this in other essays of mine as well from similar perspectives. The rapid acceleration needed to achieve earth orbit, let alone lunar orbit, produces G-force difficulties. We would require a very long cannon to spread the acceleration, or have means to protect equipment and crew. The stress on the ship superstructure itself would be a formidable problem.

The screw projectile would convert more energy into spin and accelerate more slowly up the barrel. The inclined plane of the screw is a propeller, after the fashion of Leonardo Da Vinci’s famous imagined helicopter, but hardly that spread out in conical base to point. This means that the earth atmosphere would help propel the craft through the atmospheric portion of its flight. As the air thinned, the less atmosphere for propulsion would be mitigated by less air pressure to overcome.

As for the deadly spin of the screw, we would have a spin free, self-stabilizing inner core with control blades, jets and shaped surfaces. As for the G-forces on the crew or sensitive equipment, I refer you to my essay: Tolerating High G: An Essay. We suppose a rotating gondola or cockpit to deal with stress on the anatomy. Rugged rockets, small nuclear explosions or solar sails, or other propulsion could be used at the terminal portion of the trajectory to make the screw spaceships more flexible in function.

MOLE SHIPS: This sci-fi conception has been played out at the movies with respect to the vehicle. We might add a forward screw cannon to break up the rock before the vehicle traversing the distance traveled before it. In hotter lower regions, the malleable rock would simplify movement with the counteracting problem of staying cool within the ship. In this case the cannon would be closer to or touching the target upon firing into the rock to screw out a tunnel. See the passage on the screw cannon drill below for a few more ideas on this concept.

SCREW DRILL GUNS: We use the shell to drill through rock. The distance should be minimal from target with enough space to prevent barrel burst and blowback damage. The shell should have grape cluster explosive self-destructing charges to shatter the shell. We want it out of the way for the next firing. This could be used to penetrate fortifications or for mining or creating tunnels in general. I see a great future in digging aqueducts through mountains to bring water from windward to leeward slopes, and as a means of minimizing the use of dams. Dams have their drawbacks for a number of factors: environment, silting up, downstream erosion.

TORPEDO: Would the inclined plane of a screw have value in propelling torpedoes through the water? What are the water propulsion characteristics of the screw?

SUBMARINE: Would the screw design of a hull have some advantages as a submarine propulsion system, likely a minisub? The core would be non-rotating while the outer hull turned, screwing into the water. How quiet would it be? How reliable or prone to breakdown would the hull propulsion system be?

FINAL COMMENTS: The liquefaction of the shell to penetrate armor is one method of piercing armor, a jet of lead under momentary high pressure. The melting of the screw point under great pressure would soften the line of penetration, be sealed in very tightly by the screw tapping into the armor. Because the screw shell is inherently slow, slow explosives with more energy content are at least conceivable such as petroleum products. This would bring up the cooling problem, but barrels with fins or water cooled are some options for that. Back to Table of Content



Other Works by the Author

[(*]Available online[)*]

Collected Poems I
Collected Poems II
Elements of Physics: Matter
Elements of Physics: Space
Elements of Physics: Time
Unified Field Theory: An Essay
Space as Infinity II
Golden Age Essays
Golden Age Essays II
Golden Age Essays III
Golden Age Essays IV
Golden Age Essays V


About the Author

My current biography and contact links are posted at Shakespir.com/profile/view/EdRochon. My writings include essays, poetry and dramatic work. Though I write poetry, my main interest is essays about the panoply of human experience and knowledge. This includes philosophy, science and the liberal arts. Comments, reviews and critiques of my work are welcome. Thank you for reading my book.

Back to Title Page

Screw Ballistics: An Essay

A brief preface lays out the purpose of the essay. Does increasing rifling to the screw level have advantages in weapons, or otherwise? Chapter 1 discusses screw ballistics design, types of shells, the breech, barrel, accelerant, and cleaning methods of the barrel. We note that the inclined plane of a screw is a propeller and affects trajectory and velocity. Chapter 2 wonders if the practicality of spaceships fired by cannons is aided by screw ballistics. By converting energy into screw twist, the early trajectory through the atmosphere uses this energy. A screw slows down acceleration while storing energy in screw twists to protect ship from G-forces, splitting energy between twist and forward motion. The core would not rotate and counter-levered against the hull. We discuss earth boring mole ships using screw ballistics and boring guns for mining, penetrating bunkers. We wonder if the screw could be used for torpedo and submarine propulsion. This is an offshoot of screw ballistics technology. We wonder if slow explosives with higher energy content work well with screw ballistics due to long burn time.

  • Author: Edward E. Rochon
  • Published: 2017-05-12 23:35:12
  • Words: 2441
Screw Ballistics: An Essay Screw Ballistics: An Essay