Experiments Against Ironclad and Fortress Armor of 2008

[seacoastartillery]

                                                                   EXPERIMENTS  AGAINST  IRONCLAD  AND  FORTRESS  ARMOR


     During the spring and summer months of 2008 Seacoast Artillery Company will conduct a respectable number of 1/6 scale penetration experiments with our scale 100 Pdr. Parrott Rifle and our last prototype 7” Treble-Banded Brooke Rifle. 

     The scope of these experiments will encompass a wide variety of targets and a wider variety of materials.  As a general guide, we are using Alexander Holley’s,  A Treatise On Ordnance And Armor, Volume Two.  Eventually we hope to do a complete re-creation of General Totten’s experiments of 1853-1855 at the United States Military Academy at West Point, New York.  This may take three or four years, however, as we have to make a completely authentic 1/6 scale Army 42Pdr. first!  We also hope to duplicate some of the very well thought-out targets which were employed by British designers to test out armored plates fastened to the first ironclad ship’s sides.  We also hope to test out some scale armor of the same type used by CSN Commander John Mercer Brooke, Robert Parrott, Rear Admiral John A. Dahlgren and General Thomas J. Rodman.

     Initially we will use fairly simple targets made out of easily available materials like 12L14 leaded steel and the mild steel used for U-channels and I-beams.  As time goes by we will build and attempt to penetrate more historically accurate armor targets made according to authentic riveted and bolted designs with historically accurate materials like wrought iron plates, thick and thin, and thick, cast iron and timber backing plates.  Also we will test out some solid bolts on earth-work fortifications which feature green and dried logs, rammed-earth, sand and marsh grass traverses, and mud-bricks.  Second and Third System fort construction using masonry, of both granite and brick construction will also be tested.  Hopefully we can get some Rosendale hydraulic mortar to cement the miniature masonry. 

     Initially we have these projectile materials available for the manufacture of Brooke and Parrott bolts:


1.   12L14 leaded steel to simulate wrought iron

2.   1018 low carbon steel

3.   4142 alloy steel

4.   4150 alloy steel

5.   O-1  tool steel

6.   D-2 tool steel

7.   S7 tool steel

8.   Wrought iron


WE NEED YOUR SUGGESTIONS HERE.


     Initially we have these materials available for targets:

1.   Solid Oak

2.   Yellow Pine

3.   Structural steel (mild, low carbon steel)

4.   12L14 steel

5.   Boiler plate (low carbon steel)

6.   Brick

7.   Granite

8.   Rammed earth

9.   Sand

WE NEED YOUR SUGGESTIONS HERE TOO.  Are we missing some here?  Certainly there must be more.


10.  Tabby, an oyster shell cement; thanks Terry C.  A Tabby method of preparation; thanks KABAR2.

11.  Timber Clad and COTTON CLAD;  thanks Lance.

12.  Coal barges for ships attempting forced passages; thanks T.K.

13.  Palm log faced earthworks; thanks KABAR2.

14.  Clay soil:  thanks Kabar2.

15.  Wrought iron;  thanks T.K.


     The very first test we will conduct if our range ever dries out, maybe this weekend is the  Proof Test of our last prototype Brooke Rifle.
This will consist of a 1/6 scale powder charge which equals 3 times the standard service charge which was 16 pounds or 1,555 grains of  BP and a bolt which equals 1/6 of twice the standard bolt weight which was 240 pounds or 17.77 ounces.  Just like in our Ironclad Tests of 2006, the target will be a  piece of 1” thick Boiler plate.  The long bolt will be hardened S7 tool steel at 57 Rc on the  “C” scale with a 12L14 pinned and bolted sabot. 

WE ALSO NEED SUGGESTIONS ON THE DISTANCE BETWEEN GUN AND TARGET.     We will seriously consider each and every suggestion.

We will try to incorporate all suggestions into our experiments and we will post the results with photos so everyone can see what happened.

Regards,

Mike and Tracy






 

[Terry C.]

     Initially we have these materials available for targets:

1.   Solid Oak

2.   Yellow Pine

3.   Structural steel (mild, low carbon steel)

4.   12L14 steel

5.   Boiler plate (low carbon steel)

6.   Brick

7.   Granite

8.   Rammed earth

9.   Sand

WE NEED YOUR SUGGESTIONS HERE TOO.  Are we missing some here?  Certainly there must be more.

Tabby.

Not sure of the exact recipe, but oystershell tabby was an essential building material in the coastal areas of Georgia and northern Florida, and used extensively in fortifications up to and including the Civil War era.

[Terry C.]

Okay, I had to go in and do some actual work (dammit) so I didn't have time to dig through my photos this morning.

Up first are three photos from Fort Clinch on Amelia Island, Florida that show that tabby was still an important building material even in the age of masonry forts. Fort Clinch was 'under construction' during the Civil War and never officially finished before hostilities ended.

The bare foundations in the foreground of the first photo are tabby. One can only assume that tabby was used in the foundations of all the buildings.

The deck in front of the gun mounts in the second photo is tabby. Whether or not this would have been bricked over, I can't say.

The third photo shows exposed tabby fill in the walls of the bastions. This I know would have been covered over with brick and concrete. I don't have a photo of it, but there are also sections of the outer wall that are missing the top brick layers and these are filled with tabby as well. Just about every substantial structure is made from tabby-filled brickwork.

You might go as far as to say that Clinch is a tabby fort with a brick veneer.


Tabby is a very durable material. The last two photos show the citadel and barracks at Fort Frederica on St. Simons Island, Georgia. Built in the early 1700's, they are made almost entirely of oystershell tabby.


So... you need a good authentic tabby recipe.

[KABAR2]

Will this help Link at bottom of page.

Allen <><

TABBY PREPARATION
Original tabby was made from a mix of slurry of water, homemade lime, local sand, and oyster shells. Occasionally, aggregates of broken glass, brick or other similar products were added. The mixture was poured into a wooden form or rectangular bottomless cradle made of finished boards approximately two inches thick. The length of the cradle varied; the height was 20 to 22 inches in the eighteenth century but was reduced to 10 to 12 inches in the nineteenth century to minimize collapse and provide greater strength. The sides were held in place by dovetailed braces. The tabby was tamped and leveled by hand.

Round pins set at regular intervals held the cradle in place during the entire process. The tabby air-dried in its cradle for two to three days. After it hardened, the form and pins were removed and placed atop the first pour or “round” for subsequent rounds, thus building a wall in a layer-like fashion. The finished wall was then brushed with a broom before stucco or whitewash was applied.

Minute modifications to this procedure distinguish Tabby Revival tabby from its copied original. In addition to the commercially available Portland cement and lime altering the mix after 1880, the cradle was modified to eliminate the use of pins: huge clamps now held the sides. The qualities of the cement enabled builders to discard the previously essential stucco.

The sand was always from a local body of water. Sand from salt water was washed to remove as much salt as possible, since salt causes decay and deterioration, such as spalling. Oyster shells, procured from Indian middens or trash piles, provided a well-washed aggregate and, when burned, produced the third ingredient, lime. A "rick", or bonfire, was built, starting with a frame of hardwood tree trunks surrounding a deep pit filled with pine knots. Layers of logs and oyster shells were then piled on top and set afire. The intense fire burned the shells, turning them into a white powder called quicklime, which reacted with water to set or cure the mixture. After 1880, this burn was omitted in favor of purchasing pre-bagged lime and Portland cement.

Tabby making was labor-intensive and dependent on weather. February through September were the recommended months for manufacture. This allowed builders to avoid winter freeze-thaw cycles and rainy, hurricane-prone autumn months, and take advantage of months of high humidity, which shortened the setting time. Drying tabby was protected from rain by palmetto branches. With the introduction of Portland cement – imparting increased setting time among other properties; tabby builders heeded this traditional advice, but may not have always needed to follow it.


http://historyfieldtrips.org/explore/artifacts/tabby.asp

[seacoastartillery]

     Thanks Terry and Allen; hard to believe we forgot about Tabby.  After walking on all those sidewalks while exploring Savannah, Georgia that were made of Tabby, you would figure that we would remember that essential southern building material.  You fellows are a great help to us, as we want this to eventually be a very thorough and comprehensive series of experiments.  Thank you!  We found several photos of this material in fort structures, but all have been covered better by Terry's photos, except one which follows.

 
In the upper left of this embrasure at Fort Sumter, Charleston, SC you can see a couple oyster shell pieces in the Tabby which surrounds the gun muzzle.  There are four materials in use in this embrasure.  They are Tabby, an iron plate around the inside edge and of course the brick masonry under the Tabby and the modern repair cement of the outside edge and outer face.




    Mike, "Fire up the oyster shell furnace!"

Regards,

Tracy and Mike

[Graybeard]

Other than the obvious entertainment value what is the purpose of the exercise?

I ask that question because as I read of the plan the first thought that came to mind was: What if any correlation will there be to the real world application in those long gone days when using miniture as opposed to full scale?

In other words while I realize you'll be scaling your target to the scale of your gun and projectile I'm just not convinced that translates to a real world effect. There is a certain amount of momentum that a 20 pound projectile carries with it and a damage it does that is all out of proportion to what 1/6 of 20 pounds is going to carry with it at the same velocity. Even if you scale down the targets size accordingly I guess I have a hard time wrapping my mind around the effect correlating to what happened in the real world scenario of a 20 pound projectile hitting the full scale target.

I have seen other scaled down experiments before and always the same question came to my mind. I guess even after seeing what they described it didn't convince me the scaled down experiement related well to the full size event. Perhaps the scientific communtity thinks it does and perhaps it really does it just doesn't seem so to me.

[KABAR2]

Other than the obvious entertainment value what is the purpose of the exercise?

I ask that question because as I read of the plan the first thought that came to mind was: What if any correlation will there be to the real world application in those long gone days when using miniture as opposed to full scale?

In other words while I realize you'll be scaling your target to the scale of your gun and projectile I'm just not convinced that translates to a real world effect. There is a certain amount of momentum that a 20 pound projectile carries with it and a damage it does that is all out of proportion to what 1/6 of 20 pounds is going to carry with it at the same velocity. Even if you scale down the targets size accordingly I guess I have a hard time wrapping my mind around the effect correlating to what happened in the real world scenario of a 20 pound projectile hitting the full scale target.

I have seen other scaled down experiments before and always the same question came to my mind. I guess even after seeing what they described it didn't convince me the scaled down experiement related well to the full size event. Perhaps the scientific communtity thinks it does and perhaps it really does it just doesn't seem so to me.

One problem with scale is no matter what you do the molecular structure can not be changed, nor the denseness of the material being tested, what a say a 10" shell will do to 3" of face hardened plate may not translate well when scaled down. In defense it can still give an idea of the forces at work.

one other item to add would to your list would be palm log faced earthworks, know anyone in Florida that can ship you some small ones?
Don't forget some earthworks would have allot of clay in them, that could soak up some punishment also.


Allen <><

[seacoastartillery]

     Bill,   Part of the reason we are preparing to do these tests is to answer your questions which we have always shared.  Especially as these penetration experiments pertain to the lighter steel or iron round shot, WE ARE NOT YET CONVINCED that there is ANY relationship between the penetration in masonry of a 42 pound cast iron shot and a 1/6 scale, 3.11 oz. steel round shot, each going about 1,400 fps.  Be assured that when we do test steel or iron round shot on ANY material, that we will have adequate cover to protect us against projectile bounce-back!!  We expect it, and being former scouts, we will "be prepared".  Thank you for your thoughtful comments.

     Allen,   Right you are; densities cannot be changed, so it may be difficult to get apples to apples exactly.  After the informal, let's just try this stuff to see what happens phase is concluded we can go forward with some more technically correct, documented experiments.  Palmetto logs?  Do you mean those wooden sponges which soaked up all the close range shot from the British naval guns at Ft. Moultrie in Charleston, SC?  A good suggestion!  Don't worry about clay content, our soil in Broomfield is so loaded with clay that you have to rototill your garden patch for about three years with two or three bales of peat moss added each year before you can work the soil at all!!

Regards,

Mike and Tracy

     

[dominick]

Mike and Tracy,  There is a book available, titled  "Report to the Government of the United States on the "Munitions of war" 1867.  Available from Lindsay Publications. www.lindsayblks.com  ISBN 1-55918-345-4   The back chapters of the book covers fortifications and iron-clad construction with cross section scale drawings of a few these structures.  Some of the topics covered are:  Iron vs. Granite,  Granite Casemate,  Thorneycroft Bars,  Laminated vs. Solid Plates,  Thick Plate shields. Iron Clad Ships, French Armor,  Warrior and Minotaur Armor,  Chalmers System of Armor,  Bellerophon 6" Plate, Hercules Armor.   I thought I would pass this on to you.  Good Luck,  Dom

[seacoastartillery]

     Thank you so much, Dominick!!  This book sounds just perfect for our purposes.  We have quite a few of the Lindsay Book's publications and we found the one on early 1900s rifling practices and tools too be very useful when we were making our rifling machine.  I think I read about tests on the Thorneycroft bar target which the British government did in Holley's book, but all these others will make a great addition to the information available to us. 

     The production of these targets will take some time, but I believe we can post the ultimate proof test of the third prototype of our 7" Brooke Rifle on Sunday evening.  Mike has way too many military small arms to shoot so cannons have to take a back seat on this trip.  We will see just how strong our new cannon and a 1" X 12" X 12" piece of boiler plate really is!

Thank you very much,

Mike and Tracy

[lance]

Mike and Tracy, if i understand wanting suggestions for this test? then i'm thinking you'll have to build a miniature cotton press. You're guns should do well against Timber Clads, Tin Clads, and Iron Clads. But what about the forbidding Cotton Clads? Or, i guess you could just build a cotton bale shore battery.

[Artilleryman]

Are your targets going to have a vertical face or will you try some set at an angle?  (Devise something to catch the ricochets.)  I assume that you are familiar with the attempts to make armor penetrating rounds to use against angled surfaces.  This sounds like an interesting project.  I will be interested in the results.

[Cat Whisperer]

...
 I assume that you are familiar with the attempts to make armor penetrating rounds to use against angled surfaces. 
...

Not an easy task.  Anyone have successs at it?

[seacoastartillery]

     Lance,    Great idea!!  I was just thinking today about those western river Tin Clads which will be pretty easy to simulate with 2" equivalent armor plate made of wrought iron, or initially, with really low carbon structural steel.  I also remember that coal barges lashed to the sides of the vessels were used by the Federal flotillas when they forced a passage passed a heavily fortified place like Vicksburg, MS.  I'll have to give you credit for Cotton Clads; I've heard of them, but have never seen a photo.  There is a photo out there someplace of a Confederate artillery battery around Memphis, TN, I believe which has lots of cotton bales strewn about after a battle.  If you guys can find a source of raw cotton, let us know.  Thanks, Lance!

     Norm,    Most of the targets used by CSN Commander Brooke were vertical, as he was looking for performance against the Federal Monitor's turrets and sides, but even he tested armor targets having a 35 deg. angle, and the British did so quite a bit at Shoeburyness.  At Portsmouth they tested the 100 Pdr. Armstrong  on 4.5" wrought iron plate at 51 deg. off the vertical with very poor results.  Unfortunately they fired round nose cast iron shot, not flat nose shot such as was used by Whitworth, Brooke, Parrott and others.  There came to be a consensus by about 1860, however, that a flat or almost flat(Brooke) nose was superior to the large radius ogive nose shape for armor penetration.  A comparison of the large radius Palliser shot and the flat nose Whitworth shot was noted in British tests in the late 1850s and the Whitworth was favored.  As for collecting the shot, we will simply invert the angled target surface so that it deflects the  impacting bolt downward.  Our bull dog tendencies will force us to stick with this project until we learn quite a bit.  Glad you are interested and thanks for your insightful comments.

     Tim,     Rodman and Dahlgren in the north  knew how to do it.  Crush the armor with 440 pound cored shot going 1,500 to 1,700 fps at close range which was the fate of the CSS Atlanta.  Parrott had good results with the 200 Pdr. Parrott rifle and they were mounted on Monitors and other Federal naval vessels.  CSN Commander Brooke manged to hole an 8" thick wrought iron target several times with the 7" Treble-Banded Brooke Rifle at 285 yards and believed that at 500 yards or less, the monitors were in mortal danger, the trouble was, they knew this from results of impacts of bolts thrown from much greater ranges.  We only know a little about all this now; hopefully we will learn a lot more as these experiments are performed.  Thanks for asking.  Take lots of pictures, Tim and have a GREAT TRIP!!

Regards,

Tracy and Mike

[gulfcoastblackpowder]

It sounds like you have a good deal of information regarding test firings from full scale guns.  The most significant tests would probably be the duplicates of these. 

The hardest part will not be in scaling the guns/projectiles, but in scaling the targets, especially with nonhomogeneous (i.e. nonuniform composition) materials, such as the proposed tabby, woods, granite, and brick (I'll use tabby as an example).  A scale test would probably require scaling the tabby itself - using 1/6 finer grain sand than was used, as well as crushing the shells to nearly 1/6 their scale in traditional tabby, not to mention scaling the overall geometries used in the construction of forts/strongholds.  Of course, I say probably because, there's no way of knowing how/if reactions of a scaled material correlate to full scale without doing tests.  In some cases, scaling the target may not be necessary or possible - like tabby.  Tabby's strength comes from it's weakness - it acts as a sponge, absorbing the impact rather than trying to deflect it.  This inherent property may change substantially when scaled.

I think the main thing you'll ultimately obtain from these tests will be the performance of your scale models, but it will be fun to perform them and to what, if any, conclusions you can draw.  Perhaps using other projectiles (most of yours appear to be solid steels) would yield a nice comparison on how the various materials/shapes interact.  For instance firing chain, grape, hollow, explosive (this one may need to be excluded for safety/legal reasons), or other shaped projectiles, in additon to any odd material projectiles that were used (I am not an expert on this, but I imagine people in battle would throw just about anything into a cannon when needed).

Also, be careful angling the targets downward as some new rules apply.  The force exerted by the projectile will be directed upward, so securing the target is important - not just so it doesn't get pushed upward (safety concern), but any movement of the target would also absorb some of the energy of the blast (integrity concern).

How do you plan to measure the force of the blasts?  Simple remote observation, or with strain gauges, calipers, etc?

Should be really interesting to see the results, and really fun to obtain them!

[lance]

Mike and Tracy, you got to check out this cool web-site: cottonman.com     He is down in North Carolina and offers raw cotton,even miniature cotton bales. Should be just the thing for you to build a nice Cotton Clad.  I also have a picture of one of the Confederate shore batteries at Yorktown that used cotton bales,no picture of a Cotton Clad though. I'll try and e-mail you the pic i have if you want?

[dan610324]

why an "secret" email ?? 

WE ALL WANT TO SEE IT   

[seacoastartillery]

      We just got back from the high plains north of Denver, Colorado, so we will post the results of the first experiment now and answer these questions later.  Send it Lance; thanks!

Decided to use the second test rifled Brook practice barrel rather than our first complete Brooke cannon for the reason that we were a little, no, a lot leery about putting that S7 tool steel bolt , hardened to 57 on the Rockwell 'C' scale down that really accurate barrel!!  With 1,555 grains of BP behind that 9 oz. bolt, it came out with some authority!!  The 12L14 sabot DEFINITELY engaged the rifling!





As you can see we dug a two foot deep pit for this PROOF TEST on the last of the prototype Brooke rifled test barrels.




The projectile was barely lodged in the plate a plug of plate was punched out on the backside.





The 1" thk boiler plate, 12"x12" was pushed back about 1/2" into the rock hard prairie clay soil.  The test barrel jumped up in the air about two feet with it's landscape timber and 35 lb. block of 1018 steel.  Volumes of smoke and dust rose above the pit.




One-half of the bolt sticks out and you can see how the whole plate is bent.





That knarly looking thing is the end of the bolt just inside the plate backside.  The punched plate plug is beside the oblong hole.





We just barely touched the bolt and it fell out of the hole in two pieces!  The pieces and bits came off the half to the left; the other side was all there.  See how it sheared through the plane coincident with the axis of the two sabot anti-rotation pins and the sabot retaining bolt.  Why?  Should we have tempered this bolt down to 53 Rc?





Quite a hole there with a bolt shard stuck fast.  Mike is using the plate for shielding as he attempts a new load in his Carcano; 5 qts of oil will save you, Mike !!!





     Well, what do you guys think.  Is this a good start?  The ground shook when that plate was hit.   

The most significant tests would probably be the duplicates of these. 

     We agree with you, gulfcoastblackpowder, if we can duplicate some of these tests of ordnance, projectiles and targets as they were originally performed, maybe we can reveal some  interesting parallels.  For instance, we might fire a wrought iron bolt with a milled, (turned skirt type) base at a scale, wrought iron, built-up layered plate target at a scale distance of 47.5 yards, (1/6 of 285 yards) to see if the effect would be similar to CSN Commander Brooke's while using exact scale powder charges.

     We also agree with your logical presentation of difficulties in producing scale targets.  Tabby would be tough, no doubt, but scale timbers or mounds of clay soil backing will most likely be less problematic.  Although we will never fire any explosive shells, all of the others you mentioned will be definite possibilities.  You mentioned other shaped projectiles.  One which we will definitely try is the Stafford Saboted Bolt, a sub-caliber bolt which is shaped startlingly like a modern, ultra high velocity main battle tank bolt.  Some of the Federal Navy ships were required to carry a few in case Confederate ironclads appeared.  We would love to get a copy of those Stafford bolt vs. armor experiments. 

     The results of these tests will be measured by mostly mechanical means such as the weight of metal displaced, size of hole or depth of dent or gouge.  If there is one thing we can assure you of it is our ability to measure these results.  We have lots of inspection equipment and know how to use it.  Hope you stay with us on this adventure!  We will make every effort to present the results logically and clearly.  Thanks very much for your comments!

     Lance,    You're right, Cottonman has a great site.  We really like the looks of those bales, but they are a little small.  We will probably get some raw cotton, some burlap and some 1/6 scale straps and run it through our miniature hardwood cotton press, yet to be built.  Will oak or maple handle the pressure required to make a bale which is 4.7" square X 9.7" long?
Hard to believe you could get adequate protection with even two bales if rifled artillery was brought to bear on your position, but maybe it would be OK for blocking 6 or 12 pdrs. or 18 and 24 pdrs. at some distance.  Maybe?  We will see; this is improbable shielding, but we could possibly be surprised.  We will try it.  When?  Can't say for sure.  Thanks for this very unusual, but historically accurate  idea, Lance.

Regards,

Mike and Tracy

[Double D]

I understand your one sixth scale  logic in the range.  But I believe the logic  just in the scale sense is faulty.

Reasoning would say if you are going to reduce things  to one sixth scale then everything must be reduced to one sixth scale to be equal---including physics; velocity , the effects of gyroscopic stability, ballistic coefficent etc and you can't do that.  Since you can't do that you can't reduce range.  The only thing you can do is reduce demensions of your target material.  Remember Julian Hatcher's work in the 1920's and 1930's on the effects gyroscopic stability of the penetrative ability of projectiles.  The 1860's guys may not have understood what Hatcher learned later, but they sure experienced the effect of the principle.

I think if you are going to reshoot the orignal test with one sixth scale at the original velocity you must shoot at the original range to achieve the original ballistics.  If not you must figure out how to achieve one sixth of all the ballistic factors or your test is not conclusive...fun but not conclusive.

[KABAR2]

M & T,

I have one question on the 1:6 th cotton bales........ how do you correct for the weight/Density of the cotten from 1:1 to 1:6 ?

[cannonmn]

If you run out of other targets, it would be interesting to see how far a projectile would travel through peanut butter.

[Cat Whisperer]

If you run out of other targets, it would be interesting to see how far a projectile would travel through peanut butter.

THAT's IT!

I can remember some peanut butter (from C-rations) that was ABSOLUTELY bullet proof!!!

[KABAR2]

THAT's IT!

I can remember some peanut butter (from C-rations) that was ABSOLUTELY bullet proof!!!

Yeah,

I have some Nam era C-Rats with the little tins of peanut butter in them........ they are the only thing left that's eatable !  

[lance]

 Explain scale to me. A cotton bale weighs 500 pounds,so what will a 4.7"x9.7" bale weigh? Not all Cotton Clads were ships with bales stacked on the deck,some had double bulk heads with compressed cotton bales in each bulk head.Let's say you have to build a shore battery, and all you have is 500lb.cotton bales. The pic i have looks like they had an unlimited supply of cotton bales.How many bales would you use? How does all this work in scale?

[seacoastartillery]

      Lance,    It is truly amazing how some people have a real talent for distilling complex subjects down to a few important points.  You are one of those people.  Some may disagree which is their right, but the way Mike and I understand scale is this:  Scale refers to all weights which implies material properties including densities remain the same and only the dimensions of the scaled down object changes in direct proportion to the full size object.  We have no information on construction of Cotton Clads so we can't comment on those, but a scale shore battery with embrasures and maybe parapets made of cotton bales could easily be built with all items scaled down equally.  Since we cannot afford to do this, we must decide how many full size bales would the artillery have had to penetrate to cause damage to the batteries materiel or personnel.  We would then place that number into our test fixture and fire away.
      As for the weight of a 1/6 scale cotton bale, you divide the full size weight, 500 lbs., by the cube of the scale you are using, in this case 6, so 6x6x6=216.   500/216=2.32 lbs.  So a 1/6 scale cotton bale dimensioned according to the Cotton Convention in New Orleans, La of 1895, would weigh 2.32 lbs. 

      Cannonmn, Cat Whisperer and KABAR2,     We will settle the value of peanut butter as a target at this year's New River Valley Cannon and Mortar Shoot in Floyd, Virginia.  When we get there, Mike and I will get a 4" Dia. steel pipe about 25 feet long and fill it with the peanut butter of cannonmn's choice and then seal the ends with Saran Wrap and tape.  We will align the pipe with the our cannon's axis and bring one end of this peanut butter "torpedo" within 2 inches of the muzzle for MAXIMUM EFFECT!  We would, of course, offer the privilege of lighting the fuse to the peanut butter target's originator, cannonmn.  We would also mention to him how insulted we would be if he did not stand by, directly behind, the 7" Brooke Rifle as he fired it.  It could be the most humorous video clip ever produced for his legions of U-Tube fans.  FYI, John; Ed will be standing with us about 25 feet to right or left of the gun!

      KABAR2,    Only dimensions and weights change, not density.  If you change the density of any of these materials, then you change the physical properties of the material and that material's ability to resist an impacting projectile which has been reduced in size proportionally.  In our opinion we should merely reduce the quantity of material present to resist the shot. 

      Double D,    Mike and I discussed your comments for about three hours today, a long lunch it was.  Please allow us to illustrate our thinking on this topic.  Lets say that you were on a design team in 1925 charged with the design of an improved 16" naval gun capable of increasing the projectile velocity up to 2,700 fps to meet the requirement of a twenty-two mile functional range.  You are given a paltry $50 budget to do your projectile impact experiments.  So you figure you can do reduced scale tests only.  You buy a surplus 30-06, a Springfield, '03 and the engineering machine shop produces a few bullets which duplicate scale weight, about 150 grs., size and hardness of the naval shells.  The proportion is 1:51.95=.308:16.0.  You realize a big problem exists; in order to hit your proportionally reduced target, you must reduce the range.  Your rifle has only about one-tenth the range of the 16 inch gun.  What do you do?  You must reduce the range, but by how much?  Practical considerations take over and the ability to hit and produce an effect on the target brings the target closer to, say about 200 yards.  So what produces  the effect on the target?   You decide:  energy at the target distance and bullet form.  In order for the energy of the .308 dia. bullet to be proportional to the energy of the 16" round, the velocity MUST be the same at the 200 yards range.  Using govt. instruments and charts at your disposal you calculate the big gun velocity at 200 yards and range test your 30-06 to get reloads that will match that big gun velocity, about 2,625 fps.  Then you can do your impact tests on the 5/8" armor plate at 200 yards.

     So, if there was enough data available from those Civil War experiments on specific velocities at a given range, we would be far closer to Apples to Apples.  Alas, there is not.  We have to be happy with approximations and SWAGS.  However, we firmly believe, that if you hit a scaled down target with a like-scaled down bullet at the same velocity as the full-size, original, at ANY convenient range, you will achieve a correct, proportional result. 

     Getting back to our experiment; we are trying to duplicate the efforts of Commander Brooke when he was testing the 7" Treble-Banded Brooke Rifle along the James River just south of Richmond, VA in 1863 before its delivery to Charleston, SC.  The bolt was a 120 pound wrought iron, bolt designed for armor penetration.  The range was 285 yards.  So we have to determine a simple way to predict the rate of the bolt's velocity decrease over it's entire max range.  The max range of the 120 lb. bolt at 1,300 fps muzzle velocity is 8,000 yards.  The maximum range of our 1/6 scale bolt is only about 2,000 yards due to it's much inferior ballistic coefficient and much reduced powder charge.  In rough figures we contend that our bolt sheds it's initial velocity at a rate approximately four times as fast as the full-size original did.  So, for the velocities to be close to the same, we must reduce the range so our bolt which quickly slows down can match the originals velocity at 285 yards.  With all values expressed in yards, we find that 2,000 : 8,000 = X : 285,  X = 71.25  Our scale thickness target will be placed at 71.25 yards where we believe the velocity of 1180 fps for our 8.89 oz. bolt will pretty closely match the velocity of the 120 lb. original at 285 yards.


      Terry C.    I finally swallowed my pride and asked my son to work on the "still capture" problem I had with my little camera videos.  ZackaryX solved my 5 hour problem in about 3 minutes!!  So here is the first still which is from, "Penetration of the 1" Boiler Plate", the movie:

It's a little small, but it does show quite a comotion as that thick steel plate was struck.  We estimate the velocity of the 9 oz. bolt conservatively at 1,600 fps.  That's 22,388 ft. lbs. of energy on target!



That's our thinking on these subjects,

Mike and Tracy

         

[dan610324]

well now I cant keep quiet any longer , why are all people so negative to this tests ?? I believe its very fun , amusing and interesting . I don't care if its scientific correct or not .
I think its nice to see all efforts that's put into this project to amuse other people here at the forum . this must be in the top 5 of unnecessary knowing , but I love it 
if the peanut butter penetrating test ever will occur , then I promise to visit the test firing range to do my own very scientific investigation , how many percent of the spectators will survive the laughter from seeing such an test    that's extremely scientifically important to know , because if to many dies I believe FBI will Ban the video from you tube      then I'm lucky to have seen it when its happened , if I survive   

[gulfcoastblackpowder]

I like the idea, but I think if you're going to do it - try to find some significant data in addition to having fun - there is, after all, a lot of work involved in setting up the shots.

I think in addition to traditional targets, using some modern ones would also be interesting - like a sheet of Lexan, ballistic gel, kevlar sheet, high density foam, etc.

[lance]

Mike and Tracy, I find this test fascinating and thank you for taking the time to share your results and knowledge. With the ultimate proof test being a complete success,what will be the next step? I understand what you are doing with these tests and look upon it very seriously. This next question has to do with the 7" Brooke coming here for the New River Valley Shoot. If i rig up a slow moving, smoke belching ,Iron Clad of your choice,would you take a shot at it?

[Cat Whisperer]

Mike/Tracy -

Good thinking.  You've outlined the starting premises and drawn your expectations of parallels to full scale.  The results will either duplicate or not the observed results of what was achieved at full scale many moons ago.  From that comparison you can draw conclusions to the accuracy of your 'design of experiment'.

In addition, you can compare the effects (in small scale) of different velocities on a give target/angle of incidence.

These observations, obviously, would lend some insight to the effects on similar steels with similarly shaped projectiles of what-ever scales - by comparison of your results with known results published in yester-year.

Thanks for your taking the time and effort for this research!

Peanut butter is next.  Although, since George Washington Carver (who did his undergrad work at ISU and later did (if I remember correctly) his fundamental development of the growing of peanuts Tuskegee post Civil War).  So, I surmise that peanut butter is likely to be pre-1898 but post CW.  It is also questionable as to whether it's EVER been an effective implement of armour.

[Cat Whisperer]

...
... the New River Valley Shoot. If i rig up a slow moving, smoke belching ,Iron Clad of your choice,would you take a shot at it?

WOW!  Does this imply a NEW category of competition?  MOVING targets?  Does this mean we NEED a body of water on which to place the Ir'n Clads?  (Or can it be simulated by using a remotely controlled device to move the iron-clad target from left to right?)

Should be a duck shoot!