Big Daddy of Mortars

[Preacher_of_Boom]

http://www.palmerstonforts.org.uk/fortlog/mallet.htm




http://www.greenwich.gov.uk/Greenwich/YourEnvironment/GreenSpace/Monuments/Mallet%E2%80%99sMortar.htm


http://www.armchairgeneral.com/forums/showthread.php?t=33964


Built in 1857 by the design of Robert Mallet. Mallet's Mortar has a bore of 1 yard!!! One shell it fired weighed 2986 lbs. The mortar itself weighs 40 tons!!!

So, I wondered if anyone ever built a scaled down version of this bad boy?  1/10 scale would have a 3.6 inch bore, right? Or, about 1/4 scale would be bowling ball size. How do you calculate the weight of a scaled down cannon or mortar?

El Cazador 66, Do you have one of these?

[Preacher_of_Boom]

http://riv.co.nz/rnza/hist/mortar/mort4.htm

[EL Caz 66]

Hey Preacher, that some mortar !! Nope don't have that one sitting on a shelf... YET!!! need to do some research.

Ed

[Cannonmaker]

what goes up,  must come down,  all 2986 lbs worth,        heads up guys

Rick

[GGaskill]

Divide the weight by the cube of the scale factor, so a 1/4 scale guns would weigh about 40 tons/4 x 4 x 4 = 5/8 of a ton.  1250 lbs if an American ton, 1400 lbs if a British ton.  A 1/10 scale would divide by 1000 so 80 lbs or 90 lbs.

[walter t]

Hi All,
That thing is a beast , I wonder how many cans of GOEX FG it takes per shot?
Walter T

[Preacher_of_Boom]

It must be a British ton, because the only reference to it that I saw said it weighs 40 "tonnes." 

[Artilleryman]

This mortar is made up of sections that are assembled on site.  I read somewhere that when the mortar was fired it leaked gas (smoke) at all of the joints.  It would have been interesting to get the reactions of the gun crew when it was first fired.

[Preacher_of_Boom]

Divide the weight by the cube of the scale factor, so a 1/4 scale guns would weigh about 40 tons/4 x 4 x 4 = 5/8 of a ton.  1250 lbs if an American ton, 1400 lbs if a British ton.  A 1/10 scale would divide by 1000 so 80 lbs or 90 lbs.

So, hypothetically speaking, if I weigh 200 and am 6' tall, how big would a 1/3 scale Tony be? 2 feet tall and how many lbs? Obviously, I am doing something wrong, since 200 / 3 x 3 x 3 = only 7.40 lbs.

What am I doing wrong? Thanks!


Tony

[GGaskill]

All right, let's work through this.  A one third scale George would be 2' tall, 1/2' wide and 1/3' thick.  Full scale weight is 270 lbs, so one third scale weight should be 10 lbs.  People are close to the density of water (they can float in water or sink in water depending on how full their lungs are.)  Ignoring the round nature of human physiology, a full scale rectangular George would be 6' tall, 1.5' wide and 1' thick which would be a volume of 9 cubic feet.  A one third scale rectangular George would have a volume of 1/3 of a cubic foot.  9 divided by 1/3 is 27 which is the scale factor (3) cubed.  Water weighs 62.3 lbs per cu ft so full scale weight would be 560.7 lbs; one third scale weight would be 20.7 lbs.  Needless to say I am not rectangular, but the weight ratio is 27 (3 cubed.)

So 7.4 lbs is right.

[Preacher_of_Boom]

You're a good teacher then. I got it on the first try!

It just doesn't seem right, but when you described the thickness of a 1/3 scale George it became much more clear.

It just goes to show that the saying is true. The only time I was ever wrong was the time I thought I was wrong. 


Artilleryman, I bet it put some hair on their chests real quick when that big bad mortar went off, or it might have singed what they had! It sounds llke it could have used a set of Fel-pro gaskets.