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/sci/ - Science & Math

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6395005 No.6395005[DELETED]  [Reply] [Original]

How can I figure out how many newtons are required to penetrate one centimeter of steel?
Would the force required change linearly with added surface area penetration?

>> No.6395011

well its force per square inche so i would assume it depends on what your trying to penetrate it with and the size overall, building something fun?

>> No.6395017

>>6395011
Something like that.

I'm trying to figure out if it's possible to scale up a ballista enough to fire a relatively large projectile through a half meter thick steel plate.

>> No.6395038

>>6395017
half meter thick? are you trying to pierce the moon?

>> No.6395045

>>6395038
An M1 Abraham.

>> No.6395141
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6395141

Bump

>> No.6395811

>>6395005
>>6395045
http://upload.wikimedia.org/wikipedia/commons/2/2a/Projectil_deflection_effects.jpg

http://upload.wikimedia.org/wikipedia/commons/a/a1/Sloped-armour-slide.png

also M1A2 turret has been calculated to be like 780mm of armour steel against APFSDS (armour-piercing fin-stabilized discarding sabot)

>> No.6395840

>>6395811
also, i think it would be easier to use HEAT arrowhead as it´s penetration capability doesn´t depend on speed. It may be harder to get materials and make one, but it´s more likely to work out.

estimated penetrations for HEAT rounds:
1st gen diameter x3.5
2nd gen diameter x7.5
3rd gen diamter x10

M1A2 turret armour estimated to be similar to 1060mm steel plate so assuming your homemade HEAT would be similar/worse than 1st gen military HEAT you would need to make it over 300mm diameter

>> No.6395916

>>6395840
and if your HEAT has similar effectiveness ratio to a WWII era HEAT munitin (150%-250%) it needs to be 710-450mm diameter, so i would recommend just stealing some AT weapons rather than building one yourself

>> No.6395922

>>6395916
>aiming for the turret

>not just aiming the tracks or drive gear...

>> No.6395927

>>6395840
After Iran stopped sending precision, military grade EFPs to Iraq the local yokals started fashioning their own crude ones.

They actually weren't half bad at fucking up our up armors. So I think it can definitely be done.

>> No.6395932

>>6395922
frontal turret is thickest place of modern tanks, so a charge that can penetrate that can also penetrate rest of the tank.
if i could choose where to aim, i would stoot enginebay from above, but its rare to get a perfect angle and placement when shooting a tank

>> No.6395933

>>6395922
>>6395932
also, shooting tracks would only stop the tank, so it could still shoot back at you.
tracks work as spaced armour so penetration after those is close to zero

>> No.6396368

find out how many newtons penetrates 1mm and multiply by 10.

gg OP

>> No.6396394

>>6395933
A stopped tank is a dead tank. The crew has to leave eventually. or get smoked out.

>> No.6396557
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6396557

>>6395005
For very simple approximation you can use this
http://en.wikipedia.org/wiki/Impact_depth
For more accurate stuff it gets very complicated and highly context dependent.

>> No.6396586

>>6395045
>>6396557
Modern antitank perpetrators are made out of depleted uranium and move at 1700+ m/s. I dont think newton's approximation will be useful unless you achieve those speeds.

>> No.6396626

>>6396586
Sorry I didn't read the whole thread. Yeah a ballista is going to have a lot of trouble with a M1 Abraham. But there are low tech ways to mess with a tank.

A hidden pit with steep walls can let you catch one and slowly bury it alive in relative safety if the hole is deep enough to keep the guns from reaching you. (this is simple and very effective with some advanced planning)

Covering it in flaming oil and tar from a trebuchet can ruin its day if it hits certain parts of the tank.

Then there is the matter of the tanks up keep, crew has to eat and the tank need fuel. Cut off the supply line and its days are numbered.

I would need to better know the resource you have available, but I know tanks aren't as all powerful as people think.

>> No.6397503

>>6396394
>implying they wouldn´t just repair it in couple hours

if you have to stop a tank with a giant ballista, you will be a huge target, and clearly don´t have good enough weapons to take a tank out so they are safer inside the tank while waiting for the rest of the division to roll in and help

>> No.6397507

>>6397503
not really a ballista doesn't have a thermal heat signature. It would be an optimal weapon to use at night with a steel / glass plate cover to obscure the user. the tank would never see you. Anyone with a hot barrel is gonna get insta killed.

>> No.6397517

>>6397507
yeah, hut tanks have other nightfighting sensors/cameras than just a thermal camera
(IR equipment, searchlights, crew sometimes has personal NF equipment sometimes...)
how do you intend to hit a tank with a ballista at night without getting detected if your ballista is bigger than a regular house?
you have to get close if you want to hit a moving tank with extremely slow munitions.
finding a stationary tank would be hard as they are likely to be at guarded base.

>> No.6397533

>>6397517
You won't need too expose yourself, you fire it at an angle over an obstruction when you estimate the tank is past the range of the vertex. On the nose is an ir camera. The ir camera is hooked to a rasberi pi that will interpret the heat signal through a dvi cable link, issue commands to 4 servos on the tail to aerodynamically guide the iglo class projectile balista arrow to the target through corrective steering.

Behind the ir camera is a steel rod connected through a copper convex plate which rests on a 'pressure cooker' 'backpack class efp'. The frontal 1/4 inch convex copper plate cover filled with 4 pounds of black powder, within .6M away the tip of the nose where a steel rod connecting through the center of the copper plate hits a primer in the back of the 'pressure cooker' which will detonate the powder charge which upon explosion will create a liquid copper molten jet at temperatures of over 3600 F be more than sufficient to penetrate the tanks top armor over the hot engine block destroying the tanks turbines and setting it ablaze.

>> No.6397639

>>6397533
if you plan to hit the top of the tank i would suggest to use molotov cocktail taped on the tip.
ir/heat camera will guide it to the engine.

>> No.6397702

>>6397533
As cool as that is I should point out that ballista cannons not mortars, so the "down from above" doesn't play to their strengthens. If you are going to do that you should go with a trebuchet as they can reach much higher energy levels. see >>6396626

Also if you are letting us use black powder and microcomputers, it opens up so many options. An array of light air cannon with special kinetic rounds could really mess them up if you have light gases (helium or hydrogen) and can make a barrel to handle the output.

I saw a display where a dinner pea nearly penetrated a Bradly fighting vehicle's armor, made it bow out to near a foot into a metal foil balloon. Yes, the kind of dinner pea you eat, doesn't really matter what it is when it is moving that fast. Switch the dinner pea out with something like a harder steel bolt with a lead core and watch it punch small hole in the the tank.

What kind of scenario is OP working with here anyway?