Help me wiff my maff.

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yankeejib
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Help me wiff my maff.

Postby yankeejib » Mon Sep 18, 2017 3:53 pm

Mach 7 for a 100 mile projectile takes how long? Ma 7 is about 5000MPH at sea level? So 100 miles takes about 1.2 seconds if it maintained constant velocity? So how do you estimate the deceleration and drop from gravity? When will the commercial version be available?

http://politicnewsusa.com/2017/09/18/u- ... at-mach-7/
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Professor Stu Padasol

Doing what others find difficult is talent.
Doing what others find impossible is genius,
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LWP
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Re: Help me wiff my maff.

Postby LWP » Mon Sep 18, 2017 4:11 pm

Can't calculate deceleration without knowledge of the coefficient of friction of the projectile (size and shape). Considering the range,
there's not much drop in trajectory in 1.2 seconds, the same drop as you would get dropping a baseball for 1.2 seconds, because earth's gravity is constant near the surface.

I think the new littoral warships were designed with this weapon in mind, I hope they can generate the electrical power required.

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Hand and Steel
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Re: Help me wiff my maff.

Postby Hand and Steel » Thu Sep 21, 2017 10:56 am

Does the railgun take Glock mags?
"Our great war is a spiritual war, our great depression is our lives."

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yankeejib
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Re: Help me wiff my maff.

Postby yankeejib » Thu Sep 21, 2017 6:26 pm

LWP wrote:Considering the range, there's not much drop in trajectory in 1.2 seconds,


This was my thinking. You fire it so fast that it continues in a straight line while the Earth curves away and everything is a miss high. You would almost need to slow it down a little to let the projectile match the drop along the sphere. It adds a new dimension to standard parabola ballistics. One of my college physics exercises was to calculate how fast you would need to fire a ping pong ball to accomplish various tasks like knocking down a NFL lineman, breaking a window, or penetrating a wood door. I got an A because I used my Commodore 64 to recreate scenarios with variables like wind and barometric pressure. As I recall, 8K MPH ping pong balls are lethal.
Sincerely,
Professor Stu Padasol

Doing what others find difficult is talent.
Doing what others find impossible is genius,
Why be difficult when, with a little more effort, you can be entirely impossible.

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Hand and Steel
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Re: Help me wiff my maff.

Postby Hand and Steel » Fri Sep 22, 2017 8:03 pm

yankeejib wrote:You fire it so fast that it continues in a straight line while the Earth curves away and everything is a miss high. You would almost need to slow it down a little to let the projectile match the drop along the sphere.


Would gravity have much of an impact on curvature? And couldn't you conceivably decrease velocity by simply increasing the weight of the projectile?
"Our great war is a spiritual war, our great depression is our lives."

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yankeejib
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Re: Help me wiff my maff.

Postby yankeejib » Fri Sep 22, 2017 9:23 pm

Hand and Steel wrote:
yankeejib wrote:You fire it so fast that it continues in a straight line while the Earth curves away and everything is a miss high. You would almost need to slow it down a little to let the projectile match the drop along the sphere.


Would gravity have much of an impact on curvature? And couldn't you conceivably decrease velocity by simply increasing the weight of the projectile?


Didn't Newton prove a feather and a rock drop the same rate? I admit it's been a while since I studied motion and I'm too lazy to really remediate. I suppose the effectiveness of the weapon relies up the speed of a projectile on impact (I'm thinking of that FN 5.7 pistol here). Maybe you aim low and graze the horizon 15 miles out? I do know that it takes 17,800MPH to achieve orbit....LOL
Sincerely,
Professor Stu Padasol

Doing what others find difficult is talent.
Doing what others find impossible is genius,
Why be difficult when, with a little more effort, you can be entirely impossible.

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Hand and Steel
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Re: Help me wiff my maff.

Postby Hand and Steel » Sat Sep 23, 2017 12:00 pm

I'm not thinking so much of the weight of the projectile directly causing faster drop so much as the increased weight decreasing forward velocity so that it would take longer for the projectile to reach the target, therefore increasing the amount of time in which the projectile could drop. I could be wrong on this, physics and arithmetic were never my strong suits.
"Our great war is a spiritual war, our great depression is our lives."


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