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A working model of a electromagnetic mass accelerator of high power

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DerAlbi

Mon Dec 10 2018, 05:03PM

Registered Member #2906 Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727

Sulamain: arguing about the speed of sound in this situation is not useful. You can vary the speed of sound no matter what, you can even neglect the term completely or make the speed of sound half as fast... V2006 is claiming 2x velocity and 4x the energy.
Simulation says, that his acceleration takes place in 10 - 12ms. One could subtract this from the audio time measurement and get a better estimate of the muzzle-velocity. Including those 10ms sets the speed to 40ms instead of 38. Nothing changes the fact that is not 50, 60, 70 or 80 and never ever 100m/s or and the claimed 1.6kJ never ever happened and never will happen with this build.
Its all based on the fact that the gun moves 5cm backwards during a shot.

V2006

Mon Dec 10 2018, 05:14PM

Registered Member #61550 Joined: Thu Apr 06 2017, 03:23PM
Location:
Posts: 86

DerAlbi with math you are bad too:

"My gun at 40m/s and 20J has the same kickback as a 9mm gun when shooting because Impulse = ProjMass*Velocity is nearly equal"
- at 20 joules of energy and speed of 40 meters per second the recoil impulse of your model is equal to 1 KG x M/S (m = 25 gramm, v = 40 m/s
- 9mm gun when shooting has a recoil impulse of two to three times more than your 25 grams at 40 meters per second (m = 6 - 9 gramm, v = 300 - 420 m/s, mv = 2 - 3 KG x M/S)

What a recoil impulse will be at a speed of 100 m / s you do not know. Because you have no such model.
If you confuse what you want (100 m / s) with what you have (40 m / s, 20 Joules), there is no truth in your calculations.

V2006

Mon Dec 10 2018, 05:50PM

Registered Member #61550 Joined: Thu Apr 06 2017, 03:23PM
Location:
Posts: 86

Sulaiman Ballistic pendulum with such energy it is dangerous to try

V2006

Mon Dec 10 2018, 07:34PM

Registered Member #61550 Joined: Thu Apr 06 2017, 03:23PM
Location:
Posts: 86

fur DerAlbi:
The conclusion about speed and energy is based on the breakthrough of the door and the steel sheet with a thickness of 2 millimeters behind the door
accelerator weight is almost equal to human weight
When launching a projectile, the accelerator rolls back.
It is as if a person was thrown back by the recoil of a gun.
I still agree that the velocity of the projectile from 63 m / s to 80 m / s
It fits the pulse of recoil of a powerful hunting shotgun:
mv = MV
m = 40 gram
v = 500-600 m/s

M = 385 gram
V = 63 -80 m/s

According to my initial calculations, the speed was 60-65 m / s.
What corresponds to the recoil momentum of a powerful shotgun:
P = MV
P = 60 M/S x 0.385 KG = 23.1 KG x M/S

*My accelerator layout can be significantly improved in the same dimensions.
There is still room for two - three capacitors 10 000 microfarads, 450 volts.

DerAlbi

Mon Dec 10 2018, 07:35PM

Registered Member #2906 Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727

Oh come on -.- This is pure trolling.

What a recoil impulse will be at a speed of 100 m / s you do not know. Because you have no such model.

25g * 100m/s = 2.5 kg * m/s.

See, i know. Without a model. And heey, its actually exactly

2 - 3 KG x M/S

Troll. You shouldnt be here.

klugesmith

Mon Dec 10 2018, 07:37PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714

Sounds like there's disagreement about actual projectile velocity.
I would not depend on any results from simulations and/or from coil timing.

Ballistic pendulum seems like a good way to get accurate answers without measuring small time intervals or quantifying damage to targets. Maybe organized coilgunners could adopt a common design.

It works for a wide range of projectile sizes and speeds. Today's Wikipedia article says "Robins experimented with musket balls of around one ounce in mass (30 g), while other contemporaries used his methods with cannon shot of one to three pounds (0.5 to 1.4 kg)."

Nearest experience for me was 25 years ago, measuring the energy of "dry ice bombs" (plastic soda bottles pressurized until they burst).
Following the classic "cylinder and piston" model for thermodynamic work, I launched solid concrete pistons almost vertically from a 6-inch-diameter cold gas mortar. A representative outcome was measured flying time of 4.1 seconds for a 10 kg projectile. That works out to maximum height 20 meters, velocity 20 m/s, momentum 200 kg * m/s, energy 2000 joules. Measured with mechanical stopwatch (no electronics).

V2006

Mon Dec 10 2018, 07:39PM

Registered Member #61550 Joined: Thu Apr 06 2017, 03:23PM
Location:
Posts: 86

DerAlbi it was literally written by you "My gun at 40m/s and 20J has the same kickback as a 9mm gun when shooting because Impulse = ProjMass*Velocity is nearly equal"

V2006

Mon Dec 10 2018, 07:44PM

Registered Member #61550 Joined: Thu Apr 06 2017, 03:23PM
Location:
Posts: 86

klugesmith good idea. But I have no money for such experiences right now.

DerAlbi

Mon Dec 10 2018, 07:48PM

Registered Member #2906 Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727

And you wrote literally 1.6kJ. At least my claim can be corrected and has valid origins. And it was made in a private conversation via email in an effort to explain to you that impulse and energy is something different. You observed high impulse, thought it was high energy. Now you publishing parts of private conversation with the only (correctable) mistake i made.
What for?
Cover up your 1.6kJ bull shit? I was wrong, so its ok that you are wrong?

V2006

Mon Dec 10 2018, 08:24PM

Registered Member #61550 Joined: Thu Apr 06 2017, 03:23PM
Location:
Posts: 86

DerAlbi This is not a personal conversation - you wrote it here:
DerAlbi
Wed Dec 05 2018, 11:50PM
"My gun at 40m/s and 20J has the same kickback as a 9mm gun when shooting because Impulse = ProjMass*Velocity is nearly equal, while kinetic energy (m/s*v^2) is vastly different."

I can be a little mistaken - you did not send the device for measuring speed

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