# Search results

1. ### B Has anyone ever built a superconducting quenchgun?

Has anyone ever built a functioning superconducting quenchgun? Or has the theory or practicality of it's operation ever been questioned or disproved?
2. ### B Calculate the *Acceleration* after a (mostly) elastic collision?

How can I calculate the ACCELERATION of a stationary steel ball after being hit by a moving steel ball. I know how to get the final velocity but how long does it take to accelerate to that velocity from zero? Does it depend on the elasticity of the materials? I guess we need to know long did...
3. ### B Temperature regulation in Earth orbit

If I had an object in an orbit around the Earth that I kept continually shaded from the sun, how cold would it get? Assuming the shade device was not physically connected to and was sufficiently far away from the object to not radiate any heat to it. And if I actively adjusted how much shade...
4. ### B Orbit circularisation/insertion spreadsheet

I am trying to create a spreadsheet that will calculate: The minimum delta-v required to circularise the orbit of a projectile that has been fired horizontally from the Earths surface at a given velocity. Completely ignoring atmospheric drag. See the attached spreadsheet. The steps are...
5. ### B Is the water pressure below ocean waves constant?

If you are stationary say 10m below the ocean surface does the water pressure at your location vary with the waves. For example: When a wave crest is above you than means perhaps 12m of water is above you. Then a few seconds later a trough is above you so only 8m of water is above you. So you...
6. ### Linear Induction Coilgun with superconducting projectile

If you have: A Linear Induction Coilgun, basically like a series of Induction Furnaces, using copper coils with high AC current at a high frequency. Where the projectile travelling inside those coils has a shorted superconducting coil around the outside of it, embedded in the ceramic projectile...
7. ### Skin effect and magnetic field of a flattened conductor?

A conductor with a large high frequency AC current causes a "Skin Effect" meaning that most of the current flows at the surface of the conductor. What does the skin effect look like if you have a conductor with one side flattened? And what does the resulting magnetic field look like? See...
8. ### Heat-shield for a Mach 30 missile at 10km for 10 seconds?

Using an ablative carbon-carbon heat-shield, what thickness would be used up? Or might a ceramic insulator be able to handle it? What would happen if the nose was solid aluminium? How can this be calculated? What information do I need to figure this out?
9. ### B Delta-v for orbit if already at ideal velocity and altitude?

Lets assume you could fire a 100kg projectile using a coilgun at 1 degree above the horizon and have it arrive safely at 400km altitude travelling at 7.8km/s (or slightly more if that helps). How much delta-v would it need to correct its trajectory into a stable orbit? If it matters lets...
10. ### Would a 10km/s projectile disintegrate at sea level?

Assuming you could fire a projectile at 10km/s. Polished aluminum, almost solid, same size and shape as an artillery shell. Most people say it would disintegrate due to the friction at sea level. But would it really? I heard someone say it would just ablate some of the aluminum. And that 1700...
11. ### Delta-v to overcome atmospheric and gravity drag at 13km?

Wikipedia says that: Atmospheric and gravity drag associated with [space] launch typically adds 1.3 to 1.8 km/s to the launch vehicle delta-v required to reach normal LEO orbital velocity of around 7.8 km/s (28,080 km/h). Does anyone know, or know how to calculate/estimate/simulate the delta-v...
12. ### How fast to shoot a bullet for it to hit the moon?

Ignoring the fact that the atmospheric friction would probably disintegrate it. I know that to achieve LEO takes around 10km/s delta v. But only 2km/s of that is to overcome the drag and gravity. So you could shoot at 2km/s, get to LEO altitude then it falls back down because it is not at...