# Search results

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

Yes I have tried searching :smile:, couldn't find anything ever built. The same guys were writing papers about it since 1979 though.
2. ### 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?
3. ### 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...
4. ### 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...
5. ### B Orbit circularisation/insertion spreadsheet

Ah ok, VERY interesting! So I might need to make a spreadsheet using this and compare the two to find the lowest second burn value for a reasonable LEO.. (I'm thinking between 300 and 600km)
6. ### B Orbit circularisation/insertion spreadsheet

Awesome thank you so much guys! :smile:
7. ### B Orbit circularisation/insertion spreadsheet

Minimal delta-v on the "second burn" certainly is the aim. The delta-v of the "first burn" doesn't matter at all, happy for it to be inefficient. So does that still mean the first type is better for me? If so let's go with that. Are there names for those 2 types? Thanks.
8. ### B Orbit circularisation/insertion spreadsheet

No not up first. So you shoot from sea level horizontally. Lets say you shoot at the correct speed for a 400km orbit. As the Earth curves away the projectile gains altitude. So it reaches 400km, and lets say it hasn't slowed down at all so it as at the correct speed for a 400km orbit. But it...
9. ### B Orbit circularisation/insertion spreadsheet

But it needs to change the trajectory right? Not just the speed. Can you give an example of what you mean? Launching from sea level and entering a circular orbit at 400km.
10. ### 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...
11. ### Inverter or Generator

I also have a van and would recommend not using battery power for anything big (ie heating or cooling). Use a gas heater or run the engine and use the RV heater. If you have a large invertor it will be very inefficient when being used at a low level. If you really want to do this maybe have 2...
12. ### 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...
13. ### B Delta-v for orbit if already at ideal velocity and altitude?

OK I have finally put together a spreadsheet using your excellent instructions. I am getting slightly different figures than your example but its close. Perhaps its rounding errors, your example was a different flight-path than my calculations use, or I have made a mistake somewhere? I would be...
14. ### Linear Induction Coilgun with superconducting projectile

Got it, thanks guys.
15. ### Linear Induction Coilgun with superconducting projectile

Or can you not really induce eddy currents due to the Meissner effect?? It would be a Niobium-titanium superconductor by the way, so that is Type II.
16. ### Linear Induction Coilgun with superconducting projectile

No answers? Put more simply: If you induce eddy currents in a superconductor using a strong magnetic field, does the superconductor heat up at all?
17. ### Linear Induction Coilgun with superconducting projectile

Sorry it is in a vacuum. Pre-cooled and transit through the barrel is less than a second.
18. ### 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...
19. ### Skin effect and magnetic field of a flattened conductor?

Thank you both for your replies. I think this thread has been answered but feel free to message me. To answer your other comments in order: Jeff: I am thinking of Linear Induction Coilguns not Railguns. Yes for orbit insertion. The payload would start as ice and have the volume/pressure to...
20. ### Skin effect and magnetic field of a flattened conductor?

The efficiency of the conductor shape depends on those factors? Perhaps you are alluding to my suspicion that it may not be possible to put that much energy in without melting the projectile? Well anyway I would say: How much does the aluminium projectile weigh ? 100kg total, 50kg of which is...
21. ### Skin effect and magnetic field of a flattened conductor?

Yes sorry I am thinking of an induction coilgun so your description is exactly what I mean. The blue conductor is a hollow aluminium projectile in a barrel of wound coils. So as you say the magnetic fields induce eddycurrents in the projectile which in turn lead to motion of the projectile. I...
22. ### Skin effect and magnetic field of a flattened conductor?

I mean the same cross sectional area of conductor/copper, they have different internal cross sections of coolant.
23. ### Skin effect and magnetic field of a flattened conductor?

OK following on from that, which of these shapes would induce the most current into the blue conductor? And perhaps rank them in order? I would assume A D B C E. The orange conductors are coiled around the blue conductor. They are hollow with a coolant being pumped through them. Assuming all...
24. ### Skin effect and magnetic field of a flattened conductor?

Wow you're not wrong, interesting stuff! :woot:
25. ### 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...
26. ### Heat-shield for a Mach 30 missile at 10km for 10 seconds?

I understand that its very complicated and inaccurate. But what information would I need to know in order to get an approximate answer? Lets say just for the ablation scenario?
27. ### 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?
28. ### B Delta-v for orbit if already at ideal velocity and altitude?

Awesome, thank you so much :smile:
29. ### B Delta-v for orbit if already at ideal velocity and altitude?

Is there a formula/spreadsheet I can use to work out other launch angles?
30. ### B Delta-v for orbit if already at ideal velocity and altitude?

Great info thanks! :smile: