Recent content by Jake110

yeah that's the conclusion i came to. I'm just going to get a small weather balloon and build the frame around it.

right, I've posted on the smallblimps forum, there really not being helpful. emailed the guys at airship.com. tried finding other companies that might help but still having trouble. haven't got a reply from either airship or imagine inflatables. seems if a company deals with airships/blimps at...

I starting my third year project at university and I'm going to be designing and building a miniature airship (no more than 1m in diameter). i was just wondering if anyone here knows any companies that sell small airships, or do custom orders since i really only need the helium envelope and...

damit, you wouldn't happen to know an equation for the field strength outside the central core would you?

I have this equation for the magnetic field strength of an electromagnet but it’s in the form of multiple polynomials. Here is the page where they all are: http://www.netdenizen.com/emagnet/offaxis/solenoidoffaxis.htm since it gives values for e_8 and p_8 I tried using the main equation up...

i was looking for this same equation a few months ago, bloody hard thing to find but i found it! for a thin shell solenoid use the equation found here: http://www.netdenizen.com/emagnettest/solenoids/?thinsolenoid for a solenoid with a shell use the equation found here...

It’s going to be pulsed. I’ll just use 10 for h then. Thanks for all the help guys, really appreciate it.

thats a pretty good rule "If you can smell it, it is too hot". the only recommended current limits I've found are just for single wires, not windings. i'll aim to keep it using the least number of layers so i don't need to worry about temperature gradients. as for the convection coefficient...

Your using the equation W = I2R that Bob S posted to find Q right? Q being power. So T_0 is the temperate it’s at to begin with and T is the final temperature? It can be rearranged to form T = \frac{Q}{h*A_0} + T_0 And using the melting point of copper (1357.77 K) I can determine if...

i don't know, it seems to simple. wouldn't it use more variables than just current, surface area? f95toli what way were you thinking of? i can deal with somewhat tricky.

f95toli: that’s why I’m having trouble figuring out what grade of wire to use, sure there are amp limits for non bundled wire on the AWG wiki page but I can’t find any amp limit for the wires when they are bundled together like in an electromagnet. I was thinking I could use a chain equation...

Since running a current through a wire will increase the temperature of the wire, is there an equation for calculating the increase in temperature? I’m thinking it would vary depending on the cross sectional area of the wire, the temperature of the surrounding material, the starting...

sorry, A Level is a two year program involving 3-5 subjects for students 17-18 years old, its what we have here in England. I'm 18 so what ever the equivalent level of education is in your country. anyway, I talked to a guy on another forum and it seems to find the vector area of a 2D object is...

so I'm i getting this right, its the same if the gap is vertical through the coil from the top to the bottom? so then G would be the horizontal distance of the gap?

thanks for the reply but i think the equation i need the vector area for is wrong. plus I'm only at A level so i don't really understand that equation. EDIT: unless its not the vector area of the entire object but just the cross sectional area, i think i just need to calculate the vector area...