Recent content by R_Rose

So I'm trying to figure out what kind of energy that I can expect out of a few different setups. Here are the barrel bore diameters. .224 .308 .5 .77 The barrels are usually rifles and some projectiles are full size (size of bore) while others use sabot's where a .224 or .308 can be shot...

I'm trying to figure out how to calculate the difference between applying different extremes in spring arraingement for tension applications parallel'd, series and mix of them.I have some springs which are about 18” long and stretch to 30”, so they stretch 12”. If 8 springs are available and the...

Thanks for the reply! I am not factoring in air resistance. Maybe this will make things more clear. Someone hooked on a spool of line/cable that is released as they descend. The spool is attached to either an induction motor (or generator of some kind) or a brake pad/clutch plate of some...

I'm trying to figure out how much energy needs to be absorbed, radiated or displaced from an object falling from various heights. To make this clear, the "item" is a person so the weight can vary from 70-350lbs and the height let's say 60-3500 ft. Obviously the speed at the end will determine...

Thanks for the link! I was wondering if the values could be estimated from comparing similar materials such as: from table: http://www.engineeringtoolbox.com/friction-coefficients-d_778.html aluminium - mild steel = .61 Copper - Mild Steel = .53, .36 (IDK why 2 values are given...) Graphite...

I agree with you about the numbers probably being taken from a common source or a chain of references leading back to one source - THIS is one thing which I fear the Internet has allowed to happen all too often and it could lead to very bad consequences. As for the materials listed, I need to...

I'm interested in finding out what the coefficient of friction would be for a few different materials such as:Copper on aluminum Copper on graphite graphite on aluminum I'm not sure if it matters if the order is reversed such as Aluminum on copper vs copper on aluminum.. also I've seen that...

I'm trying to figure out how to best filter some liquids. A 5 gal bucket is filled with some filter medium (say sand on top 1/2 and fine charcoal on bottom 1/2). The liquid is slowly added at the top and gravity is used and vacuum may be used at some point with a complete seal along the bottom...

Vacuum bags are used to infuse various things with liquid resins such as fiberglass or carbon fiber. It seems that the higher the vacuum the better (and possibly faster) the infusion works. Could it be more effective to use a vacuum bag and also have the entire bag in a pressure chamber to get...

I'm trying to design some novel cross bow designs and also trebuchet's with the trebuchet (similar to catapults to those who don't know) using springs or a combination of weight and springs. I'm looking into using linear springs and pullies for the crossbow depending on whether they can be...

If the motors are all the same and they are wired in parallel, wouldn't they all run at the same speed? I'm not sure why brushed (universal??) motors would be better. I was trying to design the motor layout for using multiples and it seems to get complicated (in my arraingement) when...

Well I guess it is similar, except one is comparing engines, mine is comparing identical motors with a much higher number needing to run together.

I have a dilemma with the design of a device I want to build which is acquiring the correct size motor (shape & power) in my price range (even finding one within specs). I have found that the motors from cordless drills are ideal for this application (due to size, price and availability) so...

I'm trying to figure out a way to get better results in a "pumpkin launching" contest. The goal is to launch an 8-12 lb pumpkin (or bowling ball) as far as possible.One method is going to use elastic, bungee or large rubber/latex bands as the method of propulsion. The problem is there are...

I heated epsom salts in the oven at 450F to make some make-shift desiccants and it went from white (some even clearish) crystals to solid white powder (caked together) with the edges turning a light shade of brown and a deeper brown at the 4 corners of the pan. Can this damage the MgSO4, is...