Engineering

hey all . At the moment I have a forty dollar gift voucher for a hardware store and my plans are to turn that forty dollars into something more (because Im broke and bored ). I have friends who would buy a case if I could make my ideas come true . I'm intending to build the case from scratch and I just want some advice on a couple things I'm tossing around in my head . Whats the best way of making a mould ? at the moment I'm thinking of just plastering a couple layers of wroughted mesh , any other (easier) alternatives . What kind of polymer is best & cheapest to use in a mould ? Any other advice from people who've attempted this .

I'm taking part in a local water-rocket competition. I was thinking about building a rocker-aeroplane hybrid as the distance rocket. I used a delta wing design(swept-back at 25 degree) with a T-tail. However, my rocket has a tendencency to stall after launch (approx 30m). Further trimming odes not fix this. Does anyone have any ideas? P.S.: I have built a conventional rocket for the distance category in the evnt that this fails or the wind is too strong. (so don't suggest me to build a conventional one: I have already built it) For the duration category, I got problems with the parachute deployment system. the problem is either holding the nose cone stable during …

can any1 get me a website or send me some shematics for a turbojet? andrewweber@xwires.net

I was reading some articles on the "future" of TVIP, that is TV over the internet. Is this stuff for real ? How on earth can a tv signal be broadcast over the internet? I think this is a case of really PURE HYPE! A tv signal needs at least 4MHZ bandwidth so if 1000 people over the internet want to see that station (from anywhere in the world) the tv station server would have to send the digital IP packets at 4GHZ! and what if all of a sudden 10,000 people wanted to see the station? then the TVIP server would have to send the signal at 40GHZ! THAT TO ME SOUNDS LIKE PURE HYPE!!!

ok i seen some 1 selling plans for an ion gun that can pop ballons at a 8' range i love trying electronics projects but this one seems a little far fetched. does any 1 have any experience with this type of application and any links if possible

Hi there!!! With the ongoing rise in perfume prices, I'd really like to know how I can refill an empty perfume bottle (ex. Polo Sport, Acqua Di Gio) without having to break the seal. Can anyone here help me out? Thanks!!! Gio

I don't know much about machines, hydraulics, or engineering, but I want to make something that can shoot badminton birdies at high velocity. I'm not sure how to make it, how the machine would work, what the machine is made of, etc. I'm limited on money so I can't make anything that costs a lot. My first idea was to use pressurized air or something. Would that even work? The birdie is light. Where would the pressurized air come from? How do I build a machine that uses this concept? How would the birdies load? Where do I get my supplies from?

would it be possible to make a real working lightsaber? i think maybe plasma could be manipulated by a magnetic field for the beam. put somthin in if u hav any ideas

Hey guys, I have a Core Engineering exam tomorrow, and theres a few questions from past papers that I'm stumped on. If someone could give me some tips today that would be great. How are rails in railway tracks made? How do the relative costs of initial setup, tooling and materials change with the number of components and manufactures? How does the molecular weight of a polymer affect its properties? How can I draw an FCC crystal and indicate it's Miller incide on the same diagram? Name and sketch the process by which most domestic ceramic products are manufactured Give an example of a simple forged component and sketch the important features of the dies yo…

Hello, Can some people please explain the differences between solar cells and photocells. Is it only, solar cells use photoelectric effect to create current and photocells use the effect to detect light. THank you in advance

I dug a nice big toroidal power supply from a broken 400w RMS speaker set and I'm trying to get it to work to supply low (relatively) voltage and a decent amount of current. It has three leads on one side and two on the opposite. Red/white and yellow/orange/black in case it matters. The resistances I read are as follows: Red - White 2.1 Yellow - Orange 0.9 Black - Orange 0.9 Black - Yellow 0.9 (I don't have any way to measure inductors, so this is a rough guess) Now before I tested this out, I hooked the yellow & orange to 110 VAC wall socket and it, of course, flipped the breaker. How can this be used to step down AC voltage if Ohm's…

I am going to be doing a degree in electrical engineering once i have finished my A-levels (maths/physics). I will have approx 9 months before i start and i would like to learn some theory as i only really do pretty basic stuff in physics with regards to circuits etc. What kind of books should i start out with to get me at a reasonable level of knowledge before i start the course?

hey if i have a simple ac generator (i.e. a coil of wire roating in between two magnets), to get power out of it i need to connect the wire to a thing called a "commutator", is that right? i can't quite figure out exactly how this all works... -Sarah

I would like to make a double-parabolic mirror like the one here for a project. How good of a reflector would gold leaf be? Would it be better, worse, or about the same as aluminum foil? Keep in mind, I'm going for the quality of the reproduced image. Thanks P.S. Any hints on how to get a hold of the exact dimensions of the parabola they use? Thanks.

I saw this thing my math teacher made. At first it looked like a gumball machine with a sphere for the gumballs and a pole that holds it up. The device actually made lightning pop out. When he turned off the light and switched the machine on, lightning shot out of it. He put his arm next to the thing when it was on and it made his muscles twitch. He says the muscles responded or something to it because they are electrical. It made a classmate's hair stand up on end. The class made held arms and the shock went through everyone. It made my feet feel weird. It crackled when it hit someone. It felt like someone pinched you. If you used a microscope, you can see burns because …

not dutch force.. i've got that one.. not electronic's lab either.. i've got that one... i'm looking for other forums that are just as good as those..

I'm a student doing a research project on PCB's (printed circuit boards) for my Digital Manufacturing class. I will be discussing the current technology used today for constructing PCB's and the future developments of ink jetting circuitry. In regards to the first part of my project (today's method of making PCB's), I have been surfing the web all day to find a website that has a simple step-by-step procedure of how a PCB is built, but all the websites I have come across are so detailed and do not have a clear cut "list" of how a PCB is made. They all suggest different methods and I would like to know the general one that is used. I am aware of a copper clad on …

I`m in charge of several 2 stroke engines for agricultural use, once upon a time 2 stroke fuel was available then we had to use 4-star fuel and add 2 stroke oil to it and mix. NOW! the 4-star fuel is no longer available in the UK and so in addition to adding 2 stroke oil, we have to buy Unleaded fuel and mix yet another compound with it! apparently with some cars this happens too, the cars that ran on 4-star fuel have to either add this new addative (like Redex) or get the engine converted. I`m wondering if I can convert these engines to run on Unleaded alone without all the faffing about like an A` Lev chem exam! I don`t mind adding the 2 stroke oil, but wit…

This is a pretty cool site... I decided to register and ask my very first question.... I am developing an Excel Spreadsheet tool for learning purposes which demonstrates effects on power generation of automobile engines by changing various specifications like charge temperature, rpm, bore, stroke, displacement, manifold pressure, volumetric efficency, etc. The part that I don't have figured out is the part I am least familiar with... combustion characteristics and burn time. I know that rate of change effects, mixture, temperature, pressure, etc effects burn time... but how. I would like to have a magical equation that takes in account mixtures (of Air, N2O, Meth…

http://informationweek.com/story/showArticle.jhtml?articleID=163104221 Here's Cornell's news release complete with lots of cool pictures: http://www.news.cornell.edu/stories/May05/selfrep.ws.html

Now that I have your attention... Out of utter curiosity, how many people here have built a hovercraft from scratch? P.S. Couldn't think of a thread title. If any mods want to, uh, rename it with something more... intelligent, feel free.

I want to pulse a set of 6 LEDs. It should be one led at a time, not all 6 together. There is a site that shows how to pulse a single LED, but how do I get to pulse 6 of them, actually even 4 will do. The LEDs will run off a 3.7V @ 1070 mA. I tried to think of a simple solution without messing things up as space is also a constraint, but I ain't getting nowhere.

I am trying to build a house with a minimum amount of money as possible, as time, money, loans are short . I am currently just putting in a foundation does anybody have any smart ideas on reducing the cost of building the frame work. eg. I was going to use blocks but labour for building them and plastering makes it quite expensive. I would still like the walls to be stong and look as if blocks were put their???????????????

Some drunk driver hit a phone pole running from the cops near my house and when they were repairing it, they replaced the stoplights. I asked the workers if I could have the old ones and they said sure. Now I have 2 stacks of 3 lights (red, yel, grn) and I can wire them up simple enough so they all come on. What I want to do it wire it so they alternate, something with a small timer that will just rotate which light is on. I was planning on getting a plug with a remote to turn it off an on. Any ideas?

Why can't we make motor engines based on water, it sure has hydrogen in it? it would be a lot cheaper than converting to electricity or hydrogen. Alternatively we may build some sort of electrolytic system in hydro engines to seperate the elements, then all you'd have to do is pour water in as fuel. Maybe someone's about to make a lot of money on hydrogen.