Questions tagged [design]
43 questions
278
votes
12 answers
Why are four-legged chairs so common?
Four-legged chairs are by far the most common form of chair. However, only three legs are necessary to maintain stability whilst sitting on the chair. If the chair were to tilt, then with both a four-legged and three-legged chair, there is only one…
Karnivaurus
- 2,981
41
votes
4 answers
Why do most office chairs have 5 wheels?
(Inspired by Why are four legged chairs so common?)
I've been wondering for a while... Why do most wheeled office chairs have 5 wheels?
My guess would be that while stability vs. simplicity results in 4 legs, adding mobility to the equation may…
5
votes
3 answers
How to multiplex several light sources into one optical path?
I'd like to design a device that takes 4 channels of light from sets of LEDs and multiplexes them into one optical path, which finally creates a rectangle pattern of light that is approximately 30mm tall and 1mm wide. This is to be used with a line…
John V.
- 51
5
votes
1 answer
Tuning fork having 2 arms
Why there is 2 arms in the tuning fork? It can have 1 or more than 2 arms. If we think to create more resonance, then we can construct a tuning fork having many arms
user157918
- 59
5
votes
3 answers
Can anyone estimate what proportion of water remains after I flush a toilet?
Imagine I have a clean toilet with some amount of water in the bowl. When I flush the toilet much of that water will be displaced by the tank's water. I want to work out (or model really) what amount of the original toilet bowl water will remain…
yesimay
- 59
5
votes
4 answers
Why do aircraft inner wings lose lift when turning?
first question here, so please be gentle!
I'm reading an entry-level engineering course book and am currently up to discussion of aircraft design.
There's one particular statement that is unclear to me:
Turning with the wing level is aerodynamically…
James
- 207
4
votes
2 answers
From which side should I solder electrical feedthroughs into a vacuum flange?
I work on an experiment that requires electrical connections to a vacuum vessel, which is submerged in liquid helium (LHe). For sending the signals into the vessel, we use a feedthrough flange. I am currently redesigning this flange, but there is…
Martin J.H.
- 1,637
3
votes
3 answers
Design of a common table fan
A few questions about the design of a common table fan, such as below.
Does the round disc (silver in the image) in front of the blades serve any functional purpose?
Does the metal casing around the blades serve any functional purpose except…
u17
- 133
3
votes
5 answers
Electronically controlled fusion reactor
It seems that currently, only two types of fusion reactor styles are being used for large scale testing: the Stellarator and the Tokamak. Both of these and a whole bunch of other designs have been developed in the 1950s and '60s. They are based on…
x5444
- 33
3
votes
1 answer
How is/do they plan on having fusion energy collected at the National Ignition Facility?
I was just watching a program on television showing how the method they use at the National Ignition Facility to attempt to achieve fusion is to fire extremely powerful lasers at a small pellet of fuel sitting in a vacuum at the center of a large 10…
mring
- 931
3
votes
2 answers
Proof Human Designs for Fusion Could Work
Are there convincing proofs on paper that fusion is possible the various ways humans are trying to design machines to do it or is the only way absolutely proven to work in theory also the only way actually working reactors (i.e. stars) work, that…
mring
- 931
2
votes
1 answer
In a fusion reactor like Tokamak, how is fuel injected without destroying the fuel injector?
Plasma temperatures in a tokamak are around 100 million C.
Presumably for a power plant that will run for a long period of time, fuel will have to be injected and "burnt" products will have to be removed.
How will this be done without destroying the…
DrZ214
- 744
2
votes
0 answers
Reason for audio speaker diaphragm shape
Why are the diaphragms on audio speakers usually a cone with a dome in the centre? I don't know much about acoustics but my guesses would be:
it just empirically sounds better, the design was found through trial and error
an acoustically better…
Ed Ayers
- 121
2
votes
2 answers
The strength and control over the strength of electromagnets, correlation between the strength and weight of the magnets
I am currently working on a project that aims to use the attraction & repulsion between two electromagnets as an alternative to weights, from a physiotherapy and rehabilitation perspective to help people build muscle and strength but who would not…
LJT.Design
- 21
1
vote
0 answers
Building a Binary Water Transistor - Fluid Mechanics
Imagine a water transistor—a device that allows water to flow between two points only when a specific water pressure is applied at the base. This transistor operates without any electrical components or mechanical springs, relying solely on…
פז בורשטיין
- 11