An engineer starting a clean sheet design has a great many factors to consider before deciding how he/she wishes to configure the overall system.
We already have much good information in this thread. I see nothing to argue with. So I’ll add a few thoughts based upon my experience.
Heat...
I've seen the cone idea work well for an 80 ft drop in which you win if the egg survives and you have the shortest drop time. Put fins on it and let it fly like an arrow or rocket. They used several sheets of paper laminated with glue for more thickness.
Edit: the cone needs to crush on...
To really understand the answer you might Google "specific fuel consumption." Every engine has a set of curves showing how much fuel an engine will burn under a certain load and at a certain rpm. So they are 3 dimensional curves, which an engineer will study in great detail before making an...
On the subject of jibing, and using the US spelling: the first time I jibed was the only time it ever caught me by surprise and the first time I capsized a sailboat. It was an 8 foot pram that was the first boat I built myself. My mother made the sail and my dad made the spars. I was in...
When I got my engineering degree, it was nothing more that than a license to continue learning, which I've been doing for nearly four decades. The single most important thing I learned in my early education was how ignorant I was about so many things, and that I had better correct that...
Here in the USA, commercial boat design and construction is heavily regulated for boats carrying freight or more than six passengers. Privately built and operated boats have none of that. I've built, repaired, or modified hundreds of them. I have to get them inspected, but that is just to...
Johnca: most boats like yours put the skeg at the rear of the boat. Keeps things stable, like an arrow in flight.
But moving it forward makes the boat more responsive. So it is a trade off.
Think of canards on an airplane. They make the plane so unstable that nobody thought of using...
I've done this experiment under water with a rubber hose. Breathing becomes very suffix difficult only a few inches under water. At three feet it is completely impossible.
I networked at great length with a ship design engineer who specialized in minimizing sea sickness to passengers and crew, a very sophisticated specialty. Some effort is given to minimizing roll, but far more effort is put into making the roll period far outside the range that normally...
I see many are getting very close to understanding the solution to the original question, but not quite getting there. Or perhaps maybe they are there, but are having trouble communicating it such that all can understand clearly.
Many and probably most vessels have a center of mass higher...
A turn is an acceleration, and for that the sum of the forces must add up to a vector in the direction of acceleration. Draw a free body diagram, and you will see that the direction of that resulting force underwater is in the opposite direction for sail and power boats.
That applies to the...
DahnBoson: When I first saw the idea of mining asteroids I figured it was either a bunch of stupid idiots or a practical joke. Then I saw the list of people who were doing it. They all have a reputation of being serious business men and engineers, and they all have a long history of doing...
I’ve spent a lot of years working in aerospace, and recognize many of the top people in Planetary Resources as top in their field with a long history of top performance in the space business. They are very smart people. They have the understanding of what it will take to get the job done, and...
Danger's description of Jake brakes is the best yet in this thread. In a gasoline car, if you lift your foot off the gas, the engine will provide a regarding force to slow the car down. If you down shift to make the engine spin faster the braking force is greater.
A diesel provides almost...
Good answer, but we can carry this thought experiment further to see that the ice will feel cooler because it will conduct heat from your mouth more quickly.
If you put water in your mouth it will immediately start to increase in temperature and feel less cool.
If you put zero degree ice...
You could put your own system together with standard parts. They make very small cryogenic coolers for IR cameras that get below 80 K. Some weigh less than a pound.
Lockheed in Orlando makes several very nice ones for the military, but they use technical talent from nearby UCF. You might...
You have the old style pancake brakes. If the system were maintained correctly you should be able to modulated them.
Most trains and trucks have the newer Maxi brakes. They operate exactly the same as your brakes, air applied and spring released. But they have a second actuator with a...
I find that interesting. I was in the heavy equipment and trucking business for 25 years, and I've never seen an air starter. I've heard of them and I've read about them. If a customer wanted me to design one, I could offer him several different design approaches. But I've never seen one...
Whoever posted that sign shows a great misunderstanding of the braking mechanisms used by trucks. Air brakes make very little noise. But they are often supplemented by a Jake brake, which screams very loudly. They are intended only for descending mountains, but I've had many truck drivers who...
Actually, Danger does bring up a good point. The hydraulic system on modern automobiles has a quicker response time than an air system on a truck. I suspect there is a problem with scaling the truck's air system down to automobile size that makes the response time difference an even bigger...
A large crane is going to have a hydraulic system driving many things anyway. So it costs nothing extra to power the load brakes with hydraulics. But all the mobile cranes that I've worked on up to 500 tons have air brakes for the road brakes. Some are air over hydraulic.
Hydraulic brakes...
Nobody worries about small air leaks, but hydraulic leaks bother everyone. Air fittings are cheaper. You don't have to bleed an air system. If I had more time, this list could get to be very long.
The title on this these is confusing because a system that uses air to actuated a hydraulic brake system is called a "Air over hydraulic brake system."
When connecting brake lines between many trailers or cars, air works much better than hydraulic. But there are many different types of air brakes. In some cases the air actuates a hydraulic brake system. The most common is a canister that has two actuators in it. One is air applied, spring...
Heat transfer considerations give us competing and conflicting objectives.
If our objective is to make the ice last as long as possible, then drain the box. The liquid makes the heat transfer from the sides of the box to the ice much more rapid, which leads to quicker melting of the ice...
The meat of some species will be degraded if you put the fish on ice while still alive. But then once they are dead, you want to cool them down as quickly as possible. This is what the chilled brine tank on a commercial boat is for. You can approximate this by leaving the melt water in the...
It will outgas carbon dioxide, so as long as you can handle that safely you are good to go. If you seal it in a bag, expect the bag to eventually fill up like a balloon and burst. If your freezer has a magnetic seal, expect it to pop the seal if the box is not otherwise vented. If it is a top...
No matter what time of the year it is, your engine is designed to heat the gasoline up to about the same temperature before it is ignited. It does this using waste heat from the engine. So for the subject currently under discussion, the only difference between summer and winter is that the...
There are a lot of things happening here that complicate the design engineers have to consider that are beyond the scope of the simplified analysis you saw in the textbook.
Actual forces required to stop the truck are higher. Wheels have a larger radius. Both of these mean that you need more...
How many hinges does the door have?
If more than two, then you have a statically indeterminate problem, which is much more difficult to solve. Then you would never be completely sure of the answer because of uncertainties in your input data.
If I were designing the door, I’d make a...
The foam will give you about 60 lbs of buoyancy per cubic foot. Perhaps a little less depending on which foam you select. I assume salt water. A little less in fresh water.
That also is interesting. I guess that either idea might be valid, depending on how the guy is strong. I've not done much tug of war, but when I work as a rigger we would sometimes put the whole crew on a rope to apply a load to it. We got best results when we put the strong guy in the back...
In theory, it does not matter where you put the strong guy. But I've found that he normally does better in the back because he can wrap the rope around his arm in that position, or even around his waste. Either gives him a better grip. But as already mentioned, it is dangerous to wrap the...
Also, clouds are a radiation heat shield to keep more heat on the ground. So above the clouds the air is also losing heat to the cold of space much more quickly.
Air can only be warmed in two ways. The ground can conduct heat to it, or it can absorb light energy passing they it. Clean air and thin air absorb less heat than thick dirty air near the ground, and of course air at altitude can't get as much heat as air near the ground. Everything works to...
Temperature drop means that energy has been transferred to somewhere. That has already been explained. Feeling hotter means one of two things, and in this case probably both are happening. More heat is being transferred to your body and your body is less effective at getting rid of it...