Recent content by Pkruse

Locomotives and ships converted away from coal and wood burning engines mostly because the labor costs were much less with either a diesel or a gas turbine. This is the same reason ships got rid of their sails.

Mine are reversable, so the air could go either way. Look at the pitch on the blades and compare it to an airplane propeller.

Probably not for depths as shallow as you are talking about here, at least from the perspective of hull design. But depending on what sort of seals you select, it may be a good practice to prevent seals from leaking. If you are very concerned about leaking, you may try presurizing the system...

The dynamic kernmantle rope used for fall protection by climbers is specifically designed to absorb quite a lot of energy. To complicate things further, the climber has a whole lot of choices as to which rope to buy, each with different energy absorption characteristics. That is why the rope...

Lots of ways to do that. The question is which means works best for this application. But then you have not told us anything about this application except the input and the output. The idea to look into block and tackle design is a good one, and the most obvious. But by the time you figure...

I'd design the hull for whatever pressures I desired, and then use the lake to test it. Just weight the hull down and lower it to depth on a rope. At this point, the hull need not have all the expensive stuff installed. You are just testing the hull. Designing for these pressures is very...

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...

This should be an interesting discussion. I look forward to following it. But one thing to consider is that with airplanes, the speeds are much higher. That means that sudden changes in direction or speed are seriously limited by physical considerations of F=ma. Some aircraft will routinely...

Yes, Kozy, alcohol burns in a manner similar to high octane gasoline. It has less energy content, but if you increase the combustion chamber pressures, the increase in efficiency can more than make up for the lower energy content of the fuel. But burning it without matching the engine to the...

It is easy enough to Google them. All engine manufacturers publish technical data on their engines, including a number of curves. I’m normally most interested in the specific fuel consumption curves. That tells me at what rpm I want to run the engine for various loads. Normally, the...

I have little knowledge of racing engines. My experience is with practical working engines. It is common to reduce the pressure ratio when adding boost. The idea is to give the combustion chamber a little more volume. Without the boost, that would mean less pressure. But with boost, you...

I'm an old guy with a blood pressure problem, so I've talked this one over at length with my doctor. I need some salt for my body to function properly. The trouble is that my normal diet provides much more than I need. So he told me to cut down. Then I get hauled to the emergency room in...

PhanthomJay is right. It would help to draw a free body diagram. You will also have to either know where the CG of the door is, or assume it to be in the center of the door. If that be so, the weight will work out to twice that required to open it. (Drawing the FBD and working the equations...

Back when I used to work heavy equipment, civil engineers would often ask me how much pressure a piece of equipment applied to the ground, so that they could design a concrete slab to park it on. I've seen all sorts of schemes to measure contact area to divide the axle weight by. But that...

You already have much good help in finding the simple solution, but it should be noted that in my experience shaft imbalance often becomes the dominant factor in real rotating flange design. Either because of a manufacturing error or because of a potential mechanical failure.