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Steam Powered Underwater Jet Engine
Bob Vila's Hammer writes "An Australian engineer, Alan Burns invented a very efficient underwater steam powered jet engine. "Steam that is produced from a petrol or gasoline fueled boiler emerges at high speed from a rearward-facing ring-shaped nozzle into a cone-shaped chamber. Shock waves created as the steam condenses are focused by the chamber to blast water out of the back. Besides powering watercraft pretty efficiently, it can also be used as an extremely robust pump. Pretty Cool."
From more to less likely:
(1) Efficiency could peak at 300HP designs - it may be that any larger becomes horribly inefficient. Since it relies on squeezing compressed air and steam into an open tube, there might be a point at which there simply is to much room for the reaction to take place in given an incoming water velocity.
(2) The design may not be completed - possible design flaws may limit this versions' abilities to scale up.
(3) They may simply not know how big it can scale if their simulator isn't powerful enough to run a detailed simulation of a larger engine.
Well, I'm sure somone else has noted this : a nuclear energy source like on a warship would be perfect for supplying the steam. By venting the secondary steam from the boilers directly into the water like this you could easily get ten times the power with the same size engine (though you'd need more higher output reactors) I am sure an engine like this would be EXTREMELY noisy, so the warship would have a set of these steam jets it could fire up when it needs to move somewhere fast, and some quieter source when submarines are a worry. Imagine an aircraft carrier and a few destroyer escorts with flank speeds in excess of 70 knots (it would have to have hydrofoils as well, because otherwise the hull speed would be to limiting. Yes I'm aware it might be decades before a carrier this sexy is built, if ever). Sure it would be vulnerable to torpedoes, but the idea is it could be a MUCH more threatening weapon with this kind of speed. It could patrol a larger area, escape from danger, and have a certain intimidation factor when its located somewhere since it could arrive suddenly, launch a strike force, and depart before the enemy was aware.
As long as were speculating, imagine an even more effective weapon, a ship loaded full of missiles and rocket launched drone strike aircraft (so no human pilots risked. Yes I'm aware that such aircraft might be say, half as effective as human piloted planes but if they cost 1/4 as much to build its a MUCH more effective weapon. It could very well be cheaper to turn out somewhat dumb long range missiles and semi-reusable drones by the thousands, with no additional pilot training needed. The "pilots" would be a group of technicians behind consoles far from the battle, with embedded computing in the planes doing most of the flying, the human being just to pull the trigger. Without all the risks of training pilots and maintaining aircraft (the planes would be stored in sealed containers until needed, with a small set used for training) and the fact that these planes don't need nearly the quality control in manufacturing (if you lose 10% of them in a mission due to shoddy construction but they cost half as much or less to build its definitely worth the trade off) you'd have a better solution than at the present.
Why isn't this done already? Well, in the 1970s and earlier where most of the present airplanes were designed, communications technology and computers were not good enough or reliable enough. Today, most of the money is spent on operations and on a couple of new aircraft. Also, the current leadership is made up of pilots, who don't want to be replaced by scrawny pasty faced techs sitting at control stations. Finally, there's a current bandwidth problem : military communication satalleits don't have the capacity for the hundreds or thousands of video links needed.
Why did this get modded up? While there are no facts listed, the company does describe the engine as "Very quiet" on their web site! Have you ever gone for a ride in a small boat of current design? I wouldn't exactly classify them as silent. In fact, it's more along the lines of too loud for even a shouted conversation of any useful length. Without any facts you're fears/claims are meaningless and alarmist. For all we know the lack of prop cavitation and direct transmission of engine vibration through the drive shaft to the water might in fact make this a quieter engine! No claims can be made without seeing, using and testing it ourselves, or reading reliable documentation on the subject.
This sounds amazing:
* Cheap to produce
* Incredibly robust (no moving parts)
* Efficient (although they don't give any numbers)
* Safe(r) for the environment
* Multiple uses (pumps)
* Scales well in a small package
Without seeing any numbers, it sounds like it beats the pants off of outboard engines. My 70HP Evinrude has been rebuilt twice because of sand-suckage, and standard jet impellers are too inneficient.
So what's the catch? I want to see some real numbers. If there's no catch, then I hope and think this thing will revolutionize the small-craft market.
Sure, both this and supercavitation are cool, but they aren't going to play well together. The whole point of supercavitation is that it keeps (liquid) water away from the hull. This guy pretty much needs to inhale as much water as it can get.
You might be able to get away with mounting a ring of jets around the hull near the aft along with (or in place of) the control surfaces, but I'm guessing you'd still get into trouble with the extra turbulence.
Won't somebody PLEASE THINK of the ENVIRONMENT?!?
/second, raised approx 3 degrees.
Sigh. Let's look at some numbers, shall we?
Volume of water going through (arbitrary example) 20cm dia steam-powered jet engine at 10m/s: 3.14*.10*.10*10 = 314 litres
Volume of water in 1 square kilometre of 20m deep ocean at 20 degrees: 20 thousand million litres.
Time to traverse 1km in boat at 10m/s = 100 seconds = 31,400 litres of 4 degree warmer water.
Mix 31,400 litres of 4 degree warmer water with remaining 19999968600 litres.
OH DEAR GOD, NO! IT'S 0.00000628 DEGREES WARMER!WE'RE ALL GONNA DIE!!!!
So, if 1000 boats all simultaneously traversed the same 1km square section of water, the water temperature would be temporarily raised 0.0628 degrees.
Well, better discard this invention and go back to conventional petroleum powered motors, for surely they are the safest, most environmentally friendly way to proper water craft.
(This dose of reality brought to you today by the concept of common sense. Please try some.)
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.
I can't conceive how it will function as a primary power source because of the mechanics that would be necessary to start the process.
In the same manner, you won't have a "neutral" since it probably can't be turned off and on rapidly for docking maneuvers, et al. Perhaps it could use buckets like a jetski (or any jet aircraft using clamshell reversers), but I wonder how well it reacts to a high backpressure created by such a device....
Maybe we'll get to see some of that great KABOOM action when these things explode or when two boats collide!