A person on a different forum linked this site for me. I've given part of the thread below if you'd like a bit of background for my question.
Question:
Given primitive materials, (metal and welding supplies but nothing else) could a master welder create efficient windmill vanes. If that is possible and said windmill is mounted on a 120' Viking long ship with a propeller through the keel, would it be able to propel the ship. Normal operations would be by conventional sail, but a Viking long ship does tack well, and I'd like something that windmill to allow them to sail directly into the wind.
I do understand just how odd this question is, but what I'm really asking is how much horsepower could say a 7-12' radius windmill generate and an opinion on how hard it would be to build the vanes given high motivation and skill. (20' might be possible if required. I'll be using a steel light pole for a mast and I don't know the stresses involved.) Last but not least, could such a windmill be designed to allow the vanes to collapse like a "Lady's fan" so it could be lashed to the mast when it wasn't in use.
I'm not looking for blueprints, but an expert opinion. If I write about something like this, I'd hate for knowledgeable folks to assume the design was fantasy.
My first book has made it all the way to the publisher's desk, where I'm told it will sit until I have a second. The first was a bit of cliff-hanger. I'm working very hard on the second and hope to have it finished by the end of the summer. Actually, I hope to have it done in two weeks, but it will take all summer for my wife to fix it. (If you can't write, but discover a need to write a book, I suggest you marry an English teacher.)
The books are sci-fi and the story line is about a section of a maximum-security prison that marooned on an Earth-kike planet stuck in the stone age. My creative prisoners are now building a boat to make contact with the natives. I am thinking about creating a windmill devise to power a propeller. I'm also still trying to design the ship. (it needs to be large enough to carry 100+ on a 2000 mile voyage.) Sail will provide the main propulsion, but I thought about using a windmill for special work like very narrow channels, or to maintain headway in a storm.
Now for the question, given steel, wood and welding supplies, how would you construct a such a windmill, and more important a propeller? I need to add they have a parking lot full of cars, but almost no fuel.
Let me backtrack a little.
Quote:
Originally Posted by deficiency4math
i agree, windmills would just be too complicated and would have a million variables to go wrong, especially in a storm! Sails, two, three masted, depends what you want, and maybe oars or a man-powered fishtail. (make sure to get the sailing right, as im a sailor, and i dont want to read shabby sailing! wink) by the way, it sounds pretty interesting, so whats the name of the book, so i can look out for it?
End Quote
I am trying to limit the sci-fi to how they were accidentally sent a different planet. I'd like everything else to be science, or engineering. I believe that humans are almost endlessly creative, but I'm not. Thus, I've used places like this to find out if something is possible, and to get tiny thumbnails about how to do it. I've gotten help in other places on many odd topics... like how to make a windmill.
I agree that building a windmill from scratch would be impossible. But, when I was a senior in high school, my parents bought a ranch... Truly "Green Acres," but that's another story. :smile: The only source of water was a windmill and a cistern. I was always impressed with how simple that Aeromoter windmill was. We took it apart once to grease and repack the bearings.
My creative convicts only need to pull a drive shaft and rear end from one of the cars to have the "motor" part of a windmill. I think they'll be using one of the tall steel light polls for a mast. One of the inmates is a former nuclear power plant welder, and he has plenty of supplies. They also have steel from the roofs, metal buildings and security doors. What they don't have is any sort of press, or high temp furnace. Part of the reason to build the ship is to get coal so they can work metals beyond welding.
They can have plans (via their computers and text books) for any sort of design they need to build, but they don't necessarily understand what they are looking at.
One of the things I don't know --- hence they don't know is just how much energy would be provided by a the type of vanes they could produce. I don't know how much would be lost in transmission and how efficient a propeller they could produce. I had originally thought of having them build a Knarr (Viking merchant ship) but a yachting form suggested I consider something with an outrigger for safety. (I had hoped to use a canting keel for extra speed but it looks like that would be beyond them technically.) I'm trying to understand advice about design and ballast and the strength of wood versus ripping up a whole building to make the hull out of steel.
The problem is that all I know about propeller design and windmill vane design is that small difference create large changes in efficiency.
Bottom line, given the welder's skill, could he make an efficient windmill vane and a good propeller. If he did so, would it produce enough power to make a difference. I.E. given a 20 knot wind how fast would a 120' Viking long boat be able to head directly into the wind? If that doesn't work, I guess I'll just have to figure another way to keep them from being blown on to the rocky coast.
I do thank you for your advice, I do understand just how off the wall this sort of question is.
