Hello all!

New user here. Im a mechanical engineer student, and have been contemplating building a land yacht for a long time now. The time has finally arrived to do so! As a college student, I will strive to keep this as cheap as possible, and as a mech. engineer student, as clean and streamlined and well designed as possible. With this in mind, I turn to all of you for advice and thoughts.

So far, I have collected materials. The sail I intend to use is from a 1972 Atlanta Kolibri Koralle Jr. 12 foot sailboat. The mast for this boat is 17' 4", flying about 85 sq feet of sail. I dont know if this number includes the jib. I understand that many people like to trim their sails for a flatter sail and higher top speed.

Question 1: What are peoples thoughts on this sail, and it being used as a land yacht sail? Would it be ok to use as is, without trimming?

Question 2: What is the reason behind not using a jib on a land yacht? Would the use of one likely cause the front tire to 'spin out', as the center of effort is further forward on the craft?

(Boat information page) www.boats.com/boat-details/Glenmore-Sailboats-Ltd.-Kolibri-2-12/136710

(Boat picture page) www.rvharvey.com/kolibri.htm

Now, thats what I have for the sails. On to the wheels. Today I collected several different kinds of wheels. I have attached a photo. The largest are 16x6.50, while the smaller are.... 9xsomthing? I have been contemplating using the 3 large ones. The main surface this will be sailed on shall be the beach, with some use in a parking lot. I have been thinking, that instead of the 16x6.5 wheel for the front wheel, I should make use of a wheelbarrow tire, as its profile is round.

Question 3: What are your opinions on these wheels? Would the larger ones be suitable for use on a land yacht? Thoughts on a wheel barrow wheel for the front tire?

Now with all this in mind, the wheels, the mast, etc, what would people think as a appropriate width for the wheel base, and what do you estimate the performance to be? My goal with this is to go as fast as possible, for as cheap as possible, and have fun.

Thanks everyone!

Hey all again!

I also have this sail as an option. Well, actually I have 2 sails this size in my garage. The issue is that I dont have a mast, or a boom. It requires a 520 cm mast, and the longest I have available is a 460 cm mast. That, and I dont have any money, or know how to tell if these masts would be appropriate.





Question 4: Which sail would be better? And does anyone know if its possible to extend a windsurfing mast 60 cm?

Niykon.....gidday, welcome. You have the bug too, I have been looking at your

wheels, i would describe them as sorta agricultural, heavy and some would be

hard to attach, needing a hub, exta weight. All wheels will work, what is best

to try for is the simplest, lightest. That will give you the best speed, heavy

wheels will take the hardest pounding. Your experimenting will get you the best

results. There is mobs of wheel info here, troll back over the pages in the forum,

someone , somewhere will have given it a go before. Best of luck.

Hiko said...

OH Wow that NX sail I would say would recut into a very good landyacht sail
Most landyacht sails are around 4 to 5 sq metres
There is instructions on this forum on how to do it if you have the means
Do you have the means ? There is a post on this forum where a similar sail to that was made into two landyacht sails Try the sailmaking section
460 masts will be fine I have two of those and yes they can be extended
Hiko

Well, The idea behind getting such large sails, was the fact that I would like to go very quickly :P Im moving from sailing catamarans, to getting into land yachts. If most land yachts are 4-5 sq meters, then my 11.5 sq meter windsurfer, or my 7.8ish sq meter sail boat sail should be able to take me faster! One would think anyways, I know it doesn't quite work like that, but I can wish right?

Anyways, I was thinking that since my sails are so large, I would need larger wheels. Thats why I chose those ones , j murray. But you are right in describing them as agricultural. They are off of a riding mower, I do believe.

the biggest hurdle to overcome with a landyacht is weight.

you are best finding lightweight wheels like the 8" x 4" plastic fallshaw wheels many of us use here, they have the added bonus of taking cheap bearings or high quality sealed bearings- and as an extra bonus- plastic wheels dont rust when used on salt lakes!

however, if you have to use the mower wheels you already have- reduce the tyre weight by shaving the tread off with a "razor blade plane" which can be purchased for about $5.00 at any hobby shop.

also try and reduce the stub axle and hub's weight by finding someone that has access to a lathe and get them to take as much metal off as possible.

I tried to use lightened suzuki hatch 10" wheels and hubs for my first version of a lake lefroy mini land yacht- and it was just too heavy to work.

The plastic wheels were magic when I fitted them.

Gday Niykon, welcome to your new addiction.
a couple of suggestions
since youve already got the tools and know how to use them , my suggestion would be to start with something with plans that has been a proven performer
ie the Lake lefroy Mini. Although an experienced metal worker my think it all looks to small and simple, what you are also learning is some simple basic principals regarding weight,balance,steering orientation , material sourcing,wheels and tyres.................
most of the mini builders here have either built thier own designs first, then kicked themselves and built a LLM, or built a LLM then gone on to experiment on thier own ideas. The chassis construction would only represent an easy weekend for somebody woth experience in the tools and techniques
Having built and sailed such a simple yacht you will find the desire to build your own design happens very quickly, and many of the basic questions youve asked here will answer themselves. there are plenty of options for the basic materials
keep in mind that a yacht the size and agility of the LLM can be easily sailed on tight little carparks as well as on your lovely US drylakes.
the best speed for one of these little yachts is 65mph in your speeds and 30mph is possible in a carpark.
I have been warned by the law on 2 occasions for speeding in small carparks

Hey all! Got another day towards starting the build. Today I collected some more materials, items and photos.

First up! front wheel



I pressed out the crappy bearings, and pressed in some nice sealed high speed bearings. Come later, I will get it balanced. You guys think it will make a good front wheel?

Also, while I was looking around, I came across this:





It is an aluminum solar car wheel, fitting 20" hookworm tires. I thought it was ironic, seeing as it mounts the same kind of wheel everyone seems to be using for their land yachts. Unfortunately this one is damaged. But, its in good enough shape that perhaps a mold could be taken from it, and the wheel reproduced in carbon fibre. Would anyone be interested in something like that?

-Next up, building materials. I have aluminum available, but im worried about the material properties, crack propagation, the need for heat treatment, etc. Do people use aluminum much? What kind of dimensions are we talking about?
-I also have steel available. Again, what kind of dimensions are we talking about?

-Next up: Titanium!

I have Ti-2 and Ti-64 titanium tubing available. Again, I worry about the material properties again. I think it would be far to flexible, and not quite rigid enough. l also dont have a ton of it, and want to save it for a later project, or perhaps my uber land yacht, if i build another after this. Thoughts on titanium as a material?

Next up: Ive decded upon the rough direction I would like to go with my first yacht. I understand everyones advice on using the LL mini as a basis for my first yacht. However, since im going to be using the sailboat sail and mast for this one, I think the LL mini is well.... far too mini. I think with that sail on, it will just be too tippey. So instead, I think I shall go with something like this:


I can tie the mainstays to the two wheels on the sides, and the front to the front wheel. If I want to, I can make use of the jib with that front mainstay, but lets start small.

Thoughts people?

A jib will only slow you down. A yacht like the one pictured does not use fore stays. as they tend to disturb the air flow to your sail. Mostly the mast is self supporting (dont need stays)

But thats the thing guys.... I dont have a sail that I can go chop up. The one that I can go chop up, I cant afford to buy a mast for it.... And I dont have a sewing machine, etc to modify it. The only sail I have is the one for the boat :/

Lol, I did indeed have a part in building that solar car there :P I designed the entire body, from a-z, as well extensive fluid flow analysis in SolidWorks, as well as scaled wind tunnel testing on a 3-d printed model of the body. Heres a bit better photo of the car :P

As far as the facilities and knowhow to work with the Ti, I am indeed fluent in this as well. We usually let the CNC mill do the machining, but I was one of the 3 welders for our car, which was constructed from 90% titanium.

Anyways, thanks for the encouragement. Its good to finally hear a "go for it!"

Also, I would like to hear more about this DIY mast of yours. Can I get more info?

Gizmo said...

If you have access to good materials and good design tools GO FOR IT !!!! ( but try and keep it in the design specs for that class)
The use of titanium would be interesting on a LLMini built with a steel weighs about 25-30 kg, the use of titanium may reduce it say 10kg, but remember the main weight factor for small yachts is the actual pilot.
As for sewing machines and old masts its amazing what you can find when you put feelers out at work, schools or clubs.
If your also into modern design I hope you have seen these yachts.... mind you some are just concepts and haven't been built
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=55001
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=53255

What class are you referring to here? I'm not actually planning on competing in any events. I actually live in Oregon, and locally,I have access to zero salt flats, dry lakes, etc.... The planned place for operating this is going to be on the beach :) So, no rules, no limitations based on some competition regulations, etc.

So since im going to be on sand, loose, packed, whatever, im going to need more power out of the sail. Its also the reason I have chosen wider back tires, and the largish front tire.

So, I wonder something. What would happen if I recut my windsurfing scale, giving it the correct shape, but leaving it as large as possible?


What would be the approximate shape, if anyone could draw it. I understand that such a large sail isnt really needed for these smaller karts, but im intending to build a largish cart here :)

Thanks gizmo! The links are some good reading.

However, theres nothing in my area, or any real interest on my part as of yet, to race this in competition. For now, I would like to build this, and make it big, fast, fun, cheap to build as im on a college budget, and well designed.

Lol thats awesome. It even has a headlight!

having seen the piccies of the titanium tubing, you have about 3 good masts there! im sure you would slot together something fantastic from them. They look to be telescoping sizes. you wouldnt need to do any welding
keep in mind that my 3 seater only has a 8m windsurfer sail, so 11m is huge. if you are sailing on an oregon beach, presumably you will want something that is capable of dodging logs
i know your just busting to build a monster first off, but I read what your saying, and I keep thinking that its all just ideal for a LLM as the first project.
The class 5 OTT yacht photo you showed us is really like saying," Ive seen a formula 1 race car, so i'll just build one and drive it".
But yes the boys and I will help as much as possible
that wheelbarrow wheel you showed is ideal for all your wheels on a yacht up to say 6m sailarea. you will need to put a fixed spacer inside the bearing housing to keep the bearings in place.
I suspect the solar car wheels will become a lot of work to make them fit the bill

Clemco said...

I must disagree here. The OTT class 5 design is no more work or expensive to build than an LL Mini.

I would have to agree. The only thing that is really more complex is the fact that you must 'suspend' the seat from the frame, as opposed to sitting atop the frame for the mini. Other then that, I would say their complexity is about equivalent.

Hey clemco, or anyone else, do you have any photos of the steering setup?

Hmm.... not quite understanding what you mean here. Do you mean that the steering knuckle needs to point at the contact patch the wheel makes with the ground? And whats this 30 degree measuring?