G'day Cameron! Well that is a very innovative idea indeed!

I'm sure no one at your school would have read this forum, so just build a lefroy mini and claim it as your own design. I'm sure Paul (the designer) won't mind!

Hi Cameron, The idea of Design and Tec studies is to enable you to work in the outside world, in perhaps in an engineering field.... I would have hoped that if you are at year 12 level you would have come across some things like "gravity" and "friction" if you haven't google them before you start.

But firstly skis... have you tried to ski on flat soft sand?, if not try it!! and this will tell you how much friction you will need to deal with.
With wheels on soft sand you will need to try which suits your needs, try a wheel barrow, try a bike, try a sack truck, try a car.....and if one works .....why?

Try the basics first rather than your hard earned time and money on the finished project, you will achieve more for yourself.

ps.
Cameron down load this Free CAD program www.cadstd.com/lite.html
It is a simple program and easy to learn and will help you greatly in your Design and Tech class.

Very true Giz, Sorry Cameron disregard my comment. Perhaps just use the Lefroy Mini for inspiration!

Hello and thankyou everyone for all the replys .
i REALLY like the idea of skiis and i think im going to give it a go because even if it doesnt work it doesnt matter its the innovation it does not matter if it fails.
Also when you say have skiis to "hydroplane" on the thin water do u mean having 2 back skiis and 1 front skii? because one of the ideas i had was to have all the parts you need on the land yacht and not have additional parts that you have to bring along with you , but i guess i could do it the way i was going to do it aswell to lower the back skiis at an angle but what if they grip in the hard sand :P .


Just a few things

1. i dont no how to put wheels onto an axel and i dont no what type of wheel i should use for hard sand and wat wheel to use for the front wheel.
2. sail sail sail i have no idea how to make a sail or where to buy one from secondhand so any help there would be greatly appreciated.
3 in the photo attatched i dont like how he is laying down so much i would like to be able to sit up a little bit more then that

4. Just a general question where the sail ends and the boom is why do they have an extra triangle section of sail under that where all the ropes go why don't they just have the ropes running directly under the boom?

Yeah i think i am going to try to make it run on skiis i will be able to get it to work.
I will be all good just need tires and a second hand sail

Answers to some of your questions.
front wheel with a small ski for hydroplaning ..... possiblity!
small triangle of sail nder boom. Im assuming your refering to the blokart style setup. This allows wide rotation ofthe boom without it getting tangled in the A frame. A common problem in A frame style chassis. The boom is IN the sail. A good solution to the problem.
If the Chassis has no A frame , ie like the Lefroy Mini, then a " traditional " bom set up works fine.
As Laurie said you can search the for sail section based on state for a cheapy. sail in your area.
When you project gets further along try posting in the the general section to ee if anybody can donate an old sail or sell one really cheap for your project.
this has worked for a high school building project that is happening at the moment.
That laying down position is for comfort , speed , and more comfort. he could get lower

seriously lower

Cam- if you used an unmodified sail and boom from a windsurfer that would give you the clearance to sit up higher due to the shape of the sail- but the downside is it makes your centre of gravity higher(tried it myself), a plus is that you can pick up the sail, mast and boom dirt cheap from most council recycling yards or from local windsurfers who have given up on the sport, or have more gear than they can use and will give some away for a good cause.

The seat can be found at the recycling yard- or your school might have a few damaged chairs stacked away you can scrounge!

I would recommend building a lake lefroy mini- and make an extra set of rear axles with skis attached instead of wheels, mount the skis so they can flex on pivots of some sort. inboard mounted skis will make it easier to tip over..

Front ski could be mounted on the same shaft as the front wheel after you take the wheel off (the wheel is only held on by a pin) but the geometry of the steering might mean using a small universal joint (taken from the steering column of a car) to keep the ski flat on the ground when you turn the steering.

I would imagine that skis could be picked up from a recycling yard too- there are several sets of skis at our local yard- and we are in western australia where snow is a bit scarce!

Ohk just a recap of this.
I shouldnt worry about getting a sail yet becuase it should be fairly easy to find one and easy to install.
How can i make a removable rear axel? to make it interchangeable wheeles/skiis?
I really dont get the whole universal joint thing?



Thankyou everyone !!!!

Hey!! What about making small catapillar tracks for soft sand instead if skis??

Cam-
the axles are pretty simple- its just a short piece of steel shaft that the wheel slides onto- and is held in place by a pin. pull the pin out and the wheel slides off the shaft.

another variation is to use 20mm or 3/4 inch threaded rod and use a nyloc nut instead of a pin (if you have any trouble finding the pins I can post you some as we have thousands of them at work).

the universal joint is needed as the steering on the lake lefroy mini landyacht uses a form of steering where the wheel "lays over" when you turn-(much like leaning a motorcycle or bicycle over in a turn) it is very effective and simple to build. If you tried to bolt a ski on the front axle without a uni-joint of some type, when you try to turn the rear of the ski would dig into the ground and the front of the ski would be pointing up in the air.

As you intend using your yacht on sand- I would be looking for the widest wheelbarrow wheels you can find, for the rear skis scrap my original idea and use a similar system as I proposed for the front axle's ski- just take off the rear wheels by removing thier retaining pins, slide off the wheels, and slide on the skis which could be mounted on a simple collar which fits over the axle shaft and is also held in place by the retaning pin.

I can understand you wanting to have the skis and wheels fitted to the yacht at the same time- but a very important principle of landyachts is being as light as possible (quoting the guru-"lighter is righter!)

I reckon you should draw up a set of plans based on the mini yacht as shown on this website, but to suit the materials you have access to, and show them to your manual arts teachers and ask them for a bit of advice- the skis I cant really advise if you should use waterskis or snow skis as I have no experience with either but at a guess I would say water skis are possibly better as they have more surface area to support the weight/ but the downside being more drag...it might come down to what ever type of ski you are able to find.

The one real advantage you have is your school should have a fully equipped machine shop with lathes, milling machines, welding equipment of all types, drill presses and a bunch of very experienced teachers who want to show off how good they are at using them.

If your teachers are anything like the ones I had at school- there will be more than one landyacht pushed out of your school workshop!

sn said...

just another hint- you will need some pulleys too for the ropes.

they can be scrounged from old exercise machines at the dump or recycling center, or from the street verge during "council pick-ups"

Caterpillars???? Caterpillars ???? did someone say caterpillars i been tracken them for years, never caught a one I think they trained mite work, however they would be slow The writes wishes to acknowledge that sometimes he could suffer some senior type moments

hills said...

Hey!! What about making small catapillar tracks for soft sand instead if skis??

I can remember back in the late 1970'2 early 80's there was a ski business in yanchep W.A. using caerpillar type skis on the grass slopes (snow is a bit scarce around here.........

they didnt last long though.

Tracks like those take massive amounts of power to drive them . Had an ARGO 6 wheeler with tracks fitted over the wheels. It would go very slow and constantly overheat and get bogged in any kind of mud.
One day we removed the tracks to get out of a bog and the machine came to life.
never fitted the tracks again
Oh and the Ludic is FRENCH monsieur Not ENGLISH. its a Seagull
you can buy em from Pheonix Landyachts in QLD
very fast whenyou push them to thier limits

Well Iand you , my friend are infor a speed shock!!!!!!!!!!! make sure you sail your new sat up ONLY onthe smoothest hot mix, take plenty of spare spare wheels a they cook on the turns, keep the seatblet tight as rocks under the wheels will stop you real fast!. We did his particular experiment way back in 1992 around the streets of Kambalda west.
The local copper kicked us off the street AFTER he'd had a go[:D
Our yacht was bigger with a 16" bike wheel on the front.
Enjoy