Forums > Land Yacht Sailing General

Two more Lake Leffroy minis are hatched.

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Created by mulgachook > 9 months ago, 13 Nov 2016
mulgachook
NSW, 3 posts
14 Nov 2016 1:28AM
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G'day All, You have a great thing going here. 18 months ago while bouncing around some ideas for activities for a scout venture in Darwin some scout leaders there mentioned the fun they had had on landyachts at a jamboree in South Australia. A bit of searching on the web and you fellows came up with just what was needed. So Mud Skipper (light green) and Blue Swimmer (blue)were the result.
Great plans and the humour behind some of the construction descriptions shows true craftsmanship - Thanks Paul and crew.
The design brief was for something that could be used on Gunn Point beach which has plenty of room at low tide. Having a tiny bit of Scottish ancestry from many generations back meant as much as possible had to scrounged for the build. The Darwin Tip shops helped immensely here.

Chassis was the traditional stop sign tubing. No choice but to buy new RHS for the rest because any RHS disappears quickly on the farm. Initially the wheelbarrow wheels were bought from the tip shop for $5 each with no two matching and bearings ranging from fair to loose and crunchy. I did not know how they would go on the sand so when a set of four nearly bald but still pumped up 8" golf buggy wheels popped up these were grabbed, again $5 each. (after getting my cousins to machine up and laser cut hubs for these the price jumped a little. )

A number of visits to ebay picked up a variety of sails, masts booms and odd bits. One sail cost me 99 cents but it was a 100km drive to pick it up. My collection of eighties and nineties windsurfer boards has grown!
The seats, booms and some of the masts were salvaged from Mobile telephone base station antennas. Many of the older mobile phone panel antennas you see on poles and towers have fibreglass front covers and are scrapped when pulled down. They make light weight seats. The booms were cut from mobile phone base station omni directional antennas and these particular ones used thin wall epoxy glass of about 60mm diameter. As well as the windsurfer masts a number of VHF base station whip antennas were cut down to fit into the mast step. Full circle here, 20 years ago the manufacturer of these antenna said they had sourced the antenna radomes from a mast manufacturer.
Apart from old pulleys from my yachts spare parts box there was no real cheap option there though BCF has some discounts a while ago.
The final result was the two shown with a third on the go now. The day the venture landyachting was scheduled had a light breeze that wasn't quite enough for the older teenagers to get too excited but the smallest lad there had a ball, getting up on 2 wheels easily. Approx 4m sails were used then. Today with winds varying between 30 and 50 kph and a 6.2m sail we had a ball running Mudskipper around a friends farm near Bourke. Black soil tracks are bumpier than sand and the burrs made running off the tracks a little uncomfortable.
Blue swimmer is still with the scouts in Darwin and Mudskipper is back here in Bourke. We are trying to work out where to find a treeless claypan or salt flat. After todays fun version 3 has been given the go ahead.
Version three will probably have a chassis based on an aluminium Gyrocopter 65mm RHS rotor support given to me, it still has the gyrocopter registration sticker on it which is pretty cool. Bolts and plates will be used to adapt the rear axle and steering assembly.

Cheers
Colin










Chook2
WA, 1201 posts
14 Nov 2016 9:00PM
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That is an outstanding effort!!!
Well done.

sn
WA, 2447 posts
14 Nov 2016 10:04PM
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B.R.A.V.O. fellas!

Good to see the 7th law being put to use

If you were a bit more to the west, I could help out with a few bits and pieces.......


stephen
[another Gilwellian]

landyacht
WA, 5765 posts
17 Nov 2016 9:30PM
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thanks for reminding me why I put those plans out in the first place..building stuff and salvaging all in one go. i can go to bed happy now

mulgachook
NSW, 3 posts
25 Nov 2016 3:55PM
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Thanks for the offer of bits SN. By now I have worked out what bits I have here that can be used so the masts and boom are covered, Frames are easy to make up and I have plenty of spare seats.
Has anyone had any experience with using quad bike wheels?? These are another thing that is not uncommon at Darwin tip shops with plenty of the smaller chinese ones expiring up here. 19 x 7 -8 is one size I have four of and a couple are pretty close to bald so should have less rolling resistance. again I will have to make up hubs. (fixed rear axle on quads and front axle shafts are pretty thin) To get more speed do we have to go to narrower, higher pressure wheels. The slide out axles of the mini are so easy to swap over. I found the mini to be pretty stable ,the wheels lifted reasonably predictably and it was easy to stay on track. Would the heavier and wider golf buggy wheels have an influence on handling? A number of times when going into a hard tack at speed the sail seemed to drift the back wheels around. A bit unsettling at first but a good rush, just like doing hand brakies.
Next time a good wind comes through we will be out again experimenting with bigger and smaller sails and probably a stiffer mast, the amount of flex and whipping in the mast last week was unbelievable. A few cars coming down the main road must have wondered what was hurtling through the paddock towards them.

Colin

landyacht
WA, 5765 posts
3 Dec 2016 3:22PM
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youll probably have to make some custom hubs for quad wheels but it has been done successfully

mulgachook
NSW, 3 posts
4 Dec 2016 2:59PM
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Shall do that and let you know how the next one goes.

mineral1
WA, 4388 posts
15 Dec 2016 5:54AM
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All I can say is WOW!!!
Well done. Like the wheels on Blue Swimmer. No idea if they are more user friendly or not, but the set up looks great.
Chook2 or Landy, will this set up be better than normal, or isn't it of any difference.?

landyacht
WA, 5765 posts
15 Dec 2016 6:53PM
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fat tyres have to be light weight aAND runnable at low pressures. often lown mower wheels are rather heavy and when you pump em up you lose any advantage. going larger diameter is more effective. but there is still a need to stay light. some of us run 26x2.5 tyres on a 3.0" wide rim which allows us to drop the tyre pressure down to 25lbs when racing on rough ground. chook races with 4.5 and 4.8? tyres on 4.0" rims

Chook2
WA, 1201 posts
15 Dec 2016 10:19PM
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Yeh I'm using Surly 3.8" wide "Fat bike" tyres on "home made" 26" x 3 1/2" wide rims at 12-15 psi for soft ground.

These fatbike 3 1/2" rims have cutouts in between the spoke holes and a PVC liner allows the tube to push through the rim in a controlled manner. The beauty of this is when you hit a wheel rut or bump, rather than raising the whole wheel, it punches the PVC liner/tube through the rim and absorbs the impact and keeps the wheel in contact with the ground rather than slipping downwind. They are unreal for traction. Our custom rims have 9 internal carbon spokes fitted and disc sides.

Fitted here to my old mini yacht.



These wheels work really well as they have very little rolling resistance.
I'm just looking into 5 1/4" wide x 26" in 120 thread casings, to fit these custom wheels we made, as I've worn out my second set of 3.8". But the 5 1/4" are not available in Australia yet.

I fit 2.5" x 26 " Hookworms to these rims for racing the class 5 on hard salt at Lake Lefroy at 28-32psi

My original "Code Red" 5.6 mini I fitted with lawn mower tyres (Fairway mower smoothies) I welded a hub into the rim and machined it to take a 20mm bearing each side. (sorry bout the crappy phone photo, Phone cameras weren't that good in 2010)

They made a huge improvement to floatation on our soft ground compared to the fallshaws, but took a bit to get them wound up/accelerate.
Like Landyacht said they are heavy tyre casings with steel rims designed to be really robust. These were just for floatation/fun and I went back to Fallshaws on the back for racing just by fitting other axles and wheels.
It was well worth making them for fun times on soft ground.

Bynorthsea
87 posts
16 Dec 2016 2:37AM
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Here is my yacht with beach tyres the 20x12 slicks make it so much easier when hitting soft areas, the back end can drift a little and aquaplanes at speed but that's all part of the fun. It is marginally slower compared with small wheels but you keep going and the extra outboard weight means you can push hard without wheel lift.




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"Two more Lake Leffroy minis are hatched." started by mulgachook