Welcome to the forum Tim
Interesting you are from the OYLE of WOITE I have an aunt there in Ryde
Building a lefroy mini is a fun thing to do and quite a few
are getting built If you look through the forum you will see they have been built from various matierials according to what is available in the builders area
Steel sizes vary from manufacturer to manufacturer and will definitely vary from country to country so some flexibility is necessary and a hard and fast matierial list will not be that helpful to you
Sorting out the matierials is part of it ! All the info is on the forum
Welcome again
Hiko

Although using recycled materials can be one way I acutally prefer to use new tube the reason is you actually need very little of it, its fairly cheap and in Aust. approx $10-12/m and you get the stuff you need and with no rust... The frame constructed from new materials costs less than the price of one new wheel.

I posted a list of steel etc on camerons construction project thread,
I think it is on pages 6 and 7

the cutting list covers almost the whole lefroy mini (I think the pedal assembly is missing)

Dear All,

My apologise for the layout - I've not quite got the hang of the high tech displays yet.

Dear Hiko,

I know Ryde but it’s a bit far away from where I live in Ventnor (all of 12 miles!!!!).

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Dear Jay,

I work for the Isle of Wight Council so I’m hoping to scrounge the parts from other departments.

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Dear Gizmo,

You have a valid point regarding the condition of the tubes. Hopefully what I’m offered won’t be in too bad a condition. But if they are I can then consider buying them as they are only short pieces so won’t be too expensive.

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Dear LandYacht,

Thank you so much for the list.

Regards, Tim

Dear All,

Is there a reason I cannot use aluminium instead of steel. I only ask because there was some scaffolding up outside work today and when I asked the workmen what metal it was they said it was aluminium. As it does not easily rust I thought it would be ideal material but the weight may be a problem.

Regards, Tim

Wasn't there a song about a council worker who goes sailing this is getting a bit odd! maybe a splinter group is happening here,LOL. Did you expect this kind of interest Landyacht?

I did consider aluminium poles but welding it was my biggest problem as well. also the alu poles flex much more than steel.
Jay

Edit.....it was Deacon Blue, Dignity

Alloy scaffold tube has been often used in the past, but before the "torsion frames"
Perhaps you could make a small "joiner frame out of steel, a bit like Aus 230? and use the scaff tube for all the plug ins?
Scaff tube should be 48.4 by 4.48mm wall, and it is a very high grade of alloy . With that sizing 50mm by 2mm would not allow tube inside, so you have to step up a bit. Accurate fits are not as important as you might think, except where needed to keep the wheels lined up.
Remember that tube is measured outside diameter, pipe is measured inside, so a 50mm pipe is bigger than a 50mm tube. So a 50mm pipe would be good enough!

Yep I am dreaming, but you get the gist? Corrected now!

In gizmo's thread "another LLmini" he has pictures showing his landyacht rear axle stiffening brackets made of flat bar instead of rod- which I think he is also going to be using for the rear seat mounts and seat belt mounting points.

The rods dont need to go that far forward- only about 250mm or so. (maximum)

One thing to look out for is excess weight- longer brackets =more steel= more weight to drag around.

I am no expert- but I think the round tube flexes better than square tube- which is too rigid.

FWIW, the reason this kind of yacht first appeared was largely based around the issue that fully triangulated yachts (which is the "best" engineering solution) are very flighty, wheels fly too readily, they dart around, and are generally difficult to sail.
A number of "solutions" appeared in the mid 80's and these "torsion tube" yachts were seen to be the simplest solution. The brace bars to the rear axle are simply to keep it square to the main tube, so 45 degrees is the "best solution". This means they are normally only around the 250m to 300mm range. This still allows the wheels to kick out of line with each other to some extent, but considered acceptable. I will disagree a little with Hiko, the back axle bends back and forward too, (especially on unsmooth surfaces) only resisted by it's mechanical ability, so it's the dreaded C word (compromise) between being too stiff, and getting back some of the issues in the first paragraph, or too soft and flexing out of line.
Way back, I was involved with a number of experiments with different sizes, wall thicknesses and material spec of the backbone, and I was clearly shown that there is a strong link between these and the performance of the yacht. Having said that the rig is still the vital powerhouse. Just like all forms of wheeled sport, it's a case of translating that to forward motion, and any thing else is fine tuning. And sadly I will disagree with many on this forum super light weight is not the answer, and I know this flies in the face of physics. I have built a yacht (Class 5) which weighed 23kg (yes really) and it was a bitter disappointment. 20kg of ballast transformed it to one of the best I have owned. (and there are over 100 of them)
Daily ramble finished!

kiwi307 said...

The brace bars to the rear axle are simply to keep it square to the main tube, so 45 degrees is the "best solution".

So as a brace the component should not flex in the plane of the bracing. Therefore flat bar should be better than round (weight for weight). If there is still doubt use right angle or T bar. Clever use of angle or T bar allows dual use (ie seat mount).

And sadly I will disagree with many on this forum super light weight is not the answer, and I know this flies in the face of physics.

Paul and I proved this at Yeppoon. Diablo (an LLF Mini) came in at 34 kg without mast, sail, boom or rigging. A standard blokart fully rigged allegedly comes in at less than 30 kg.

Paul raced my blokart at the event proving himself to be one of the best sailors there and my blokart to be one of the best prepared.

After the racing we went head to head, me in LLF Mini and he in blokart.
He has verified that he could not catch me and I was not even sailing the yacht properly.

He got quite pissed off when after 3 or 4 klm I stopped to roll and light a smoke
I have built a yacht (Class 5) which weighed 23kg (yes really) and it was a bitter disappointment. 20kg of ballast transformed it to one of the best I have owned. (and there are over 100 of them)
Daily ramble finished!

Quote Paul:-theyachts tend to get rather skittish over rough ground and will rebound and bounce rather than grip and keep powering through.

Under power and speed on fairly smooth sand I found the yacht to be unforgiving of steering mistakes. They are a mean machine.

These land yachts seem to be a continueing leasrning curve.

Oh well, at least you had a smile on your face. It was Bank tobacco and Rizla Licourice papers which are difficult to roll with in damp conditions.

WightWave said...

Dear All,

I've got another question, if I may. Could someone confirm the measurement of the LLMini along the rear axle from the inside of one wheel to the inside of the other wheel.

Regards, Tim

From the INSIDE of the L wheel bearing to the INSIDE of the R wheel bearing is 1100mm +/- 3mm or in your language 43 1/4" (approx)