Forums > Land Yacht Sailing Construction

Class Five Design

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Created by blake52 > 9 months ago, 3 Dec 2010
Nikrum
TAS, 1972 posts
11 Dec 2010 12:03AM
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Clemco,
I daren't ask you to "Take it all off" so hows about you do a plan for this layout

""Here's a close up of the front end.""

The odd thing here is I have only just purchased a Sky Tough Rim and the same Maxxis as you show in your last pic' I guess we just have good taste when it comes to tires.[}:)]

aus230
WA, 1659 posts
10 Dec 2010 9:17PM
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Clemco,
Is that bolt below the cables to adjust the steering rake. That would make thing a lot simpler to do some experiments with. I like the idea of having a little suspension maybe something for me to try next year, I guess it would help stop sail shake to.
cheers
vic

blake52
123 posts
11 Dec 2010 5:05AM
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Wow! Very cool rubber band suspension! I didn't get it at first glance.
I just published a link to this forum on the NALSA.org site.
This weekend (it's still Friday here) I'll start posting design-related photos I've collected.

I am not that comfortable with the cable steering on the Rocket it seems to loosen and get sloppy fairly fast, but with a solid rod steering and suspension, the bump would be transferred right back into the pedals (unless there was a "soft" connection).

Clemco, what's the "French" setup?

Hiko
1229 posts
11 Dec 2010 10:33AM
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I have been reading these comments on cable steering with some interest especially the one from Blake on the Rocket steering above.
If there is one thing very good about my Rocket it is the cable steering so I will run through it.
First the cables are 1x19 yacht rigging cables which have minimal stretch tensioned with rigging screws until they twang.
Second the cables closely follow the line of the front spar so that when the spar bends it has minimal effect on the cables. This is a feature of the Rocket design
Thirdly the tensioning up takes practically all the play out of the pivot points
unlike a rod setup.
Fourthly the cables are always in a straight line unlike a rod which when pushed
or bounced up and down unless very stiff /heavy will bend, introducing steering
issues.
I know of no other system that is as good or light and very rarely need to adjust it

Finally the suspension pivot point setup on my rocket is in front of the steering
pivot so has no effect on the cables. It has other effects but not directly on the steering


I feel cable steering often gets a bad rap but when we consider aircraft have used the system successfully for years we need to look elsewhere for the reasons for bad steering

blake52
123 posts
11 Dec 2010 11:03AM
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That is a very interesting front! I see you solved the problem of the cables going slack when the suspension works by putting the hinge ahead of the steering. What are the "springs" made of? I need to add some turnbuckles to my setup and compression fittings so things can't slip. I can almost certainly make things better without getting rid of the cables. You are right about the weight.

I'll post history/tech pictures soon. Here is my favorite humorous one. Just after sailing across what looked like just a slightly dark spot on the playa in southern New Mexico. Turns out it was a thin dry crust over a foot deep mud. From 50mph down to 2 in about 50 feet the front of the seat went under and filled the boat with adobe.


blake52
123 posts
11 Dec 2010 11:17AM
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Last version of my first landsailer (we called them sailcars). This version was the product of several years of light air the next year it blew really hard and everybody took their yachts home in pieces. The stayed rig was a disaster really. It put astounding downforce into the mast step. Originally built with hang glider parts...two other, smaller,

landsailers were built from the leftover parts as it evolved. Fed 5 in the background.

blake52
123 posts
11 Dec 2010 11:24AM
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My US Fed 5 at speed and parked on crazy wheels


Hiko
1229 posts
11 Dec 2010 4:54PM
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Hi Blake
You have some interesting shots of yachts there Thank you for posting them
The springs in your query are short pieces of carbon sail batten
Two each side seems about right I really dont get out often enough to properly test
some of my theories unfortunately

aus230
WA, 1659 posts
12 Dec 2010 12:03AM
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hi Blake
whats the idea of the crazy wheels?
cheers
aus230

another front end idea


One of my memorial moments





blake52
123 posts
12 Dec 2010 12:18AM
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Crazy wheels let you walk away from the yacht and not worry about it sailing of without you. You can leave the sail sheeted so it doesn't flap and the yacht swivels into the wind. Rarely, in a really strong direction-shift puff a yacht will blow over, but then I have seen a lot of tipped over yachts right themselves and sail away. The axles of the crazy wheels point at the contact point of the front wheel. The disadvantage is the sail stays up being toasted by the sun.
Blake

aus230
WA, 1659 posts
12 Dec 2010 12:32AM
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now that's a good idea are they on both wheels

Hiko
1229 posts
12 Dec 2010 3:21AM
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I have never seen that crazy wheel idea before
Different surfaces - different solutions US 246 looks like a quick yacht to me

blake52
123 posts
12 Dec 2010 4:49AM
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Aus 230,
that is one wild wheelie...I've gotten all the wheels off, but never that high; you and the boat both survived! The current owner of US 246 seems to be trying for more extreme gymnastics.

Yes, crazy wheels on both rear wheels, hard surface required...Lake Lafoy?

US 246 was a blast; its only really unique feature was horizontal sheeting; I'm adjusting to my Rocket and think I will enjoy it just as much once I get it dialed in.

Is the blue boat an older Airtrack? The one I have pictures of has a cowling over some of the details. Nice to see one "naked."

aus230
WA, 1659 posts
12 Dec 2010 8:57AM
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Maybe you could post some close up pics of the crazy wheels, maybe a sketch of the design .would be much appreciated. Great example why this is a great site.
cheers
aus230

Clemco
430 posts
12 Dec 2010 2:19PM
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The French have added a shock absorber from the rear of a mountain bike. As long as the rotation of the fork only allows the steering rod to move up and down there is little effect on the foot peddle. Just a matter of attaching the steering rod in front of the pivot point of the suspension.

Hiko
1229 posts
13 Dec 2010 4:24AM
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Interesting seeing different ideas
Looks like to me that French one doesnt have any layover on the steering so the front wheel would have to be very strong/heavy to resist the side forces
Maybe all the carbon offsets that

blake52
123 posts
13 Dec 2010 12:58PM
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There are two of those headed for America as we speak. There is caster, the steering pivot is not vertical, but you're right it doesn't flop much. There is so little weight on the front of a class 5, it doesn't seem likely that stress would be a big problem.

I think it's interesting how similar the basic frame layout is to AUS 230 and The Clemco boat where the front strut ends at the base of the mast rather than extending back into the seat. I hadn't seen a good enough photo to tell. Sure is a lot of carbon and Kevlar showing!

I'll post drawings about the crazy wheels soon (maybe in a different thread). Mine were just built of construction lumber and lawn mower wheels. There are a zillion variations with one common factor, the axles of the wheels point at the point where the front wheel touches the ground.

aus230
WA, 1659 posts
13 Dec 2010 1:39PM
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Frame of aus230



blake52
123 posts
14 Dec 2010 2:51AM
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Different "Devils" different design. No wonder I'm having a hard time figuring out what is the latest version.



These photos are from this year's worlds 2010

Hiko
1229 posts
14 Dec 2010 5:05AM
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Check out those sails
Cant figure the advantage in that steering I thought that was old school
I wonder how the inboard end of the front spar is mounted A vertical post down from the chassis?
Me being a relative newbie to this sport Blake how much difference in performance would you say between a YOTT type and a Fed 5? Assuming all else is equal of course
Bear with me I have never seen a Fed 5 in the flesh so to speak

Nikrum
TAS, 1972 posts
14 Dec 2010 8:42AM
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CLEMCO,
Re Your post 10/12/010 6.13AM.

Front Suspension. You mention a Nolathane Bush in the Pivot of the steering..
Looking and thinking I feel that as good as it appears to be it could be streamlined. I am not knocking your build at all but hope to add to it's beauty and simplicity. Have you ever thought of using something like a Truck Leaf Spring Bush as long as can be bought. Surely the Damping effect of the Nolathane?? Circular Sandwich would serve the same purpose as the leaver system and Inner Tube. You may well have already tried this style but than again maybe not.
I doubt a Land Yacht would flog a bush like that as hard as a truck underload would.

Ron

blake52
123 posts
14 Dec 2010 6:23AM
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Hiko,
"how much difference in performance would you say between a YOTT type and a Fed 5? Assuming all else is equal of course" All things are never equal, but as soon as a YOTT (NZ Rocket) showed up at our races the Feds quit winning. It makes very little sense to me that the low chassis doesn't work just as well especially on smooth hard surfaces, but for several years at the worlds all the winners (and second and third and fourth...) have been YOTT; the last fairly competitive low chassis boat I've seen was Bill Fisk's small-wheeled, super-fast Pacific Magic (May have not remembered his name correctly).

Hiko
1229 posts
14 Dec 2010 6:34AM
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I also find it hard to figure why there would be such a difference everyone says so
so it must be right One thing I have noticed with this sport though is small differences
compound up into large differences The rich get richer sort of thing

blake52
123 posts
14 Dec 2010 6:48AM
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That was Bill FINCH, AUS 11 with the astoundingly fast PM at the 2002 Worlds. The boat stayed in Nevada, but isn't nearly as fast without Bill piloting it.

Clemco
430 posts
14 Dec 2010 6:49AM
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Nikrum said...

CLEMCO,
Re Your post 10/12/010 6.13AM.

Front Suspension. You mention a Nolathane Bush in the Pivot of the steering..
Looking and thinking I feel that as good as it appears to be it could be streamlined. I am not knocking your build at all but hope to add to it's beauty and simplicity. Have you ever thought of using something like a Truck Leaf Spring Bush as long as can be bought. Surely the Damping effect of the Nolathane?? Circular Sandwich would serve the same purpose as the leaver system and Inner Tube. You may well have already tried this style but than again maybe not.
I doubt a Land Yacht would flog a bush like that as hard as a truck underload would.

Ron


Hi Ron, The Nolathane bushes are not in the pivot of the steering head but in the pivot of the suspension. Yes it is a leaf spring bush from a Suzuki 4x4. You could be right though, it may be all that I need and I could dis-guard the pivot which could be causing the some of my cornering problems. Less is indeed more when building landyachts.
The two bolts welded either side below the bushed area were to attach pulleys for the cables to run through. They made the steering really heavy and I found I didn't need them anyway but have not yet got round to cutting them off. I am seriously thinking of changing it to a solid rod system like I did on the mini.

Nikrum
TAS, 1972 posts
14 Dec 2010 11:25AM
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Yeah! CLEMCO,
I reckon something around 70mm mark might be good, you hopefully will get a vibration effect as well as a little shock absorption along with a small amount of Springing action.

When in doubt always Refer to Occam's Razor;

"Entia non sunt multiplicanda praeter necessitatem"

"Entities should not be multiplied more than necessary"

"If two theories arrive at the same conclusion the simpler of the two is usually the correct one"

If you didn't know about the Razor you do now.

Oh! Something else I just thought about. Steering Cables. Do you know of the Spring System that works with opposing double deep "U" peices (I don't know there name) I should heavy enough ones fitted somewhere in the cable system (Maybe at the peddles, protection from too much salt water) would hold the cables under a good tension stopping them from going slack at any time.




Ron

Hiko
1229 posts
14 Dec 2010 2:52PM
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blake52 said...

That was Bill FINCH, AUS 11 with the astoundingly fast PM at the 2002 Worlds. The boat stayed in Nevada, but isn't nearly as fast without Bill piloting it.

Thats how I feel about my Rocket I think its astoundingly fast but not with me aboard

landyacht
WA, 5921 posts
14 Dec 2010 6:34PM
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Bill did say at the time that the yacht was his fastest but unable to catch the french OTT's. its great to hear it from another source

aus230
WA, 1659 posts
15 Dec 2010 10:03PM
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Hi Blake.

I like the look of those devil yachts. I got the idea from a pic of one of them to build aus230.
Couple things have changed since then. How is the mast step now attached to the front wheel tube, it looks like it must swivel inside the seat and have some sort of suspension attached below the mast step.

The wheels look like they are aluminum, I scoured the world trying to find out where they where made, no luck so I ended up making my own. Is there an address somewhere, just in case someone wants to buy some. I will be sticking with mine as they are quite lite and have had no problems with them.(once I sorted out a few problems with the first set)

Cheers
aus230



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"Class Five Design" started by blake52