Before I describe my new steering arrangment, I wish to thank Paul and everyone else for their effort to produce the drawings for the class 5 sailer. What a superb job.
I have studdied every drawing and comment I could find about steering geometry and the angled rear axle tubes, the "Y" design. It was very interesting to read that for the most part, the swept back axle tubes offered greater speed and quality of ride. I have no idear why a higher speed is obtainable but I offer my two cents worth as to why better riding qualities seem to be the thing with swept back axles. I suggest it is because of having a much longer axle tube as a swept back style. For the same wheel track as the class 5 drawn by Paul, the straight "T" axle is 400mm shorter on each side.
This 400mm extra length in the sweep back may offer more flexing, hence more shock absorbing qualities (IM humbleO). As for performance enhancement, the "Y" shape might offer a better center of mass position. As for any other of my thoughts, I am all out of them and at your mercy.
Now for my new steering arrangement,
I have decided to go with the "laid back" style of steering tube and will set it up at 35 degrees. The foot steering bar swings in a true horizontal motion and is coupled to the tube via a unique lever system using only one more set of combined levers. There is no slop or play in the system and the push rods swing in an arc of no more than four degrees either side for left or right. The actual wheel will rotate to 60 degrees on either side. Is 60 degrees enough? not enough? or just right? Any greater than 60 degrees and I think you would go end over turkey as it were. It is very hard to explain without a picture exactly how this will opperate and even worse, I don't have 3D ability on my CAD program.
I have never seen an example of this arrangement before, so it may not have been used before. I can't wait to actually build the structure and display some photos for you all. I will try and describe the basics of how it works.
As you swing the foot bar, a connecting rod is moved forward and backward in a horizontal plane. This rod is coupled to a short lever on the LHS that pivots from under the frame and is fastened to another lever on the opposite side (the RHS). The length of the levers' axle is only 70mm or less. From the other side (the RHS) the final push rod is connected to the steering tube. (now wasn't that simple?
). A photo is a definite must so you can understand all this. Anyway, I have absolute confidence in my design and if I have to hand draw it then I will do so. The secret, as you all know, for absolute success with any linkage system is to have all the angles of the rods and levers set up in exactly the correct position.
I have a set of Fallshaw wheels lined up and I hope to get them in my eager hands within two weeks.
Kody
Sounds good. Your using the dual crank/lever to change the direction of your movement? Not unlike how a bell crank on a model aircraft works (thats if I have your design right).
One question; how are you going to attach your pushrods to the levers? As i understand it you'll have four attachment points (foot pedal, lever 1, lever 2, fork) and slops not going to be too good of course?
Goodluck and dont forget some pics. We love both kinds; construction and final product 
Without a drawing or photo Im guessing 2 rods one on each side ? you only need to do this if you have the front all wrong. The steering on an ice flyer is a good example of this. . You should only need 1 rod or 2 cables
Hi Lachlan,
You have very good insight in defining the RC belcrank system. Yes, I used the same design principles as used on RC aircraft and full size. I have made some awsome scale aircraft (1/4 scale) and have designed an RPV of 10 foot span for the Toledo Police in Ohio/USA. The RPV was used for airiel surveilance and search and rescue work. It carried heaps of cameras that transmitted in real time. I left the US before the RPV was finished built.
Using quality ball joints and rod ends I can remove all the slop from the system and have a precise steering mechanism that is very light in weight. I have managed to produce a CAD drawing of the system and will post it tomorrow with explanitary notes for you all. The drawing is definitely not to scale but it will explain the mechanics involved for easy understanding of the system. I hope you like what I have. If nothing else, it will give you something to chew on and think about for future use (maybe).
Kody
Wow! I actually got this to reproduce on the web page. What a lot of work to get to here. I cant take out all the side blank parts so please forgive me. Its lots of lost space.
OK. The steering tube from the wheel (shown in Red) is laid back at 35 degrees. The lower Red part is a lever that is fastened to the small Blue shaft that is mounted on the bottom of the main tubular chassis and free to rotate. It is ESSENTIAL that the small RED lever is parrallel to the RED steering tube, ie, it is also set to 35 degrees. The lever at the top, small Blue Lever, is set HORIZONTAL and is connected to the RED lever via a shaft using ball joints or rod ends. the final choice depends on availability and precision quality of the part. The Blue lever on the Left Hand end of the Blue Shaft is set VERTICLE. The Black Rod at the top of the Blue Lever goes to the Steering bar which is swung with the feet in a true horizontal plane. The angular movement at the top of the Black connecting rod between the 2 small levers can be kept at about + or - 4 degrees. The final amount will depend on the length of the rod and distance it is mounted to the outside of the Red Steering tube. There will be absolutely NO slop or play in the system. Your comments are most welcome on the design. Someone is sure to ask me, "Why do it this way?" The best answer I can offer is the same answer why stupid idiots climb Mt Everest, "Cos it's there and I can." I also enjoy what I do and I guess that's the best reason of all.
Kody
Thats what I thought you were up to. Looks good and I'll definately be keeping an eye on your project.
Why is it very important to have the red items parallel? I'll give my guess; is it so left and right steering ability is unbias? Having them parallel means movement toward the fork is as close to linear as can be in both directions. Having the dual lever arrangement in the first place means a greater degree of pushrod movement thats more perpendicular to the fork axis.
Forgive my guess work, just thinking aloud. Trying to learn something.
The only problem that I can see is that you will have to push left to go left, like an aeroplane.
On most landyachts (I think!) you push left to go right. See the linkage here:
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=33801
I'm a firm believer in standards, if there's a standard then it's best to follow it, otherwise you end up with all manner of problems down the road...
I'm also sure you'll be able to figure out how to reverse the linkage 
Dang, didn't pick that one up.
Looks like both levers on the same side or a crossover pushrod from the pedals.
Wow! That looks great, but as Nebbian said it would be hard to get used to after using the existing steering (ie push right, go left). The current layover steering requires you to push or pull horizontally against the 30 degree (or 35 degree in your case) lever which introduces a high load there. Yours would eliminate that. Just might need to move both levers to the one side so those of us used to the old method don't run into each other.
I was thinking about this at work today and came up with this. Probably already thought of it but I just thought I'd post incase you didn't.
Same as your design but the second lever that actuates the forks is 180 degrees to the lever from the original design. Check out my groovy paint picture
That lever would be pretty close to the ground wouldn't it. If you hit a rock or a mound it would take over control of your yacht.
What do you mean take over control! Thats why its attached to the steering pedals Some people, just never happy. Not really, its a very valid point.
All depeds on what ground clearance the yacht will have i guess. None of mine have less than 200mm, its also located fairly close to the front wheel and gets a fair bit of shielding from that (wouldn't want it placed 1m away though 
). Aditionally the pivot for the lever could be higher as could be the attachment position on the fork.
Just thought i'd add it to the thread to ponder over. Its by no means a complete design, just illustating an idea
Hi guys.
Many thanks for your most welcome comments. Yes, the steering is set up the same as an aeroplane. I used to do a lot of private flying which explains the system and where the idea came from. The critical link is the one from the Blue lever to the Red lever. This must needs be as long as possible. The longer this link is, the smaller the swept angle at the top of the link. This is why I placed the compound levers underneath the chassis. I am more than happy to pilot the rig all "kakky handed" but it does make it difficult for a guest pilot to drive it. The main reason I drew it as shown is because I haven't drawn out the levers all on one side yet to see what clearance is needed to clear the links and rod ends. This will be my next drawing and the steering will be completely "standard" in movement.
It is essential that the two stated axies be parrallel so the forward and backward rotation is equal and will produce a uniform rate of turning, or as near to it as possible. To have the lever set at 180 degrees will definitely place it in harms way so I didn't go that route at all.
I drew up the standard three view drawings to examine the geometry and pros and cons of such a design and I am very happy about it. The system will definitely work and do what I want it to. If you have more questions, please ask them.
Kody
Could you design me a steering setup like this!
[URL]http://myspacetv.com/index.cfm?fuseaction=vids.individual&videoid=28142288[/URL]
Hey landyacht: did you mean the iceflyer steering system is good or bad? Interested because thats what I based my steering on. What can one do to stuff the steering up?
I believe this will do the same thing. the beautiful design you drew was similar to what was being used in the very first layover steerings. Then Mike Hampton used a sailboard joint in the fed 5 ,then Seagull used polyurethane in the standart.
cheers Paul
Ahh. . . thanks for that. Just remembered I have the set of iceflyer plans on the PC to look at so had another squiz. I totally forgot about the dual pushrods, I too thought the secondary pushrod was useless and therefore left it out with my designs. I see they have two seperate pedals to steer which is why they used two pushrods, I wonder why. Sloppy joints, want to keep them under compression during steering?
Thanks for the info about the hose use. What length of 'hose' did you use between its fixation points to allow sufficient movement? The twisting motion is a problem I did run into 
. What do you think the chances are of using the hose trick on a class 3 sized yacht? I don't feel confident but I've never used it before.
EDIT: Dang! Beat me by 5 mins with a post. Scrap the questions about hose length between fix points. Thanks for the pics.
That piece of hose I sent you should do for 2 ie cut it in half. we use exactly the same front end on LOVE,PEACE and INSANITY . that yacht is 100kg,3 people and 9m of sail area. The connection has come adrift once on that yacht. We were beng towed by a V6 commodore in a parade and the yacht went off the road and the front got stuck under a van. THEN the steering pulled apart.
Travis Bartlett , who builds beautiful class 5's in Kambalda uses 12mm hydraulic hose to do the same thing.
