Hi Everyone!
I would like your input on my Land Sail Design. Its my first hack at it so be nice = ). Most things are fairly well dimensioned but some things are just assumptions. Let me know what might be improved.
The frame is designed to be broken down into parts. I will post an exploded view soon.
To all the engineers out there, yes I know I did not properly dimension my drawings.
Some of the assumptions I used that I would like checked by you all:
1) 1.5" Nominal, schedule 40 Steel piping for the frame (2in square for rear axle and under the mast); too light/heavy?
2) Full Land sail weight, no riders ~ 150 lbs; is this too heavy for a twin?
3) 13in - 16in wheels, frame will be ~6 to 8in off the ground - is that ok?
4) Mast step positioned ~41in from rear axle
5) Mast step approx 2in inner diameter, 36in tall @ 7 deg rake angle.
6) What size of sail do you recommend for a twin and what is the diameter of a standard mast both SDM and RDM?
7) How much distance should there be from the frame to the boom? ... or from the top of your head to the boom?
Thanks for your input Everyone! Would love to hear your ideas for improvement on the design! Once I start building, I will post pics. (..might take a while though, just starting to gather materials).
WOW great drawings..... Welcome to the forum.
Must you have a twin seat yacht? The trend has gone to single seaters even for young children just reduce the sail size.
Here is a link that you might find interesting....
www.seabreeze.com.au/forums/Land-Yacht-Sailing/Construction/Build-a-Landyacht-Lake-Lefroy-Mini-Yacht/
Just a quick notes on your design.. for every join is a weld, and unless you are are a structural welder, the weld will be weaker than the base tubing. So the fewer welds the better. Simple structure yachts are easier to make.
Have a look through the link to the Lefroy Mini Yacht and ask questions. (regardless of how strange they may seem)
Thanks for the input Gizmo!
Yes, I have spent hours on the forums learning, making notes and designing my own yacht. I will be building a twin instead of a mini for various reasons I wont go into = ).
This yacht is also meant for fun/social use, not for any racing or attention to the "standards".
If it is possible for me to bend the pipe I will do that instead of welding my joints.
Yes bends can be done and they are stronger than welding....
Here is a pic of the beginning of a yacht, needing only 3 bends. The size of this yacht is Mini size but could be expanded to make a twin seater.
Welcome to the Forum runin2dson,
Great Drawing, however you do need to refine it a little as said by Gizmo. When laying out anything in life always apply Occum's Razor and finish up under the KISS principle. The simpler the better in fact, again as noted Bends are Better than joins and the less of them the better. It seems that as far as the Steering goes the tendency is more to the Flop over type and wheels of the Wheel barrow size 4.00-480 X 8" = 16" OA are the ones. Here in Aus' the recommendation is for a Brand called Fallshaw, These are 8" X4" Plastic Rims with a Rib pattern Tire. The bearings have to be of a high quality and are generally changed about for our purposes. To just bring the axle out of these wheels and directly across the Chassis to it's partner is quite adequate and gives an 8" ground clearance. Some builders prefer to set the wheels at an angle by splitting the Central Chassis part of the Axle and setting it at a few degrees to lower the profile of the machine, this again would depend on the Surface you intend to sail i.e. If you are going to be a Sod Buster on a rough paddock then Chassis high should be at least at wheel center height. Also have a look at the Ski Axle post in Construction for Take Down ideas. Ih yes! Have a look at AZUSA.com
Ron
Design looks great!
I have one quick question though:
The steering pedals look like they are centred, are you going to sort of poke your leg across the other person to hit the opposite pedal?
Person on the left uses their right foot, person on right uses left foot[}:)] Crashes to come....
A point I've just noticed and think I should make, further Research is up to you.
point, Position of the Mast Step should be much further forward than is currently shown. Roughly 1/3rd of the way back from the Front Axle. No doubt "Landyacht" or some other will give a correct proportion, feel free to ask his advice. The tendency, as I am quickly finding out is for the wind gusts to Swing Rear of the Land Yacht as it is driving you forward or in sharp turns (Power Slides).
I mentioned in an earlier thread the Rear Axles. Consider the surfaces you are going to operate on and perhaps drop your Center Of Gravity COG. The reason I make this point is that the Lower the COG is the Lower the better for operation without Tip Over in a Slide (Power Slides are Great Fun). It will have a greater tendency to Stabilize the Craft when the Wind Lifts the Upwind Wheel.
I also feel that you should be warned (No one else has!!) Land Yacht Building is extremely Habit Forming/Addictive and it seems that once is never enough.
Ron
I have assumed you have based your design from this fairly dated design...
A few things that concern me about that design is the very rigid structure to support the mast, many yachts these days use a chassis that twists a bit to take some pressure from the mast base and to stop the mast snapping like a carrot.
Sail size for a twin yacht ideally about 5-6 sqm and a slightly fuller cut than a race sail as it needs to deal with the extra weight of 2 people.
Many twin yachts in Australia use 2 plastic chairs (lunch room style) as the seats as they are low cost and easy to obtain.
Again, thanks all for the input!
Frame bending: yes i know its possible = )... just not sure if i can get my hands on a bender without buying it... But again, I know aluminum would be nicer to keep the weight down (but as that will not happen for me) is steel going to be too heavy. The full land sail will be around 150lbs.
Steering: this design actually has two petal positions. One centered for a single rider and one offset for two riders. Also, the steering setup has approx 2in of trail which should give decent stability and not too much "flop"?
Mast Step position: I was trying to match the cg of the rig+riders with the center of effort of the sail. If the sail is going to be offset one way or the other, is it better to have the CE just behind the cg? My drawing of the sail is just a guess... not actual dimensions so Im not confident of the CE. However, from most of the designs Ive seen the mast step is between the rider and the steering pedals.
Seats: I figured it would be easy and light to sew seats from sun shade fabric -> very durable, easy to install and light.
Doing bends just adds to the complexity of a yacht, why do you want to put that many bends when a straight tube will do the same job.
The idea of a sewn cloth seat I like but keep in mind the ground clearance, you don't want to hit a rock at 60kmh with only shade cloth between you and it.
Here is another design that might be worth a look at.
A couple of things i would looks at, get rid of as many ofthe bends and weld/cut type bends as you can,, and possibly move your mast step further forward. you are building a 2 seater and having a rig further forward may help give you more "grunt ", rather than speed . with upright front forks that are laid over that far you get a tendency for the steering to get heavy, and not want to recentre, so perhaps look at that too.
have you approached the designer of the plans you are adapting and discussed some of their ideas for a 2 seater. It may have been done already with that design base.
And some taller back wheels
So 2 things...
- I can change the design... but why are bends so bad? I can understand that welds will be weaker (though Im not a bad welder) but at most I would cut out 1 of the 3 major bends.
- Yes, I did model this after the sirocco design... that being the only twin I have seen so far. Is that a bad thing?
Bends add complexity to a design, I have a hydraulic pipe bender that will give basic bends but the pipe springs and flexes when being bent this makes it very had to do identical [repeatable] bends on various pieces of tube. Car exhaust installers have good benders but they charge per bend.
Most people want to build it as simple and cost effective as possible so that why most yachts are built from straight tubing.
Often manufacturers often put in a process to try and stop people copying their product [I do with the electronic stuff I make]
Most manufacturers accept people will copy their product to some degree but they get annoyed when you start manufacturing multiples of them.
Even more anoyed when that copy is breaking comercial copy right. Look at Occum's Razor a Simple Pipe "Y" Frame. Think of extending the Axle Bearers and then creating a Twin Seat for Driver and Passenger
Simple? No? Always keep in mind the Kiss Principle. The whole thing in any mans language is a Triangular design. A Spine of 3" water Pipe (Solid) With a Simple "T" Axle setup is good being careful to put the Load (Gross) weight just forward of the Rear Axles. The width of the Chassis would be less than a meter wide and Axle width to be added when assembled around 2 meters. The Chassis could be Designed at around 4' to the Mast Step with a removable section to the Front Steering of around 2 - 3foot. Flop Over Steering included. Myself after having used 100% Carbon Fiber Masts for Axles would use them again. A simple 2 place unit could be made conveniently compact for travel Gizmo's suggestion is a good place to start.
Sit down and think carefully and make sure your design is symmetrical and put it together logically and you will come up with something that uses minimal Welds and Bends. Use 16" / 24.00/4800 x 8 Barrow Wheels and you can't go wrong. Most products can be found at your local Tip Shop/ Recycling Depot and a selection of Rims/Wheels at AZUSA.com. Search and Research will get stuff Cheaply and give great pleasure as to the savings made and a bunch of fun beating the SYSTEM.
Ron
PS, I don't know what part of the States you live but there are Surfers out there that Bust Gear, you can recycle that too (I did)
Here's another commercial built rig to look at. Its a 'manta twinjammer'
Pretty solid, lots of them here in the states
Also, I just got an e-mail from a fellow El Mirage user, and he has a Manta Twinjammer 1600 and a Santana twin 500 for sale. I do not know anything about the condition or price, but if you are interested in buying, PM me. The seller lives in Tehachapie, CA
Great ideas guys!
I do like the simplicity of the Manta design and will draw up some new plans based on that. It should save on weight and be a bit cheaper to build as well (though I do like the solid structure of the sirocco type frame)
Also, what hardware is commonly used for the steering push rod coupling, ie between the rod and the front forks there is inconsistent geometry. Do you use a ball and socket type connector? What do you find works well?
Oh, and being an "engineer type", I love to design and build....so I will pass on buying a used rig just to have the pleasure of building it myself (and...it is cheaper I admit). That's half the fun!
you could use ball and socket / rose joints/ rod end bearings or what ever you call them in your neck of the woods, but I have noticed that a lot of fellas on this forum have been using a short piece of hydraulic hose that is an "interference fit" as the coupling.
being steel reinforced it has proven to be flexible but strong- and is secured into the tubes with a screw or bolt.
best part is its easy to find and cheap! (offcuts from any hydraulic hose maker)
The pacific magic is really too soft in the rear to suit a 2 seater. we did try it, not that flash.
the linkage in steering when you have on a yachtwith push pull pedals and upright steering can be as simple as a through bolt with a rubber washer inbetween, to allow for flex.
the more difficult linkage is used whe a layover steering is incorporated. this is a more complex movement which needs a higher degree of twist at the wheel end of the yacht. thats when you need the polyeurathane joint, the hose,or the windsurfer base.
not PVC ron, dont know where you got that one
Silly me]
I couldn't think of the name of the stuff and was trying to get the idea across.
Perhaps you should be wearing the White Spandex. My White Knight in your Green, Arrowed Stead[}:)][}:)]
Ron
That is really SICK!
Hey runin2dson,
I used these 'inline ball joints' from McMaster Carr. They work well, but are probably gonna set you back a bit more than the hydro tubing.
Cheers
The Sirocco looks like a nice unit, very smart. However I make this observation, it may be wrong but. It seems to me that it is designed with multipurpose in mind ie. Land, Ice, Snow etc. Usually with machinery there is a Design Trade Off when this several things are catered for in a single unit. Yes, it can be a great thing for those that have access to most or all venues those designs then come into their own. I think, though, when you are designing for a single purpose, perhaps Speed or may be passenger experience on Salt/Clay Pan then a design suited specifically to that purpose should be used to get the absolute best from your machine. For instance the Lay Over type steering will allow a lower Front Profile to reduce Wind Resistance and keep that profile down, suited more to a Cowling to further cut Wind Resistance. Perhaps I am wrong, so I've just thrown these thoughts into the mix for further debate?/
Ron
runin2dson,
On further study of your design I would be further inclined to Cut down the width of the Rear Beam Axle, cutting it to say 1" outside your seat. Include Bends into the Side Bracing to give Pilot and Passenger Body clearance etc.
This then would allow the use of removable Rear Axles giving greater Transport flexibility and were those axles long enough they could give a wider adjustable Rear Wheel Base for heavier conditions. just a couple of thoughts to add food for your thought.
Ron
runin2dson
whereabouts are you in the states? If you're close, we might arrange a meet someplace......... Like a dry lake bed!!!!!!!!!
Cheers, John
