Of all people to ask that question! You disappoint me Test Pilot, everyone should know that! By Honing ones Mind, Not trashing it against Rock Piles.
Ron
.. Better still a Load Cell mounted in a 3" Tube with a Mast Step affixed to it, This then is mounted in a Base which could be mounted to a Ute. One could drive the measuring device to a Venue and test several different Sails whilst Logs are kept of Wind Speed and Torsion Loadings??? I may be wrong but it is just a thought.
Ron, the only fault with the drawing as you how it, is that it is only going to give a raw figure of pressure exerted by the irg. Reason..the hinge joint you have introduced is not replicated on any yacht I have ever seen. If you think the 500kg "insignificant", just try the experiment I suggested with a 500kg pull at the height of the centre of effort.
The maths for power generated is well known, and will surpirise you how little a sail develops. If you do a bit og googling you should find it, or else find a copy of the tome by Marchej and study to your hearts content.
There is a great deal to be said for empirical testing, that's what I spent many years doing, accompanied by some very deep scientific minds. But as far as I know, wheels are still round and there are plenty who have to re-invent them.
Test Pilot,
Will you never learn? You must complete your statements. Yes You do sharpen the Mind but you also finish up with a Pointy Head.
KIWI307,
Yes you are right and I think I said I would leave a lot of that detail up to the Brains Trust. My Diagram was only designed to Measure the Torque/Twisting Load at the Mast Base transferred through the Mast Step. If one is really serious one could take every single point of the height of a mast X the sail width at that point and begin to measure the KW at a given Wind Speed and the sum of the total Height
/Area added together and put through some fancy set of equations and really confuse yourself and any one that tries to understand "WTF" you are talking about GODDAMN it Kiwi just cut it out. Will you? I am getting confused trying to put this together
Ron
Whats the point of trying to measure the forces on the mast?.... you can't change it.
If you want to measure things try measuring the rolling resistance of a yacht and is there a link between tyre pressure v surface v wheel size?
Do balanced wheels improve performance?
Just another thing to think about... how much wind drag is against your arm if you place it out the car window at 60km/h? Now how much drag is against your body, legs and arms sailing at 60km/h?
All of these things CAN be changed and would be worth measuring.
OK, so the load going through the mast step of a Blokart would be what do you think?
What, then was the point of measuring the Stress at the Mast foot and on the foot of a Mast Stay Wire? If an Upright Pole is Stayed to the ground then any force opposing the Stay will naturally throw Force from the Stay Wire directly down the upright pole to it's anchor point. My point was that that the main force against the same upright Pole without Stay was a direct torque against the Pole Anchor Point and a tendency to lift the Anchor point as would happen if one Stayed that Pole on the down wind side.
My Diagram was intended to show the Torque at a Mast Base, measure this then Put a set of Bathroom Scales directly under the Mast Step, zeroed prior to placing the Class 5 on them. The Land Yacht should be fully rigged and anchored at the down wind tire and check what is happening on the scales as the wind increases speed.... I believe the the weight will drop off with increased wind-speed until the LY tips on it's side.
I think with the above, I have stated the "Bleedin' Obvious"
Ron
Fallshaws are better than cheap Chinese Muck. Why one uses a Safety Belt in a Land Yacht to some it is Bleedin' obvious to others there is no reason for using these things so we don't bother.
Fallshaws are better than cheap Chinese Muck. Why one uses a Safety Belt in a Land Yacht to some it is Bleedin' obvious to others there is no reason for using these things so we don't bother.
Gizmo,
Yes! I tend to agree but what ever happens to curiosity at this point ie. I just like to know for the "Hell Of It" I built a Land Yacht precisely for the same reason. I am unlucky enough to have one of those minds that likes to know **** "Just For The Hell Of It". Why would I want to know where the Center of the Universe Is What relevance does have or will it make any difference to my life the answer to that is If there is a Center to the Universe and it were in a different place, (Not that I would be aware of it) I most likely would be a totally different Being. Note; I stated "Being" and the word "I" is a generalization of Universal Beings.
Don't try to tell me I am wrong in this for I shall die with that belief. I do not ascribe to religion, hence the Big Bang Theory is my Doctrine. It is shown that all mater can be compressed to a Single Point in Time/Space at which All Scientific/Physics Principles break down and cease to exist in any form we know of. However I do not believe that, I think that at the point of break down the Universe exists still perhaps in a different time Frame, Dimension I do not know and perhaps this Species never will. The Big Bang could be well be a continuous thing which for some strange reason I feel may well be the case.
Giz' I am not a educated man but my mind continues to play in these areas and will not give my the peace to just accept things the way they are, hence I was never a Good Soldier as I would get myself in the Crap for wanting to know the reason behind the Shiite I had to do, This was always thought to be questioning the command and never for its true self. KNOWLEDGE. Once you have it when the time comes it is there to help one protect oneself and with any luck his Brothers In Arms.
If you are able to accept things as they are That is you, I cannot and so question my very being in the hopes of understand what WE ARE and why we are so contradictory.
Ron
P.S. Thankfully we are not all like me as I probably would have spent my life Battered and Bruised---------------or Worse.
PPS I just thought of a comparison to my life. A Scene In the Matrix Trilogy. Where Neo is confronting the Person in Charge of it ALL/God and All around are Monitors with Neo questioning it All.
I perceive that you are saying that a Human is as Strong as a Horse or that 2 horses are not capable of lifting a human (Well maybe not one that is really FAT). No matter how you look at it a Human is a direct part of a Windsurfer system being as they use their Body weight to counter the Wind pressure against sail, Mast and Boom. Again just watching what was happening to My Windsurfer Mast the other day I don't think any Human would be capable of holding any part of it as it bent under load. If you think you can hold it then I will watch you TRY! The Mast held rigid at the Mast Step bent a good Meter outwards from the Axis of Travel I don't think I have ever seen a Windsurfer mast bend that fare and seriously doubt that a horse could hold the Leverage created on the Land Yacht. I will also say that in those conditions I did have cause to let the Sheet out to get a;ll wheels back on the ground. This all gets back to the very questions I have been asking about Torque Pressure at the Mast Step for which I think there are the odd persons about that seriously doubt my Sanity I am not insulted by the doubts as at Time I seriously Doubt whether I have all my wheels on the deck as well.
I perceive that you are saying that a Human is as Strong as a Horse or that 2 horses are not capable of lifting a human (Well maybe not one that is really FAT). No matter how you look at it a Human is a direct part of a Windsurfer system being as they use their Body weight to counter the Wind pressure against sail, Mast and Boom. Again just watching what was happening to My Windsurfer Mast the other day I don't think any Human would be capable of holding any part of it as it bent under load. If you think you can hold it then I will watch you TRY! The Mast held rigid at the Mast Step bent a good Meter outwards from the Axis of Travel I don't think I have ever seen a Windsurfer mast bend that fare and seriously doubt that a horse could hold the Leverage created on the Land Yacht. 
Just to give a comparison this class 5 was traveling at approx 80 kph when this picture was taken. The landyacht has less surface drag so does not need to generate much power.
Yep! Clemco, Nebo
I'm with you on that, however after once again studying the mast this Afternoon in gusts up to 30K and the LY having almost come to a Stand still the mast reached out graphically then began to straighten up as speed increased. I also noticed that at approx' 10degrees from the wind the Mast had straighten up dramatically as well as accelerating reasonably well. That is something that still amazes me, coming so close to the wind and at least holding speed. I am positive that at times I was traveling at least double the wind speed and some times close to treble the speed. Again at one point the upwind wheel lifted off and I put it back down too soon
I am beginning to get brave now and want to hold to 2 wheels for awhile.
Back to mast deflection. It is very hard to get a real comparison between the 2 types of vehicle and the requirements and dynamics are very very different. Actual KW gained at 15kph on a sail of a given area would or KW developed per Square Meter would be good but inaccurate as that would not take into account Wind Shear and Area variance at various heights of the Mast. The only true way would be to test every Sail Individually and measure the Forward Thrust. I would think there would be a lot of energy lost just in stopping the wind from taking its natural path and Deflection before Thrust begins .
Ron
Ron, I have sat back for a long time re your claims of how close to the wind you can sail. If what you claim is correct, in relation to TRUE wind, you have the absolutely best LY on the planet. 45 degrees is closer to the truth. Even 10 degrees to apparent is absolutely amazing!
The figure of hp which has been quoted is higher than anything else I have seen, which is why I suggested you do some research on the Marchej books which are deeply esconced in very sound, well researched science, which seems to appeal to you.(Also keeps me off the hook on being rubbished)
You also suggeted a few posts back about measuring sail area, again another well known thing, even appears in the rules on this site I suspect
Kiwi307,
I do not remember that. Quote me please. I do not know my sails actual area but am using a rough approximation. I know about triangle measurement but it is all the little bits outside the main triangle that stuffs me up.. I guess I could layout an actual Sail and spend hours working out it's area, may-hap one day I will get up the energy and do it.
As for the performance of Occum's Razor, there things happening there that do not ring true. Even I feel the same as you do but something is defying logical perception. I want a second opinion and have no one here to disprove what I am seeing. I have the Airport windsock pointing in a specific direction, 12O'clock, and the Razor pointing upwind 11 O'clock and better. There are some buildings around but the upwind houses are 300mtrs away??? Buggered if I know what I am seeing but there's the facts. Go Figure.
Nebian and Clemco,
I have been studying those Pic's there is something there that neither of you have realized
and hence not thought about.. Study and think.
I gotta leave this stuff alone, it's starting to do my head in.
Ron
Hey Nikrum, please don't take anything I say as having a go... I really enjoy these discussions, and would dearly love to be proven wrong
In the end you've got more experience sailing a landyacht than I do, so please set me straight if I've made a mistake
I got to thinking about this power from sails thing
I remember looking at that book by C J Marchaj mentioned many years ago It made my head hurt then and not wanting it to hurt again I thought I would do an exercise down on the ground so to speak
I once owned a cruising yacht and cruised it many ocean miles It weighed 20 ton had an 83hp diesel which could push the yacht at a genuine 7 knots in flat water
Allowing for prop losses etc of 20% we get say 66hp
That same yacht in the right conditions has on many occasions averaged under sail only 8 knots or better over long periods of time measured on the chart and currents etc allowed for
It had a sail area of 1000 sq ft 400 in the main sail and 600 in the genoa
Sorry about the imperial measurements but by my calculations I figure that a
5 sq m landyacht sail could easily generate 3hp or better based on the above
Comparing the above pictures of sailboards v land yacht is comparing apples and oranges...
The sailboards are using a fibreglass or carbon fibre mast and the land yacht would be using Ali. the bend and flex characteristics would be vastly different
Has others considered using masts that have more for/aft flex and less side flex similar to what is used by Finn and OK sailing dinghies?
With sail power measuring... what wind speed? what aspect ratio sail? what draft/ camber in the sail? at what angle to the wind?
What has MORE power.... a tractor or a race car? [power not speed]
And to measure a sail have a look here for a guide.
www.seabreeze.com.au/forums/Land-Yacht-Sailing/Blokarts/Blokart-sail-measurements/
Hey Nebo, DEFINITELY no offense taken. Like you I love these discussions. If I thought you were being offensive I would say so. Discussions like this are pitting each others knowledge against each others and drawing out what is correct and what is not. In the end we should have a knowledge base that is the very best of the sum of the membership. There is no place for hurt feelings in that. Should someone resort to direct Slander and abuse i think they should be ejected from the Forum. Having said that one can joke about but and enjoy the remote company.
Like I said I forgot and have asked you to remind me so that I may make my excuses. More experience I only sailed a Land Yacht for the first time just before Christmas. My sailing experience on water was over 40 years ago. BUT I do observe. 
Ron
PS. I will reply to Gizmo, Hiko ans Nebo later
[}:)][}:)]
Hiko, you are right that Marchaj (corrected spelling) makes your head hurt. I like your comparison of power, however a though (and from Marchaj), is that the power of a sail is NOT proportional to the area, there is a scaling effect. You can't get double the horsepower from a sail twice the size. I can't remember what the ratio is, but I do remember some the stuff that was done in Bristol at British Aerospace in the late 70s, and a 5 metre sail was sub 1hp. There are all sorts of corrections for altitude, density etc ad nauseum, which is why all the pure science stuff does not use windpeed, but a corrected unit named "slugs".
FWIW when Gossamer Albatross was being designed for the X channel flight I think they rated a human at 1/7hp for extended time frames.
In answer to Giz to Hik ( Damn I Kill me!)
On sails and HP/KW I tend to agree with the 3hp thing but going by what is being said I think the only true way to test the theory is to Set up a Wind Experiment (Mast and Sail Set up in free running bearings and rotatable with Stress Gauges in place and take measurements in all directions. On thinking about what has been happening about me as I sail it would appear that running Down Wind with the Sail Reaching there less speed happening but as you generate speed then that can be increases greatly along with power by swinging away from the wind and hauling the sheet in to further increase in power and speed seems to happen when one swings further into the wind though the machine seems to be a little slower to gain speed tighten the sheet to the max and and bring it right up toward the wind and it seems that one can get fairly close to the wind. This is what I am experiencing up to a point once you start to get very close to the wind you start to drop off speed at and increasing rate until the sail Luffs.
I found out earlier today that running on sand/Beach that it takes a lot more power to move a vehicle and all bets change with the degree of firmness of the surface. Hence the Airport is the very best surface to run Speed Trial on. High tire pressure and Tarmac = very low rolling resistance. It is a pity the swine are filling my Tarmac up with Gravel Heaps. Nobody uses it = nobody uses it. Somebody uses it for fun= Everybody wants to Spoil FUN. Sorry for the Bad Language I am thinking.
Even Tractors and Cars is like Comparing Apples to Oranges and Land Yachts to Windsurfers (This will cause an outcry) as the Land yacht is the Pure Bread of the line, The Windsurfer by the nature of the medium it works in has to be designed more like a Tractor to get itself moving fast enough to break the surface tension where as the Land Yacht has a very low Rolling Resistance/Surface Tension to deal with so is designed to use the wind more efficiently for it's purposes. This is not a sneer at Windsurfers but is a fact of life. The greatest advantage of Land Yachting over Windsurfers is that I have never in my 65 years seen a Crocodile or Shark out on Salt or Clay Pans or dry land chasing anything, let alone Land Yachts[}:)][}:)]
Ron
Damn I Kill me!)
