Just working out a build

Ok Guys quit it Already you are making my head hurt..

Why The Hell! Do I start these things

Questions like wheel alignment etc get my head working and analyzing the Dynamics involved or at least the ones I can obviously see.
If one takes a pair of upright wheels and aligns them to parallel each other it is a fairly easy task to achieve, however if one then lays the Wheels over tops inwards or outwards then aligning them becomes more difficult with the increasing angle. Now we take one wheel out of the equation and study its actions. Its action will be the exact opposite to the one we will look closely at. Take a wheel, any size will do for this exercise, out onto the drive way. Cement is better than the Lawn. Now gently push the wheel and let it run freely and study it's behavior. We've all done this stuff as kids. Don't just look at what it does but study what is going on. Firstly it rolls upright and slows as it slows it starts to lean, the more it slows the more it leans. Now it doesn't continue straight ahead nor does it just go in circles but runs in a sort of Helical action of an ever decreasing spiral. Careful now! we don't want it to run into a Naked Singularity and disappear up it's own Rotational Axis Hell of a way to loose a perfectly good wheel, that.

If we take the wheel now and hold it on an axle and force it to run in a straight line and start to slowly allow it to lay over at an angle we are disturbing the natural balance that would put it into a decreasing spiral. The wheel still wants to go into that action but is being forced against it's physical action to run straight although all the natural dynamics are still acting on the contact area of the tire with the ground.
What is happening at that Contact Area/Patch Here I may have problems getting it all together but hopefully enough to get you guys to study the problems.

At the contact Patch we have Curved surface being forced to run in a straight line, hence we have a bunch of Dynamics fighting each other for control. The Upright wheel has only a small amount of the curved surface wheel dynamic ie. The contact Patch is zero at its center and given that the Patch is larger than zero we have the beginnings of the curved surface with every molecule away from zero, consequently the dynamics all oppose each other equally. Therefore we have zero toe-in/toe-out and the beginnings of Tire Scrub/Wear with every molecule out from zero. As we lay the wheel over we upset the dynamic in that direction causing an imbalance and the Patch to shift to the side of the lean with the wheel wanting to take an increasingly circular rout and the axle forcing a straight rout. **** My Head is Hurting!!! Resulting in a tendency to want to steer below the earth surface and this can't be done. With all these forces in action we then complicate the matter by introducing a second set of opposing dynamics, namely the second Rear Wheel. Whoa! Now we want to try to align all this to run perfectly parallel
'alf yer luck!
With some LY's running on wheels laying over at 20 degrees? others at 10 degrees or What Ever. So we, somehow, manage to get all this as near as Damn It! to aligned.... Great! It looks Sweet now we take the Chassis unit outside and put a WHOLE HEAP of junk on it, Masts, Sales, ourselves and peripheral rubbish like a helmet and gloves etc. I would suggest that due to flex action of all this increase in weight on the wheels and chassis, all our hard work aligning the wheels has just shot out the window. I think taking it to the beach isn't necessary to show what is going to happen there. We aren't running on Glass and we haven't taken, into account, what the dynamic of varying sideways wind pressure are doing yet and my head is now hurting so much that I have no intention or going there[}:)][}:)][}:)], other than to say "Near enough is Good enough"

Ron
I hope this makes a little sense.

Well Now Gizmo, That is going to be one hell of a Treadmill to handle OR or the Cat for that matter. Never mind the other alternative is to drag it up and down the drive or level cemented area with an Old Time Spring Balance adjusting the alignment and torquing tendencies as I go??? "As IF?" I may look green but that is only moss from all the rain we've had lately.
Speaking of the Machines..... "The Cat is Dead, Long Live the Razor"





It seems there was a not so lethal dose of radioactive Cyanide which may explain the near demise of the Cat. Perhaps I shall have to do a major operation to replace it's Spine and splice the front suspension in.[}:)][}:)]. Ah! WtH! It was fun in the doing
I had the Cat out on Black River Beach this morning in around 20 - 30 knot winds.
I've not driven one of theses things prior to my making Schrodinger's Cat but from my little experience I would say the Cat was quite spurty in gusts. At one point she took off like a well healed Rocket straight for the Bass Strait which took me off gard and took a little reaction time to correct. I just survived that one and went on to haver a hour or so fun zipping up and down the beach struggling to keep the up wind wheel down, a few Broadsides down the sand and running backwards etc! Exhilarating. No?? So how did the Cat become a cripple?? [}:)] Bravely!
When I decided I'd had enough I steered toward Car Park and into a bit of soft sand which put extra strain on the Mast Step and Whella! Crackle Snap and Pop! the above pic's being the proof.

I won't bother repairing the spine but I will replace it with a removable system. Reasons. Though the Carbon Fiber sections were tough enough in my methods of construction I feel that there is to much Rotational Flex which at one point had the Mast leaning close to if not better than 30 degrees. This rotary action requires an instant correction of the steering to counter the down wind swing of the LY. This to me is just one extra thing to watch for when everything is happening around you very quickly and I have no desire to go to the Mainland just yet.. The Carbon Thing was just an experiment. I learned a lot, had a lot of fun building and I enjoyed the Cat's short sailing life. Disappointed? Yes! Sad? A little. But "Onward and Upward Men, Onward and Upward!
I just can't wait to break the Razor out now
Ron

Good on you Ron you have tried some new things and learned some new things and shared the experience with us Much appreciated

I've always maintained you learn more from failures then from successes. May SC's demise not be in vain Well done!

I do love a great result to an experiment! the spine was intact , just the failed glue joints and wrappings youve saved some of our first version of a future yacht.
thank you so much for keeping an eye on the mast layover angle too that was some good empirical data

Ron, you need to get yourself a GPS to record your speeds. Sorry though to hear of SC's partial demise. Great to be following your adventure, many more to come I'm sure.

Well That's Christmas Day done! Now we can all get down to the serious business of paying back our MasterCards[}:)].

A couple of points;
Steering:

I found with the cat, on hard sand that when the steering was shoved hard over that the Cat wanted to go straight ahead and acted as a brake, until she slowed enough to get traction then she swung hard.. Is this normal
Connecting rod type steering on Roll over Front Ends. This set up would seem to me to be a Twitchy steering method? and possibly require a very firm use of the feet and legs required to operate? Talk to me on this one as I want to get the best method sorted before I build the Steering for OR. It would seem from the Cat I found that the steering was a progressive thing and not proportional.

Did Santa bring all you required? No point asking "wanted" as what we get is never enough
Ron

Your seat belt should allow enough movement to move yourself forward& back again and side to side. Thats why we use a belt and not a 5 point harness. Using body weight is another way to help control your yacht.

Funny thing that Skid's, Family just seem to get in the way of our extracurricular activities,
just when you think it is all sussed out then someone comes up with something else that "Happens to be more important" than your enjoyment I only know that feeling so well. My other half is due back from NZ tomorrow evening and Have I Ever Made Hay While the Son Shone She has a definite penchant for waiting until I'm right in the middle of really technical stuff and then busts my concentration. Yu Gotsta Love 'em though, if you didn't you'd probably throw rocks at 'em.
There used to be a song out there. "We thought she was a gonna but the Cat came back, 'cos she couldn't stay away" Old C & W ditty.

The funny thing with the under-steer at speed is that the first few degrees of movement of the steering is that it is really responsive and even twitchy but then it all comes adrift until that machine slows and then it bights again that is when I sheet it in hard and do a 180 slide down the beach. It does get a bit disconcerting however when your trusty steed decides to run backwards toward the Bass Strate, "Oh Poop! I had best do something but what?? No I didn't get wet there but when I first hit the beach I crossed a shallow stream at speed, that is when I did get a tad damp.
Thanks

Ron

Test Pilot; You Kill Me!

Yup! I recon all those about you recon the same. "Trying, very trying " [}:)]

I am still undecided about the front end and wheel to use. Advice please. I am thinking that a front end the same as The SC has may light for something as big as OR one sail I am going to use is about 6.5 to 7sqm. the other about 4.5sqm. I have a 8"x2.5" Briskites rim coming and I reckon I may well use that to stand up to big Side ways thrust..

Thoughts please.
Ron

PS: Web Master. There are a couple of extra icons we could use in these pages. Head Scratching/confused, A Light Bulb Moment/Idea and maybe a couple of others.

the test is to fit it as a back wheel and the sail it hard with the wheel on the leeward side. if the rim is too narrow for the tyre the yacht will lay off at the back as you sail along the beach. your tracks will look like "scalloping' along the sand, and you will be constantly correcting your steering

I not saying the tyre will peel off the rim. most of the tyres we use are made to fit a 4.00-4.80 wide rim. , so putting it on a 2.5 rim gives you a tyre that doesnt resist side forces as well and tends to collapse its inflated shape when subject to side loads. this is less noticable on the front wheel if it is a layover type setup.
i have learnt that the most comfy existence is to have all 3 wheels the same so the most worn tyre can be put on the front
which doesnt explain why i ordered a new 16" zytec nylon wheel the other day

Looks good there Nikrum,

I thought she was a gonna!

So is the mast step metal? And it's attached somehow to the carbon spine?
And the front bit that connects to the steering bearing, that bit is metal as well, right?
Just trying to understand how it all fits together.