hi all,
i'm doing some hard thinking of building a class 5 .
and immediatly a design concideration pops in my mind:weight
my own weight that is.
When i look at a class 5 sport i think,nice,great design,love the Y frame but,
if i park my 115kg butt in that little seat and make a violant turn,it will
resolve in a demontage de rapide.
So here's my question
is in my situation the T frame a better option?
or will the Y frame do fine?
Or is there a option in between like a Y frame whit a lower angle?
OK those are 3 questions for you.
the material i build with is scaffold pipe,and for the seat im planing to use
laminated sheet's of ply reinforced whit polyester
be gentle with me
Thanx jacco
I am in that weight range. A 'YOT' over the top frame can give you a lower centre of gravity, reducing the tendancy to tip over and a seat belt will help stop you from falling out if'n you do.
Build a yacht to suit YOUR sailing conditions (or where you will want it to perform best), keep in mind that there are several people on this forum sailing on VERY flat salt lakes where a ground clearance of 10mm is fine, put that yacht on a beach with 20mm sand ripples and you are scraping the bottom of the seat, and if there was seaweed as well they often become jambed up.
I do have to smile on occasions that people go to such a HUGE effort to lower the CG of the yacht a few mm and then put up a sail with a massive top on it raising the centre of effort more than 200-300mm.
jackseman, I have assumed that you have seen the FISLY class5 specifications and the strict design regulations, there are in fact 2 different classes that are virtually the same size being Class5 and Class5 Promo and if you intend to compete in it they get quite strict at Championships over measuring.
If you want to do near enough is good enough yacht then keep in mind that your yacht will have minimal resale value because it wasn't built to class specs. http://www.fisly.org/scripts/index.php?loc=rules&it=2
Sorry Jack'. But I feel this is important in LY construction and have never seen it discussed.
Above are three layouts. Which is the most stable??
1. Classed as the neutral or standard Chassis.
2. "Y"OT "Y" Chassis Over the Top
3. "Y"UCUP "Y" Under Chassis Under Pod
Personally for Stability and Greatest Use of Center of Effort I favour 3.
This design also puts the Chassis below the Seat Pod adding to the protection of the Pilot. Given that the Torque applied to all three forms at the Mast step (Using the same sail) there then becomes quite different Dynamics applied through the remainder of the Chassis Based on this thinking I have conclude that this style of chassis would be far more stable and require greater effort in capsizing a LY constructed in this manner. I have to admit that my education in Engineering of this type is sadly lacking. Observation would say that the CofG and CofE is lower due to the fact that the Sail is lower.
The only time I have capsized Occum's Razor was due to Crossing a Deep little Run Off Trench on the Beach allowing the front wheel to be driven sideways under wind pressure then as the Rear Wheels became Airborne the Sail tipped OR over, other than this accident I have found the OR tends the Spin out under extreme sideways pressure.
The above should be discussed and put into Context for New Builders. YOT seems to be the favoured style at the moment so prejudices should be put to one side and the Mechanics behind design put to the fore..
Ron
However my mind tells me the above is correct.
Rather than jumping in from the deep end if this is your first yacht build have a go at building from a design that actually is a proven design.
The Pacific Magic is a great design and will get you into a Class5
www.seabreeze.com.au/Articles/Land%20Sailing/Original-Pacific-Magic-Plans-by-Paul-Day_1514690.aspx
This is the first yacht I built and the first I sailed it is a y over the top class5
It has quite good ground clearance as shown in this pic and will handle rough surfaces
I dont believe it is any less stable than any other design either
I seem to have done things back to front as I now have built and own two more much smaller simpler mini yachts to use on smaller venues
I think the best first yacht to build is the one that suits the local conditions the best
and will get the most use
With #3Y on the bottom you could have more mast flex from lower down so there would be difference also both y frames could have more axle flex because of longer axle length
Sorry TP1. It appears that you miss read me on the Flat Chassis unit. Assume that it is a Flat "Y" as opposed to a "T".
Gizmo. What you are trying to show me is slipping right on by.. I will have to find a Physics Professor who can discuss and define this for me..
Ron
I think the ott is really designed around 26" wheels while the flat y or t mainly use wheel barrow wheels. If you are considering racing and if you are using wheel barrow wheels have a look at the promo specs on FISLY. I don't think there would be many class5 ott in Europe that would not be using 26" wheels so you will have to make a decision on the wheels used. Both type of yacht cost about the same to build.
Cheers
aus230
thank you all for responding,
Your input is all very welcome,and i like te way that my post resolves in a interesting discussion about stabillety however,my main concern isn't about tipping over,but more about breaking the seat in half when g forces start kicking in in bumps and turns and tidle pools and all the other fun stuff.and as gizmo correctly remaks,sailing conditios are a big factor.
I'm realy charmed about the class 5 promo because i have 80% of the materials laying around,including a sail witch i made for my lake lafroy mini and messures about 5 sqm, and is pefect for it.
besides,i see a pile of pipes in my tool and hobby shed whitch are screaming at me,
BUILD SOMETHING !!
or am i the only who hears such thing's
by all means,please continu the stabillety discussion
gratzi Jacco
Jack,
My reason for throwing in the stability thing was to keep you thinking an designing. I did not know you had built a LLFMini, good start to something bigger. (KEEP YOUR EYES ON the Aussies) Seabreezers can Beg Borrow or Steel[}:)]
there machines but I think our preferred method is to Build Our Own. Take your time look for the very best in others machines and incorporate it in your build if you can. The KIWIs also do some very good works in their machines.
What a wonderful thing it is to have a shed full of that which fulfills your dreams "Yu lucky Stiff"
I would also suggest that at any point during your build "When in doubt Cry Out"
you WILL get support.
Ron
