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Author Class Five Design
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United States
103 Posts
Posted 3/12/2010, 6:12 am        Report
Greetings, I'm new here, so if this has already been discussed, please send me in the right direction. I have built a class 5 from scratch (off Mike Hampton's old plans-mostly) and owned two "production" boats, a US Fed 5 and my current boat a New Zealand Rocket. I would really like to design and build another, but would rather not just exactly copy something that exists. All the really fast boats seem to be of the frame-over-seat variety, whether they race on the beach or dry lakes, but the way the front suspension/strut connects to the 'Y' part of the frame and to the seat seems to vary a lot. The "why" of those differences intrigues me. Blake US319
New Zealand
380 Posts
Posted 3/12/2010, 6:38 pm        Report
You're not the only one Blake. The answer is to build another one.
WA
1378 Posts
Posted 3/12/2010, 8:58 pm        Report
This could end up somewhere as there has not been a lot of discussion around y framed yachts and different frame designs. Some of the discussion has been around how much they cost but I and I think Clem would dispute this as the class5's I have built have cost no more that any other yacht, The main cost has been the sail ,mast and pulleys. What has been lacking is plans ect. I would post mine but they are full scale on my shed floor.As for the front setup I have tried both the french and new Zealand type setup, I think the Kiwi design may have a more positive steering than my french design I am going to try a wheel barrow wheel to see if that improves the steering (only a problem in high wind conditions) Cheer aus230
New Zealand
896 Posts
Posted 4/12/2010, 2:35 am        Report
Welcome to the forum Blake I too have a Rocket Class 5 that I built from plans with a SS frame and like Aus 230 I dont believe a class 5 costs that much more to build than any other yacht I have done some experimenting around the steering I firstly had a rigid front end and then I fitted sprung forks and experimented with different degrees of spring with them and have now gone back to the rigid forks and a ribbed 20 inch BMX tyre a Maxxis Miracle which is the best I have had so far The previous tyres were either slicks or hookworm pattern In Europe I believe the Standarts and some of the class 5s have gone to wheelbarrow wheels on the front I have heard that these give better steering but after my experience of tyre pattern I wonder if this is the reason for better performance I have also heard the change for the Standarts was due to safety litigation issues over the front forks projecting forward and an accident with them It would be interesting to have some positive info on this
United States
103 Posts
Posted 4/12/2010, 4:16 am        Report
Seems like the goal of the chassis is to keep the wheels pointed pretty much in the same direction (avoiding toe change and self-steering) when the sail loads up and tries to bend things out of shape. Both my low-frame yachts failed at this in ways I could watch while sailing. With the mast step right on the main frame a big puff (or a strong steady wind) would twist the frame and lean the front wheel leeward if I didn't correct. If I did correct it looked seriously crossed up and had to be slowing things down. The NZ rocket (high frame) seems better; Bill's design supports the mast on a different tube from the steering. At first I thought that was only for "suspension," but maybe it allows the mast to twist the main frame, without twisting as much on the tube that holds the front wheel. I notice that AUS230 (at least the version that is the current avatar) and Clemco's NZ701 have the high frame, but the mast is on the same tube as the front wheel. How does that work out? The latest French boats, Airtrack and Plume seem to use the same concept as my Rocket, although the details are pretty different. Is it the Glens that have tubes on either side of the mast going to the front wheel (like older Airtracks)? It seems like that would really separate the sail forces and the steering ones. Non-design question: is YOTT a particular design or does it refer to a group of slightly similar yachts? Do the French or British folks ever comment here? Has anyone collected photos of frame designs (for this type of yacht)?
United States
103 Posts
Posted 4/12/2010, 4:24 am        Report
...about the wheelbarrow front...on the Standarts I think it was the result of a lawsuit from a failure of the monofork and bike wheel combination...that might just be a rumor. 400 x 8 wheels are required all-around on the 5 promos (Several have redundant steering connections too). I don't know of any other competitive class 5s using the wheelbarrow wheels, but it is a big world.
New Zealand
896 Posts
Posted 4/12/2010, 7:18 am        Report
The only steering difficulty I had with my Rocket design was in the hard turns around a mark Leaning forward in the seat to put more weight forward and keeping the sail sheeted hard in helped quite a bit but the ribbed tyre helped the most At all other times the yacht has always been OK I have always sailed the Class5 on sand YOTT as I understand it means [ Y over the top ] to define the frame type
United States
103 Posts
Posted 4/12/2010, 7:38 am        Report
YOTT I love it! So my old boat was a YUTB? OTTs were just Over The Top? I think the dubious steering when tacking a class5 in high wind is just inherent in the class. The only reason I would think a short fat front tire would be better is by adding weight up front. I've always had to sit up to keep the front down and Like you said, sheet the sail totally flat to keep from doing wheelies coming across the wind. I've only sailed on hard dry lake beds, but I'll remember the ribs if I take it to the beach.
New Zealand
896 Posts
Posted 4/12/2010, 8:48 am        Report
Ha! You might have started something here! Lefroy minis and the like would be TUTBs then? Back to class5 I have a suspicion that the only reason for the Y frame is because of the tube axle rule and to get the flex the axles must be longer I am sure someone out there will be able to tell us Also I have heard it said that the OTT design came about to clean up the underside when going through puddles etc
WA
1378 Posts
Posted 4/12/2010, 10:12 am        Report
I will know how the barrow wheel goes tomorrow , first race day of the season. I have made both front ends interchangeable and only takes a couple of minutes to change back to the 20"wheel. cheers aus230
New Zealand
896 Posts
Posted 4/12/2010, 10:21 am        Report
The acid test ! You are the man Vic The barrow wheel wont look as good tho to my eye
United States
103 Posts
Posted 4/12/2010, 11:18 am        Report
The Standarts with the small wheel looked funny to me at first; now it just looks normal. The Y works for pushing too so you don't run over your feet, and in a YUTB it lets you get the pilot lower. I'll be interested to see how it goes on AUS230
WA
1149 Posts
Posted 4/12/2010, 12:40 pm        Report
Lake Lefroy mini"s are SOTT's Seat Over The Top (not refering to the pilots drinking habits)
New Zealand
896 Posts
Posted 4/12/2010, 6:38 pm        Report
Oh OK I was thinking TUTB Tee under the Butt
United States
103 Posts
Posted 5/12/2010, 12:24 pm        Report
to continue the silliness: my US fed 5 was YITS 'Y' inside the seat...
United States
1048 Posts
Posted 5/12/2010, 4:36 pm        Report
My latest might be 'BUTT' Bars Under The Tub.... By the way Blake, I saw You had ivanpah as a favorite place. Where abouts are You located?
United States
103 Posts
Posted 5/12/2010, 10:53 pm        Report
Ivanpah is on the California Nevada border about 30miles from Las Vegas.
United States
1048 Posts
Posted 5/12/2010, 11:34 pm        Report
blake52 said...
Ivanpah is on the California Nevada border about 30miles from Las Vegas.
I know where the lake is, I was just curious where You are located. I live in northern LA county....
United States
103 Posts
Posted 6/12/2010, 10:50 pm        Report
sorry, I'm in Albuquerque,New Mexico. Shouldn't reply to posts read without my reading glasses All our closer dry lakes are currently politically unavailable. So Ivanpah seems to work, despite the 10 hour drive.
United States
103 Posts
Posted 7/12/2010, 12:08 am        Report
AUS 230...how did the front wheel experiment go?
WA
1378 Posts
Posted 7/12/2010, 12:11 am        Report
I tried the barrow wheel on aus230, The results where that the steering was more positive in sharp turns but I will be replacing it with the 20" setup as I found that it made the front end very rough and was the first time that it was not smooth to sail I have a spare maxxis miracle tyre to try (as hiko mentioned) So I will see how that goes. Cheers aus230
United States
103 Posts
Posted 7/12/2010, 1:55 am        Report
Air pressure is like that for me. 20 psi in the front is smooth but slow; 40psi is fast but chatters like crazy tackling even if I sit up to turn. (20 in bike front) Too bad the Wheelbarrow wheel isn't the magic fix. I've thought about a spoiler or rudder in front, Maybe a solid disk front wheel would do well to add aerodynamic steering since the wheel comes back under control once the tack is complete. The solid disk was really scary when high-speed reaching on my Fed 5 since the crosswind puffs tended to steer the boat without me doing anything.
QLD
6471 Posts
Posted 7/12/2010, 7:32 am        Report
blake52 said...
sorry, I'm in Albuquerque,New Mexico. Shouldn't reply to posts read without my reading glasses All our closer dry lakes are currently politically unavailable. So Ivanpah seems to work, despite the 10 hour drive.
Albuquerque,New Mexico. That is "Breaking Bad" country. If you went out to one of your dry lake beds there with a motor home you might have the DEA swarming all over you. Say gidday to Walt and Jesse for me.
WA
1555 Posts
Posted 7/12/2010, 9:56 am        Report
All our closer dry lakes are currently politically unavailable. If you went out to one of your dry lake beds there with a motor home you might have the DEA swarming all over you.
is the problem with the DEA- or the people they are chasing- are you actually prohibited from the areas, or is it just a case of common sense being shown in avoiding an area that could turn nasty? it would be a pity if you are losing a good sailing area to some arbitrary line on a map- but understandable if it involves not becoming a moving target for some drugrunner, smuggler or similar.
United States
103 Posts
Posted 7/12/2010, 9:57 am        Report
Cisco, I'm not a big TV watcher...I had to look up Breaking Bad...we have had some strange plane landings on our dry lakes and a small tornado, our events, 30 miles from Mexico, were often visited by border patrol agents and homeland security... one even went for a landsailer ride... but our conflicts are mostly with cows, cars, dust storms and bureaucrats of the unarmed variety. I posted a link to this forum on the FISLY Class 5 forum. Maybe there will be some crossover.
WA
1378 Posts
Posted 7/12/2010, 8:23 pm        Report
Have you any pics of your yachts, Great that you have made people aware of this site. would be great to have impute of ideas from other yott sailors, Have pretty much had to use my own ideas to develop mine.Certainly had a lot of help from the kiwis
TAS
1964 Posts
Posted 7/12/2010, 9:30 pm        Report
blake52 said...
to continue the silliness: my US fed 5 was YITS 'Y' inside the seat...
Hmmmm! Sounds like a New York Jew to me. Schmuck, Putz, Yid "YITS"
WA
1378 Posts
Posted 9/12/2010, 12:02 am        Report
hi blake are there many class5 in the usa cheers aus230
United States
103 Posts
Posted 9/12/2010, 12:57 am        Report
27 Fed 5 US version made by SR Marine, 4 NZ Rockets, soon 2 Airtracks like the ones they ran in the Worlds, 3 Seagull Maxi Sports, a handful of Pacific Magic / Hondo Ratracer derivations, a NZ Fed 5, a couple of Promos, and a few home-builts that probably qualify. And, no doubt, some I don't know about, particularly on the East Coast (I read somewhere int his forum that someone was building a YOTT on the East Coast).
New Zealand
380 Posts
Posted 10/12/2010, 5:54 am        Report
aus230 said...
This could end up somewhere as there has not been a lot of discussion around y framed yachts and different frame designs. Some of the discussion has been around how much they cost but I and I think Clem would dispute this as the class5's I have built have cost no more that any other yacht, The main cost has been the sail ,mast and pulleys. What has been lacking is plans ect. I would post mine but they are full scale on my shed floor.As for the front setup I have tried both the french and new Zealand type setup, I think the Kiwi design may have a more positive steering than my french design I am going to try a wheel barrow wheel to see if that improves the steering (only a problem in high wind conditions) Cheer aus230
At Ohope we have tried many combinations of attaching the front end tube to the main frame. The French setup was really jumpy on the turns but that could be as it was used with 30 degree roll-over steering with wire controls.The skipping problem is partly due to the wires as you can only pull the wheel each side. The wire on the other side tends to go a bit slack and allows the wheel to over steer a bit then it starts to oscillate between these two points. A solution could be to install a rod steering bar. Most of the French yachts still use the "C type" with a rod steering copied off the original Seagull Quebec. As for connecting the front end to the main frame I decided on the simplest option, a straight line. I have also installed a simple pivot suspension directly behind the front wheel. This really helps keep the front end on the ground when you hit those deep ruts on the beach.
New Zealand
380 Posts
Posted 10/12/2010, 6:13 am        Report
Here's a close up of the front end. There is a Nolathane bush for a damper in the pivot. The pivoting lever has a bunch of cut up rubber inner tubes wrapped over it. If I want it softer I just roll off a couple of the tubes. I find it works best to have it almost solid, but it still flexes when I hit something hard. Also good when you get hit by a strong gust. Tends to soak up some of the energy and releases it once you have gained control. It has saved my ass many times.
 
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