Another "thrill" is full moon, night sailing. The only lights used are are low power torches taped to masts shining on sails. This allows yachts to be visible without impairing night vision. Great fun
In hindsight the wing on the berminator should have been a bit larger but it was a fun project.
After watching US772's new years video, I reckon the "Playa" should be renamed "The Playground"
stephen
Since the rules allow any size or type of tire wheel combination I am converting my yacht to accept 16" Skyway Graphite BMX bike wheels and smooth Kenda 100psi tires. The durability of the tire/wheel combo is the ticket. Less drag, less weight and less expensive than any 8" wheel/tire combo.
The Jr. dragster wheels that desertyank is using are pretty sweet and look awesome but kind of over the top and heavier, with a larger patch on the ground creating more drag. In comparing two US 6.7 yachts this weekend at Delamar dry lake, it was obvious that the skinnier, taller and lighter FED 5 BMX wheels and tires out performed the wider, shorter and heavier Airtrack wheels and tires.
These combos were both run on a dry lake but I'm sure the 8"ers would uot run the 16"ers on the beach or dirt.
Original FED 5 converted to a US 6.7 mini. Hauls ass!
The FED 5 has a unique rigging that is very efficient and has less wind drag and is highly adjustable.
Check out that mast step
An original Airtrack promo converted to a US 6.7 mini. Hauls ass too!
The Airtrack uses a conventional center pull rigging.
My next build will be a US 6.7 mini.
Delamar is approx 100 miles NE of Vegas.
www.google.com/maps/@37.3127,-114.951153,6801m/data=!3m1!1e3
Between the island and the shore is approx 5/8mi
By switching from my fabbed front end to the BMX bike front end I managed to cut 15.5 Pounds. I will post the pre re-work pics and the post r-work pics when it's done.
Front of chassis before BMX front end conversion.
And I was'nt even done adding parts!
are you putting 16" on the rear????
if so keep in mind that the contact patch is really small.for a mini powered up and sailing fast it is too small. on the front fine but not on the rear. you can lay the wheels over say 8 degrees but that will only help a bit
you will have the yacht hopping sideways as you lose traction.
pumping up to 100psi will make for a really bad ride.
typically we make custom rims which allows you to have a fatter 16" tyre (say 16x2.250 on a 50mm wide rim)
you can then let the pressure down without the tyre sliding off the rim.
this is all info regarding the front wheel. i wouldnt recommend them on the rear.
the fed 5 in your pics has bigger wheels/rims
From 8" wheel to 16" wheel rear axle conversion pics.
Before the change.
After the change
Done
If anyone wants to see a drawing of the procedure, send me a pm and I will post it.
these are the parts I made for the front end conversion.
The mast step tube is 2.375"od x .125 wall. 18" long. It will be capped on the bottom end.
The spine extension is 2x2sq tube .125 wall. It has a 1.1875 radius at ten degrees cut into one end. This is where the mast step tube welds to and gets a 1.0"x.125 reinforcing strap wrapped around it and extends down the sides of the spine.
The head tube neck has a radius like the spine and a 1.3" through hole bored .25" back from end and at 90 degrees.
The head tube is made from 1" stainless pipe 3.5" long and partially bored on the ends to accept the head race cups. The caged head bearings were replaced with loose ball bearings. 25 bearings in each cup rather than 16 bearings in the caged bearings. VERY SMOOTH! and more support from the bearings.
Parts used
W/BMX front end
Mocked up
Steering parts
Here are the BMX front end parts welded up. Included is a 12" spine extension, 18" mast tube, 16" bike front fork, cups and bearings. The mast tube is 10 degrees and the fork head tube is 20.
Now it's a roller again! On to the rider support, steering and mast tube gusset.
I have a couple of Um I wonder thoughts
I like what you are building here but I wonder about those rear wheels and I wonder about that square section spine
Round tube is much better in torsion and thats what the spine will get Square tube will need to be bigger than round to cope
I guess you could test it by getting a fat buddy to sit on one rear wheel and try and lift him off the ground by a lever in the mast step
Rear wheels on landyachts get a lot of side load and bike wheels dont get that in their normal life
They are just OK on the front but usually only with layover steering
Just saying IMHO
Hiko,
These are not bike wheels, they are the heavy duty utility wheels made by Skyway. They have an integrated aluminum hub that carries a set of 5/8"id roller bearings. The hubs measure 2.495" wide.
There are several past champions that have been doing this since I was in diapers. They have used these wheels for many years with few issues. They indicate to me that these wheels and tires are the ticket.
The torsional load test you suggested would not be viable because there is no rigging installed and there are no yachts that have all the load on the mast tube alone. There is rigging that divides the load between two points. Two inch square tubing is bigger than two inch round tubing! It is also stronger with more surface area and structural integrity.
BTW the yacht now weighs 37.5lbs instead of the 58lbs it weighed before the conversion. That's a total weight loss of 20.5lbs just on the rolling chassis. It looks like I can keep the total weight down near 60lbs or less. That's pretty good, considering that there's no way I'm not going to lose 20.5lbs.
Just my few cents worth.
I have built well over 100 landyachts. The lightest class 5 was 38 lbs with mast but no sail, and it was a complete pig. When I added weight it just got better and better. I don't honestly think that they need to be much less than 50kg. I have loads of theories, and have sailed in every continent except South America somewhat competitively in every class except Mini 5.6. I am always happy to see people try "new" ideas and see if they can make them work when others could not. :)
That mast/front fork system is going to apply massive torsional loads to the front wheel IMHO. I think that you will find the front wheel will be leaning over the moment that wind loads come into play. Happy to be shown to be wrong though.
You can see these are not your average Skyway bike wheels. They are truly heavy duty. If they break then I will buy some more. If they last one season I will be happy with them.
These wheels will also be reinforced with an aluminum disc on either side of the wheel. The disc is for aerodynamics but give a little extra strength as a bonus.
Select to expand quotekiwi307 said...
Just my few cents worth.
I have built well over 100 landyachts. The lightest class 5 was 38 lbs with mast but no sail, and it was a complete pig. When I added weight it just got better and better. I don't honestly think that they need to be much less than 50kg. I have loads of theories, and have sailed in every continent except South America somewhat competitively in every class except Mini 5.6. I am always happy to see people try "new" ideas and see if they can make them work when others could not. :)
That mast/front fork system is going to apply massive torsional loads to the front wheel IMHO. I think that you will find the front wheel will be leaning over the moment that wind loads come into play. Happy to be shown to be wrong though.
I'm sure you know a lot more about it all than I do but I gotta try it. They have been proven and I'm willing to do whatever it takes to get an edge up.
I weigh in at 250 pounds, I don't think I will have a problem with having to add weight.
Thanks for the vote!
Sorry I wrongly assumed they were bike wheels
The square tube may well be strong enough but pound for pound in torsion its not as strong as round I believe
Really only applies if we are trying to build light as possible I guess
the big issue you will face with the 16" rears is that you wont have a big enough contact patch for traction. the simply slide out from under you under side loads.
particularly treacherous in wet or soft conditions.
the tyre wear is horrendous.
i had an early mini fitted with the same tyre, and it was unraceable. that was back when we were sailing with 3m rigs too!!!!
Select to expand quotelandyacht said...
the big issue you will face with the 16" rears is that you wont have a big enough contact patch for traction. the simply slide out from under you under side loads.
particularly treacherous in wet or soft conditions.
the tyre wear is horrendous.
i had an early mini fitted with the same tyre, and it was unraceable. that was back when we were sailing with 3m rigs too!!!!
Yep found the same on the early 'Sandpipers' so much air had to be put into the tyres to keep them on the rims the contact patch touching the ground was VERY small.
But hey he's got them.... give them a try.
I think I'm going to make a bushing to be able to switch to the 8" wheels, if there is an issue. the dimensions will be: 1.0"od X .625id X 3.0"L .375 wall
Been doing a lot of horse breaking these days and not a lot of building or playing. Went to the worlds for a couple days and it was pretty good meeting some of the international pilots. The class fives and standarts are awesome and pretty fast too. Too bad conditions were hell!
Some new build info....
Based on some other builders comments and recommendations I went ahead and fitted 10" Azusa mini bike wheels to the rear. These will serve as my back up set as I will be giving the 16" re-enforced wheels a go first.
With the street tires installed on the 10" wheels the diameter is the same as the 16" hookworms. My chassis geometry will not change but my wheelbase does with the wider wheel due to a wider hub. It is still inside the rope!
Azusa 10151 10" mini bike wheel
Mounted to axle.
Inside view
Tire I ordered
Kenda K329 2.50-10
Mast tube/chassis gusset layout on a 14" square x 1/8" thick steel plate
Outline drawn
Rigging mounting holes are center punched and will be drilled at 1/2" leaving the inside edge of the hole a 1/4" from the edge of the gusset.
Chassis spine to rear axle gusset/brace to be welded at the spine/axle joint
Steering pivot point
I started with a FREE set of atomlab mountain bike platform pedals. I chose these because they have a square center section and replaceable sealed bearings and are made of aluminum.
I cut off the platforms and machined some height adjustment slots in one of the faces
I also machined the sides where the platforms were. As you can see the factory castings were less than perfect. In fear of cutting too deep and ending up in the pedal shaft bore I left them alone.
I then machined a mount out of the left over 1" axle shaft's. They were drilled and tapped to fit the original pedal shaft threads. 9/16-20.
This will be welded directly to the chassis spine
My steering pedal shaft will mount wit two 1/4" U bolts with a fabricated aluminum backing plate.
Here is the mock up
At this point the yacht is already done and painted but I will post all the images and build details in the proper timeline. I have all the pictures and am still sorting out the images and details. I will include all the information on everything except the custom sail!! You will only see a picture of it installed and ready to run.
Sorry for the delay on the build info....More to come!
