Hi Folks,
This is a follow on from 'Bill Finches old landyachts' thread and is the story of Vindicator's build.
After the sanderling experiments, I decided that I needed to build a better platform to have a crack at going faster with a wing. I felt that the yacht had to be more aerodynamic but also enclose me a lot more than the sanderling. The fuselage needed more room inside as well so all the wings sheeting system could be enclosed.
I designed the fuselage around elliptical shapes so that it was symmetrical both from above as well as from the side and with a double curvature to make it really rigid and force the axle and front plank to flex only where I wanted them to.
the other advantage was also that I only had to make one mould to make the fuselage halves.
This was one hell of an undertaking and I'm glad I didn't know what I was in for when I started! First I had to build a bench big enough - and flat - to make it on. Then, using some computer generated ellipses (more of a big deal to get in 1990 than now!) I made some profiles and mounted them on about 300mm stations (I think it was.)
From there I filled in the spaces between with whatever foam I could scrounge. At the time, I was working for Telstra and installing quite a lot of one type of equipment in telephone exchanges, which came in boxes with a lot of foam packaging which got recycled! Once the space was full, I used a hot wire to cut the foam to the shape of the stations.
After the foam was all in place, I stuck balsa strips to the stations and with a fellow lansailer and friend Chet Cox, we plastered the whole thing with plaster of paris. Once this was dry, I started sanding. A months or two later, I had it evenly sanded. There were still a few low spots. More plaster & I started sanding again
Finally, I was happy with the result and painted it with resin. And started sanding again.............
Eventually I had the result I was looking for. It took 5 months............
The mould followed. It was straight forward after making the plug and much quicker.
To get the best finish on it, I actually waxed it only, with no PVA. This was a big risk as if it stuck -
In fact, I invited everyone around when it was due to come off -
I drilled a 1/16" hole up the top in the middle and hit it with compressed air........... a couple of cracks and bangs and it released without a scratch!
(I had done a lot of waxing!)
The next stage was laying up the fuselage, which was made with chopped strand and woven rovings with 3/8" endgrain balsa as a core.
Each layer was vacuum bagged to get the best lay up, but the balsa core had to be done in segments, as I was doing it with polyester resin.
The top half was straight out of the mould and I cut out a section for the pilots cockpit. For the bottom, I cast a piece of plaster in the bottom of the mould and put plastic over it before I laid up the fuselage half and this became the axle mount.
So far so good. While this was going on, the axle was taking shape.
Just as much design work went into this as the fuselage. I considered that the sanderling's axle was pretty much spot on for the flex I wanted, but I was trying to get the best aerodynamics I could.
To this end, I worked out the rectangular cross section that I needed on the inner and outer parts of the axle and asked an engineer to calculate the dimensions of a Clarke Y airfoil to match the cross sectional area to give me the same flex. I cheated on this a bit though and had a boatbuilder laminate the axle blank with cedar and hardwood and Bruce Buddle who was a landsailer as well as a patternmaker shaped it for me. I then covered it with epoxy and Dynel cloth.
Enough for now, more later
Hi Folks, back again.
For the axles, I made new stubs and mounts, but I re-used the hubs from the sanderling. These had 6202 ballraces which were easy to get & replace & had worked so well on the sanderling that I wanted them on this yacht.
Once all this was made and mounted, it was all faired into the axle and glassed.
The next trick was to join the fuselage. This was quite a trick because I had to get down inside the fuselage and join up the inside of the shell bit by bit whilst clamping it in place to match the edges exactly, so that when I did the outside it would be seamless. To get past a certain point, I had to decide which arm I wanted forward or back as once I passed that point I couldn't change! To keep the resin fumes away I also had a vacuum cleaner hooked up to the nose to clear the air.
A day or two of doing I this, I woke up one night with a terrifying feeling of the walls closing in - a full on panic attack!
I found out I had claustrophobia! I had never had it happen before and it hasn't happened since!
It probably doesn't matter now because I'd never be able to get myself down in there these days anyway!
After that was wheel alignment, as you see here.
To be continued.................
Joining the two halves together is not a lot of fun, Just about drove me crazy doing the inside of mine, enjoying this Bill
Hi Vic, Hi folks,
Sorry its been a while, but here's more of story.
Once the fus & axle were done, I moved on to the wing.
When I made the wing for the sanderling, it was only a quick and rough test to see how it would behave & I did not expect such a dramatic result. It did prove to me that the size was right for what I was trying to do, (4 sq metres), but it was now time to make it seriously better for the next step.
To improve it, I removed the mylar covering and filled in the space between the ribs with foam as per the fus plug.
After this, I gave it 1 layer of light glass cloth, sanded it, then covered it with contact plastic. Yep, the stuff you used to cover your school books with. Works great, giving a tough clean surface - and you can remove it later with a little help from a hot air gun. I did this later with this wing and added a bit more glass & sanding to improve it.
All this was done in order to keep the shape true at speed because the point of using the section I used and its effect would not be apparent until high speeds were reached.
Here is Vindicator in its basic raw form. You can just see the little 'winglet' under the wing on the top of the fus. This is part of the sheeting. I thought after the interesting antics from the wing before that I would have a 'locked' system to stop any oscillations. It worked quite well, although the mechanism had a tendency to jam & Paul replaced it with a better one in later years.
You can see here the wing control, plus the windscreen - which was actually supposed to be a complete canopy, but it didn't turn out to be tall enough for me to see out of the yacht & I cut the front bit off & made it as you see it.
Here it is freshly painted & the shape becomes apparent.
Some time later with Vindicator livery. The yacht was originally called 'Commander D' as Telstra sponsored it, but when they had decided that their promotion was finished, I renamed it Vindicator.
A few words about the ideas I was trying to prove with Vindicator's design.
First up, the fuselage shape. As mentioned previously it was based around elliptical cross sections & this was aimed at reducing side load from wind drag, to keep traction at speed. Next was the axle, which I wanted to be able to behave as a class 3 axle does, but with precision aerodynamics to hold the yacht down. It was not meant to do much aerodynamically until high speeds were reached.
Next comes the wing, which of course is the critical bit & what the fuss was all about. As has been stated, it is only 4 sq metres. I felt and still do that you don't need very much at higher speeds if you keep the rest of the yacht aerodynamically clean enough.
As for the wing itself, I deliberately did not make an asymmetric section, as I deemed it unnecessary.
One of the critical things that happens when you are trying to reach higher speeds, is that there comes a point where you have either too much wind or too much sail. At this time you have to back off by either letting sail out, which creates higher drag, or run off further down wind, which limits power available.
This is where the section I was using comes in. It is a NACA 6315 laminar flow section. This has the characteristic that at very low angles of attack it becomes very low drag & very efficient. In other words, I thought I could get some of the induced drag to'disappear' if I could go fast enough.
It works - but not until the wind is above 15 mph and on a hard surface.
I had quite a number of goes at getting it up to that point - variously at Lake Gillies, Lake Gairdner (several attempts) and Kambalda.
It wasn't until 1993 at Kambalda that I had a chance to get winds strong enough to show what it would do & it didn't disappoint.
In winds of 25 - 35 mph it finally clearly showed that the concept works. The salt had good traction and with the strong winds it accelerated solidly until about 110kmh (where the bike speedo 'lost the plot'). At about this time, the yacht would try to lift a wheel. I had a wind indicator mounted on the wing & up until this point it was measuring about 7 degrees for the wing to work. I backed the wing off a bit to keep the axle down, the yacht settled down and took off! I'd hit the place I was trying to reach! On top of this, the axle worked harder as the speed rose & the yacht squatted down and hung on like it was on rails!
I managed to thread it through the speed trap 3 times at speeds of 140kmh plus with the best being 144 kmh. By the way, it was doing this at 90 degrees to the wind & could do it in either direction.
There are faster yachts around now, but as far as I know they are all quite a bit bigger than Vindicator.
That's about it really, I gave the yacht to Paul, as I had done what I set out to do with it, but with the proviso that A: he didn't kill himself and B: I could have a chance at killing myself in it occasionally when I had a chance to visit him.
Seems very sad that its gathering dust in Paul's spare yard, I would love to see it back on the lake.
What do you say Paul how about bringing her out for a demo at this year's regatta???
it all come s down to lake . you need a massive area to sail on, , no little yacht doing things around you . a team of volunteers to rig and unrig.
1 year , I was derigging ,and looked aroud to see that my helper had decided to go home. I spent a night on the lake with no gear or food . the next day( monday ) about 10am tourist came through as my volunteer ahdnt taken in the signs, and he helped me derig so I could go home to work.
but yes if the lake is as good as you say i will look to getting it out
Thanks for sharing!