Saturday, February 28, 2009

Rudder sleeve assembly completed (more or less)

First, I cut the sleeve to accept the shaft to connect to the rudder mount.  Not having the S.S. shaft yet I used a wood dowel to verify the fit.   The big question here was how far to cut into the sleeve.  The deeper you cut into the sleeve the wider the angle the sleeve can rotate before there is a hard stop to the gudgeon.  The picture below shows the angle I can achieve.  It is not a full 90 degrees,  but it's getting close.  My understanding is that the tiller will hard stop in the cockpit before this angle is achieved.  

I also finished the  tiller stub, which went together fairly straight forward, and glued on the sleeve.   Straight enough I hope.

Here is my access hole, through the tiller stub, to get the shaft in and out.  

The tiller stub is my first carbon tube, and I am thinking about molding the tiller itself with carbon when I have the hull and traveller completed.  You can also see that I sealed the exposed foam at the end of the tube with a piece of carbon cloth.

Here is the complete steering system for an F22.  The sleeve and rudder combined weigh about 7 lbs.  Not all that much when you think about it, but isn't it funny that we go to all this trouble to reduce weight and then stick a heavy outboard at the end of the boat.   Anyway, you can also see that I have not yet finished the plastic end strip yet.  I'm think about using the option for 3/8" nylon hardware to keep the plastic strip in place.   

Monday, February 16, 2009

Final laminations on the rudder case

Just a quick post to show the final laminations on the rudder case.  In preparation I smoothed everything out with the lighter weight QuickFair putty.

And then in one session I added the remaining layers of carbon fiber cloth and uni-directional.  I can see why people love to work with carbon fiber  The resulting patterns from the weave are most attractive.  One other comment.  You have to be careful cutting the cloth to size with the loose weave of the carbon cloth.  It will fall apart.  Orientation of the fibers at 45 degrees is also interesting as the cloth will stretch like an accordian in the most extreme way.

As it stands currently it weighs 1.8 lbs.  

Now I have to think about attaching the stub for the tiller extension.  The foam is rough cut to size but I have to shape it to the profile of the sleeve itself. Then more wrapping in carbon fiber.

Tuesday, February 10, 2009

Pivot tube mounted on the rudder sleeve

Getting the pivot tube attached to the rudder sleeve requires that a spacer plate be carefully cut and joined to the tube and the case.    I found myself using some of the trimmed off material (layers of s-glass) from the wingnet rail.   The pieces cut away on the wingnet rail for lightening purposes were just the right length for this spacer plate.  I glued two pieces together to get the correct thickness.

I just used a high density putty (cabosil and resin) and the best judgement of my  eyes to glue the spacer plate normal and parallel to the fiberglass tube.

In a similar fashion I glued the pivot tube to the rudder sleeve case.  I did not need any special clamping to keep the tube in place while it was curing.  Again I trusted my eye to get the part aligned.

The plans call for some extra carbon fiber to strengthen the tube at the top.

Then in the areas where the tube will be cut away to fit the rudder gudgeons a very high density putty (cabosil, resin and chopped up s-glass cloth) was used to build up the gap.  The middle area will be filled with a low density fairing putty and then the assembly will be ready for the final layers of carbon fiber.

Wednesday, February 04, 2009

Rudder sleeve out of the mold

The plans actually call for the use of sheet wax wrapped around the rudder blade to build up the nesessary room for the frontrunner fabric (a durable marine fabric) that will line the case.  Like the daggerboard,  the rudder on the F22 design is just pulled up and down in the case. No pivoting, which I know some builders would prefer.  I like the simplicity of this design however. The open transom design should give me good access to pulling the rudder up when needed.

Anyway,  I could have purchased the sheet wax from Composites Canada who sell sheets at a .010" thickness.  This is the proper way to do it but it would have required building up quite a few layers of wax, so taking once again the lead from Menno, I decided to try using the fabric itself wrapped in plastic.  This fabric was kindly supplied by Jay in Seattle at a fair price and I have no idea where to source it in my locale. 

Two 2x4's cut with the profile of the rudder blade provide for the mold edge for the upper and lower flanges.  The picture shows the everthing more or less in position.  The fabric was taped in place and compressed to what I hope is the correct amount.  After this I used lots more plastic tape and some dollar store plasticine (horrible stuff made in China),  then finally a number of layers of a mold release wax.  

Here is the first layer of laminate applied.  I let the first layer cure before adding the others.  I'm not sure if this was necessary.

When all the carbon fiber was applied and cured I knocked off the 2x4's from each end.  Then I removed the plastic strip from the trailing edge and was able to break the part from the mold by prying up from that open trailing edge.  It came off no problem.  I did make some initial trimming when the part was still green  and I still have some trimming to do,  but I am off to the next step of adding the pivot tube to the sleeve.

Sunday, February 01, 2009

Strengthening the top gudgeon on the rudder mount

Our excellent designer determined a weakness in the top gudgeon to rudder mount join and very promptly updated the plans with the appropriate fix.  It was a very straight forward modification so I thought to just as promptly get it done right away.

I should have an update on the rudder case soon.