F-22 Construction books now complete

Our Canadian snail mail finally moved and I received my copy of Plan Book 2 today. I had already seen many of the drawings in pdf format but the new information is very welcome indeed. It looks like I will be adding some more high density inserts into the float decks and I am relieved to see some more detail on the wingnet rail attachment to the beams and the main sail traveler. With Ian's email of the fabrication part drawings the design information is pretty much complete.

In my day job we design and build machine assembly and test equipment. I have access to good machine shops and fabricators. If other builders are interested in a bulk order for these machined parts they should contact me. Most of the cost of machining is in the number of set ups. So increasing the number of parts per setup can really result in savings and more than pay for the cost of shipping.

Wingnet rails and support part 2

The support part for the wingnet rail turned out very nice. It will be cut into the four 3in wide pieces at a later date. The edges will also have to be trimmed. This will wait until I am fitting them on the float decks. I was surprised at how strong the part appears after two days of epoxy hardening. I suspect 7 layers of s-glass might be over-kill. Looking at how much cloth the rail will be using I decided to use 6 layers of s-glass laminate on the wingnet mold.

I cut the cloth and the 6 pieces weighed in at ~58oz. I have to say that there was about 4 hours of hard work hand laying up the cloth on the mold. One good thing about the aeropoxy resin with the 2 hour hardener is that you really have a long, long time to work on the cloth. I needed every bit of this time for this large part. This resin has an amber colour so it is interesting for me to see this resin with the fiberglass only, no foam underneath.

Two days later the part is hardened enough to remove it from the mold. The untrimmed part weighs in at 108 oz. So it looks like I have a decent epoxy to fiberglass ratio. Bordering on a rave I cannot say how much the extra plastic over the peel ply helps. The plastic allows you to get out the air, pull out the extra resin very effectively and after all this I'm sure the 6 layers of cloth are very tightly packed together. This time I used some vacuum bag plastic on top of the outer peel ply layer. It works even better as it does not stretch like the cheap home depot plastic.

Now I just have to make another one.

Wingnet rails and support

Work is still proceeding on the preparation of the daggerboard for the final carbon cloth sheathing. The filling in and fairing out on top of the uni carbon fiber is going well. The board is incredibly stiff and I have this idea to get a picture of the board cantilevered horizontal out from the top while I'm standing on the tip. Hmm, as the blind man said, 'we will see'.

I've had the wood cut for the wingnet rail and support molds since the Christmas break. So I've taken some time to glue and screw it all together and get this work underway.


Above you can see the support mold compared to the full sized plan drawing. Jay, if you read this, I only changed your angles slightly. It looks close enough to me.

Above is the 7 layers of 8.9 oz s-glass laid up against the mold. Why 7 layers? Well the specification calls for 4 layers of A - spec.18oz laminate. Four layers totals 4X18=72. S-glass fiber is allowed a 15% reduction. So I require 61 oz total of s-glass laminate. To get the required number of layers, 61/8.9 = 6.9 or 7 layers. I'll be using Aeropoxy resin for these parts, as I consider them more structural and not below the waterline. As a side note I considered using carbon cloth offcuts from the daggerboard but after thinking about it, I did not want to make them that stiff.

I have not bothered with vacuum bagging this part. The cloth is very drapeable and with the use of peel ply and plastic I am quite confident in the quality of the part that I can get.


Here is the 9 foot plus mold for the wingnet rail and taped up, waxed and ready. It's all set to go as soon as cut the required cloth, peel ply and plastic.

'Doing the Uni' on the daggerboard

Happy new year! Now back to work.

I could only locally source 9oz uni-directional carbon fiber, which I verified is not close enough to the required specification of 12-13 oz weight. So instead of the seven layers described in detail in the plan book I decided to lay down 10 layers using the following strategy.

lengths of unidirectional tape starting at top (in mm)
1750
1689
1600

Then going down every 34 mm
1400
1265
1130
995
860
725
600

I think this preserves the distribution of the carbon as the designer intended.

Here is a picture showing the 10 pieces of carbon uni laid out in the board rebate.


Whetted out and under peel ply and plastic.



Peel ply and plastic removed. The board weighs about 10 lbs with the uni-directional fiber in place on one side. It looks like a finished carbon F-22R daggerboard will weigh ~ 15 lbs or less. The board still looks very rough. I promise it will look better. You can see one error in the above picture, I made the mistake of rebating too deep in the lower part of the board. It means more Quick Fair putty and more weight.
One can always improve... one learns through one's mistakes ...etc etc.

Vacuum bagging the first lamination on the daggerboard.

Cutting the 6oz carbon cloth and fitting it on the daggerboard. My plan was to hold the board at one end and laminate it down from the leading edge to the trailing edge.


I was not very happy with my hand lay up of the cloth. The cloth stretches very easy. However in the end we get it all in the vacuum bag. I cannot imagine getting good adhesion on a part like this without the use of vacuum.

Vacuum pump circuit with vacuum switch

Here is the daggerboard straight out of the bag with the excess cloth very roughly cut away and presented to the family on the living room floor. Not a perfect job but I can work with it. It is now on to the uni-directional carbon fiber.

At this point the daggerboard weighs in at ~ 8-9 lbs.

More daggerboard fairing and preparation for sheathing

I found the templates traced and cut out from the full sized plans to be very useful. I used hardboard from one of the boy's old school projects. Above you can see that I could actually get them to all stand up on their own. At this point I was getting close to final shape.
On each side of the trailing edge I cut the foam down to the fiberglass cloth that I had laid down when gluing the two foam pieces together. I then filled up the edge with fairing putty. Same process for the other side. I thought that this worked out very well.


The rotary tool showing at the top of the picture allows me to make rebates far easier. Santa was good to me this year. The above rebate is for the carbon cloth. My 50" wide cloth will not allow covering in one piece with the fibers at +- 45 degrees. You can also see the putty on the trailing edge, the larger rebate for the uni fiber and the core still showing, wrapped with the carbon fiber.

Daggerboard fairing begins

I had to think about how to position the wrapped core and keep it properly centered in the foam block. I was struggling with this and then suddenly it occurred to me that I could re-use the scrap piece of foam that I had cut off to taper the core cut out to the correct thickness. This was a scrap piece and I had to recover it from the garbage heap.. My thought was that the piece could be used as a spacer to locate the laminated core in the centre of the foam block. There would be no need to create any new spacer or other method.

You can see how much foam is actually cut off one side the core to reduce the core thickness, below. Remember that the daggerboard sections get thinner the farther you go down, and this is just one side.



Below you can see the core correctly located within the 2 inch thick foam block.

I used some polyurethane glue to lock the core into place and proceeded to machine the 4" wide rebate down the length of the core insert. I ended up using my Dremel tool with a router bit to cut the rebate. I used the inserted core as a guide to determine the correct depth of the rebate. I have since asked Santa for the proper tool.

Then the fairing begins. From the coarse we go to the fine. The initial fairing actually goes very quick. You can see above the templates of sections A-F lying on the work table. They are invaluable. With my experience of shaping the float bow caps I expect the fine touches to be interesting.