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Last Modified August 6th 1996
1st - 5th July Working in California. No building.
6th - 7th July Weekend with the family. No building
8th July I prepared the ply inserts for the tailplane first layup. To make it easier to draw the shape onto the ply I drilled two small holes in the ply and then pushed nails through the ply into the foam to provide a temporary fix. Running a craft knife blade in the rebate against the ply surface gave me a good cutting line. In order to ensure that the ply wasn't proud of the rebate surface when I was finished I used a epoxy stirrer stuck to a straight edge with double sided tape. Laying the straight edge on the upper surface with the stirrer in the rebate and overlapping the edge I could check the clearance easily. Next time I do this I won't cut the curved edge on the rebate until I have cut the ply. Having a straight edge to align against would have made this much easier.
9th July I prepared the first tailplane inner core for layup. This does involve cutting a circular hole in your workbench if you want to do the layup with the surface horizontal as the torque tube has to be in place while you do the layup. I thought about doing the layup horizontally but gave in and cut the hole. I will fill the hole with foam and fibreglass afterwards so it shouldn't be too bad!
10th - 11th July No building, too much work to do :-(
12th July Prepared the workshop for the layup and did some more preparation on the tailplane inner core. The tailplane preparation consisted of masking off all areas where I didn't want epoxy (like most of it) and fitting a foam plug into the metal tube piece to ensure that epoxy didn't drip down the tube. I used plastiscene as recommended in the manual to create an air tight gap at the edge of the foam and the metal. For those who are wondering what plastiscene is, it is childrens modelling clay that has as one of its features the fact that it never goes hard. Its other features are that it is difficult to get out of carpet and childrens hair! I used it when building my model railway to create 1/10th scale terrain models of the railway to check that the geography looked good before construction.
I am convinced that bidirectional cloth has a mind of its own. You can cut out a section of cloth off the roll, leave it for a while and the instant you touch it the cloth changes shape. For some reason it also ends up narrower when cut than when you mark it on the bench. I am now using cling film to ensure that the cloth retains its shape. As soon as a piece is cut off the roll it gets adjusted to the correct shape and placed on cling film for storage until the layup. To make this layup even easier I cut the X where the tube will poke through the cloth before I started the layup. This proved its worth as the layup is tricky enough as it is.
13th July Layup time. Following my procedure of wetting the first layer on the bench and then putting the other layers on dry proved to be beneficial here. The only really messy bit about this layup is getting the edges of the cloth trimmed inside the rebate. I trimmed each layer in turn as the build went on and then did one final trim. This was the first layup where I used a hair dryer during the squeegee stage. Definitely to be recommended. All you do is blow hot air at the cloth in front of the squeegee. The epoxy liquefies and the bubbles rise to the surface. I would say that I could squeegee out 25% more epoxy that previously, get bubbles out easier and still have a good looking finish.
14th July Inspection this morning shows most of the layup is good. A bit of sanding back was required where the epoxy had crept underneath the masking tape but that was easy to resolve. I also had a thin air void that ran along the edge of the plywood on the lower surface. I suspect that this was caused by the flox slumping as there is no bulge in the surface. The fix was simple and straight out of the Rutan Mouldless Composites book. I drilled a few small holes into the void and injected epoxy into the void ensuring that enough epoxy was pumped through to flush out smaller bubbles. Leaving that to set I cleaned up the workshop ready for the next layup preparation.
15th - 24th July One of the frustrating things about working with composites is that the climate becomes an issue when building. For the past ten days I have been unable to get the humidity in the garage down below 70% despite using heaters and a dehumidifier. Auckland has been unusually wet and even my cat refuses to go out without water wings. The only benefit is that I can't mow the lawn. I have filled my time reading Bob Nuckoll's excellent book on electrical wiring of homebuilt aircraft. This book is essential reading if you intend wiring a plane yourself. I have now alodyned my rudder hinges. This involves scrubbing the aluminium parts with a Scotchbrite pad until absolutely clean of grease and then dunking them in alodyne (a chromic acid solution) until they get an anti corrosive surface bonded to them. This is, to put it lightly, a smelly and hazardous job and is best done when the wife is not in the house. Now that these are ready I can get on with mounting them on the rudder while I wait for the rain to stop.
25th - 31st July I lied! Instead of working on the rudder I built my Rocky Mountain Instruments Microencoder kit which arrived from the USA. As well as being a transponder encoder this unit is a vertical speed indicator, and altimeter and an air speed indicator. I will be using it as my primary vertical speed indicator and encoder and as a backup to the other instruments. The kit is unbelievably well documented and goes together well over a few pleasant evenings. The kit has been designed with the first time electronics constructor in mind and should be easy enough for anyone to put together.
Now, if only that rain would stop then I could do some more fibreglass work. This is getting really frustrating, I can't work on the plane and I can't go flying. This is one thing that they don't tell you about when you start planning your construction schedule. I never expected that I wouldn't be able to work on my plane because it was raining outside!
