I haven't been taking a break or been idle for the last few months, I just didn't feel like I had a lot to update about. Basically I've been learning how to do fiberglass and trying to use the new found skill to create an acceptable aft canopy skirt.
I was really not happy with the aluminum skirts I'd made, so I was trying to fix them and made them worse. :<
When I was at VARFOF this year Kent Stitt had his beautiful RV-7A. I think he ended up winning best homebuilt in fact. He did an an excellent job on the aft skirt, and told me he'd made it out of fiberglass.
Here are some pictures of his canopy skirts. I didn't get a great shot, but it is a beautiful piece of work (his whole plane is in fact).
Since the original skirts were unsalvageable, I ordered some more aluminum for ACS but decided it was time to take a rip at fiberglass. My last experience was when I was in high school trying to fix some rust on an old Benz 220 SL my Dad bought when we moved to Germany.
It worked, but it wasn't pretty. Probably polyester, and certainly some sort of Bondo type product.
I had some West System epoxy and some light (4 oz) glass, so I decided I would have my own composite workshop.
I poked around and found a copy of Burt Rutan's original Moldless Composite Construction book. Although I'm not building a glass aircraft, the instructions, descriptions and simple pictures are excellent and easily understood. It's nearly 30 years old now, but I'd highly recommend it.
I didn't do all the exercise pieces, but I did most of them. I came away being extremely impressed with how strong simple composite construction is. I have a whole new appreciation for composites, although I don't know if I'd have the patience or skill to make an aircraft from scratch with it. Hats off to all the folks who do (like my friend Marco who is building a Long-EZ - see his progress at http://longezproject.blogspot.com/), or Nick, who is building a Velocity (http://www.velocityaircraft.com).
Here's my first start. I got a bunch of the really cheap Bondo glass from Walmart and did my first layups with that. It's about 6oz cloth, and does a pretty decent job, although because it's folded a million times into a little baggie it's hard to get it all pulled out so it is straight.
Here's my first sample after it's cured. It's *way* too heavy - too much epoxy - you can see the sheen. Doesn't really make it horrible, just much heavier than it should be and it doesn't add anything to the strength.
The pink bit in back is the core of the second layup that Rutan's book has you do. Sort of a reinforced stick.
This is the page from the instructions of what I'm supposed to make using the pink foam (I used the stuff from Home Depot that is about 3/4 to 1" thick and comes in big 4x8 foot sheets). Instructions are excellent by the way.
I was supposed to use BID (bi directional) and UNI (uni directional cloth) on this to strengthen it - 2 BID, then 2 UNI, the the foam, then 2 more UNI then finally cap it off with 2 BID. I didn't have those when I did this, so the entire thing is the cheap 6oz Bondo glass. Micro gets smeared in the gaps so it lays better, and the cloth is cut and laid on the bias so it also lays nicer.
Once I laid this piece up and let it cure a couple of days and trimmed it, I could stand on it without it breaking. Pretty impressive, especially since the glass is a bit lighter than RAF specified, and I didn't have any UNI, which would have added considerably to the longitudinal strength.
Trying a layup with a much lighter cloth I got from Eastern Burlap in Norfolk. This is about a 3 or 4 oz cloth with a very tight weave. I think they call it deck cloth. Makes a beautiful finish and very smooth.
All the layups are done on plastic, both the protect the table and also so they don't stick.
Bits from the Aircraft Spruce practice kit. This is Flox, a cotton material that is used to make structural reinforcements by mixing with epoxy.
This is a bag of micro - glass microballons. It's so fine it pours like water. The bag sort of exploded in transit, so the whole shipping box was full of fine white powder.
Some practice foam from the kit. The tan stuff can be cut with a simple hot wire gun made from safety wire. The green stuff is like florist's foam. Easily cut, but not for hot wiring because it emits a poison gas.
Some blue foam at the bottom, plus lots of micro dust from the hole in the bag.
All the practice pieces after I was done. I came away very impressed and I'm really glad I did it. I feel a lot more confident about doing work with glass, and was extremely impressed with how strong it is. It's a lot of fun to work with (at least so far). By all accounts the painful bit is the sanding, and I haven't done any finish work with it yet.
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