Sunday October 26th, glass canopy skirt

After my composite workshop adventures, it was time to start actually having a go at making the part I really needed, which is a fiberglass skirt for the slider canopy.

 I had enough confidence at this point to know I could at least do a decent job at fiberglass, but flat on a table with smooth plastic and plenty of room is not at all like trying to lay something up on a 3 dimensional object like the canopy/fuse junction, some of which is nearly vertical.

After reading and talking to some folks, I decided to cover the whole gap with blue painters tape (which will not stick or gum up even if you leave it for weeks) pulled as tightly as I could, then layer the cheap brown plastic box tape over that for a (hopefully) non-stick layer (it was). The only thing I forgot to do was insert the canopy handle and latch it. I didn't catch that til later after I'd pulled the tape so tight I moved the canopy. Oops. Came out ok anyway.

Here's the first layer of blue tape (and the wrinkles from the canopy sliding aft under the tension).  Fixed that later.

From Finish Kit

Starting on the cheap brown packing tape.  With care, you can lay this stuff very smoothly.  Does gum up stuff when you pull it off tho, so I was really glad I'd covered more than enough area with blue tape first.

From Finish Kit

Finished, and now I'm finding and marking the canopy holes and fuse edges so I can know how large the fairing has to be.

From Finish Kit

I made a paper template out of cheap brown painter's masking paper.  If I had it to do over, I'd use freezer paper or kraft paper.  This stuff reminds me of my Mom's sewing pattern paper - way too light.

From Finish Kit

Starting to pre-cut the glass for the layup.  This is about a 4oz deck cloth I got from Eastern Burlap.

From Finish Kit

Laid up the whole thing as a pre-preg sandwich with plastic and peel-ply, then laid it on.

I don't actually have a picture of the above part except in bits of the picture.  I was actually pretty funny.  Something was wrong with my hardener pump (West System) and it wasn't measuring correctly.  The epoxy came out like pliable plastic.  Turned out to make a great template later, but it was a complete failure as a fairing. Below is my second attempt, where I did just one half, again as a pre-preg sandwich with plastic.  I used my scales to weigh the epoxy after the initial failed cure and never had another problem.  This part may have been the best part I made, but the glass was too light, and I couldn't figure out how to add the other side to this one and have a good part. I think I could do it now, but at the time I didn't have the skill/knowhow.

From Finish Kit

This is the layup that ended up being the real part.  You can just catch a glimpse of the failed layup laying over the back of the fuse.  I used it for the rest of this project as a template, and it was the most durable template I ever used, like floppy plastic fiberglass.

I tried a full pre-preg layup right before this, but with the 8.6oz glass and it being about 7 feet long, I was working by myself and it got wrinkled when I put it on.  Beautifully strong and well done glass, but the wrinkles made it unusable.

I finally decided to just lay it up right on the plane, then peel plied over the top.  I pre-cut about 20+ pieces of 18" or so glass on the bias, then laid it up in one go using 3 batches of epoxy.  Took me maybe an hour total.  I was pretty happy with how it came out.

From Finish Kit

After some light trimming and removing the peel ply.

From Finish Kit

Starting with the micro.  Mixed it up too wet (first go - what can I say) and wasn't nearly smooth enough laying it on.  I spent hours and hours sanding most of this back off.  :<

From Finish Kit

After about 6 hours of sanding it's finally getting reasonable.  Did another *very* light, much drier and smooth layer, then sanded that down.

From Finish Kit

Starting on the superfil.  At this point it's looking pretty good.  I took it out to the airport and showed Nick.  He said it was nice work, which was a relief.  I was pretty happy but if Nick say's it's ok, it's ok.

From Finish Kit

Here it is mostly done.  I ended up being pretty happy with it.  I took it to the chapter meeting and several of the composite guys said they would be very happy if their planes looked that good.  That was nice to hear.  Been quite a learning curve, but it was fun.  And now I have a part I''m not embarassed to put on the plane.

From Finish Kit

Sunday, October 5th, 2014. Fiberglass school

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).

From VARFOF LongEZ & Kent's RV-7a

From VARFOF LongEZ & Kent's RV-7a

From VARFOF LongEZ & Kent's RV-7a

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.

From Finish Kit

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.

From Finish Kit

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.

From Finish Kit

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.

From Finish Kit

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.

From Finish Kit

From Finish Kit

Bits from the Aircraft Spruce practice kit.  This is Flox, a cotton material that is used to make structural reinforcements by mixing with epoxy.

From Finish Kit

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.

From Finish Kit

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.

From Finish Kit

Some blue foam at the bottom, plus lots of micro dust from the hole in the bag.

From Finish Kit

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.

From Finish Kit