Rudder & Elevator Fiberglass

I had started on the bottom rudder fiberglass the other day.  It came with scribe lines to supposedly guide where to make the skin intersection cut as well as the big cutout for the rudder stop. It turns out the part's shape is goofy enough that the rudder stop cutout was a mile off.  Also, the front curve is too pinched and won't fit around the front rudder spar like it's supposed to. I ended up cutting a big 1" section off forward of the stop.  The same issue occurs aft of the stop - the aluminum pushes the fiberglass out so much that it won't sit flush.  I cut all of this off and will put new glass down that is shaped to the aluminum parts.

I don't have pictures of it, but I laid out and drilled the rivet holes that will attach the fiberglass to the metal flange that protrudes from the bottom of the rudder.

I put packing tape on the rudder stop and surrounding pieces (it makes it a little easier to pull the fiberglass off), then laid up a number of layers to conform to the shape.  The white cloth over the top of it is not part of the permanent fiberglass.  If you put "peel ply" over the wet fiberglass, it absorbs the excess epoxy.  Then, when it's all dry you rip off the peel ply and it creates a surface that can take more epoxy without any (or as much) sanding.  The fiberglass I laid up is just to get the base shape set that actually fits around all of the rudder parts.  I'll still have to contour everything using micro.

The aft end of the rudder needs to be set up to accept a mounting bracket for the rear strobe light.  I laid out the holes and cut/drilled them.

The bolts I ordered for the elevator counterweights arrived today, so I attached the weights on both elevators.  The outside counterweight will be covered by the elevator fiberglass tips, but the weight on the inside is left in the open.  I think it looks awful, but I'm not sure there's a great way to hide it.  I'll have to do a little research and see.  I'm sure 99% of people just leave it as-is.  It has to be left accessible until at least the paint goes on, because you have to be able to drill holes in it to remove material to balance the controls.  So the only way to hide it would be to do something post-paint, which is not ideal.  I might just go the route of taking a hot chisel and "ironing" the surface to smooth it out.  That would make it look a lot better.

Elevator Tips

The elevator tips are somewhat of a better fit than all of the others, although there will still be plenty of filler used to eventually smooth them out.  These attach with pop rivets, although I still don't love how little material there is for the pop rivets to hold onto.  I will probably also use either proseal or epoxy/glass as a secondary bonding agent just to help the pop rivets out a bit.  The fiberglass holes wallow out a decent amount once they are countersunk, which means that there's just not much meat left for the rivets to grab onto when they expand. I'll cross that bridge when I get to it.  Just like on all of the other tips, I had to scribe and cut down the flanges to make them fit up against the outer ribs of the elevator.

Each elevator counterbalance arm gets a lead weight nested in the inside and outside against the ribs.  The outside weight will be covered up by the fiberglass tip, but the inside weight stays in the open.  It's a little unsightly, but a necessity so that after you've painted you can drill holes in the lead to remove the appropriate amount of weight to neutralize the control surfaces.  I cut down all of the weights to fit in the spaces, but I can't find the bolts I need to attach them.  I guess Aircraft Spruce gets yet another order from me.  I'm sure once I receive the bolts, I'll find the ones that came with the kit 4 years ago.

Position Light Lenses

Once again, no flying this weekend.  There were low ceilings during my scheduled flight time on Saturday, and my instructor isn't available the rest of the weekend.  This is becoming the norm rather than the exception, so I may have to think up some other options so my training doesn't drag on until next summer.  I'll see how much I can get done over the next month, but once fall weather really hits, I may just have to hit pause.  I could continue to fly once a month when the weather and schedules cooperate, but such infrequent flying is a pretty poor use of money - spending the first half of every lesson just getting back what I've lost since the last flight (assuming I can fly next weekend, it'll have been a month since my last flight).  I'm considering the possibility of just going somewhere with great weather for a week or 10 days in the spring to hammer out the rest of my training.  Waiting to do that would still help me finish earlier than infrequent flights and slowly chipping away at it in Seattle.  One way or the other, I'll get it done.  It's just not as quick as I was hoping.

Today I kept chipping away at the fiberglass tips.  I started fitting the rudder bottom, only to find out the scribe lines Van's puts on it are way off for cut lines.  I found out too late though, so now I need to add fiberglass back on.  The aft angle is wrong too, so I need to split the aft end apart and reglass it to the right size.

I also started smoothing out the ridges and seams on the elevator tips.

The last step for the wing tips was to figure out how I wanted to attach the light lenses.  I decided to use a single screw on the top and bottom, so drilled and riveted on nutplates.  The fit is pretty good, but when I do the final surface finishing of the wing tip I will probably clean up the intersections a bit.

Wing Tips & Rudder Fiberglass

I've been meaning to do this for a long time, but just never got around to ordering the part - since I had a recent Aircraft Spruce order, I added a flaps lever to it.  This is just an aluminum wedge that slips over the toggle switch and is held in place with two set screws.  I have flap buttons on my stick, but I put one on the panel in case someone ever flies from the right seat, or in case I just end up liking it better there (easy to flip up and down while managing the throttle).  It's close enough to the boost pump toggle that I wanted a way to differentiate it by feel.

I finished up the other wing tip today.  Lots of drilling and countersinking.  I hate countersinking in fiberglass by hand.  It never turns out good looking.  The good news is it'll be hidden and likely never be seen after the tips go on for good.  I chopped about 1/8" off of the trailing edges of the tips to make them line up with the ailerons.  I did go ahead and roughly sand off all of the mold lines and bumps, so they're 90% ready for paint.  That last step will be to scuff up the gel coat and smooth out all of the curves.  I also need to decide if I'm going to close out the portion of the tip at the aileron or leave it open.  There is a rib in that location, but that's it.  Some people close out the area over the rib with glass just to make it look a little slicker.  Maybe if I'm bored one day.

I also need to do a final fitting of the light lenses and put nutplates in the tip to accept screws.

With wing tips finally off my bench, I grabbed the rudder and started on the top cap.  This looks pretty straight forward compared to the wing tips.  I sanded down the flange so it fit inside the rudder without hitting the top rib flange, then drilled the matching holes with the rudder skin.  This cap is just put on with countersunk pop rivets.  I had to put some epoxy filler in a few places to make the trailing edge match up right, so wasn't able to get it installed today though.

Wing Tip Nutplates

I have been waiting on a shipment from Aircraft Spruce so I can continue on with the wing tips.  I decided that I am going to attach the tips with screws, so I needed a bunch of smaller nutplates (I'm using #6 screws so they are a little smaller and won't stand out quite so much).  Given the less than perfect accuracy you get when drilling in fiberglass, I bought floating nutplates instead of the standard ones.  These mount the same but the threaded portion is able to slide a little in each direction to accommodate screw holes that don't line up perfectly.  I match drilled the fiberglass to the holes in the wing skins.  The holes in the wing skin are dimpled, which means the fiberglass has to be countersunk.  Given the lip on the fiberglass, I couldn't use the countersink cage and had to do it all manually.  That's always a recipe for disaster, but no way to get around it.  I used a nutplate jig to also drill the rivet holes for the nutplates.

The result is serviceable, but embarrassingly ugly.  There's just no way to countersink the thin fiberglass without having the fibers get chewed up and holes turn into ugly shapes.  Then of course I misjudged countersinking all of the rivet holes and went too deep for most of them.  I used "soft" rivets to attach the nutplates to keep from cracking the fiberglass.  The rivets just have to hold the nutplates in position, so they aren't structural.

I attached all of the nutplates and held my breath on the fit.  At least the left wing tip seems to fit just fine.  While I don't love how close the screw holes ended up to the edge of the fiberglass, I think they'll be okay.  The fiberglass is squeezed between the dimpled wing skin and the nutplates, so there really shouldn't be much of a load that would pull the fiberglass in a direction where the screws would want to break through the edge.