Ch 20 Winglets/Rudders

Yes I though today would be a short one. Wrong again. I just had a feeling about the hinge alignment and tried a different straight edge. Hmmmm not so in line as I though. In fact I tried lots of pieces of aluminium angle and they didn’t match my old heavy metal straight edge… which is not long enough for this job. I eventually went with some box section aluminium as you see in pic 1. Even this was straight one side and a little out the other.

I have this idea that a straight hinge line will mean less wear from rudder movement. Good thing I hadn’t drilled my holes out to the final rivet size yet. I was still two drill increments under. Having done this setup a few times I had it really straight with a really straight straight edge and secured in place with lots of hot glue and pegs.

Next up was setting up the countersink tool and practicing with a few rivets until I was happy. On to drilling out the holes to #30 or 1/8″. I then cleaned up and alodined the hinges. I think they were already coated but this covered where the cuts were made and the light sanding I did. Perhaps unnecessary but no harm done. While the metal was drying I countersunk all the holes and prepped the glass.

Finally I got to mix some epoxy and made some flox. Pic 2 shows how I went from clecos to rivets I checked the alignment a couple of times too and all is good. Pic 3 shows some of the rivets but all are done. I have no idea why all this has taken so long, but this tiny little step is completed. Of course we still have the other side of the hinges to install.

Really straight hinges

Flox and clicos

Hinges on the rudder side

Using my angle iron I finally got things aligned properly. This really took a while and I ended up using lots of clothes pegs, also hot glued, to keep things steady. After all I do have to have it secure enough to drill.

Pic 2 shows after some hours the careful cutouts for the hinges. Pic 3 and after some research and thought I decided on where the rivets were going and how many. Confirming the alignment many times I drilled out for the smallest cleco size I had and called it a day.

Hot glued

Recess cuts

Finally holes

More time on that rudder join. I think it may need just a curve at the rear as well as you see in pic 1. This will work out in a similar way to one other such rudder treatment I have pics of. Nice to arrive at the same place without unthinking duplication.

Pic 2 shows that the hinges need a trim if you follow the plans sizes. Its just not mentioned in the text anywhere. I soon noticed that while I dug out foam per plans on the inside of the rudders, no way were the hinges going to fit without trimming them down. I spent all day fiddling with this and getting a nice fit. The part that sits on the rudders need a different trim to the part that will go on the winglets. Both are not just the uncut 1″ wide hinge.

I used hot glue to set up the hinges in place and some aluminum angle as my straight edge as you see in pic 3.

More edge work

Not to plans

First alignment

Over a few days I first cleaned up all the edges and had a good fit for the rudders. I soon found a problem, not completely unexpected, in opening as you see in pic 2. I chose to make the rudder top and bottom cuts in line with the airflow rather than at right angles to the hinge line per plans.

This means that as the rudder opens it scrapes at the rear end on the lower winglet. It took a bit of thinking to find a solution. I knew there was one as I’ve seen this configuration on another EZ. Going the route with the least work I have cut back one edge of the lower part of the rudder as you see in pic 3. The gap is what I will address later.

I’ll have to add some glass to one side of the lower winglet. It will work out well. I’ll wait until the rudders are on and hinges set in place before doing this so I get the optimum close out. I’m not sure if I also need to adjust the top of the rudder in the same way. There needs to be about 1/8″ clearance so we will see later what is needed.

I have to add how much I like just holding these rudder and working with them. They are amazingly light and strong. That said it has been a real bear and many hours are going into sorting out this part of the build.

Trimmed to fit

An opening issue

An offset solution

Yesterday I cleaned up the edges of the lower section and moved the wings back 90 degrees so the inside long face was again parallel to the floor.

I did more prep work today cleaning up the bellhorn area and a light sanding of the bare glass surfaces and ensuring all the cloth pieces were ready. With the room nice and warm I first wetted out the 3 ply cloth pieces. In retrospect, I was a bit slow with the rest and next time will do these as I’m ready for them. I do like foiled glass just a little stiff as it tends to stay in place better on vertical surfaces but today cut it pretty fine. The glass was just beginning to get gooey.

I microed the blue foam carefully with a small brush and then mixed a stiff batch and did the corners for a good transition. Next up I re-cleaned the glass areas to ensure no micro and then wetted that out with pure epoxy. Oh yeah…I put a black line on the winglet rudder edge just to see if this makes the trimming easier later. Of course the ink seem to bleed off into everything.

The long 3 ply pieces took a bit to be fitted snugly, especially around the bellhorn area. It all worked out although I will trim excess later. Then the 2 ply BID around the hinge locations, just a little peel ply and a gazzillion clamps to finish up. About 7 hours straight with only an hour or two yesterday. I’ll keep the room at around 25C overnight and hope for enough of a cure to get into trimming things tomorrow.

Foil layups

Micro inside edges

Both winglets pegged

I’ve spend days working on the inside area of the winglets that accepts the rudders. It makes sense to do the reinforcement 3 ply layup before finalising the rudder and winglet edges and setting up the hinges.

I’m confident the bellhorn will swing freely now and I’m splitting the layup on the winglet insides into two. The first is just the simple inside of the lower winglet as you see in pic 2. I have spent quite a few hours preparing the longer section as well as the pic just shows.

Pic 3 shows the layup complete and many of my cheapo clamps in operation. Why not ensure the three plies are hard against the edges of the winglet? Its easy.

Bellhorn gap

Lower winglet reinforcement

Layup pegged

The last few days I’ve been working on the winglet bellhorn area, carefully opening up the foam. I realised that I need to ensure zero possibility of the bellhorns getting snagged.

Meanwhile I had previously felt that the eyelet holding the cable was too tight with the bellhorn ends. It would have to wear out in time although I do have the correct measurements per plans for the width of the main arm of the fitting. I did consult AC43.13B, found nothing and went for common sense.

That said I played around with spacers and you can see in pic 1 that I’ve made up two extra pieces to increase the gap slightly. It is 4130 although I could have saved a fraction of a gram if I went and found some 6061 the right thickness. Shame on me… I do want to finish this aeroplane.

That said I did the undercoat in the green aviation primer but decided to put a good enamel topcoat on as you can see. Then a careful rivet job as you can see in pic 3.

Now this was at a final size I went back to testing the fit on the winglet to ensure no snagging given I had the final diameter. Hmmm I might be doing a version 3 of these too. I think I can get more rudder travel with a slightly longer end piece. Oh well, have to get the hinges on first and everything worked out there.

Revamped pieces

Rivetting?

Back in black

Having done all the prep work previously, today was the inside reinforcement layups for the two rudders. While I had prepared extra plies for the top of the rudder as expected I was able to make the BID conform around the corner and do it all in one piece. The plans say two ply is enough at the top, I’ll have three. My rudders are a couple of inches higher up there are so slightly thinner. A little extra here will do no harm and I feel flowing the layup around the corner will also add strength.

I first microed the blue foam areas carefully with a small artists brush and then pure epoxy on the bare glass areas. It took a while and I didn’t want to mix the two. Pic 1 shows the long 3 ply and foil in place. It was straight forward to apply mainly using my fingers to get the glass sitting in the edges.

Pic 2 shows the extra 2 plies at the hinge areas, again with the foil technique. I peel plied the edges of these insert pieces and then went to clamp aluminium angles to keep things straight. Mind you by the time I got here the glass was starting to get pretty stiff.

Another small step done and a similar treatment is due on the winglet rudder area next.

Long foil

Extra plies at the hinge area

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Pegged for the cure

Having made the cutouts I thought the rudders would separate from the winglets easily. Wrong!!

After 4 hours of twisting and turning on the left one I called it a night. The next day a careful hour on the right had it popping out easily. The left I felt must have some epoxy caught on the end. What it really needed was just a block of wood, a little courage and a couple of sharp taps with a big hammer. I still don’t understand why the problem but they were finally out and intact as you see in pic 1. I have a bit of fixing up for the left one in the winglet but all doable. I hope I’ve left enough of a space for the bellhorn. Time will reveal all.

Meanwhile I’ve drilled out the rivets on the ends of the bellhorns and the 4130N metal is off. I’m going to add a spacer here as while sanding the aluminium part of the bellhorn I lost just a bit of meat and the eyelet would have been too tight. A relatively easy fix later when I’m waiting for epoxy to cure.

Next up was a lot of sanding over two days to get about an inch down each side down to bare glass. 0.6″ at the top too. Pic 2 shows the results and a simple holder made out of foam scraps. My cheap corded dremel knock off died so I went and spent the big bucks on a proper new one. It has a quick release chuck. WOW I love it. I should have gotten one of these a couple of thousand hours of build time ago. Model 4200 if you’re interested.

The bottom area I’d already made a little bulk head when the bellhorn went in. I cleaned up the space behind that and I’ve added two ply of BID to both areas as a little more reinforcement and in line with the plans putting two ply here. This will also make the bellhorn more secure given it drives the whole rudder from this area. You can see where I mean in pic 2 before the layup.

Pic 3 shows my little layup with a few tongue depressors and pegs to keep the glass in place. A nice small job after I spent much of the day cutting glass and prepping for the larger areas on the rudders. I’ve decided to line up the hinges later.

Finally out

Prepping for layups

Bottom end glassing

This took about 3 days.. yes all I have done is cut the rudders out… well not even all the way through but the cuts are done.

I spent quite a bit of time practicing on a test piece I made trying different saws and ways to cut straight. I ended up with a new tool. The hot glue gun! How did I ever get this far without it? I played for a while a learned how to get the glue off without damaging things and practiced setting it up.

I went for an aluminium angle iron guide hot glued to the part. Oh and I spent hours too marking out the rudders and making a few decisions. The angles are per my previous log entry. See pic 1. I went for 3″ extra rudder length and then reduced that slightly with a cut line that should match the airflow in flight and the bottom of the lower winglet.

I tried quite a few small saws I had from guitar making days and bought some new ones from a hobby shop and modified the one in the pic slightly. The first cut took over 90 minutes. By the 3rd cut I had sorted out which saw worked and a technique to make it cut the rudder length in about 10 minutes. The results are gun barrel straight and very thin cut lines. I’ll have to widen them! Doing straight accurate cuts has been a concern for some time but no longer! I’ll have ailerons for breakfast now I’ve cut the rudders. I’m mainly grabbing the blade and driving that straight while pressing firmly on the aluminium angle and pulling it from the tip back so it digs into the glass slightly. The handle doesn’t get a lot of use.

There is still a bit to do before separating them from the winglet. See the next log… it might be setting up hinges…

Top cut placements

Hobby saw at work

Saw and guide

This small step is just the lower winglets at the trailing edge. What to do here? Simple, dig out the end foam and fill that area with flox. If the plane ever goes backwards I can at least have something hard for first contact. Glass to glass wasn’t really an option here.

Pic 1 is cleaning out the end a good half inch and sanding away the foam and micro. After cure I just rounded the edges a little but left a bit of a ‘boat tail’ No need for a razor’s edge here.

Pic 3 shows the angle at the bottom of the winglet relative to the rudder trailing edge. +10 degrees past the right angle. This works out pretty much parallel with the wing waterline and interestingly, to me anyway, this angle also matches some pics of a winglet that is tuffed in flight. What a coincidence.

So I’m really trying to make all this line up with whats going to happen in the air. The top of the rudder (that I cut a few days later) matches this angle too. If I’m right I’ll never know and if I got it wrong… same thing. I just didn’t go with multiple detachable winglets on this build so a few things get the best guess and application of theory and will remain unproven.

Slot cleaning

Flox filled

Another angle

Departing from the plans I’ve gone for two plies of BID rather than UNI and no joining tapes. The plans have you glass the winglets and then join them with 2″ wide tapes. I’ve joined the raw blue foam, shaped in place and then done the layup overlapping the winglet about one inch. I even overlapped at the rudder where it will be cut off with the idea that I can get a nicer match to the winglet and can just transition the extra glass, also getting a bit more strength on the bottom part of the rudder where the bell crank is.

I microed the foam, filled a few gaps and transitions with very stiff micro and just draped the BID over the part. A roller worked really well to get epoxy on the glass and lay it all down evenly as you see in pic 1.

I trimmed with scissors and did the second ply about 1/4″ shorter to transition the bump. You can see the profile in pic 2 and 3. I did a glass to glass right at the end and used a few sticks and clothes pegs to finish off. I’ll see how that goes when I trim it after cure and see if anything more is needed.

I have 3″ of height back there to protect the rudder and give a fence to span wise flow. If the plane ever tips backwards and does damage, it will be a basic fix. I’m not going to carry around extra glass and weight that might never be needed. If it scrapes on tarmac it will need a repair no matter if I put kevlar or anything else down there.

First ply of BID

Glassed and peel plied edges

Pegs for a clean ending