Ch 11 Elevators

One of those jobs I wanted to get around to. Yes the ends (TE) of the elevators were filled with micro per plans a long time ago. West 410 is about 40% lighter so I removed all the micro as you see in pic 2 and filled with the lighter 410.

I also checked that I still had full elevator travel after filling and profiling the canard. Yes, as expected, I had to do a few hours of very careful sanding to get that -15 +30 back… the +30 is easy, its the up elevator that is marginal. Anyway, job done.

I also spent some hours carefully sanding one of the elevators. I need to finish that and do the other. My idea is that this is one of those side jobs you can do while held up with wet epoxy on other parts. That said, I’d like to keep sanding the elevators and then do a skim of filler for the low spots to keep them as lite as possible.

Micro on TE of elevators

Micro removed

West 410 and a recheck

I did a bit of a final check up and its time to find a spot of the canard and move on.

I spent a lot of the day rearranging the workshop and cleaning up as I like to do a lot of the time. Not because I like cleaning, but because I know it helps with a fresh state of mind and will give me a better build. I probably clean the workshop 50 to 100 times more than my home… what does that tell you?

So no hours in the log for this. Perhaps you’d like a few photos. Pic 2 has the canard the fuselage and the wings in shot. The centersection spar is in the corner in pic three. I finally found a place to store the canard on those shelves in pic 3 too.

My next task is the winglets. I spent a good part of the day just reviewing plans and working out where the antenna’s will go and looking at shapes in my files.

I also spent a while on the net and asking builder friends about the tops of the winglets as I have to decide NOW…. a plan is forming but I’m not an expert at all on these things so its as much an evaluation and aesthetic decision process as aerodynamic.

Quick check

Assessment

Clean up and move on

After much thought and exploration I’ve decided on a 2″ wide faring at the fuselage. This is to hopefully maintain attachment of the air around the sides which would otherwise have been disrupted by the elevators.

I spent quite a while working out the distances and finally marked out the elevators and did a rough trim as in pic 1. Then a very careful time with the permatgrit files working back to the lines. Once happy I cleaned off the two ply of glass from the torque tube that was exposed, another couple of hours work. Then I made flox corner ditches as you can just see in pic two, that was about 10 minutes….

The layups here would once have seemed complex but now its just fun. I slurried the blue foam, did pure epoxy on the cleaned metal and straight glass in the troughs.

Next up was my flox mix which went in nicely. Finally I’d made a template, marked out two of them on foil, wetted this out and then cut them out with my pizza cutter. Finally I applied the foiled glass, removed the backing and ensured things were down without air and not too wet. As usual paper towels came into play.

The next day after cure I cleaned up all the edges with files and sand paper. All done as you can see in pic three.

Mark and rough cut

Prep for glass

Sealed and trimmed

Once the UNI strap goes on to hold the counterbalance weight you get a 2ply lump on the top surface of the elevators that prevent the previously obtained 15 degrees up. This is a real gottcha.

Why its not mentioned in posts and archives I have no idea. I’m here to tell you that it would be a REALLY good idea to put a joggle in the elevator blue foam before skinning. Then there is no problem.

My solution was three, yes three full days working with a heat gun, temperature measurement gun, strips of aluminium and clamps. I wanted to retain my 15 degrees up AND have a slight gap so the elevator doesn’t hit hard on the canard trailing edge at full up position. I’d heat an area clamped in place to around 140F or if you like too hot to keep my finger on it for long, that seemed about right.

I think I’m painting my plane white after doing this…. definitely a post cure to get the TG up.

Well anyway… in reality 12.5 degrees is more than enough and I’ll now get that easily. This took ages. The elevator hinge pins are done but really hard to get in and out so I’m putting them in as few times as possible. Once there is a bit of finishing work done I’ll feel OK about using lots of oil and grease! That will help a lot. On the plus side once installed they will never come out unassisted.

Heat gun at work

Getting a little gap

Check and check again

OK plans say Roncz 0.06″ around the weight, Cozy plans say 0.1″ I found a stick that was nearly .09″ and a loose fit. This is something we don’t want jammed up with ice so a little elbow room, works for me.

Yes I got a little creative with this. I made flox corners in the foam and a glass to glass bond on the bottom of the slot. I also did dry micro transitions in the lower corners as you might see in pic two. Yes I still did a slurry on the blue foam. Quite a lot of steps for a small job.

My thoughts are that I’m making a great hole in the Canard!!! Yiiiiippsss!!!! So I want this area as strong as I reasonably can make it. Maybe this is intended in the plans but it just says one ply of BID. I think after getting this far we are meant to work out for ourselves what is best in these little details.

Well the plans are a cookbook, not an engineering manual as it turns out although I mean no disrespect to the designer. I think I’m a partner in the build details and have to do my part sometimes.

Check correct gap

One ply BID

Cleaned up

Here we just cut out a pocket so the counterweight doesn’t hit anything when the elevator moves. very long story short, just take the slot down to the front of the canard so you can do a glass to glass bond there.

I spent a while making sure I didn’t oversize the hole and that I allowed the correct gap around the weight. I was a little fuss about putting this canard hole in the right place too!

The second slot was much easier to sort out. Its another place that no one will see as its the underside but I’ve tried to make it neat all the same.

It was a three day job in the end with a cure and clean up cycle.

Mark out

Cut and fit

Make it neat

This took longer than 2 hours but I sometimes feel embarrassed at how long I take to do things. Its a bit of a legacy from earlier in the build and making a few big mistakes. I can’t afford these now so I do a triple check at times. It will at least reduce errors….

Ok I added the two inboard mass balance pieces and bolted them on. Just a matter of drilling a few holes and adding the hardware..

The weights were….
CS11 (inboard) CS10 (outboard)
173.5g Left 284g Left 457.5g total
177.2g Right 274g Right 451.2g total

I chose them to equal things out as best I could. In fact the outboard one make more of a difference than the inboard BUT both elevators balanced nose down in a very positive way so its all good!

I just needed to check these were Ok before making the holes in the canard. If the weights don’t work out you can add .3lb to the nose weights… this would mean different hole sizes. Hence my check at this time.

Inboard lead weights

Right elevator check

Left elevator check

This step isn’t in the plans but it makes sense. The plans say put pure epoxy over the foam spacers. I’ve done a one ply BID layup with flox corners.

We want protection against the twisting moment so BID at 45 degrees with the corners is going to give that. I dug out the foam with my dremel down to the glass areas.

Then plastic and foil next. I made a plastic template of the area and did a rough trace on the foil as in pic two. I did make it overly generous as I let the bid overlay the sides a little for extra strength, This is one area where extra weight is good.

I did degrease the lead and roughen the metal first as best I could.

After I filled in the troughs with flox, given the foam is R100 (heavy and tough) I just coated them with pure epoxy instead of micro. Then the glass cut out with the foil backing, you know the drill right?

The last pic is after peel ply and cure, removing the excess and using a bit of sandpaper. It feels pretty strong. We don’t want these weights coming off in flight after all. Be careful with the cleanup, one ply of BID on metal can delam easily when you are filing it smooth.

Flox corner prep

BID on foil

Cured and trimmed

I was worried about drilling into stainless steel and a 3/16 rod as well. I did a net search and asked my friends for advice.

Pic one shows a jig to hold the pin. I ran a router with a vee bit down some scrape timber and then cut a couple of bits off and screwed then to the front and rear. It holds the rod nicely in place.

Then…with the 4′ long Rod Drilling jig to support the rod, I used low speed, a 3/32 bit instead of 1/16. Yes a cobalt bit is essential, some WD40 but not much as the heat wasn’t too bad.

Oh yeah I filed a flat first, and made a tiny center starting point as I was worried about work hardening the steel. Then I broke two 1/16 bits which explains the 3/32 cobalt.

I used steady pressure, cleared the chips regularly and was very careful near the breakout point easing off the pressure. I also watched at the start and rotated the rod a little to keep a 90 degree hole. Oh and I captured the drill deep into the chuck.

Then it was easy…. Afterwards I filed an angle in the end to make it fit nicely as you see in pic 3

I did this over a couple of days and worried about drilling these two holes for a few more. SS is hard!

Drilling jig

Making a hole

Post filing and fit

I started this yesterday and it took a bit to get my head around and a good read of all the versions of the plans I have… Cozy, GU, Roncz and CC Girrrls.

Of course its just make a spacer out of the same foam as the canard inserts have, set it up in the simple jig, glue together and then two plies of UNI 11″ long to wrap it in place.

Hey, so I did all that and peel plied at the end for good measure. I did the two plies on foil so it was the right length and had it all marked out on the job. Very nice. Took all day as usual and until about 8pm but I had a visitor so thats my excuse.

When its all cured I’ll clean it up and do a BID layup over the sides with little flox corners. we don’t want those weights coming off so a little sideways support will be good..

weights Left Right
CS11 173.5g 177.2
CS10 284.0g 274.0

Cutting out the spacer

5mt glue in the jig

UNI in place

The plans say get a piece of stiff tubing with .25″ ID and not the soft hardware store type. I went to 5 different places, tried to buy tubing on line and was unsuccessful Looked all around the house but nothing was .25″ ID and stiff plastic.

except…

The sort of thing you might use to write a list of where to find tubing. It turned out that the answer was at hand in a couple of biros! In fact they were .225 ID which was even better than the .25″ I was looking for. Happiness!

I microed the pens in place, less the ink and middle part, after drilling out the holes carefully using the hinge rod to line it all up. Once cured the next day I tidied up for a perfect solution to the end tubing.

I still have to drill a hole in the stainless rod. That job is for later…

Microed pen just the right size

Tip exit clean up