Empennage Attach

Section 11

Project Punch List

If you've ever worked on a project you more than likely have used a project punch list.  It's literally a list of items that need to be resolved prior to project completion.  It's different than a plan because it's more reactive in nature and will vary throughout different phases.  This project comes with the plans and it's up to the builder to resolve and plan out some of the other items such as interior, avionics, lighting, engine ect.  I track that on a spreadsheet just tossing down ideas as I think of them or track parts, prices, ect.  But post EAA Tech Counselor visit it was apparent I needed to start up a list to track various items needing to be completed or fixed.  Even though I work in IT I'm very non-technical about my list creation and I use paper and a pen.  I used to try to get fancy at work with lists but I always reverted back to a pen and pad.  So that's what I'm doing now, using a list and marking off items as I complete them and if it gets too messy with notes I'll transcribe it to a new piece of paper.

Attachment

Going into this process it seemed fairly straight forward however it was anything but that.  I tracked my time but I can't tell you what I spent on the actual attachment steps, or what I spent fixing mistakes or working through my punch list.  I also didn't take a lot of step by step pictures because I would work sporadically on things as well as jumped around to various steps as I waiting to fix certain things.

I spent some time working through the previous punch list items as well as new ones that I found. For example for whatever reason I forgot two rivets on the HS Spar... easy fix but strange I missed them. I did the deburring of parts that I had missed or that were still a bit rough on the edges.  I went over each bolt that was permanent and ensure proper torque and marked accordingly. There were a number of rivets that I had put off fixing until now.  I had used a few of those 'Oops Rivets' which I recently ordered and they worked out great.  In one particular case I had to use a wood block and hammer to level out the skins before using the new rivets.  It's not the prettiest but looks much better and after paint won't be noticeable... plus it's on the bottom of the tailcone.

Elevators Attach

I had watched some videos of this process and the consensus what it's a bit of a pain.  You have to put them on, test fit, take them off, adjust, back on... ect.  It took me an extreme amount of time because I was chasing perfection.  The important part is you don't have binding and it's free to move up and down without rubbing or hitting anything.  There's also an aspect where you want to hang them so on the outboard HS edge and the inboard Counterbalance arm there is an even 1/8th inch gap.  This ends up looking somewhat like the picture below.

The problem is in this picture the right side is an 1/8th but the left side is 1/4th.  It was even worse on the right elevator with it about 3/8ths gap on the forward end.  This drove me crazy and I must of spent a good 4 hours putting these on and taking them off 70 or so times.

I finally got it to a point that I was happy with and decided to move forward.  The next step is to get the trailing edged even and they suggest using duct tape... I did that and also used a clamp on a specific rivet location (5th in) to keep it level.  Then you methodically remove the right elevator (again!) and match drill the left horn using a bushing that Vans provides... now like most I had to use a file to reduce it enough to fit but was easy enough.  After that you take the left elevator off and put the right one back on and drill that side.  Then you put everything together, lock the trailing edges and then using a wood block you made drill the bottom of the horns evenly.  There's an entire process to this to help ensure everything straight so it takes some time.

After working through all that you can once again check the clearances to make sure you have 35 degrees up and 25 degrees down.  All was well and decided to go to bed.

Well.... something was bugging me as I laid there in bed.  Grabbed my IPad and started some further research.  My main concerns were that if my counterweight arms were bent or warped and I was using that as the primary measurement then that would affect how each elevator was hanging.  The other concern was if they are uneven then that would affect the way it flies... which is bad.

After reading about some methods people used I decided to essentially start from scratch at midnight... after about an hour I had determined that I had the rod end bearing bolts on the inboard side too far out therefore compromising their strength and that indeed there was some unevenness on my counterweight arms.  I made a post on the Vans forum with some pictures of my concerns and findings.  The short version is you want to ensure your brackets on the HS Spar are straight (Look through them) and you don't want to deviate too much from the rod endbearings initial 7/8th inch positions and both elevators should be even.  Turns out my main concern with that 1/4" gap on the forward end of the counterweight arm is a non issue.  Per Vans it's there more to provide clearance to prevent ice build up if you get into those conditions... which as a pilot is a bad bad thing.

So I did three things to resolve this.  First I made a tool to make it easier to install and adjust the rod end bearing bolts.  I took an old socket and notched out the ends which worked out fine.  I've seen other people do it with PVC or you can buy a tool as well.

Next using the method I put on the Vans post I rehung and adjusted the elevators... Truth be told I found myself randomly walking out to the garage and readjusting a number of times over the course of a few days. The end result though I'm happy with, they're even, move unbound and there's no more than a 1/4" gap on the forward part.

The last and most challenging thing was to get the extra holes on the horn welded in.  I got the information of someone who was able to help me get it welded... I did the grinding and he did the welding and turned out great.  Come to find out he's done a similar fix on someone else RV in the past.  I didn't take any pictures of the process, just wanted to work through it.  After they were welding and cleaned up I was able to redrill the holes in their new places following the same steps as before.  This time after I removed them I had to reprime and topcoat each horn since I grinded off a lot of the powder coating.  I'm not sure how prone these are to rust but if anything it was done more for aesthetics.

Redrilled and Primed

Rattle can white

Parts and Prime

I did a number of things out of order in this section. With my elevator horns messed up that sort of threw the linear aspect of the build off a bit. So not to just wait I jumped around and started making the brackets required for the HS mount and elevator trim set up.  It really helped out that the pictures in the plans were to scale so I was able to complete a piece, check it against the drawing.  I'm not sure what people use to get their parts looking like they were done with a CNC machine but mine are more of an artisan 'build a plane in your garage' type pieces.  I use a chop saw with a metal cutting blade, a band saw and a grinder.  It gets the job done but again not every piece is perfect for example on the HS shims one side of each is more rounded than straight.

HS Shim

Trim brackets

Trim cable brackets

Working out of order there were a number of other parts I deburred, drilled and cleaned so I could prime everything at once. It included the control arm that connects the elevators to the bell crank assembly, the elevator trim housing and some other minor pieces.  Using the last of my AKZO I primed everything, including the inside of the control rod.

Horizontal / Vertical Stabilizer Attach

This process was very straight forward per the plans.  In essence you line everything up according to a rivet point on the tailcone and ensure it's equal in distance.  You use a wood block to help keep it in place and then match drill.  Since this was the area where I added some additional depth to the bracket I ordered some longer AN bolts to use.

Likewise the Vertical Stabilizer was straight forward to attach.  Had to do some match drilling, it's also where I noticed I was missing two rivets... anyhow all fairly simple with the hardest part being that you have to fit your arm in a small space to get to certain bolts. There is a step to apple Anti Seize paste which may not really be needed now but for fun I applied it anyway.

Once you get to the step above you take everything back apart to deburr and clean up the pieces in preparation for putting it all back together.

Elevator / Rudder Attachment

Since you previously drilled and test fitting everything this step is a complete non-factor.  The only added challenge is getting your hand in the space under the VS to put the bolt, washers and nut on.

Likewise you have to have equally small hands to attach the rudder.  The good news is unlike the Elevators the Rudder went on without much adjustment. Took me about 4 tries to get it positioned correctly where when measured per plans was fairly accurate.  Final fit and measure can happen during rigging.

Elevator Trim and Control Rod

There are two components that need to be built in this section.  One is the control rod which is fairly straight forward.  Takes a bit because you need to prime the inside of it and give it time to cure completely before putting the ends on.  And with all my pieces in the tailcone I painted them as well.  Connecting it was straight forward but required you to make a wood triangle to position the bell crank in a particular position.  That coupled with locking the elevators in the trialing positions guides you to how much you have to adjust the control rod bearings.

The elevator trim actuator assemble takes a bit more time. Mine came out fairly tight taking a bit of force to make it move.  However once I hooked up the motor it really functioned fairly smooth when I hooked a 9 volt battery to it.

I bolted it in place in the tailcone but didn't run the cables to the trim tab.  Knowing at some point I'll be removing the elevators I will leave connecting this all together at a much later date.

This concludes the attachment section and will need to do a bit of reading before attempting the next section which deals with fiberglass.