More control mount and control stick work - 6 hours

Managed a pretty decent day in the garage. I was dreading cleaning up the cuts made in the control stick mounts. Basically the only way I could see doing it was to use good 'ol files. I clamped the pieces to the table and went to work. I was expecting it to take a long time since the aluminum was thick, but it goes extremely fast. I had everything done in just over a half of an hour. I took a little extra time to make sure that both pieces were equal and then I polished them.

I then fit the control stick cross member WD-610 to the mounts and found the correct combination of washers.






Next step that I wanted to do was fit all of the control stick pieces. This turned out to take a considerable amount of time and effort. All of the control pieces need a bit of work at the pivot point locations. The brass bushings do not fit nicely inside the control pivot points. They all need to be reamed. As well, the AN4-27 bolts do not fit nicely inside the bushings so the inside of the bushings need reamed as well. As it turns out, I don't have the proper sized reamers for this job. So I went old school on the task. Fortunately I have a good selection of drill bits and an endless supply of adhesive back sandpaper. I wrapped a small piece of 600 grit paper around a slightly smaller drill bit and used that to polish the inside of the control stick pivots.
 
 Working the pieces back and forth, stopping to check fit and redo many times till I was happy with the fit of the bushings and confirmed there was no binding. Next was to do the same to the bushings to allow good fitment of the AN4-27 bolts. Fortunately this process is quicker on brass than it is with steel.

After that The pieces are ready to assemble into the yokes of the WD-610 cross member. The plans have you grind the ends of the stick pivots and the bushings to allow a slip fit into WD-610. Using the exact same method used for the aileron pivots I trimmed down the bushing to the proper size. Again very tedious and time consuming work. In the end I had everything trimmed for a perfect fit an virtually zero play in the controls. Everything fits extremely well and no binding. I wanted to protect the exposed steel on the ends that were trimmed so I touched up with automotive touch-up paint that I have that is almost the same color as the Vans powder coating.


I want to be sure that I do not wreck the finish so I will give the paint 24 hours to dry before I assemble the sticks. Since I have a little time left, I moved on to countersinking the center section for the nut plates.
 
I had a difficult decision to make. The plans call for AD3-3.5 rivets to secure the nut plates however I have always been leery about countersinking too much. I'm terrified that I will go to far and end up having a "knife edged" hole that everyone wants to avoid. After much reading and discussing the matter with my buddy mike who is an experienced AME and builder. I've decided to use NAS1097 AD3 rivets on all the nut plates that are secured to thin aluminum. Anything thicker than 0.060" I will use the standard AD3 rivets.  

Drilled the control mounts - 5 hours

Next step was to "fabricate" the F-633 control mounts. I had to laugh because they are already fabricated, you just need to drill a few holes and lighten them up. I drilled the uppermost hole(s) to the dimension shown. The plans have you drill the hole to 3/16" dia, which is not enough for an AN3 bolt, very close, but not enough. So I polished the hole with the dremel and 800 grit sandpaper until I could press fit the bolt in.

Next step I bolted the control mount to the center section and carefully squared the mount with the center section using a big square. I checked this with a few different squares and few different ways. then I clamped the piece, re-checked square.

I then flipped the center section over and lightly back drilled the hole with a #12 bit to start a shallow pilot. I then removed the mount and set it up in the drill press and finished drilling the hole with the 3/16" bit. The result is a tight hole, but is perfect in fit and location with zero play.

Next the plans give you the option to cut down the angle for optional weight savings. Everyone seems to do this step on their build logs. So I figure why not.  I marked out the dimensions, and drilled the radius holes. Then I began to wonder, just how much weight savings is there? I should have weighed the piece before I drilled. But this will give you an idea of how little weight there is in those pieces. I suspect you save about 50 grams total. Haha, what a bunch of work for 50 grams. (I know is about the sum of all parts...but I just had to laugh)



Next step is to fit the control sticks at this point. I dug out the pieces and tried to fit the co-pilots control stick WD-611 & F-669 and it just wouldn't slip in. I see that I have some powder coating over-spray as well as a bump internally caused from the welding of the bracket on the outside.
 
In fact the overall fitment of the bushings, etc in the pieces is a bit poor and I will need to polish/ream so that nothing binds. This will take a little time. For the WD-611 piece, I softened the powder coating with MEK and then used some sand paper to take down the paint. I used the dremel to take down the weld bump and them polished the inside with 3m scotchbrite on the dremel. The fit is now great. I move onto the bushings tomorrow.   

Finished match drilling center section - 2 hours

It was a pretty quiet and small day. I managed to finish match drilling the #30 holes on the F-704A/B/C/D pieces on the drill press. Also countersunk the F-704G vertical bars. Then family came over so I couldn’t hide in the garage.   
 
 
One item that was bugging me was that when fitting the close tolerance bolts, one side of the section was a bit more troublesome and some of the anodizing has rubbed off inside the hole. The other sets did not look like this one. Due to the critical nature of this area, I was concerned that this could be an issue.

I had emailed Vans, and they indicated that rubbing off the anodizing was inevitable due to how tight those bolts are, but not to worry. Apply some grease to the area on final assembly and that will protect the finish.

Started the Center Section Bulkhead - 7 hours

A fairly big build day today. I opened up my center section package that came with the wing kit a couple of years ago and laid all the pieces out on the table.

First item of business is to drill all of the pieces for the snap bushings. I had set up the drill press and the unibit to enlarge the holes that are pre-drilled for you. I started with the F-704C and D pieces, then moved on to the F-704A and B outermost holes.


Next I began to mark out and drill the innermost holes on the F-704B (aft) bulkhead.



The more tricky part is marking out the holes on the F-704A (fwd) bulkhead. Vans provides you with dimensions, however these make the holes extremely close to the rivet holes for the center ribs. Many folks have noted this issue in their build logs. To make things worse, the holes in my fwd bulkhead are not symmetrical making the left side ok, but the right side is certain to have edge distance issues. I must have measured and re-drawn the hole locations about 4 times. Very frustrating and slow work. Nobody really comments on the logs and forums as to the acceptable solution. I found that the RV9 vertical dimension was 1 19/32, as opposed to the RV& being 1 17/32. I also reasoned that the 5/8" hole for the bushing was just a wiring hole, so I decided the best approach was to preserve the edge distance at the expense of slightly moving the location of the 5/8" holes. The right side hole will need to be moved slightly above and to the right to maintain proper clearances.

 


Drilling was a tedious process, many measurements taken and adjustments made during the drilling to ensure the holes were perfect. I do not want to mess up this part! In the end, I'm extremely pleased with the outcome. Edge distance from both holes to the center of the rivet was 0.2655" which is well within limits.

Next step was to attach the 704C & D pieces to the 704 A & B center sections and fit the close tolerance bolts. I will admit that I did not enjoy this process. Very stressful to get those bolts in, with the fear I might be doing something wrong. I used a small amount of aviation grease and then wiped it off so the bolts weren't dry. I noticed that left side went much better than the right side on the aft bulkhead. It only took firm pressure with the palm of my hand, while the right side took a couple of light taps with my small mallet. After examination of all the bolts and trying them all. I found this. Not all bolts are the same. Some bolts fit a tiny bit better than others, often the bolts hang up on the initial insertion as they tend to have a very slight bulge after the threads stop. I've read comments that this happens to the bolt when they cut the threads. In this area, some of the cadmium plating comes off when inserting the bolts. I most certainly will buy new bolts during final assembly, but these ones will be sacrificed for the build process. I should note that the bolt fitment improves once you have the bolts in and out a couple of times. (But its still tight, which is good).


Next I set up the assembly on the drill press to match drill all the holes.

I then installed the 704-G vertical bars with AN4 bolts and clamped the assembly. Using the hand drill, I "Marked" the holes with an initial drill. This gives a really good pilot hole to use on the drill press with reducing the chance I oblong the hole or drill it crooked. As I have found...never miss an opportunity to use the drill press when working with thick material. 



Finishing up the #30 holes on the drill press.

Crow Harnesses have arrived!

I was incredibly surprised to come home from flying today to find that my Crow Harnesses arrived on a Sunday! Wow. I ordered them early Monday morning Dec 17th and they landed on my doorstep today the 23rd (a Sunday!). I was not expecting that considering they were shipped USPS/Canada Post and shipping in Canada is always slow.

Firstly, I ordered directly off the website and chose the Kam Lock RV6/RV7/RV9/RV14 restraints with Pads in the Pro Series with Black Hardware (2" width). I called Crow to ask a bit more detailed information on the 2" aluminum adjusters and the response was they were a cleaner look than the steel, however he mentioned there was not much if any weight savings. Since I really wanted the red pull tabs, I opted to stick with the steel adjusters.

Taking them out of the bag, they are just beautiful.  

Straight away much of my pre-order concerns where taken care of at first glance. The Kam lock itself is much nicer that previous pictures as looks to be similar to those used on the Hooker Harness setup. The diameter is 2 5/16" and they are about 1 1/4" thick. In my opinion not cumbersome at all.

I was most happy with the attachment fittings. Reading past reviews it seemed that modification was required for the bolts but it seems that this has now been rectified. The crotch strap is not sewn at the bottom attach point allowing it to be adjustable and have that fitting in the pre-cut opening of the Van's attach bracket. The crotch strap attachment fitting is drilled for an AN5 bolt.

The lap belt and shoulder harness attachment fittings are slightly smaller and allow for an AN4 bolt.

I pulled out the scale and one complete set of belts (for one person) weighs 1585 grams or 3lbs 7.9oz.