Well, last Saturday, Jan. 4th, my wings went on for the first time! I logged a whopping 39 hrs in the week leading up to this...long days/nights...by far my best weekly output of the build. It was a good push as I got a lot done in preparation for this day.
Because I didn't have the space in my garage to do the fitting (unless I did one wing at a time) when the plans called for it during the fuse build, I figured I would wait as long as possible to do this. If you plan to wait to mount your wings like I did, there really is nothing that would stop you from doing this. It did not impede my work progress to mount them this late in the game. Just so you know, you have that option if space is limited.
I invited 9 people to participate in this little endeavor. Not because I needed that much help by any means. There are reports of guys doing this by themselves (although I cant imagine how or why?), but I think 2 or 3 helpers is plenty. Quite a few of the people on the invite list are behind me in their construction progress, so they wanted to witness how its done for their own education, knowing full well I had plenty of hands.
Of course, as is often the case in Colorado, the weather didn't cooperate for the mounting party. It was snowing and quite cold and icy when I woke up bright and early Saturday morning. Sheryl and I headed down to the hangar at 7am to prep the plane before everyone arrived at 9am.
Of the 9 people I invited (2 from Colorado Springs 60 miles away), every single one of them showed up. I was pretty floored by this as I thought, rightfully so, that some people would stay home because of the weather. Two things come to mind when I think back on this, #1 I have great friends, and #2 we have hearty people in CO...a little weather doesn't stop us from getting shit done.
Beforehand, freezing the bolts. I'm not sure how much this really helps with just an ordinary freezer (you need colder temps I think to get a noticeable difference), but I figure it cant hurt to shrink the close tolerance bolts, even a little. Remember, these are not interference fit bolts...they are close tolerance--big difference. The hardware store temporary bolts will have the same diameter as these...they are just not close tolerance.
Prep work...buy some cheap hardware store bolts (these were 5" long) and cut them and turn them into drift pins on the grinder. You'll use these for the initial fit. Wait to put the good bolts in for the last time. You will need to remove the wings at least once before permanently mounting them....more on this later. I also purchased a 50' tape measure for my triangulation measurements.
My hangar mate Bill (building an RV8) has a nice tail lift that I borrowed to lift the tail into a level attitude. This is a gosh darn handy tool that I've used previously, grateful he lets me borrow it whenever I need it.
Sheryl and Sean Thomas await the crew, drink some coffee and try to keep warm. Both of them were there early to help me get setup...many thanks to both of them for their help.
The crew finally arrives and we get ready to start moving wings. I climbed into the "tub" to line up the holes and insert my homemade "drift pins". I used LPS-1 to lubricate them and the spar. Grease will also work.
And away we go...I told them, "you break it, you bought it" with a chuckle. Its not the money that would make me cry...its the work that went into these puppies that would hurt the most. In all honesty, I had no reservations with my crew. Many of them have helped me several times over the course of my build and they always treat my stuff like it was their own...great guys!
Moving the first wing into place...drum roll please....
Checking to make sure the lower fuse lip doesn't get caught on the bottom side of the wing. It easily cleared, but keep an eye on this.
Sean and Bob jockey it into position as I direct them from the "tub". It just takes a little wiggling...pushing to get it lined up, nothing to it really.
Bam...we have a successful dock! Temp bolts are in...right wing in place!! Wow, that was easy.
Now for the left side...again, very straightforward and uneventful.
After we got both wings temporarily mounted...I stood up and for the first time looked out over my beautiful stubby RV wings from the cockpit and smiled from ear to ear. That was pretty gosh darned glorious! Although not captured in this shot, everyone took photos of me in this position...it was pretty funny as 9 people busted out their camera phones. I felt like a rock star on stage!
Now that the main spar was in place, it was time to set the sweep and incidence in preparation for drilling the rear spar.
Since the plane was on its gear, we couldn't run our string line on the ground. It had to get up and over the gear. My crew came up with this idea with some 5 gallon buckets we had handy. Those combined with some 20 lb dumbbells that Sheryl let me borrow and we had a great system.
Next, you string 4 plumb bobs (2 on each wing) from the leading edge. The two center ones, closest to the fuse should be your reference points. Those two aren't going to move much at all. Now you want to swing the outer two in line with the inner two. We are looking for a zero sweep for this. Van's says, within 1/2" is acceptable.
Once we got the plumb bobs lined up nicely, we shifted to a triangulation measurement from the wingtip to the centerline of the aft fuse. The plumb bobs tell us if the leading edge is straight, this triangulation measurement will tell us if you are perpendicular to the fuse. You will have to jockey each one until they sync up. If you move one, it will affect the other. Just be patient and keep tweaking it until it all lines up nice.
Mr. Armstrong lends a hand, what a great crew! We finally got the sweep dialed in satisfactorily. We ended up with 1/8" difference in the triangulation measurement and a 1/8" sweep on the right wing. Unfortunately moving one would compound the other, so we figured the 1/8" is well within the 1/2" Van's states and called it good. I was actually ecstatic with how straight it came out. The 1/8" triangulation measurement is within a ~16' measurement...so that 1/8" discrepancy is about 0.7% away from perfection...less than 1%, amazing with all of the tolerances involved in the parts and considering they were hand built by me. The 1/8" difference on the wing sweep is an even smaller percentage, as it is spread over the almost 25' wingspan.
We clamped the wing in place and also drew a reference line on the rear spar with sharpie to make sure we had a good visual reference before messing with the wing incidence. Remember these are not independent of each other. Moving one very well might affect the other. We double checked both before committing to drill.
Make sure you get your longerons level...use your incidence block and a level to dial in the correct incidence. Amazingly, the incidence on both wings was almost perfect from the get go. We really didn't have to move it much to get them dead on perfect. Its crucial to get these identical so your airplane flies straight.
One note, the plans say to level the fuse laterally also and then measure the distance from the floor to each wingtip. I didn't do this step as I see it as unnecessary and you are counting on a perfectly level floor over the 25' span. The main spar (not the rear spar) controls this dimension, if its off what exactly are you gonna do?...Van's doesn't say either. I think its just a measurement to make you feel good...or bad. The incidence and sweep are much more important. You're call on this one, these are just my thoughts.
Time to drill a #30 pilot hole. The key here is to maintain your 5/8" centerline to edge distance on all parts, this is crucial...not only on the rear spar, but also the mating fingers coming out of the fuse. I did my measurements and came up with a "window" and marked it with a sharpie...then drilled in the center of the window. It came out exactly like you would expect, centered up nicely. I also didn't have to grind off any rivet heads or any of the rear spar or fingers to get it to fit as is sometimes the case.
I used a long drill bit so that it was easier to see if it was perpendicular to the rear spar in two planes. I did not use a drill block because I couldn't fit one in there while I had a clamp in place. The clamp on the rear spar was more important to me than the drill block. I had two helpers (in each plane) spot me to let me know if I was straight.
This method worked great, I would do it this way again without hesitation. Even so, this was an intense experience...you screw this up and you are in a world of trouble. I've heard that replacing the rear spar is not fun!
After the pilot hole, I stepped up the drill size in increments, finishing with a 0.3115" reamer. The reamer is not completely necessary, but it sure is a good idea. In these pics, you can see my relief when it was done.
And the money shot...isn't that purdy!?? The bolt had a nice snug fit, which made me smile. We also nailed the perpendicularity as the bolt head rested nicely on the spar.
I broke my fancy safety glasses and Sheryl was kind enough to tape them back together with scotch tape...yes, I look a little like a dork! Thanks honey.
It was pretty amazing to stand back and get a gander at the ol' girl finally trying on her wings. We're getting close now, she finally looks like an airplane!
Sheryl finally signed the airplane, I was happy to have her be part of this milestone and getting up at the crack of dawn on a Saturday morning. I think she'll always remember this day as we fly around the country in our airplane we built.
If you've been reading my blog over the years, you'll know I say, celebrate your accomplishments! I had a special edition Oatmeal stout (I really enjoy dark beer) by a local Colorado brewery that I busted out for my mounting crew. I only had this one bomber, so we all just got a taste...but this was some fine beer, very tasty. After we polished this off, Sean and Diana broke out a bottle of Stranahan's Colorado Whiskey (which happens to be my favorite whiskey these days) and we celebrated a little more. We then went and had some lunch before heading on our way.
So, in summary, this was really a piece of cake...very easy to do. Its very important to do it right, but my advice is don't lose sleep over this because its not difficult. We didn't mount my wings permanently. I still need to pull them back off and do my bottom wing nutplates before installing them for good, but that should easy to do with one or two other guys when I am ready, the hard part is done, another milestone in the books.
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