Gear Leg Fairings HOBBS 2570.0 hrs

I tackled the gear leg fairings about a week ago. Although I don't need to have these done for first flight (I'll fly "dirty" for the added drag until the engine gets broke in), I wanted to get them mostly done for my initial weight and balance calculations.

 

I assumed this wouldn't be a big deal to install, I mean, they are just cosmetic fiberglass fairings...right? Well, turns out this was a naïve assumption...if you get these crooked, they will have a bigger impact on a straight flying airplane than crooked wheel pants. That surprised me...and made me not take this lightly.

 

The instructions are a little hard to follow...but reading through them a couple times, I finally got the gist of what the goal is. Once I did, I just did this on my own...basically not referencing the instructions again. First step is to make sure your fairing is straight and not twisted.

 

 

Use your cleco clamps (you have some of these right?) to hold 'er straight. Cut out the 1:1 template from the drawings set. Wrap this around your gear leg...again, getting it nice and straight. Hold it up to the light to make sure both sides (edges) of the template are aligned. Now use a sharpie to mark your cut line.

 

 

Once you get it cut to size according to the template (a little big actually), slap 'er on the gear leg. You may have to trim the length to get it fitting properly. Install your intersection fairings if you have them (mine are from RVBits and they rock...good purchase, love the finish and fit of these). These will essentially help to hold your fairings in place while you do your fitting.

 

Now, hang a plumb bob of the fuse centerline. Stretch a double string from the leading edge to the tail. The goal is to get the trailing edge in the center between the two strings.

 

Hang a plumb bob off the HS...draw a line at fuse center, measure from there to the plumb bob string. Adjust to make it the same dimension as the trailing edge of the gear leg fairing. Note that the plane is in a level flight attitude for this task. I just eyeballed that the string line was also level. You are trying to set up a straight datum plane, which will simulate the airstream. It sounds more confusing than it really is.

 

Notice that I did not jack up the airplane to get it off the gear. Same strategy that I had for the wheel pants. Unless the gear toes in or out when its lifted, the wheels and gear legs are straight. So I disagree with the plans on this step. Again, your call whether you agree with me or not.

 

I am bonding my intersection fairings to the wheel pants. Some guys just screw these in place. I always intended to do it this way for the clean look. When Sheryl and I were at LOE this year, I showed her versions of both and asked her which one she liked better. She chose the blended look...I knew there was a reason I liked her. :) Notice the split line I will cut into the intersection so the wheel pant can be split.

 

Lastly, drill your holes for attaching the intersection fairing to the fuse. These holes will get nutplates later. I didn't get any pictures, but the trailing edges get a piano hinge to keep it closed up nicely.

 

I am continuing to work on these as I have time...but since they aren't required for first flight, they are not on my current priority list. These are gonna look nice when they are done.

Roll With It HOBBS 2570.0 hrs

From time to time I like to post inspirational stuff (click on the tag in the right column to see them all) on my blog...to keep the juices flowing. Building can drag you down if you don't take the time to remember why we are slaving away the countless hours, alone in a hangar or garage for years and years on end. Whether it be exotic trip reports or sweet aerobatic/formation videos like this one from Brad Benson, as posted on VAF. This gets my juices flowing...how about you? Nicely done Brad...with both the flying and the video production! KPR!

Closing In! HOBBS 2570.0 hrs

The hours are piling up as I approach 2600 total on the HOBBS. I still shake my head in amazement how naïve I was when I thought it would take about 2000 hrs to finish up. Obviously WAY past that figure and still counting! But...boy, the finish line is in view now, first engine start is coming soon. No pics this post (I'll post some later this week).

 

I pulled off my left wing--did my dimpling/platenuts, deburred my rear spar holes and some general routing of wiring and pitot/AOA tubes--and put it back on again, solo. It was pretty easy with adjustable sawhorses...lift the tail to a level position, strategically place the sawhorses under the wing and carefully pull/wiggle the wing off the fuse onto the sawhorses. Do your prep work and reverse the process to put it back on. Really not that difficult if you need/want to do it alone.

 

So, the left wing now has the close tolerance bolts in place...the bottom two were a bugger to get in since there is no room to swing a hammer! But...with a little sweat equity, they are in and ready for flight. I buttoned up the bottom skin overlap and installed my wing root fairings. Ran my pitot and AOA tubes back to the ADAHRS. Last steps are to torque the wing bolts (apply torque seal) and hook up wiring...that'll come tonight. Its very cool to see that puppy on permanently. I'll move onto the right wing on Tuesday.

 

As some of you know, I track my hours worked on a spreadsheet. It just gives me a barometer of how much work I am putting into the project. I started off wanting to average 15 hrs/week (and I'm closing in on it). It doesn't sound like much, but over the course of the last couple years...its harder than you think to average that and still work a full time job and have some kind of life outside building. Here is a view of what my tracking looks like...as you can see, the pedal has been to the metal since the wings went on Jan. 4th.

 

 

My spreadsheet showing the last couple months...week, hrs worked, HOBBS total, weekly average.

 

Here is my graph of the last 120+ weeks...yes, I am an Engineer, I like pretty graphs. I find it interesting to view this and reflect...it really gives you an idea how the hours fluctuate as life gets in the way sometimes...notice the 'zero hour' weeks in there? It happens...just gotta keep at it, steady as she goes. As I always say, "its not gonna build itself!"

 

Oil Accumulator HOBBS 2514.0 hrs

 

How is this for a view outside my hangar bright and early on a cold, crisp sunny Saturday morning? Summer seems like a long ways off...that's for sure.

 

 

When I decided to postpone the wing mounting for a few weeks, I took advantage of the extra time to research and then decide on adding an oil accumulator to my setup. With the half raven system and now this 1 Qt oil accumulator, I should be able to get 7 seconds of full inverted flight. That will be sufficient for my mission for this plane. Without a counterweighted prop, this is as far as I feel comfortable going with inverted systems. It will allow me to fly sportsman aerobatic competitions without any "cheats". Because this mounts to the firewall, it was good to get this mounted before the wings went on.

 

An oil accumulator controls engine oil pressure during surges or loss of pressure. The way it works is, its a pressurized canister holding a pre-charge of air on one side of a piston and oil on the other. As the engine oil pressure comes up after start, this will compress the air and fill the canister with oil. If the engine loses oil pressure, the air will force the oil back into the system protecting your engine. Once the pressure comes back up (roll upright), it reverses the process and fills back up with oil until the next time you need it. I followed Ron Schreck's of Team Aerodynamix VAF post regarding installation. I am still working out the details of the plumbing however....pics of this later.

 

I ordered mine from Summit Racing (great service and selection). They also have hard to find Aeroquip fittings if you ever cant find what you need at ACS.

 

If you plan to add one, keep in mind, this isn't small...it holds a quart of oil so its gotta be somewhat large. Trying to find a place to mount it wasn't easy.

 

This is the only place I could do it with my setup. Its not ideal since I cant see the air gauge without removing the cowl. I could remote mount it, but I'm hoping its a "set it and forget it" kind of a deal. It should hold pressure pretty well.

 

Some measurements to give you an idea...its posted on the site also. Again, this is all I have for install pics right now...the hose routing wasn't easy, I have some hoses on order and we'll see how it all goes together.

 

On to other things. I got my prop cable finalized with some creativity. The cables I am using don't have a threaded nut, so I had to capture it with a homemade bracket as shown here. Its 4130 steel so its not going anywhere.

 

As I was getting the prop cable fine tuned...I, of course had to install my center console again. Got it dialed in nicely with almost a full throw on the prop (within about 1/16" for now).

 

A gratuitous FAA shot of me bundling wiring under the panel prior to wing mounting.

 

A couple weeks ago I was using some duck bill pliers to pull on some tie wraps when the tie wrap broke and I proceeded to jam the end of the pliers into my face about a half inch below my eye socket! It hurt like hell! After I cleaned up the blood, I realized my flying career might have ended right then and there. Not many one eyed pilots passing an FAA medical that I know of. Be careful! I went out and bought some nice safety glasses and planned to wear them all the time...which I broke during the wing mounting.

 

Working on wing details...the fuel tank attach brackets need a little bend added to them. Not much to it...add a nut plate on the tank and drill a hole and you're done.

 

Unfortunately I had to remove my tanks to get to a fitting that was buried behind a wing rib on my auxiliary fuel tanks. This was kind of a pain to get to the bolts on the z-brackets. I timed myself, it took me exactly one hour to remove one tank.

 

Lastly, I was finishing up the plumbing for the smoke system. This hose will from the pump to the firewall. Notice the needle valve for fine tuning the smoke oil flow rate.

The Eagle has Wings! HOBBS 2491.0 hrs

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.