And More Nutplates... HOBBS 221.5 hrs

After I finished the fuel tank nutplates I thought I was done...nope. Still had nutplates for 6 inspection covers on the underside of the wings and four more for some wing attach bolts. This wasnt as bad, four per, so 'only' 24+4 more nutplates. Child's play after doing all of the fuel tank versions. Not too much exciting in this post, just chuggin' along.

Rivet, rivet, rivet...

Rivet tape to protect the spar while bucking...and tape on the bucking bar for the same reason. Treat these babies with TLC!

The finished goods...nice to take a look at a job well done

Priming the holes with wash primer and q-tip

After drying, blends in nicely with the gold anodized spar

And of course, a celebratory beer after finishing ALL of those nutplates. I had no idea it would take so long to do this step. I'm starting to see why the wings take 400+ hrs to complete! :)

More Nut Plates HOBBS 217.5 hrs

Tonight was more of the same...more nut plates. I finished the right spar and am almost done with the left. After I finished drilling the countersinks I mixed up a real small batch (like a couple tablespoons) of wash primer and dabbed a q-tip in all the holes to protect the bare aluminum before riveting. Most of the rivets can be done with the squeezer, a handful in the 'wing walk' area had to be bucked because of the tight space. No problemo.

Wing Construction Begins HOBBS 215.0 hrs

Now for the fun part, I finally got started on the wings after all of the dinking around with finishing up the empennage. Lots of progress this week as I logged 19 hrs in the shop. I was gung ho to get drilling on these spars...but wow, it was a flashback to when I first started my empennage. I read the plans, looked at the drawings, read the plans again, looked at the drawings again and was paralyzed to finger the trigger on the drill to cut some metal!! haha! I literally spent at least a half hour looking everything over before drilling to make sure I wasnt making any mistakes. This, after I had already previewed the plans before the wings arrived so I was familiar with the task at hand. These wing spars are probably the single most expensive parts in the entire airframe....you do not want to screw these up! On top of the fact that these buggers, more than any other part on the entire airplane is literally what your ass is hangin on in flight. If my engine quits in flight, I have lots of options for a safe outcome. If my wing seperates in flight, the only option is to kiss your ass goodbye and wait for impact with ol' mother earth. Consequently, there should be a high degree of concentration to do a good job on these puppies...so all of this gave me pause. 

First order of businees is attaching all of the fuel tank attach nut plates. I think there are 64 #8 screws per tank? So if thats correct,128 nut plates, which means 3 machine countersink holes per nut plate. Even without the math (I'm too lazy), you should be getting the picture here....lots and lots of countersinking to be done. On top of the fact that the thru holes for the #8 screws is too big to hold the pilot on the #30 countersink. So what happens is the countersink tends to chatter because of the loose fit. Van's states this will happen and its ok, and really it would be for the design intent since the nut plate is the aligning feature. Although I certainly cant accept shoddy work like that on my plane. ;) So, reading through Dan Checkoway's site, he came up with a solution by adding a scrap piece of angle alum to act as a pilot hole. I didnt do it exactly like he did because I only did one hole at a time but it worked out good, just time consuming. The countersink for the #8 screws really is too deep for the 0.062" alum angle so it blows out the thru hole which makes it very difficult to keep the countersink nice and symmetric. Not a big deal because the thru hole isnt being used for alignment, so its just a cosmetic issue. I did my best to keep it looking nice, some of them came out obround but most of them came out real nice. I was happy with my efforts on this excercise. I also, because of my previous building experience did the bottom side first. That worked out good, as my first ones were the worst of the bunch...but nodody will every see them. By the time I got to the top side I had it dialed in nicely. The microstop really worked great. I set it up initially, tightened everything down and never had to readjust it! I had been told to be careful with this tool as it has a tendency to move..I kept checking, but 'no joy'. Very consistent depth on the countersinks if used properly. 

An interesting label Van's puts on the spars telling you not to ream the holes for the close tolerance bolts that attach to the center section. They are tight...and are supposed to be for obvious reasons! You would think a builder would consider this, but ya just never know and its better to be safe and put a notice just in case. You certainly dont want your wing attach bolts shearing while pulling a 3g turn! That would make for a bad day!

Marking the wings so that I have the correct orientation, dont want to build these suckers upside down! They are almost symmetrical, very subtle differences to tell you whats up and down. I expect, after a while I will be very intimate as to which is which, but until then better to be safe than sorry.

My homemade depth guage tool. A #8 screw ground down so just the head is left. Then I super glued that to the end of allen wrench. Now I can check my countersink depth as I go. Now, keep in mind that the screw wont actually go in this countersunk hole, the dimpled tank skin will and the screw will go in the dimpled skin. But essentially the dimple is the same size as the screw head (I checked..its a smidge on the shallow side but I think it'll be ok for a nice tight fit) so this is what Van's says to use. Much like factory rivet heads, after drilling so many, after a while I could tell by the look if it was deep enough so I only check about every five. 

And a shot of a test fit with screw and nut plate...looks good eh?

My added piece of angle alum for the pilot hole...I had this left over from my rudder excercise. In this photo,  you can see I am using clamps...that didnt work too well as they tended to move around too much. I later switched to cleco-ing the angle in place...much better results.

And the finished goods...that looks purdy doesnt it?!

Looks like this was done on a CNC machine doesnt it? hehe

On a different note, this was my 'fathers day' present to myself. Yeah, yeah, not a father unless you count my pets but hey it was marked down fathers day weeked from $58 to $35 at Home Depot. Couldnt pass it up...and wow, it sure is nice to have to clean up all of the alum shavings from the countersinking.

Wash Primer HOBBS 207.0 hrs

I ordered some Sherwin Williams Wash Primer from Global Aerospace. You cant get this stuff locally so I had to have it shipped and pay the HAZMAT fees which is aggravating because it so expensive. With shipping and HAZMAT, it was about $50 to have it shipped. Part of the process with the airplane building process I am learning, you gotta deal with it unless you use an automotive paint system which I'm not interested in...call me an aviation snob. :) 

Wash primer is essentially a very lightweight, cheap (relatively speaking) self etching primer. By using this, I dont have to alodine or acid etch before shooting the primer. That is kind of nice, less hassle, and its the same primer that Van's uses on its quick build kits. I tell ya, it didnt have nearly the coverage of my two part epoxy primer. I had heard it went on very light, but gosh, this was kind of extreme...it doesnt look like I even got it coated evenly as hard as I tried. I think on my first round I had a clogged tip on my spray gun. After a conversation with good ol' Dad (thanks Pop!), he advised storing and soaking the tip (it just unscrews from the gun) in a coffee can of MEK to keep in clean and clog free. Good tip (no pun intended!) as that certainly seemed to help and the next parts came out a little better but similar. I think it will be ok, but it just doesnt look very esthetically pleasing which kinda bothers me. It really looks almost identical to the self-etching rattle can I have. Anyway, this will protect the aluminum where I removed the alclad. My prep process was scuff the surface, clean with dish soap and scothbrite, air dry with compressor, wipe down with acetone and then paint. So I have the HS, elevators and trim tab painted and stored now. They're not perfect, but I'll fine tune them later. Still gotta do the VS and rudder! ugh

It turns out that my wing stand doubles as a very nice paint rack!! Gotta love it when it works out that way, I can just lie and say...planned it that way!! haha! Sounds good doesnt it?

Right elevator...

Left elevator, the dark discoloration is the Epoxy filler over the rivet heads. I decided to fill in all of the rivet heads on the top surfaces of the HS and elevators, out of boredom I think! :) It was a lot of work, but it should be as smooth as a baby's bottom when top coated. I won't do any other parts like this...the wings would be way too much work for my taste, but the empennage has been done...and I'm sure I will be happy with it now that its done.

And last but not least, the trim tab. You can see in the left side of the picture where I had some adhesion problems with the epoxy filler. I inadvertently forgot to scuff the surface before applying the filler. Damn! Will have to revisit that later...another lesson learned.

Electric Trim Tab HOBBS: 205.0 hrs

As I get the empennage finished up and ready for storage, one of the things I havent addressed yet is firing up my servo motor to test its function and to also cut my all-thread rod to length. On top of that, a known problem is the all-thread rod not having enough clearance for the motor to run its full range of motion. I am mostly impressed with the engineering on this aircraft but this is something that is less than stellar. I noticed three things that are not designed properly with the elevator trim tab.

First, the all-thread rod interferes with the elevator skin, the clearance cutout is not long enough. Second, the plastic fitting that attaches the all-thread to the trim tab motor also interferes with the skin. And lastly, I am not getting the full up and down travel that Van's says in the plans. I dont see any way that you could get that much travel with this design. Van's calls for 35/25 degree travel up/down. I am only getting about 20/20 degrees. I have room to adjust this slightly if needed to get more down travel but I'll save this til later. For now it is good enough. This is another issue that other builders have had so I feel confident it isnt just me installing it wrong. This is not the end of the world however and maybe thats why Van's hasnt fixed it. The all-thread interference is easily fixed by elongating the slot, some guys bend the all-thread rod but I wasnt comfortable with that option and didnt see the need. The full travel in the Van's specs is not needed from what most pilots say.

Here is my 6V battery that I bought from Home Depot to test my motor. It runs a little slower at this reduced voltage but it is adequate for testing purposes. I ran the motor to the stops both directions with no problems. Just switch the wires to reverse directions. Of course it doesnt go that far when attached to the trim tab because of the constraints mentioned above. This little experiment was kind of fun and made for a pleasant evening work session, the motor moved nice and smoothly.

In this photo, you can see where the all-thread rod interferes. This view is without any modifications.

And here is a shot of my intended cut to elongate the clearance cutout. First I drilled a 1/4" hole and then trimmed with a cutoff wheel in the dremel tool.

And the finished result after filing the sharp edges and then running some scothbrite over the edges to smooth it all up nicely. Turned out very nice, looks professionally done. :)

In this view you can see it run all the way to its constraints after trimming. You can see that the all-thread rod is all but touching the skin and the black plastic attachment is also resting up against the skin. This is the limiting factor in the travel of the motor. Disappointing, but as I said, it'll have to do for the time being. The system is nice and tight. One thing you need to be concerned about with an elevator trim tab system is in-flight flutter which can be catastrophic. Its very important for the trim tab system to have NO play or loose parts, and it seems to satisfy that requirement nicely from what I can tell. The piano hinge and the motor do their job well.

Body Work HOBBS 204.0 hrs

Spent some time sanding my empennage, prepping it for a coat of Wash Primer and then storage. When it comes to doing fiberglass work it can be a laborious job. There is a saying that goes something like this, "you are done when you get tired of sanding". Trust me, I'm almost there! :)

Inventory Finished HOBBS 202.5 hrs

Last night I finished up the inventory. It did end up taking me another two hours, those bags of hardware took a little longer than I expected to count. I also labeled all of my parts bins, which is a slow process. But, I'm ready to rock and roll now! Amazingly, every single item was present and accounted for! Van's really does a nice job with this. There were at least two instances where I was sure I was missing some hardware...and low and behold,  I ended up finding it eventually. One bag of hardware fell on the floor and was under my cart. :) The only thing that hasnt been inspected are the two main wing spars, I will do a thorough inspection of these as I start working on them. They are the first parts I will start drilling on.

Wing Kit Arrives HOBBS 200.0 hrs

Today the wing kit arrived. Unloading was a non-event since the driver helped me out, although he isnt required to. We just carried the crates into the garage and used the dolly sparingly. Turns out his daughter is a helicopter pilot in the US Navy so he was interested in the building process and asking questions about the project. One of the crates had some shipping damage, so he stuck around while I opened it up to check the contents...no internal damage! whew... Nice guy, after a little converstation, I thanked him for his help and he was on his way.

Then the fun began. For someone who is passionate about aviation, this has to be the best thing outside of Christmas! Unpacking the crates is really a blast. Inventory is not quite as fun but still interesting to see all the little parts and start creating a mental picture of where they all go in the assembly. The gold anodized center section and the main wing spars are really beautiful to the eyes of an Engineer, nice craftmanship to be sure.

I tore into the crates and the inventory like a hungry wolf taking down his prey...and 3 hrs later I was almost entirely done with  upacking, storage and inventory. I just have some misc hardware bags to go through to finish up. Thats pretty quick for a guy working alone...goes to show how anxious I have been to get this kit. Here are some pics from day one of the wing kit inventory...

The main spar crate...

As always with Van's, professionally packed...

My flop tube for fuel intake during inverted flight...

My 'deluxe' fuel caps, they are pretty nice...are they worth the $150 cost delta?? hmm, not sure, but I'm still happy I got 'em. I will get them engraved later.

This is the gold anodized center spar, the two main wing spars will attach to this. It will sit right under the seats in the fuselage.

Monday Delivery HOBBS 196.0 hrs

Wing kit is arriving monday (6/21) between 12-2pm. It was crated thursday morning...monday afternoon delivery, three days to ship, not too bad. I will be working from home that day and I think I have a strategy to unload it by myself whether the driver offers assistance or not. The crates arent too heavy (200-300 lbs) but they are certainly too big to carry by yourself so I will use my furniture dolly as needed. I know Bryan would probably help out but I dont want to have to ask him to take time off work for this. He was able to unload his alone without a problem (I was on my way over there but they arrived before I got there!). So, my new baby will be arriving monday...exciting!

Wing Shipment HOBBS 195.0 hrs

Its now official, just got a call from Van's...my wings shipped this morning! So, if you're keeping score, my order was final early monday morning, 6/14/2010. With that math, it took them about 3 days to crate them. Now we'll see how long it takes to arrive via FedEx freight...they provided me with a tracking number but it doesnt appear to be in the system yet.

Oshkosh 2010 Booked! HOBBS 195.0 hrs

Last week I bought my airline tickets to Oshkosh for the annual AirVenture celebration. I'll be doing my same ol' routine, camping in Scholler Campground right on the showgrounds, which is the only way to go in my opinion. Its the best way to soak in the Oshkosh ambience. Spending nights under the stars with 30,000 other aviation enthusiasts from all over the world. Ultralights flying overhead as you BBQ a steak while savoring a cold drink. Walking distance to everything including the night time entertainment at the Ford theatre, Theate in the Woods and BeerVenture (a gem which Samira and I stumbled across last year)...whats not to love?! I will be spending 4 nights/5 days. I am flying into Milwaukee and renting a car for the short drive into Oshkosh. This is the same thing I did last year and it worked out pretty good as the drive was not bad at all. With major vacations somewhat 'on hold' for aircraft construction, this is my only real trip of the year so I am certainly looking forward to it. On top of the fact I cant wait to check out all the RV's that will be flying in...lots of examples to examine!

Purge Return Line HOBBS 195.0 hrs

I had requested information from the guys on VAF about extra stuff to order with my wing kit. I received several responses that were interesting and useful. One of which was the fact that with a FI (fuel injection) system, most guys install a purge return line back to at least one of the fuel tanks. So, of course I had no idea about this so I had to do some research. I'm still learning about this, but I at least got my feet wet on the topic.

This is my take, although its certainly not needed, it is regarded by guys who have done it as a nice option to have. When a fuel injected A/C engine is shut down, the fuel can/will vapor lock because of the hot engine. It usually isnt a problem unless you try a restart before the fuel has had a chance to cool. The added purge line provides a way to pump the 'hot' fuel back into the tank (or tank intake line), then select the other tank and replenish with 'cool' fuel and voila. Guys that dont have this option state that you can put the mixture to idle cut-off, turn on the fuel pump for a few seconds and accomplish the same thing.

Here is an example of a fuel system taken from VAF (Author: Rick Mellor) to give you an idea of what's going on for a typical fuel system in an RV7. As you can see Rick has plumbed in two seperate purge return lines, one to each tank. Although I think that is overkill and will add one more point of failure to the system, I do plan to add one for convenience. Probably will route to the supply line so I dont have to cut another hole in the tank. Bottom line, I shouldnt have to worry about this option until starting on the fuselage and FWF stuff. It was interesting to read about though, always learning when you build one of these suckers...the knowledge base keeps growing!

On a different note, this turned out to be my final shopping list added to my wing kit. Most of it was low dollar stuff except for the deluxe fuel caps, those ran $200! They're proud of those suckers. All told, I spent about an extra $350 on all of this. Always something...

Longeron Angle 7/8/9 AA6-125x3/4x3/4x15'2"
AA6-063x3/4x3/4x6' (extra angle for misc brackets)
Misc grommets of several sizes
50' roll of 3/4" conduit (for wiring)
Flop tube (1)
Deluxe fuel caps (note: $52 total credit for standard version)
Pro-seal (1 qt) ...I realize I may need more later
Fuel tank test kit
AN833-6D (extra for fuel line)
AN833-4D (extra for vent line)
AT0-032X1/4X8' (Soft Al tubing)
AT0-035X3/8X6' (Soft Al tubing)

At OSH, I will be looking at lighting and heated pitot options as I am still undecided on these.

So, the wings are being crated this week, wing stand is built, plans previewed...I am beyond excited to get started on them!

Wings are 'a Coming! HOBBS 192.0 hrs

Originally I had a May 17th ship week for my wing kit. That would've been about right considering my finances. But, I recieved a nice letter from Van's stating that the wing kit delivery had been delayed almost two months!! As you can see, my new delivery date was now July 12th!! Ugh! Rumor has it, it was a supplier shortage issue that was causing the delay but I never heard that officially. So, I settled in for a two month wait that I hadnt anticipated. But right around the end of May I recieved a call from Barbara at Van's saying...your wings are ready to ship, we just need you to send in the balance due. I was pretty excited to hear that, but also caught off guard. My money was tied up in company stock which I needed to sell. Of course the stock market was down when I got the call from Van's...so I ended up sitting on it for almost two weeks waiting for a favorable selling price before pulling the trigger. I finally got it done last week, but it took several days to work its way through the system and be deposited into my account. Long story short, I just got off the phone this morning with Van's and my wings are now bought and paid for!!! wooohoo! Should be crating them next week with delivery by FedEx freight coming either the end of next week (6/18) or first part of the following week (6/21).

I ordered several misc items to add to the shipment. I added one 15'2" extra longeron 1/8"x3/4"x3/4" angle, one flop tube, deluxe fuel caps and a 50' roll of 3/4" conduit for wiring. The extra longeron piece was a suggestion from the VAF site that I liked. There are a few fuselage parts sent with the wing kit. Because of their length, they easily fit in the wing spar crate and are too long for the fuselage crates. The 15'2" longeron piece being one of them. The strategy being, order an extra just in case you screw one up because it would be difficult to ship after the fact. Then if you dont use it, you can cut it up for misc brackets that are almost always needed during construction. Angle aluminum is always handy to have around.

So the last couple weeks I have been finishing my garage. Painted the other side of the floor and fiinished painting and texturing the walls. Then I built a rolling wing stand. I will post pics in my next post.