Wing Kit Arrives!!!

It came as somewhat of a shock when DOG Aviation received the call from FedEx saying they had two crates ready for delivery. Wasn’t expecting the wings for at least another two weeks. But it will be good having the parts here so when the empennage is completed, there will not be any down time waiting for parts to arrive.

                                               Ken (the FedEx delivery driver who delivered the empennage kit)
                                               amazed me once again with his skill at backing up that big rig to
                                               the DOG Aviation receiving bay.

                                 Moving the crate containing the wing spars to clear the way for the second crate.

                                                Crate containing the wing skins, ribs and miscellaneous wing
                                                components. Notice anyone with a big Cheshire cat grin?

                       After signing for the delivery, Ken and I took a few moments to catch up on how his family
                              was doing along with his expressed interest in following the construction of the airplane kit.

After the parts delivery, spent the next hour or so doing a little cleaning and rearranging things so all the crates had a home and out of the way (mostly). Having most everything on wheels makes for easy rearrangements.

Removing Protective Coating From Rivet Lines

There are two schools of thought regarding the protective thin plastic coating Van’s has on all the parts. One group says take it all off and be done with it and the other feels leaving it on parts as long as possible prevents the Alclad factory coating on the aluminum from getting scratched and possibly leading to corrosion. I lean towards the second group even though it requires a little more work on the skins.

                                 Using a straight edge and a soldering iron to melt a cut line into the film coating.

                                                        Pealing the protective film away is now a snap.

Builder Tip:

Don’t drag the point (tip) of the soldering iron down the skin ... you will put a scratch in the aluminum. It is better to use a cone shaped tip and drag the side of the cone down the plastic coating or if you have spare tips, just round off the tip altogether.

                                                        Skin with plastic coating removed from rivet lines.

Undersized Rib Flange Holes

When doing the test fit of the vertical stabilizer skin to the vertical stabilizer skeleton I discovered the undersized holes other builders have mentioned.  I remembered reading about a hole being undersized on the first flange hole at the forward end of the VS-1207 rib, but that was a long time ago and figured it would have been resolved by the time my kit was assembled … apparently not.

                                                The undersized holes on VS-1207 are the ones on the first flanges

                                                on the left … both upper and lower.

Thus far, all the parts from Van’s have fit together perfectly (prior experience with Van’s parts has shown if it doesn’t fit, the assembly is being putting together incorrectly) … so when I saw the hole in the skin was aligned with the hole in the rib but I couldn’t get the Cleco into the hole, I knew something was wrong. Then I had a flashback and remembered reading about this minor issue.  Drilled the two holes out with a #30 drill bit and now all is well.

Vertical Stabilizer Test Fit

Before metal prep, some dimpling and priming I wanted to do a test fit of the vertical stabilizer skin to the vertical stabilizer skeleton.  Sounds simple … right?  Well, yes and no.  It turns out I had to assemble and take things apart twice before the parts would fit together correctly. The plans call for trimming some metal off the narrow end of a few of the ribs. Not wanting to over do it, I did not remove a ton of material and as it turned out I had a clearance issue so had to take the ribs out and trim some more material off to get things to fit better.

                              Sliding the vertical stabilizer skeleton into the skin. It is a really TIGHT fit at the leading edge.

After trimming more material off the ribs, things were looking much better but the first rivet holes on the leading edges of the ribs are a bear to get aligned correctly. The taper of the skin on the leading edge wants to push the first rib tab on the ribs off to one side. The only way I could get a Cleco in the hole was to use a broom handle and slide it up through the lightening holes in the ribs and push on the leading edge of the rib to move the rib tab to the correct position.

                                                The completed test fit … yep, looks good … so on to dimpling,
                                                metal prep, primer and final riveting. To bad it needs to be taken
                                               apart for priming.

Machine Countersinking The Rear Spar

The plans call for machine countersinking the vertical stabilizer’s rear spar at six locations on the lower portion of the spar. The holes need to be countersunk to accept 3/32” flush rivets. In this case, the reason for countersinking rivets at this location is because the lower portion of rear spar will mate to the rear of the fuselage cone … therefore the mating surface needs to be flat with no rivet heads sticking up.

                                      Countersinking the rear spar using a 100 degree cutting bit in a countersink cage.

BUILDER TIP:

Based on prior experience I have found that countersink bits used with hand drills tend to make holes in thin metal larger. A good way to help minimize this is to first drill the proper sized hole into a piece of hardwood and place the wood under the piece of metal being countersunk. Align the wood piece so the tip of the countersink bit goes into the hole drilled in the wood. This really helps ... a lot. Give it a try on some scrap aluminum. Unfortunately, in the photo one can’t see the wood piece under the spar I was countersinking.

From left to right - countersink cage with a cutting bit installed, a cutting bit, a cage without a cutting bit installed.

Avery makes a nice countersink kit consisting of cutting bits and a high quality cage made with bearings as opposed to bushings. Most builders (myself included) will want an extra countersink cage (or two) because it takes time to get it adjusted correctly to cut at the proper depth. Once it is adjusted, you tend to want to leave it dedicated for that size cutting bit.

For those not familiar with how the countersink cage works, I’ll try to explain by making the simple sound complicated. The round shaft protruding from the cage assembly connects to a hand drill or drill press which rotates the shaft. The end of the shaft inside the cage has a threaded hole which the desired sized cutting bit screws into. The shaft is spring loaded and when downward pressure is applied, the shaft slides deeper into the cage allowing the cutting bit to go deeper into the hole to be countersunk. While the inner shaft is spinning, the outer portion of the cage does not spin as long as you hold onto it.

Now the time consuming adjustment I mentioned earlier ... there is a depth stop adjustment because one needs to limit the depth of the cut. Without a depth limit stop, it is very very  very easy to countersink much deeper than desired … thus there is a cutting depth  adjustment.  Unfortunately, the depth adjustment is all trial and error so one must make sure they start shallow and slowly adjust to the proper depth. The bits cut metal fast so it takes time to slowly get to the proper cutting depth. Once the tool is adjusted you are off to the races for it only takes a few seconds per hole.

The cage is on a threaded barrel and adjustment is made by loosening a locking ring at the top of the assembly then pulling back on the lock and screwing the cage in or out of the barrel. This essentially makes the cage longer or shorter thus allowing the cutting bit to go deeper or shallower. If you double click on the above photo it will come up larger.  Looking closely at the photo, you will see I have loosened the locking ring and pulled back the lock then wedged the mandrel of a rivet between the cage and the lock so one can see the locking teeth and also how small of an adjustment that can be made.

A close-up of the six countersunk holes on the rear spar.

HVLP Spray Gun

Originally an inexpensive Harbor Freight spray gun was purchased to spray the primer … but then I figured gee, after priming hundreds of square feet of aluminum during the build, I may just get good enough at spraying to want to try tackling spraying the outer finish coat as well. (Plus the tip that came with the HF spray gun is larger than the tip size recommended by the primer manufacturer and various sized tips are not available at my local HF store).  That said, the DOG Aviation procurement department went into action and found a seemingly great little HVLP gun that has a lot going for it.

Eastwood’s  Concours HVLP spray gun and the DeKups disposable spray system made by DeBliss. A special adapter is screwed on the gun to accept the DeKups system. The spray gun has four different sizes of tips available and the gun only uses 4 CFM of compressed air, so most any home air compressor will work well. Also the DeKups system is made in at least three sizes ... my initial choice is the 9 oz cup because most of the priming will be done in small batches.

To the right of the spray gun in the above photo is the disposable top and disposable soft thin plastic cup (think bladder). Paint is placed in the disposable cup and the disposable lid is placed on the cup … all that is placed into the container to the right of the disposable cup and the locking collar on the far right keeps it all together and also allows the assembly to be attached to the spray gun. One cool thing about the DeKups paint system is it allows the user to paint with the gun upside down … (which may come in handy for painting the bottom of a fuselage while lying down on a creeper).

Spray Booth Completed

Have not posted for a while, so have a little catching up to do. Decided to make a simple enclosure made from PVC pipe to go around the spray box to help keep overspray contained.

                                      Shower curtains will be hung from the PVC pipe to make up the sides and top.

                                 Decided not to glue the joints, so the use of pins makes it easy
                                               to break down the booth when not in use.