You know the old adage – “How do you eat an elephant? One bite at a time!”  During my assignment to the Air Force Flight Test Center at Edwards AFB, an airplane building colleague in EAA Chapter 1000 had that statement posted in his workshop and it’s absolutely true.  How do we tackle a huge project like building an airplane?  One step at a time.

Today we took a big bite out of the elephant and finished riveting the fuselage “canoe.”  If you’re joining this program in progress, in RV-speak a “canoe” is the stage of fuselage assembly when the major components – tailcone, center section and firewall – are riveted together while upside down, looking like a large aluminum canoe.  Ellen and I spent practically the whole day finishing up a bunch of fuselage rivets, including the wing spar carrythrough, forward belly skin, and firewall areas.

Here’s an iPhone panorama of our canoe at the end of our session today – click on it for the large version.

We ran into one problem area.  A couple of aluminum angles on the firewall bottom just don’t leave enough room to buck a few of the rivets on the lower firewall stiffener.  Van’s offsets these rivet holes a little aft to provide more room, but the extra space isn’t enough to get a bucking bar in there without beating up the angle.

Some folks remove a little material from the angle to allow those rivets to be bucked, but I elected to use blind rivets.  Fortunately, I had some Cherrymax CR3214 structural blind rivets on hand – they’re the Cherry equivalent of NAS1097 “oops” solid rivets – they have 1/8″ shanks, but also have a flush head that fits dimples or countersinks for 3/32″ flush rivets.  So all I had to do was drill the problematic holes out to #30 and use the Cherrys.  Problem solved…

To paraphrase an old Tom Cruise movie, “Cherrymax…there is no substitute.”

The result of all that work?  A nice, smooth belly skin.

Another picture of the final product…I knew you’d want one.

We need something to hold the fuselage at a convenient height, so one of my tasks for the week is to fabricate a rolling cradle that will let us make the most of our limited shop space.  We’re also rearranging the shop to free up enough maneuvering room for future work, like installing the canopy and hanging the engine.

We made some serious progress on the fuselage this weekend!

On Friday, Ellen and I finished backriveting all the smaller rivets on the forward skins.  After crawling out from under the fuse, I found some graffiti.

I mangled a couple of rivets because we were rushing, hence some related graffiti…

And those of you who speak German will recognize the wordplay on this bad rivet…

And on Saturday, my friend and fellow RV builder Captain John came over and we drove all the AD4 rivets (big rivets, for you who aren’t airplane geeks) left in the forward fuse.  A few hours of work yielded a lot of progress.  Here’s the pilot’s side…

John and I also shot the remaining baggage area rivets where I had previously experimented with Hysol to fill some gaps between skin layers.  These bends came out a lot better than expected, certainly worth the mess and time it took to apply the liquid shim…

Captain John did a hell of a job bucking the AD4 rivets.  They’re pretty damn close to perfect.

Another picture?  Sure, why not?

I had to remove the AN3 bolts blocking some rivets in the firewall corner gusset; that’s the center right area in the picture above.  Getting those reinstalled and torqued was a little bit of a challenge, but I managed to frankenstein together a torque wrench extension that worked pretty well.

We’re on to the final stretch…just a few more rivets on the belly and longerons, and it’s canoe-flipping time!

The last major task on the fuselage canoe was getting the forward belly skin in place. That, in turn, meant mixing up some nasty, gloppy Flamemaster CS1900 firewall sealant to seal the firewall-to-skin joints.

This stuff is a pain to work with…it has a consistency something like taffy, and it doesn’t adhere very well to stainless steel. Its only redeeming characteristic is that it’s one of the few sealants capable of withstanding the 1000 deg F temperatures the firewall is supposed to protect us against in the (hopefully extremely) unlikely event of an engine compartment fire.

Before troweling this stuff on, I un-clecoed the side skins and pulled them back to expose the firewall side flanges.  I also pre-positioned the belly skin just above the firewall (big thanks to Mike Bullock for posting his sealing process, I copied it verbatim).  The blue painter’s tape is there to keep me from making a complete mess of everything else behind the firewall.

This stuff doesn’t spread well…if you don’t apply a lot of pressure to smooth it out, it stays “lumpy”, for lack of a better word.  Here’s what it looks like when applied…it’s actually smoother than it looks.

Here’s the final result, with a few side rivets set for good measure.

More riveting tomorrow…

So I was reading some posts on Van Air Force about shims and using a flexible epoxy called Hysol as a “liquid shim” in areas where the skin-to-structure fit isn’t so good.  So as an experiment I bought some Hysol EA9394 from SkyGeek and tried it out, first on the conical bends at the rear baggage compartment floor.

The stuff comes in a two-part pack.  After I mixed it up, I troweled it into a syringe…

…and injected it into the areas around the conical bend where the aft skin tabs don’t nest so well into the center skins.  The Hysol should fill any gap between the tab and skin, hopefully preventing big dimples when the rivets are set.

I had a little Hysol left over, so I shot some into the gaps left by poorly-fitting aux longerons in the forward fuse.  Vans makes these parts by joggling the ends, which means that some areas don’t fit so well.

The proof will be in how the skins look when we rivet them…I hope this wasn’t a waste of a day.

It’s Saturday and after the blizzard it’s 20 degrees outside and we have two feet of snow in the driveway.So do we bundle up and dig out the cars, or do we stay warm and dry and work on the RV? That’s an easy question to answer.

First thing we did was finish riveting two of four of the front floor stiffeners.  I was able to squeeze most of the rivets, but a couple required the classic buck/shoot method – no problems.

After finishing the stiffeners we moved on to fuselage side and belly skin rivets.  Some we were able to back-shoot, for others Ellen ran the rivet gun and I bucked.  We had a few rivets to drill out, but we made good progress.  The tungsten bucking bar is worth every penny I paid for it…made short work of some difficult-to-reach rivets.

I’m especially happy that we got most of the rivets done in the baggage floor where the side skin curves into the belly. Considering how much of a pain it was to get the side skins bent to the proper curve and fitted to the belly skin, this area came out really well.  Once again, Ellen did a wonderful job with the rivet gun!

Another picture?  Sure, why not…

We probably can’t avoid shoveling snow tomorrow morning, but after we do we’ll be back at work on the fuse right side.  We’re getting really close to flipping the fuse “canoe.”

After a quick round-robin trip to Delaware to deliver our daughter back to college, Ellen and I got in a short riveting session this afternoon before the Super Bowl.  We did all the aft tailcone longeron rivets, including the “keeper” rivets that secure the longerons until the aft upper skins are installed.  As usual, Ellen did a great job running the rivet gun.

One more thing…the walnut stick grips from Pioneer Aircraft arrived.  I really like the look and feel of these grips, and the switches have a nice, solid feel.

Guy at Pioneer was a pleasure to work with, and I’m looking forward to using the grips.

Back at work today after a couple of weeks off attending to other issues…Bob DiMeo came over and we spent several hours riveting fuselage side skins.

Not a lot of visual progress, but progress nonetheless.  Big thanks to Bob for driving down from New Hampshire for the day!

Happy New Year!  The project has taken a back seat to other priorities over the last few weeks, but today I had the opportunity to fix a problem that has been bugging me for awhile.

Seems that when I drilled the lower firewall weldments to the large longerons that support them, I managed to mis-drill a couple of the holes so that they weren’t perpendicular to the longeron, making it impossible for a bolt and nut to seat correctly around the hole.

I guess I’m not the first person to make this mistake, since there were a couple of threads on Vans Air Force on how to fix this sort of problem.  The solution of choice is to fabricate some angled shims or washers that allow the bolt head and locknut to be fully supported.

Here’s the shim I fabricated for the forward hole, there’s another one just like it on the underside of the joint.  As you can see, the hole was pretty far off perpendicular.

The aft hole wasn’t so bad, I was able to grind a couple of AN960 washers to serve as shims.

Here are a couple of pictures of the end result. I’m not proud of the screwup in the first place, but the fix worked well and I’m happy with how it came out.

Now it’s back to riveting!

I’m back at work on the project after a hectic Thanksgiving.  Saturday was devoted to home improvement – carpentry and electrical stuff.  Sunday was all about the RV. With a little squeezing and bucking I riveted the F-684 firewall gussets in place.  These were a pain in the arse to fabricate, so getting them attached was satisfying.

I also pre-riveted two auxiliary longerons in place, because the clips which attach the longeron to the firewall would be really tough to get when the firewall is in place.

When I drilled the armrests to the F-705 bulkheads, the angle drill wandered – poor technique on my part – and egged out a couple of holes.  Yeah, I know it’s only an armrest, but I put in a doubler anyway.  Call me obsessive.

I got the baggage compartment structure installed, but then realized that I forgot to enlarge the rudder cable passthrough holes. So they’ll come off tomorrow and get drilled.  With all the firewall parts in place, I also built in the forward fuselage structure.