Wiring Your Plane with the Vertical Power VP-X

Marc Ausman of Vertical Power demonstrates a basic aircraft electrical wiring setup using the new VP-X solid state electronic circuit breaker system.

So, we picked up a 4″ no-hole yoke from Avery Tools, and with this we were able to squeeze those tight-quarters rivet placements. And if the photo below were at all legible, and/or there wasn’t a bookshelf in the way, you’d see that, yes, we do in fact have a set of completed tail feathers.

We then jumped right into riveting the stiffeners to the rudder skin, since Dad had spent the last several weeks doing the trimming, drilling, dimpling, deburring of the rudder components. We used the C-frame backriveting technique for most of this job, but found that is was not quite as foolproof as we would have liked — we still ended up with some clubbed rivets.

We’ve since decided that the thin skins of the moveable surfaces, coupled with #40 holes and dimples, cause the rivets to move around a little too much in their holes, resulting in some of them bending over while driving. We might try a slightly smaller drill bit (#41?) next time.

We then moved on to bending the rudder trailing edge with the great 2×8 press brake that Dad fabricated (I’ll get some pictures of that process when we do the elevators), and we were pleasantly surprised with the results. Following the advice of several other builders, we taped a wooden dowel to the inside of the trailing edge to ensure that we got the proper bend radius.

Finally, we assembled and drilled the rudder understructure, and prepped the parts for priming.

Of course, no airplane work session can be without its pitfalls and heartbreak, and this one was no different. While match drilling the rudder understructure, we noticed that we’d over-trimmed the R-710 rudder horn brace, pictured above. This caused our drilled holes to be too close to the top edge (the bottom edge in the picture) to meet minimum edge distance requirements for a 3/32 rivet.

After much debate and hand-wringing, we decided to order a replacement part, and we moved on to priming and riveting what we could of the rudder skeleton.

Oh yeah, and last but not least, here’s a picture of me, doing … something.

EAA Video: Airventure 2010

Time to get psyched for Oshkosh, “The World’s Greatest Aviation Celebration.” Be there or be square!

EAA Video: Blast From The Past, Part 1

Check out this great EAA archival footage of fly-ins from ’50s and ’60s. Campy, but cool!

EAA Video: Remember the Foxjet?

I ran across this cool promo video for the Foxjet ST600 while checking out my EAA feeds. Designed in the late ’70s, the Foxjet was the predecessor to the modern VLJs (very light jets), and had some of the same shortcomings. But this video is worth a watch just for the cool retro music and cheesy special effects. Learn more about the Foxjet here.

EAA Hints for Homebuilders: ELT Installation and Testing

EAA Tech Counselor Dick Koehler discusses the federal regulations and installation techniques for emergency locator transmitters (ELTs).

For some reason, while using the Cleaveland squeezer, we ended up with some “clubbed” shop heads, illustrated below from MIL-R-47196A, the military specifications for driven rivets.

Although we carefully aligned the flush sets of the squeezer, and watched the shop heads as they formed, the fact that these rivets had “dumped over” escaped our attention until we took a closer look. Some example photographs are included below.

With the tiny AN426AD3-3.5 rivets, it’s difficult to get a properly-sized shop head that adequately covers all of the drilled hole beneath it. If we moved the set or bucking bar just a little off center, we got results like these. We found we had a much easier time forming acceptable shop heads with the bucking bar rather than with the hand squeezer.

At this point, we’re still not comfortable using the squeezer without it being solidly mounted to the workbench.

We called our Tech Counselor, Tom, and he graciously agreed to return just a few days after his first visit, to confirm our suspicions that these rivets needed to be replaced. Before his arrival, I carefully inspected each accessible shop head with a flashlight, then marked any suspect rivet with a permanent marker.

Tom agreed that some of the clubbed rivets would need to be replaced, but also added that the odd rivet here or there with an imperfect shop head might be considered acceptable, while several bad ones in a row should be drilled. We’re still developing our own sense of quality workmanship, so Tom’s advice was again invaluable. Thanks again, Tom!

So, after completing the vertical stab, we went back to the HS, and spent a couple of hours drilling out and replacing rivets. We got fairly adept at the process, and won’t have any reservations about replacing bad rivets in the future.

The good news, however, is that the horizontal stab is now done! Both the HS and the VS are now in temporary storage, as we move on to the empennage control surfaces.

We’d had great luck with the bench-mounted squeezer while riveting the HS rear spar, and this time was no different. Everything turned out great, including the countersunk AN426′s near the base of the spar. Having the unwieldy squeezer affixed firmly to the bench makes a big difference in the finished product.

We’ve also gotten fairly adept at riveting with the Sioux 3X gun and tungsten bucking bar, although we seem to have type-cast ourselves a bit. Dad’s been doing all the shooting and I’ve been doing the bucking. We’ll have to learn to switch up sometime soon, but we’ve really got a good rhythm down so far.

Ah, “The Robot” — a Christmas gift from my sister to Dad — has made all of our riveting success possible. This little oddball from Mars has illuminated the inky depths of our shop head ignorance with its eerie blue LED light since the very beginning. It has become virtually indispensable. I highly recommend picking one up next time you’re in that neck of the solar system.

We’ve had a bit of bad luck when using the Cleaveland squeezer free-hand (more on that later), so we used the rivet gun and bucking bar for the remainder of the riveting. You’ll notice the duct tape on the bucking bar — it helps to pad the sharp corners and keep them from scratching the primer while the bar is “bucking” on the shop head of the rivet.

After getting the forward spar and ribs together, we clecoed on the skin and started tacking it down from the center outwards. Once again, “The Robot” came in handy for inspecting the shop heads deep inside the assembly.

Once we were done reaching inside the stab to buck, we clecoed on the rear spar assembly and began riveting around the edge of the skin. Although we could have reached most of these with the squeezer, we kept up the gun and bucking show, with good results.

There were a couple of rivet placements — the leading edge of the stab and near the big rudder hinge bracket — that we couldn’t reach with squeezers or the bucking bar, so I went ahead and ordered a 4-inch “no-hole” yoke from Avery. Hopefully that will aid in accessing those tight spots.

Other than that, however, the vertical stab is done. Bwahhaaa! On the the rudder!

Today we began work on the vertical stabilizer, which — being very similar to the horizontal stab — went much more quickly than we’d anticipated.

Dad had already done most of the prep work on the VS parts, including edge deburring the ribs and finishing the rear spar doubler on the Scotch-brite wheels. Dad reported that the 1″ diameter 3M Cut & Polish Wheel from Cleaveland Tool (mounted in the Dremel) made deburring the big lightening holes a breeze.

So, we blasted right into match-drilling the understructure and the skin, including the rudder attach brackets on the back of the spar. The VS skin is much easier to get on and off the ribs for some reason, maybe due to the fact that there’s no center nose rib.

After drilling, we flowed right into deburring and dimpling, and — even though we planned ahead of time not to dimple the fairing attach holes on the lower edge of the stab — we got a little ahead of ourselves and dimpled a few holes that didn’t need it.

We also dimpled and countersunk the holes at the bottom of the rear spar — the ones that butt up against the fuselage attach point and thus must be flush riveted. Once again, the microstop countersink mounted in the drill press made short work of this task.

Next, we moved right into the surface prep and priming process, exactly as we did on the horizontal stab. This time however, we had the benefit of good weather and temps in the upper 60s. We decided to stop with only two coats of the SEM primer this time; it saves weight and primer, and leaves just about the same finish as the three coats we did the first time.

So in a single day’s work (thanks to the great preparation by Dad) we managed to knock out a sizeable chunk of the vertical stab. We should be able to finish up the riveting in just a few more hours.

The first order of business was to have our progress and skills reviewed by an EAA Technical Counselor. A tech counselor is an experienced builder or mechanic who volunteers his time to help newbies such as ourselves with the inevitable problems and questions that crop up during the build. So last night Dad and I hosted Tom Olson of EAA Chapter 33, and he gave our work a thorough inspection.

Happily, Tom seemed pleased with the quality of our work, and we spent a couple of hours chatting about tools, techniques, components, and those amazing flying machines called RVs. Tom’s endorsement really boosted our confidence, and we hope to see him at regular intervals as the project continues. Thanks, Tom!

This morning we set up the shop to continue where we’d left off, which was on the left half of the stab, with only the HS-707 nose rib riveted in place. We began by riveting the forward spar assembly to the HS-706 and HS-708 ribs, and then we got busy putting the skin on.

As many others have mentioned before, a tungsten bucking bar is worth its weight in gold, and after today, I’d have to agree. This little baby fits into all kinds of hard-to-reach corners, and it’s so dense that you really only need to have a couple of fingers holding it to get a good shop head on the rivet. I’ll stand by what I’ve said many times in the past: Good tools make all the difference.

Dad and I worked all morning, and developed a good rhythm between shooter and bucker. Good communication and a steady rhythm seem to be the key to setting perfect rivets. We set 200 rivets today and didn’t drill out a single one. Good stuff.

In just a few hours, we managed to finish all of the bucked rivets on the interior of the stab, so all that’s left for tomorrow will be squeezing the edge rivets with the hand squeezer. Almost there!