Our RV-3 (Tsamsiyu) has been flying since day one with a Whirlwind 151 three-blade prop (the one with the yellow tips). Fabulous propeller—light weight, constant speed, great aerodynamics—that gave us tremendous performance, both in cruise and climb. The airplane will climb 3000 fpm at sea level or run down the ocean beach flat out faster than the airframe was designed to go (if you let it). But nothing lasts forever.

The 151 was one of Jim Rust’s early designs and he has learned a lot in more than a decade, refining both aerodynamics and mechanics to the point where the 151 has been discontinued in favor of the newer 300 series (the one with the white tips). And since the 151 was discontinued, he doesn’t have any parts for routine servicing or overhaul. So it was only matter of time before it became an expensive paperweight. And since I’ve been very happy with the 300 on our RV-8 for a year, Jim made us a good deal on a new prop for the RV-3.

The swap was simple—we didn’t even need to take the spinners off! The old prop (with the yellow tips) was added to Jim’s collection, while the new prop (white tips and beautiful carbon fiber-weave blade faces) was carefully balanced and proved to be smooth as silk. Since the performance is more or less comparable and we were swapping constant speed for constant speed, we simply did a new weight & balance calculation and made a logbook entry—it’s not a significant enough change to warrant a new Phase I.

I flew the airplane (from our home base near Reno) down to El Cajon (just east of San Diego) one day last week in cold temperatures (and great tailwinds), arriving about 10:30 a.m. By 12:30, the airplane was ready to fly with the new nose! Kudos to Jim and his team, as well as to painter/artist extraordinaire John Stahr, who pre-painted the spinner to match the rest of the airplane before the prop was ready. I flew the airplane back to Big Bear Lake for the night and headed home the next morning getting some qualitative performance data—it felt faster and climbed better! The winter air in the lee of the Sierra was too rough to get good quantitative data but I took it up the next day and saw a speed increase of about 3-4 knots flat out and probably a 10% increase in climb. Given that the airplane’s redline is 183 KTAS, I guess that getting 181 (WOT, full RPM, leaned for best power) is probably good enough when it comes to speed.

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I have spent 50 years working on airplanes of all types and materials—from tube and rag to metal plus a bit of composite. I have learned all sorts of fabrication and assembly skills. But one thing I have missed out on (probably because I took calculus instead of shop in high school) is welding. I have always admired those who could weld and love to see fine weld work. As a senior engineer in complex space programs, we talked about devices and components that had been welded, and evaluated their readiness for flight—but I had never really done it myself. With a bit of slack time between major airplane projects, I figured it was finally time to give it a try. (The fact that my wonderful wife gave me a welding helmet for Christmas probably gave me a clue that it was OK to explore a new skill as well.)

There are lots of different types of welding and the truth is that this is more of a sampler endeavor for me than something I am going to use in my routine airplane work. If I build a ragwing, I’ll most likely have someone else weld up the fuselage. Aluminum airplanes require precious little welding—and what there is (exhaust systems for instance) requires considerably more skill than I am probably going to develop. But there are reasons to weld around the shop—making tools, brackets, storage and fixtures, for instance. Owning my own hangar has me looking around at things that I could make, such as tie-down fixtures and workbenches. So forget the gas welding—I bought a multi-purpose unit that does stick, TIG and MIG.

Finding welding classes in a world where there are shortages of skilled welders is problematic—all the classes are full of folks wanting to get a job, so dilettantes aren’t welcome. But many of my neighbors are skilled at welding and they were happy to show me the basics, then turn me loose on scrap piles of steel to see what I could do. So far, I have pasted together a lot of scraps, cut them apart, and tacked them back together again.

So far, TIG seems to be winning out over MIG for the kind of work I need to do—mostly building small tools—but it’s nice to know I can stick bigger pieces together (like shelves or machine bases) when I need to.

So, no, welding isn’t an essential skill for the homebuilder. But it sure can come in handy—and if you’ve got slack time in the shop, it’s worth the time for “education and recreation.”

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As anyone who studied for their private pilot exam 50 years ago should know, airplane propellers should be parked horizontally—that’s so that when it rains, and the wood of the prop gets wet, both blades absorb the same amount of water, and you don’t get a heavy blade. Yeah….this is still technically correct, but really only applies if you have a wooden prop, and while there is probably a higher percentage of wood props in the E-AB world than on SPAM cans, most pilots are now flying behind metal or composite.

Wandering around our hangar this morning, with airplanes of different sizes and stances, I noticed that I have a different system for parking props—all of which are either metal or composite—that make the hangar safer and more navigable. And no, none of the props are parked horizontally.

The RV-3 sits kind of low (it’s a small airplane) but the prop has three blades and sort of long—one of those blades could stab you right in the eye if not positioned properly. One blade straight down keeps you from banging that one with your legs, but that puts the tips of the other two right at eye level, so one blade straight up seems to be the safest configuration; it puts the other two tips low, so they just take out your knees.

The RV-6 has a two-blade prop, and sits sort of like a low-rider. If you put the prop horizontally, you get stabbed in the throat if you approach the nose from the side, so vertical (or slightly canted off vertical) is good. Slightly canted is better in  case someone lifts the tail—you’d hate to stub the prop blade on the floor if it was vertical!

The Tundra sits tall on its big tires, and frankly, you could probably put the prop horizontally and few would walk in to it, but we’ve got a few tall guys in the airport who drop in once in awhile, so vertical is safest.

The RV-8 is hiding in the workshop space so no picture, but with its three-blade prop on a nose held proudly high, it is similar to the RV-3—just don’t leave one blade horizontal or it will stab you in the eye before you see it.

And lastly, there’s the propeller-less ankle-biter… the Subsonex. No prop, but that pitot tube sits right at shin-level, just waiting to trip you. Once you see it, you can’t look away – you’re like a moth attracted to a porch light… you can just see yourself walking through it. So we have to give it as wide a berth as a prop, just to keep us—and the airplane—safe.

If it’s just one airplane in a T-hangar, you can do what you like but if you coexist with other machines in group hangar, propeller parking is something to think about!

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The inspection, fortunately, isn’t all that hard as long as you have a borescope. And of course, I have a borescope but it has been getting a bit long in the tooth, is a bit buggy to connect with my i-Thingy devices and was old enough to have poor resolution. So into the shop came a new Teslong borescope designed to work with an iPhone and providing sharp, high-resolution pictures.

Here’s a tool tip! I liked my old borescope’s straight tube (with an articulating end) because I could maneuver it precisely. The new Teslong has no stiff section, so it is a bit floppy, making it a challenge to get it to go where you want. But you can fix this with a plastic soda straw—just slit the straw lengthwise with a razor, slip it on and tape it in place. Now the last 10 inches of the bore scope is rigid and more easily maneuvered. Yes, the end still articulates.

The inspection required enlarging a tooling hole in the outboard rib of the stabilizer after moving the elevator counterweight out of the way. This was easily accomplished with a step drill. Sliding the bore scope in and angling it around for a good view was a quick task, and voila! No cracks were found on either side of the -6 or the -8. Logbook entries made, service bulletins filed until next year, when the inspection has to be repeated.

But what about the RV-3? Well, it’s also fine but took a little more ingenuity. Since there are no outboard counterbalances on the elevator, the tips are glassed in to the end of the stabilizer, providing no access from the tip end. But the stabilizer is short on such a small airplane and the empennage fairing comes off. There are only two ribs on each side of the stab—root and tip—so with nothing in between to be navigated, it was a simple task to (once again) enlarge a tooling hole and slide the borescope in, this time all the way in, and confirm that we had no cracks. “Whew!” (I dread having to repair a cracked spar, not because of the metal work, but because of the custom paint job.)

Of course, we did the RV-6 inspection as part of its annual condition inspection in February—so at least that airplane is out of the shop for awhile. But the SubSonex jet gets its annual physical in March so, once again, we’ll have a patient in the examination room!

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More recently, I was working on another little task that required a very narrow-nosed socket wrench. In the past, I have butchered cheap sockets on a bench grinder, most notably to have a tool that fits Lycoming connecting rod big-end bolts. But now realized I could have a whole set of such custom sockets with the new lathe skills I’d been learning. Off to Harbor Freight for the sacrificial victims.

It’s a simple matter to set the lathe up to move the tool at a 5 degree taper angle, and I proceeded to turn down the entire set of sockets (one at a time) until they were tapered to a knife edge. Given that it is a set of small sockets and torques rarely get very high, they should do the job—whatever that might be—in the future. Since things were all set up, I did regular and deep sockets at the same time!

Hey, what’s all that racket on the internet? Oh dang, a new service bulletin just came out that affects all three of our RVs… get the tools out!

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So what about keeping busy in the shop? Well, our shop work is in transition. We managed to move the eXenos project into a neighbor’s hangar that was big enough for the 46+ foot wingspan before winter really descended—and finished assembly. The airplane was weighed, paperwork filled out and everything is ready for an airworthiness inspection (since completed). But arranging that with the holidays and a number of other constraints has been problematic. And, of course, the hangar isn’t being used for anything else and the ramp is in the shade so there is now a good foot of frozen slushy ice trapping the airplane until we get a good thaw. Even if we get the airworthiness certificate soon, it’ll be hurry up and wait….

So the shop is fairly empty, and we even cleaned things up—put away tools, resurfaced a workbench, sorted and stored a bunch of parts. But that just means that there really isn’t much to do between condition inspections on all five family airplanes. Those do come around!

But lest this sound like nothing but complaining, there is an advantage to “slack time.” It can be used for education (and recreation, I suppose). Everyone builds different skills in their lives and one of the skills I have missed along the way was welding. So that was on the list—picking up a multi-purpose welder and learning how to stick scrap metal together. It’s been a fun time learning how to MIG and TIG—a lot of random pieces of shop steel have been sacrificed in the pursuit of knowledge and skills. Lots of inadvertent holes have been burned into some pieces, but every day we get just a little better—and yesterday, I made my first actual “thing”—an adapter for my slide hammer that allows me to pull Lycoming case through-bolts. It could be prettier, but its functional!

Next time: fun with the lathe…

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The first and biggest reason I passed not going to the show was because we are finalizing paperwork and ground testing on the electric Xenos, getting the flight test plan in shape and flying the other airplanes when I can to get the skills back up for flight testing. That means doing lots of slow flight and stalls, plus shooting engine-out landings to make sure I have knocked the rust off from a winter that has seen us go weeks without opening the hangar doors. Now that the storms are leaving a day or two gap between them (although they are still coming), we’re getting up and burning Avgas and JetA so that I’ll be ready to simply let the electrons flow through the motor in the eXenos when we’re ready.

But flying isn’t the only thing keeping me busy—there is always something to do in the shop. I’ve been learning how to weld (a skill most guys learn in high school shop, but hey, I was taking math and physics, finishing a pilot’s license, and working on airplanes—one has to have priorities…), and felt that I’d stuck enough scrap together, so it was time to build something. I’ve borrowed a neighbor’s engine stand for past motor work so thought “hey, I can build one of those!”  I actually started with a beautifully machined top plate from a machinist friend, and figured that all I needed to do was stick some legs on it. I used some pictures from the internet for design inspiration, and made up my own dimensions after discovering a nice piece of angle steel in my hangar corner that had been used for landing gear alignment.

Then of course, I changed my mind about welding to that gorgeous plate, so I crowned a piece of 1/4” steel (again—having a machinist friend is really handy!) and did some cutting and milling to make a plate to which the legs are welded—then the really nice plate is bolted on top of that!

Casters are really cheap on Amazon it turns out, and they come with mounting bolts—some steel flat sick from Ace Aviation Supply  (and they think they are just a hardware store) completed the bill of materials, and the TIG torch got a workout. Some primer and pant, and voilà—proving once again that time in the shop is always useful. Not that fly-ins aren’t useful as well….but I’ll get my fill at AirVenture!

And with the welding project out of the way, its back to prepping for that eXenos flight… now where is that EAA Flight Test Manual again?

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After almost eight and a half years of on-again, off-again building (other airplanes and projects seem to keep getting in the way), we finally had an airworthiness inspection of the eXenos project today! Normally, an announcement like this would be accompanied by a picture of the inspector handing the applicants their airworthiness certificate and operating limitations, but due to some unique circumstances, that will come in a day or so. For now, its good to know that the FAA was happy with the airplane and all of our submitted paperwork, and its just a matter of dotting a few “i’s” and crossing a few “t’s” with FAA headquarters until we can put the paperwork in the machine and get it ready to fly!

Why the further minor delay? We’re hoping to include the brand new option of doing a Task-Based Phase 1, and since the process was only approved about two weeks ago, it is taking a special effort between the Reno FSDO and a number of people in Washington to round up the necessary approvals and signatures. That’s right—we’re doing a little pioneering work so that this can become routine for everyone in the near future. And effectively, the delay doesn’t really mean much, since our weather in the neighborhood of the Sierra Nevada has been so atrocious  the past two months that it has been hard to keep the skills up for test flying. Now that we might be seeing a break in the storm cycle, I can get back in the air every day and do the necessary practice and skills work-ups to be ready for the first flights in this unique vehicle—an electric motor glider.

Our visit from the FSDO today included two inspectors, Gerry and Ryan, who started out going over all our paperwork, and finished off with a thorough inspection of the airframe and the unique power-plant configuration. They did find the one missing rivet we left for them, and one bushing that was on backwards—great job guys! We’re all struggling a little bit with the contents of a Condition Inspection checklist for the electric motor and power system—aside from checking for wear on the two or three moving parts, and looking to make sure that the wiring is intact, there really isn’t much more to do. The Xenos airframe is similarly simple, but Louise is busy creating a detailed checklist which will “meet the scope and detail of Appendix D to Part 43” for the annual condition inspections, since she’ll be getting the Repairman’s Certificate for this aircraft and doing the annual ritual to keep it “in a condition for safe operation.”

So here’s hoping that we’ll be able to make a formal “birth” announcement of this new flying machine in a few days. There are a lot of fine folks working behind the scenes to make it happen, and we thank them all. Then it will be on to a Task-Based Phase 1 with a very different kind of machine.

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The container – familiar to anyone that shops at Costco and enjoys those little peanut-butter-pretzel snacks – is full to the brim. That’s fuselage, wings, tail, and any accessories such as gear leg fairings and cowl attachments. Top be completely open, we probably used a few solid rivets here and there for minor things like cowling attach hinges, but the airplane is 99% built exactly to plans. Well, except for the firewall forward installation of the electric motor.

We’ll keep you up to date on the process of getting it in the air—as soon as we figure out how to fill out the online “paperwork” system that the FA has instigated since our last completion.

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