I have to say, it looks suspiciously like — a brand new airplane engine!!!
Admittedly, there’s not much building going on here, but there are some cool details to look at. The engine comes with its Engine Control Unit (ECU) – the computerized module that monitors and manages the engine performance. There’s a fusebox and dual voltage regulator module. And, there’s a completely assembled fuel pumps module. Early Sling 2 kits apparently required building up the internal plumbing with two 2 pumps, check-valves, hoses and clamps. I’ve been spared all of that. Each modules are matched to the engine serial number and were presumably used to test run the new engine (for about an hour) at the BRP Rotax engine factory in Austria.
There are some small parts for specialized electrical connectors that I’ll send off to my wiring harness builder for incorporation. There are also some bushings and hardware for mounting the Whirlwind propeller, which should arrive in a few days.
A lot of thought has gone into the instrument panel. With two 10″ Garmin G3X Touch displays, remaining Sling 2 panel space is at a premium. I still needed to tuck in a GTN 650Xi navigator, GMC 507 auto-pilot control and a G5 backup flight instrument. With all that gear, finding places for switches and circuit breakers took me a while to figure out.
A Vertical Power VP-X Pro, solid-state circuit breaker system, completely eliminated panel-mounted circuit breakers. The arrangement of the quite modest number of switches has been carefully laid out. Workflow and purpose were key considerations. I’ve taken advantage of advice and feedback from many sources. So far, I think it’s turning out beautifully.
There’s a tremendous amount of functionality in the touch-screen avionics. That reduces panel clutter enormously. Remote GTR 20 VHF (COM2) radio, GTR 245R audio control and GTX 45R ADS-B (in/out) transponder are all managed through the touch-screens. There’s also integrated engine monitoring and display.
There’s so much stuff, that getting a professionally designed and fabricated wiring harness is clearly the only way to go. The absolute top shop for this work is Midwest Panel Builders in Lapeer, Michigan. They’ve been setting the standard, especially for the various models of Sling aircraft.
The integrated capability of all this equipment is truly astounding – off the charts compared to more traditional steam gauges that have been the mainstay of small GA aircraft for decades. I simply cannot wait to slip into the cockpit and learn how to put this technology to effective use. It’s going to be huge fun. My plan is to earn my instrument rating in my own technically advanced airplane (TAA) . That’s a thing, believe it or not.
Big Wednesday kicked off with a scenic morning drive from Sequim to a freight forwarding company in Kent, Washington. My engine and firewall forward kit was shipped Cargolux air-freight from South Africa, changing planes in Belgium. The goods arrived a couple of days earlier at Seattle-Tacoma International Airport (KSEA, SeaTac). Having cleared customs, it became available for me to collect.
I’ve looked forward to a day like this for I don’t know how many years. Having an absolutely brand new airplane engine is almost too much for me to grok. I’ve been harboring thoughts of rebuilding the O-32O in my ’84 Warrior, almost since the day I bought it 20 years ago – but, it hasn’t happened. It’s still running strong at TBO. And now, I’ve got the Holy Grail in hand – a factory new airplane engine! Oh my!
This new engine and the Sling 2 airplane I’m building are a match made in heaven – 21st century all the way!
After a gallant effort on the original RH wingtip, I ordered and received a replacement RH wingtip. The new part still had too much length and thickness at the trailing edge, but the workmanship of the layup was much improved and it had noticeably better overall shape. It has still taken lots of work to get the new RH tip to fit. But, it’s coming along and it’s going to work out well.
The LH tip is proving to be huge headache. Despite extensive rework, it’s now clear that the LH wingtip isn’t close enough to the proper cross section to fit and it would take extraordinary effort to get it in the ballpark.
Just like the RH wingtip, the length of the LH part at trailing edge is too long and the trailing edge profile (taper) is too thick to fit the trailing edge wing skin. But the kicker is the overall height. It’s just too narrow – top to bottom. It’s almost 2 cm short, at the widest point.
Trying to stretch the height of the LH tip requires too much force. The LH wingtip has no imbedded reinforcement strip on the bottom edge. The top reinforcement is out of position. Without proper stiffness, the tendency for waviness between the rivet holes would be profound.
To continue with the original LH wingtip, I’d have to section the part and almost re-manufacture it. I’ve decided that it’s much too much time and effort, although I have seen one other builder go to such lengths and spent over 130 hours on just trying to get his wingtips to fit. I’m at more than 40 hours on wingtips and I’m going to cut my losses and get a better baseline part.
I went ahead and negotiated a new LH wingtip from the factory, as I did for the RH side. They’ve kindly agreed to send me one. Kudos to Sling Aircraft for standing by their product. Stay tuned.
One things leads to another. A question about the factory-installed rudder cables got me started down the road of test-fitting the vertical stabilizer. I was very pleased to find that it was easy to do and the fit appears to be excellent.
I hadn’t really expected to do this step just now. But, in order to evaluate much about the rudder cables, the entire control mechanism for the rudder and steerable nose-wheel needs to in place and adjusted. I learned this during a customer support exchange with Sling Aircraft’s Jean d’Assonville. I’d called him because I was concerned that the rudder cables may have been installed improperly during factory the quick-build of my fuselage. Jean assured me that it was very unlikely that the cables were wrong.
I was wondering because the KAI talks about one cable being slightly longer than the other. Somehow they seemed to be the other way around. Jean said that the only way to properly evaluate the setup would be to assemble everything. It only takes 15 minutes, he tells me! LOL. But, he really meant it!
It’s going to take me hours and hours, over days and days, to get the entire rudder control mechanism in place. That’s not only because I’m slow and plodding, but also because I’m not ready to install the nose-wheel yet. It’ll all just have to wait until I get the avionics rack, LRU’s and harness in place while the wheels are off and the fuselage is low and as easily accessible as it can be.
So then. I still don’t know for certain that the rudder cables are installed properly. But, I did get inspired to get the VS out from storage in the house and get it fitted on the fuselage. Technically, that’s progress! The nice fit between the fuselage and vertical stabilizer is satisfying too.
The fiberglass composite wingtips are needing a lot of rework. I don’t really believe it was intended be this way. What’s a simple amateur home-builder supposed to think?
The biggest area needing attention seems to be where the inside trailing edge of the wingtip is supposed to fit into the narrow skin at the tip of the wing. Several issues are being dealt with. Overall length is too long – by about 2cm (almost 1/2 inch). And, the fiberglass structure doesn’t match the contour of the wing profile near the TE. The taper of the fiberglass needs to become quite narrow. Plus – it’s all got to look pleasing and with and both wingtips ending up to be nicely matched – both aesthetically and aerodynamically.
I’ve decided that some sort of struts are needed to help the wingtips fit the contour of the wing. The kit instructions indicate that the wingtips are just match drilled and riveted. But, just letting the rivets pull the fiberglass shape seems like it’s going to lead to unwanted waviness from dips between the rivets. I fabricated simple struts to take some of the tension load off of the rivets. We’ll see how that goes.
I’m making progress, little by little – but it’s slow. Rework involves epoxy and with winter temperatures, each cycle needs a full 24 hours or more to cure. There’s plenty of sanding and shaping to do. Check fit. Then repeat.
I expect building an airplane to take some work, so I’m not going to complain too loudly. I fill terrifically privileged to be doing this project.