The trip itself wasn’t easy, and if that sounds silly to say about flying across the Atlantic from extreme Southern the Northern Hemisphere in a small plane, we’ll grant you that. Making the trip were four pilots, one of whom requires hand controls after a motorcycle accident. And sadly, Sling president Mike Blyth couldn’t get his U.S. visa in time to make it to OSH, so the big party had to take place without the big guy. He did make it three-fifths of the way, but couldn’t legally enter the U.S.

The details of the trip are fascinating and include more challenges than you can shake a wing at, but they made it. For all the details and amazing pictures, visit Sling’s site, where team members have documented all of it, leg by leg and blow by blow.

And if you’re not familiar with Sling and/or its HW model, you soon will be, as they are selling like whatever the South African equivalent of hot cakes are. I’m told, they’re hot cakes! The company came to OSH with almost 150 orders for the HW kits and we understand that in just the two days the HWs have been at the event, the company has taken around 25 more orders for the pretty new model.

The post Sling Flies Not One, Not Two, But Three High Wings Across the Ocean to OSH! appeared first on Plane & Pilot Magazine.

Pilots lined up to try them out and were enchanted by the fighter-like handling yet simple and affordable construction. And as much as customers loved the designs, from early on, there was a hew and cry for a high-wing Sling.  

And Sling made it happen, though Sling had intended to fly the new Sling High Wing to AirVenture 2021, complete with a 17-hour flight over the Atlantic from Africa. However, COVID-19 quarantine requirements made that impossible.

Globe-Trotting Development

Ten years ago, on the last leg of another round-the-world voyage, the low-wing Sling 4 had shown its remarkable ability to lift a massive load and fly for 27 hours non-stop from Rio de Janeiro to Cape Town. It accomplished that two-up, including a cabin full of survival gear and baggage, with its basic Rotax 914 engine. Yet many wondered what the Sling 4 would be like with more power. 

The advent of the Rotax 915 iS with 141 turbocharged horses provided Sling Aircraft with the opportunity to update the Sling 4 with not just the more powerful engine but also a new and faster wing. The result was the Sling TSi, which has become the aircraft in most demand from the Sling factory—particularly after a number of prominent social influencers in the USA began building their own under the 51% rule. 

Slings use conventional pop-riveted aluminum and come in three levels of completeness: 1) ready to fly, which may be flown in the USA as a demo aircraft; 2) the quick-build kit, which conforms to the 51% rule; 3) the basic homebuilder’s kit.

With more than 90% of the Sling Aircraft factory’s production now sold outside South Africa, the Sling 2 and 4 range have been a phenomenal worldwide success. The demand kept the factory too busy to be readily distracted into designing and building the long-awaited High Wing.  But it was always bubbling away in the background, and for a number of years The Airplane Factory (as it was then called) employed former Boeing aeronautical engineer Mel Verity to work on the fuselage modeling. 

The Sling High Wing made its first flight as promised before the end of 2020. That development and construction had continued through the COVID-19 lockdown is testimony to the dedication and commitment the Sling team brought to the project. It took six months before the Sling Aircraft factory decided that the High Wing was developed enough for us to review, although Pitman insists it is still a prototype. 

A major design departure from the low-wing series is that a composite structure is used to handle the loads and compound curves required for a smoothly shaped high-wing cabin. 

High Wing Development

Reflecting the unexpected complexities of converting a low wing to a high wing, the Sling HW had an unusually long gestation. In the past, The Airplane Factory has shown itself able to create an all-new plane and just roll it out the hangar and fly it around the world. The Sling 4 launched on its round-the-world flight a mere 20 days after first flying. 

The big change was the advent of the Rotax 915 iS in 2018. Unlike Rotax’s first attempt at fuel injection—the underwhelming 912 iS—the 915 really was a big step forward. To match the new engine, the renamed business Sling Aircraft took another huge leap for the development of the Sling TSi. The company gave it an all-new wing, replacing the NACA 4415 aerofoil with the slimmer, shorter (31.3 feet) and thus faster NACA 2414.  This wing is used unchanged on the High Wing.

A major design departure from the low-wing series is that a composite structure is used to handle the loads and compound curves required for a smoothly shaped high-wing cabin. It had been hoped that building the High Wing would involve just a new center fuselage section, but things are not that simple. At higher angles of attack, the high wing blanks the empennage, so the vertical fin has been made 8 inches longer than the Low Wing’s.

I met the high wing (HW) in the flesh for the first time at Sling Aircraft’s Tedderfield factory south of Johannesburg. The airfield is on the South African Highveld and is situated at 5,200 feet, which challenges the performance of many light aircraft. 

Parked on the apron, it looks bigger and somehow more substantial than the Low Wing TSi—and it is. As a 6-footer, I can walk beneath the wing. The wing has zero dihedral along the top, but as it tapers in both width and thickness, it may appear to have some dihedral. The absence of dihedral contributes to the much-admired Sling balance between lateral stability and control responsiveness. 

Blyth points out that stability in roll is naturally there because of a high wing’s pendulum effect, so the dihedral can be and is less than on the Low Wing. However, this led to unexpected challenges in designing the fuel system for the standard 26 gallons fuel tanks in each wing, as dihedral naturally gives fuel a downhill run from the outer reaches of the tanks. The Sling High Wing I tested was equipped for the Oshkosh flight and had optional auxiliary outer tanks that feed the inner standard tanks for a total of 65 gallons. These then route through the fuel selector in the cockpit roof and down to a 1.5 gallon header tank mounted behind the firewall. 

The Sling HW and TSi are immediately distinguishable by the large NACA duct on the right side of the cowl, which feeds air into the 915 iS engine’s high-volume intercooler. 

Unlike the Low Wing, with its gullwing doors, the HW doors conventionally hinge at the front. The composite doors can be slammed with reassuring firmness, but there is a need for further development to stop the top of the door from bulging out at cruise speeds. To avoid the complexity of dual latches (like a Cherokee), Sling ingeniously tried magnets on the prototype, but what that will do to the compass is anyone’s guess!

I’m always surprised by how much room there is within the compact dimensions of the Sling 2 and 4 and, in particular, what a great sense of space there is in a Sling cockpit. The HW is even bigger thanks to its composite cabin shell. Although Pitman is a skinny fellow, there was no shoulder rubbing between us during the test flight.

The rear seaters should now have more headroom, too. However, the prototype’s rear seats were thickly cushioned, so the headroom not as good as I had expected. This is, however, easily fixed by lowering the seat squab and perhaps reclining it more, as in a Cessna 182, where the backseat passengers are essentially sitting on the floor. The view out from the backseats is excellent, thanks to the large windows. 

The simple but strong bowed composite main undercarriage legs are standard-issue Sling hardware. They are mounted to the bottom of the monocoque fuselage with minimal change. The nosewheel is also unchanged, allowing the same firewall forward installation as on the low-wing TSi.

Despite our test aircraft being a prototype, it had a smooth finish from flush rivets on the wing leading edge. There is a large tear-out panel on the rear turtle deck with slotted rivet holes for the ballistic parachute cover.

Flying The Sling High Wing

Getting into the cockpit is easy. I placed my foot on the far side of the control stick and then hoisted myself up and onto the seat. However, it may have been more elegant to have used the little step on the undercarriage leg. I had been expecting a four-point harness, but the seatbelts are conventional three-point car types, with a single inertial reel.

Starting the 915 is simple. Flip on the two ignition lane switches and the two fuel pumps and turn the ignition key. The Rotax springs readily into life, and, compared to earlier engines, has less clatter from the prop gearbox thanks to its larger impulse damper.

Despite the weight of the complex engine, turbo and intercooler in the nose, and the forward CG as we were two-up with lots of fuel and no baggage, the Sling HW is still light and easy to taxi with its tricycle gear and nose wheel steering. I far prefer a steerable nosewheel to a castering one that relies on differential braking. I was pleased to see that both seats have toe brakes.

At the holding point, testing for full and free movement of the controls revealed a potential problem—with full back stick, the full left and right movement of the stick was limited by the V of my legs. Pitman says that they will adjust the bend in the stick and reduce the amount of stick throw movement required for full aileron deflection. 

The electrical unslotted flaps have a rotary knob with pre-marked positions: Up, 1, 2, 3 and Down. With the flaps selected to 1, I applied full power against the brakes, which were powerful enough to hold the straining 141 horses with ease. At high power settings, the 915 goes to auto rich and has a huge thirst for such a small engine, sucking 13 gallons per hour. 

On brake release, acceleration was good, without excessive right rudder, and at the recommended 55 knots rotation speed, it felt ready to fly. And this is where there was a significant difference with the Low Wing, as the High Wing does not produce the same amount of ground effect as the Low Wing. So, there was no gradual float into the air; rather, it required back pressure on the stick, and then we were airborne with a bit of a lurch, thanks to my rough hands, and the stall warning bleeped briefly in disapproval. 

We were almost instantly at Vy (best rate) climb speed of 75 knots, indicating a healthy 1,200 fpm over the runway end. It was natural to lower the nose to 95 KIAS and still be climbing skyward at over 750 fpm. It was a turbulent day, so it was hard to get clear vertical speed numbers.

The graphics on the large Garmin G3X EFIS make situational awareness a treat. The large 10.6-inch screen dominates the instrument panel. It easily has enough space to display all the instrument and navigation requirements. There is even an option for TCAS, and, for the Oshkosh trip, a Bluetooth satellite phone had been added as a spare radio. 

A huge benefit is the intelligent and smooth Garmin-integrated auto-pilot that can be programmed to maintain altitude, direction and attitude and even fly a coupled approach. A particularly useful trick Pitman had was to simply push the blue “level” button when he wanted to explain something. 

Sling aircraft are a delight to fly thanks to the designers’ commitment to the military specification of control forces being 1:2:5 for roll, pitch and yaw. One of the big challenges the design team faced with the high wing was how to preserve the Low Wing’s crisp control response with the low breakout forces from having almost frictionless pushrods to the ailerons and elevator. Having to route the aileron controls through the floor and up the door pillar necessitated control cables. Yet it was immediately apparent that the breakout forces are still commendably low, and the response is still crisp yet without twitchiness. 

Even though we were 7,000 feet, which is far below the aircraft’s best operating altitude, I explored the Sling HW’s speed capability. The EFIS displays power as a percentage of total rated power, and at around 82%, it changes the engine management from producing best power to best efficiency. Thus, at 81% power, the fuel burn is 9.2 gph, while at 80% the fuel burn drops to 7.4 gph. 

Thanks to the large intercooler, a typical cruise with the HW is 38 inches of manifold pressure with the prop set at Cruise for 5,100 rpm, which gives 80% power. Pitman says he works on 145 KTAS at 7.4 gph at 9,500 feet. And this seems realistic. This makes it about 3 knots slower than the Low Wing TSi.

The cockpit noise levels were low compared to most production aircraft, and as we cruised, my spirits lifted with the responsiveness of the aircraft, the smooth and plentiful power, and great view out. You really do feel at one with the plane in a Sling. And the cabin is tall enough so that you do not have to wind your neck in to see out the side window beneath the wing. Naturally, though, the visibility in a turn is not as great as from the Low Wing with its side windows that curve over the front seats. 

I tested the control harmony and roll response by cranking it over into about a 75-degree bank. It effortlessly maintained height, even though the stall warning beeped occasionally. With a full throw of the stick, a 150-degree roll reversal was smooth with little tail wag, although my feet needed practice on how little lead with the rudder it required. A few practice rolls around a point would make a smoother transition. 

I pulled the power back, thankful that liquid cooling vastly reduces the chance of shock cooling the engine. With the flaps up and the nose surprisingly high, the stall break came at 57 knots—2 knots faster than I had seen in the TSi—but then it was a bumpy day. I held the wing in a deep stall and tried to keep it straight with aileron until it would take no more abuse and gently dropped the nose. The recovery just required relaxing the back-pressure on the stick. 

With full flap and power off, the nose stubbornly clawed for the sky, and the
airframe shook until the stall break came at 47 knots—with a still-gentle nose and wing
drop. We recovered with barely 500 feet of altitude loss. It should be impossible to get it into an unintentional spin. I could
easily hold the stick almost all the way back and just wallow down at about 600 fpm at around 46 knots—a survivable escape from IMC. Nonetheless, a ballistic parachute is a popular option.  

Even deep in the stall, the elevator authority is excellent at full-forward CG. Unique to the High Wing, Sling has fitted an anti-balance tab to the right-hand elevator to lighten the stick force when full up-elevator is needed, such as on landings.

Returning to the Tedderfield pattern, we joined a Right Downwind for 11. Trim changes with flap were so small, I hardly noticed them, and selecting Flap 3 caused a slight nose-up pitch, which could easily be compensated for by reducing the power for the glideslope.

We tracked down final at an easy 70 knots—a bit fast but a speed I (and the plane) felt comfortable with. Pulling the remains of the power as I crossed the fence, the controls remained effective all the way to touchdown at around 45 KIAS in a gusty crosswind. 

The Sling HW put a smile on my face for the entire day. This fantastic aircraft delivers a simple and rugged design paired with Rotax’s very impressive 915 iS engine. 

Four Seats, Bags and Full Tanks?

There is ample space for four occupants and a generously sized baggage compartment—large enough to take a Sling bicycle. The empty weight of the plane we tested, which was fully kitted for the hoped-for Oshkosh safari, is 1,250 pounds, with a 2,310-pound max takeoff weight, so there is a 1,060-pound useful load. Full standard fuel of 45 gallons weighs 270 pounds, so with the large fuel tanks filled, you can put 790 pounds of people and stuff in the cabin. It’s a genuine fill the tanks, fill the seats, add bags and go plane—a rarity indeed. However, attention must be paid to the center of gravity as heavy baggage and rear seaters will push the rearward boundaries of the CG envelope. 

With the additional structure of the composite center fuselage, larger empennage and other changes, the Sling HW weighs about 160 pounds more than the Low Wing. However, this is more than compensated for by the maximum all-up weight increasing from the Low Wing TSi’s 2,090 pounds to 2,310 pounds. Blyth says that due to the uninterrupted high-wing area, there is more lift than on the Low Wing, which has allowed the 220-pound increase in MAUW.

The Sling HW put a smile on my face for the entire day. This fantastic aircraft delivers a simple and rugged design paired with Rotax’s very impressive 915 iS engine. 

The Slings have come a long way since the prototype Sling 2 flew in 2006. One of the most impressive aspects is the quality of finish, even for a prototype. The panels fit well, the paint job has a deep luster, and the standard of the interior finishes, such as seats, are worthy of a supercar. And it is the performance numbers that really blow you away. It is a true four-seater with a cruise speed of 145 knots at just 8 gph per hour. In comparison, a Cessna C182 of similar value will struggle to do 135 to 140 knots burning 12.5 gph.

The Sling HW is a fantastic all-rounder: rewarding to fly, with astounding flight instruments and responsive yet delightfully light and well-proportioned controls that make you feel at one with the machine. And best of all—at about $200,000, ready to fly (though not in the United States, as yet) with a high specification, it’s a worthy competitor to type-certified four-seaters that are three times as expensive to buy and run. 

Sling Aircraft has established a strong following in the USA with dealers and support across the continent. Learn more.

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This year’s Plane & Pilot Plane of the Year is the Diamond DA50, the big single from the Austrian plane maker that has been more than a decade in development, which makes its certification by EASA last year even more meaningful, seeing that it was so hard fought. It’s one of the most unusual and, in some ways, compelling piston singles to emerge in decades. 

If the year 2020 was a hard one for general aviation, and it was, for manufacturers, 2021 was even tougher. Plane builders were hardly immune to the kind of global pressures we’ve heard so much about, including scarce materials, supply chain disruptions, worker shortages and reduced FAA availability, all of which have conspired to make it hard to build existing designs, let alone develop and certify new ones.  

But there were a couple of real gems, one that we’ve known about for more than a decade, and one we were just introduced to. Both enter the arena as real players in markets dominated for years by planes from other makers. We expect both to make inroads.

Plane of the Year: Diamond DA50 RG

It’s often said, but it’s not often true, that this plane is different than any plane that’s come before it. This is true for the DA50. To understand what it is, imagine if Cirrus were to build a diesel piston engine-powered plane based on the Cirrus Jet and all that implies.

The DA50 has some built-in weaknesses that many would have presumed would have made it questionably interesting to potential buyers. Such is apparently not the case. The airplane is, based on our observation, the single most intriguing design on planeandpilotmag.com for the past couple of years. 

Like so many forward-thinking designs, the DA50 was for years a great airframe in search of the right engine. It had to be powerful enough, at least 300 hp, stingy with the fuel burn, easy on pilots in terms of noise and engine management, and capable of flying on fuel you can get anywhere in the world. Of course, that’s a diesel, but that correct diesel didn’t appear on the scene until the emergence of Continental’s CD-300, six-cylinder 300-max hp/270 hp continuous turbodiesel, which combines good power with a quieter noise profile than competing piston sixes while tacking on single-lever power. It’s a compelling package.

The power demands are very real, as the DA50 RG, despite its carbon-fiber frame and wings, is a substantial airplane, with an empty weight of 3,175 pounds and a max takeoff weight of 4,407 pounds. It’s a big and roomy airplane. There’s seating for five, and not seating for four/five but actually five. The seating layout is the same as the DA62 diesel twin, save the two smaller seats in the back, which the DA50 RG lacks, though the space is there and is great for bags, a better use of the space, in our view. Headroom, shoulder room and window area are all unsurpassed. The cabin environment is spectacular. 

The rough spots: It’s not as fast as many would like it to be, with a max speed at 16,000 feet—it is not pressurized—at max continuous of 180 knots. Its max range, at a power setting we presume was a good deal less than max continuous power, is 750 nm. That isn’t a lot of range compared to the Cirrus SR22, which one would assume is its primary competitor, though it is enough, apparently, for many pilots, who have expressed interest in or put their money down for this airplane that isn’t even FAA certified yet. And remember: All that travel will be done in a great space. The culprit isn’t a thirsty engine—Diamond says the CD-300 consumes just 9 gph at 270 hp, about half of Continental’s 315 hp TSIO-550 gas piston engine, which powers the Cirrus SR22—but rather a lack of fuel capacity. It holds just 50 gallons of Jet A, and finding space to put more is problematic, as there are no wing nacelle fuel tanks available for this single-engine model. 

It’s also not an easy airplane to hangar. With a wingspan of around 44 feet and a tail height of nearly 10 feet, few tee hangars would be a fit. 

How successful will the DA50 be, sales wise? Time will tell. Diamond expects certification for it later this year or early next year. We’ll fly it first chance we get, too. 

Read “Will The Diamond DA50 Redefine Personal Flying” to learn more about the plane.

Plane of The Year 2: The Sling High Wing

Our other honoree for a Plane & Pilot Plane of the Year award is Sling Aircraft’s new High Wing, which should start showing up on U.S. shores soon. The High Wing takes all of the goodness of Sling’s four-seat long-wing model, the Sling 4, and translates it into a high-wing form factor, with the remarkable 141 hp Rotax 915-iS supplying the motive force. With a comfortable four-place cabin, Garmin G3X Touch flatscreen avionics, including a capable integrated autoflight system with envelope protection built in, sharp and easy flying manners, and downward visibility to beat any low winger, the Sling High Wing is a powerful competitor to the most popular four-seat amateur-built plane on the block, the much-lauded (and rightfully so) Van’s RV-10. But you can put big tires on this one if you want, and we’re guaranteeing you right now that that will happen. 

Garmin Smart Glide

With the unveiling of its new Smart Glide utility, Garmin has created yet another capability that would have seemed like science fiction 20 years ago but that today can seamlessly and in the background always be ready to help you glide to a safe landing if your plane’s engine were to quit. It is, granted, a capability you hope you’ll never have to rely upon, but if you do, it could be a lifesaver. A Smart Glide description could fit in a fortune cookie: “Lost engine power? Smart Glide shows you where to go.” But the more you look into what that calculation really involves, the more complicated and intriguing it becomes. 

Smart Glide works in concert with a compatible Garmin display and navigator. The utility, which is all software and is very low or no cost in addition to the hardware it teams with, does this: You lose engine power, you activate Smart Glide (either by a three-second push of the Direct To button or the dedicated guarded panel button, if there is one), and Smart Glide puts a ring of where your glide range is, based on the plane you’re flying, obviously—the setup is done by the installer. It nominates the best airport for you to go for, offers alternate choices, gives you frequencies, and shows you your inflight situation in a colorful and easy-to-interpret manner. You do the flying. 

With Smart Glide, Garmin has once again advanced aviation safety in a way that requires little of pilots in an emergency situation while helping them make the quick and smart call and getting the most distance out of their airplane’s glide range. 

Read “4 Questions About Garmin Smart Glide You Hadn’t Thought About” to learn more about the technology.

SkyDisplay HUD

There is nothing simple or easy about creating a head-up display, but the folks at SkyDisplay have pulled off something really big in bringing to market a low-cost, high-performance display that essentially does what even the most advanced HUDs do, blend the airplane’s flight instruments (and then some) with the pilot’s view of the outside world so that the focus can be on what matters, the outside environment. 

A HUD enhances the view of the outside world by projecting an image on a transparent window sitting right in front of the pilot’s eyes. It is most useful as a landing aid, though it can be used throughout the flight. Without a pilot taking their eyes off of the runway, the HUD shows a wealth of information, like runway location and flight path and velocity vector, all features we’ve come to know and love on flat-panel flight displays. But the HUD places all of that information right in front of the pilot’s eyes and not on a screen below the pilot’s sightline to the outside world, where the stuff you don’t want to run into lies. The value in allowing pilots to focus all of their attention on the outside world makes for more precise approaches, always valuable but especially when flying low-weather precision approaches. 

A true HUD is conformal, and the SmartDisplay is. What that means is, the view the head-up display shows you using its additional enhanced vision technology matches what’s actually out there in the real world. If it displays the runway end, well, that runway end had better be exactly where the HUD says it is. The pilot has to do nothing but fly. The scan is right in front of their eyes. The data on the glass is focused at infinity, so it seems to just float upon the glass, so the pilot doesn’t have to focus and then refocus over and over to see the outside world and then the HUD data and back again. Instead, the data is just there, in focus as the pilot peers out at the world. 

SkyDisplay’s HUD is a huge advance in light aircraft safety, and, at its price of around $30,000 without installation, it is a tool that serious transportation flyers can put in their serious transportation plane and fly safer and better. 

Read “FAA Approves First Small-Plane HUD. How It Happened And What It Means.” to learn more about the safety system.

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