Slings for two or four

In the beginning the aviation world had Cessna, Piper, Beechcraft, and a handful of other recognized names. We still have many of them, but most famous brands have trained their focus on larger aircraft, while the more affordable space is increasingly occupied by Light-Sport Aircraft manufacturers and a broad array of kit-built aircraft.

“No comparison,” you might say. “GA planes are ‘real’ aircraft with four seats and have proven themselves over many years in the field.”

In the last decade, some LSA companies have succeeded enough to expand their envelope.

This story is about a South African builder that started with ultralights, progressed to LSA, and has now entered the four-seat space. I refer to The Airplane Factory (TAF) and its Sling models.

To prove its design prowess, the TAF team from the tip of Africa took a brand-new model on a trip around the world. I mean that literally. A new model the company owner is willing to use in a global circumnavigation is certainly one he believes in deeply. To succeed at it multiple times is doubly affirming.

Sling LSA — or the Experimental Amateur Built version called Sling 2 — is a mostly metal aircraft with selected composite components. Sling LSA uses a sliding canopy and is broader inside than a Cherokee.

Thrust is supplied by the market-leading Rotax 912, producing 100 horsepower and burning three to five gallons an hour. Sling is economical to buy and to fly.

Flights around the planet sound adventurous, but I found the design to have an easygoing control harmony. Sling LSA exhibits gentle stalls with ample warning, and is remarkably easy to land. Stability throughout the normal range of maneuvers I explored was entirely predictable. The learning curve on Sling LSA is shallow.

Such attributes may explain a growing number of flight schools taking on Sling for training. TAF USA staffer Jordan Denitz noted, “Two schools in the greater Los Angeles area are using Sling LSA for regular instruction and another in Nevada traded up to a brand-new model.”

In a competitive market and despite being a more recent entry, The Airplane Factory USA appears to be doing well.

Sling LSA and Sling 2 are well-built, well-supported, great-flying aircraft priced correctly, but they are not the whole story.

Growing to Sling 4

The Aircraft Factory founder Mike Blyth said, “Our Sling 4 idea began after judging the performance of a highly loaded Sling 2 during my flight with James Pittman for our 2009 circumnavigation of the Earth.”

Conceived as a 600 kilogram (1,320 pounds, the LSA standard) gross weight aircraft, the globe-girdling flight carried more than 700 pounds of fuel for the long over-water flight segments.

Calculations added to actual experience revealed that, even with a carbureted 100 horsepower Rotax engine, a two-place Sling was able to climb and perform well at 970 kilograms or 2,138 pounds.

The Airplane Factory engineers performed further evaluations, subsequently approving the two-place model up to 700 kilograms or 1,540 pounds, gross. This figure can be used by experimental kit builders, while the fully manufactured Sling LSA remained at FAA’s regulated limit of 1,320 pounds.

After Sling was accepted by the FAA as a Special LSA, the TAF team started development work on a four seater version of the Sling 2. A moderately beefed up four seater came to market with a 2,024 pound maximum takeoff weight.

“The chief differences between the Sling 2 and the Sling 4 are the wing size, the engine, and the center fuselage arrangements,” explained Blyth.

Where the two-place Sling uses a 100 horsepower Rotax 912 ULS (carbureted) or iS (fuel injected) engine, Sling 4 moved up a notch to the 115-hp turbocharged Rotax 914 UL engine.

“Although a 15 horsepower difference may not sound significant, the turbocharged engine gives full power at up to 15,000 feet, at which altitude the normally aspirated 100 horse engine would only be delivering approximately 55 horsepower,” explained Matt Litnaitzky, principal at TAF USA. “So, on a hot day the swing in power between the 912 ULS and 914 UL engine is in the vicinity of 36%, not just 15%.“

No doubt the also-turbocharged Rotax 915 providing 135 horsepower will be of keen interest to Sling 4 developments in the future. Austria-based Rotax said the new powerplant will reach the market in late 2017.

Flying Sling 4

I have a confession to make. As a true-blue light aircraft guy, with loads of ultralight, light kit, and LSA experience, I feel a little guilty saying I like the way Sling 4 flies even better than Sling LSA. This is not merely a matter of a slightly heavier aircraft smoothing a patch of rough air better than the lighter sibling but a handling qualities comment. I found Sling 4 to be very pilot-friendly.

The Sling’s flying characteristics are complimented by well harmonized controls that are at once responsive and stable, an enviable combination that allows Sling 4 to handle lightly without being sensitive.

Sling 4 achieves 120 knot cruising speed at 75% power at 6,000 feet, said Denitz. Readers may note that this speed value applies to LSA models but for most LSA, that means running at maximum continuous power where at 75%, cruise may be 5-15 knots slower. That Sling 4 can haul four people in comfort while cruising 138 mph and burning less than 6 gallons an hour assures it a place in the market.

Useful load is 992 pounds, only 44 pounds less than Sling 4’s empty weight. It can carry up to 46 gallons of fuel, providing a range of almost 800 nautical miles with a 45-minute reserve. Even with a full fuel load, Sling 4 has 716 pounds of payload, permitting three 200-pound occupants and 116 pounds of luggage or an average family of four with overnight luggage. Remember, this airplane carries all that while burning just five or six gallons an hour. No wonder 30 Sling 4s are being built around the USA.

Construction time is 1,100 hours for a standard kit, but for an extra $15,000 you get a Quick-Built Kit that cuts the hours in half, delivering a nearly complete fuselage, wings, and pre-sealed fuel tanks, according to Denitz. QB kit builders assemble the ailerons, flaps, empennage and do finish work in a program that appears on FAA’s Kit Evaluation Team approved list.

The first American Sling 4 builder recently earned his airworthiness certificate, three are expected to be flying by the end of 2016, and a dozen more are in various states of completion.

Sling 4 — like Sling LSA and Sling 2 — features digital instrumentation also emanating from South Africa and represented in the USA by Matt Litnaitzky’s MGL Avionics company.

With airplanes, instruments, training, and more, this young aerobatic pilot has steadily built a growing American enterprise using fellow South Africans as his suppliers.

Viewed overall, Sling LSA, 2, and 4 provide strong airframes, lively yet economical performance, roomy cockpits with easy entries, good visibility, pilot-pleasing handling, good useful load capacity, and are enjoyable aircraft to fly. Globe-girdling flights and a standard ballistic parachute strongly reinforce Sling safety.

If a metal, low wing, stick controlled, Rotax powered aircraft, either two seater or four, fits your need and budget, you should look closer at TAF’s Sling line.

You don’t have to fly your Sling around the world, but it’s reassuring to know it has already done that duty.

Don’t Want to Build?

If you don’t want to build a Sling — at least on your own — you have at least three options:

1. Sling LSA can be delivered ready-to-fly, can be flown without a medical, and can be used for compensated flight instruction or rental;
2. Sling 4 could be brought in fully built and certificated in Exhibition category, which comes with some restrictions; or
3. You could participate in a build program. This requires your labor but will greatly hasten the process. You can judge by the program’s name.

“A Sling 4 Quickbuild Kit can be built as a part of a Two Week Sling Turbo Build Program,” said TAF USA representative Jordan Denitz. “We have collaborated with Synergy Air in Eugene, Oregon, and a few other centers. Customers would meet the Sling 4 Quickbuild Kit at the build center’s location, spend time working on the build, and come back later to complete paint, avionics, and do the engine install.”

Speed costs money and so does a fast-build program.

“Cost for this program would be about $190,000 for a completed aircraft,” Denitz said, adding this would be “about the same cost as a manufactured Sling 4.”

Of course, such an EAB Sling remains an experimental, which means it cannot be used for any compensated flying, but it has fewer limitations than Exhibition category.

SPECS for Sling 4

Wingspan: 32 feet 8 inches
Length: 23 feet 5 inches
Height: 8 feet
Cabin Width: 43.8 inches
Empty Weight: 1,036 pounds
Useful Load: 992 pounds
Gross Weight: 2,028 pounds
Engine: Rotax 914 Turbo
Max Power: 115 horsepower at 5800 rpm (max 5 min)
Continuous Power: 100 horsepower at 5500 rpm
Never Exceed Speed: 135 KIAS/161 mph
Cruise Speed: 120 KTAS/138 mph (75% power at 6,000 feet)
Stall Speed, Clean: 47 KCAS / 54 mph
Stall Speed, Full Flaps: 42 KCAS / 48 mph
Max Crosswind: 15 KCAS / 17 mph
Takeoff Ground Roll, Hard Surface: 700 feet
Landing Distance: 500 feet
Rate of Climb, Sea Level: 750 feet per minute
Maximum Operating Altitude: 15,000 feet
Range: 780 nautical miles (75% power with 45-min reserve)

Source: http://generalaviationnews.comSlings for two or four