The SlingTSi is a modern, low-wing general aviation 4-seater kit plane designed for speed. This guide dives into what you need to look for when buying one.
The Sling TSi, introduced in 2018, is based on the Sling 4 kit plane. The kit sells for $141,000 while a factory-built one costs $295,000. It has a cruise speed of 148 knots and its 141 hp Rotax 915 iS engine has a fuel burn of 8 gph.
As a CFII and aviation enthusiast, I fly corporate jets and teach all types of pilots how to fly. Through this, I’m familiar with most aircraft, including amateur built aircraft like the Sling TSi.
The Sling TSi is a kit plane that is not certified under any category by the FAA. This is because the FAA doesn’t certify kit aircraft, otherwise known as amateur built aircraft. Despite this, it fits in the light sport aircraft category, like most other Sling Aircraft designs.
It is designed and manufactured by Sling Aircraft Pty Ltd, a company formerly known as The Airplane Factory Ltd that’s based in Johannesburg, South Africa. It follows on from the proven concept of the Sling 4, itself a derivative of the Sling LSA, which is similarly a popular light sport aircraft also built by the former Airplane Factory.
The Sling TSi can be purchased as a kit, with all the mechanical, structural, and electronic components in the box. It would take a skilled mechanic 1,500 man-hours to put everything together. For those who do not have the time or the expertise to do this, there are a number of builders who can do it on your behalf.
The Sling TSi is fitted with a 141 hp turbo sport Rotax 915 iS engine that is made by Bombardier Rotax GmbH in Germany. The turbocharged Rotax engine, means the Sling TSi offers increased power to weight ratio and comes with a dual channel Engine Control Unit made by Rockwell Collins at the heart of its Fully Automated Digital Engine Control (FADEC).
The engine has dual ignition, and together with its FADEC, reduces the engine's carbon footprint. It is rated for 141 horsepower at full take off power, and 135 horsepower for continuous use up to 15,000 feet. While it has a ceiling of 23,000 feet, the Sling TSi is only rated up to 18,000 feet for safety reasons.
The engine has a 2.3 gear reduction ratio to the propeller shaft that connects to the Airmaster propeller. Engine rpm and propeller rpm differ because of this. The Sling TSi has a three-bladed constant speed prop that is either from Sensenich or Worldwind, measuring 72 inches in diameter.
The constant speed prop allows for good climb and cruise characteristics that, thanks to its variable pitch propellers, can take advantage of the thinner air at altitude with higher blade angles. This is done by an electric governor that sits in the spinner.
One of the advantages of having an electric governor is the ability to feather the prop and extend glide distances. It is also a benefit to be able to unfeather the prop even when the engine is not running since it is not relying on oil pressure for setting the blade pitch.
The Sling TSi’s tricycle-gear configuration coupled with a low wing format gives it a unique aerodynamic profile. With gull-wing doors and a wider cabin, tapering in the front and rear adds to the overall slippery nature of the aerodynamic profile of the fuselage while giving passengers wider room.
The aircraft is built using aviation-grade aluminum. The design process was computational, which integrated perfectly into its numerical control manufacturing process that resulted in high-precision parts and joints.
The tricycle landing gear comes equipped with airfoil-shaped struts that lower the overall drag. Flushed riveting and countersunk camlocks aid in reducing skin friction drag, as does the meticulous paint job and precise milling cutting and joint work that results in joints that reduce surface friction.
The rudder is counterbalanced, resulting in lighter and more precise controls, evidenced by the leg force needed when maneuvering during slow flight and take-offs. While the elevator is designed so well that it hardly feels soft when operating in ground effect.
As an option, the Sling is able to have a ballistic parachute installed for emergencies.
The main difference pilots of conventional general aviation aircraft will feel when first flying the sling TSi is its simplicity of operation due to the abundance of advanced systems that have been incorporated at every juncture.
From the FADEC engines that managed engine health and power output, relieving you of the headaches of handling power settings. Unlike most turbocharged engines, you don’t have to worry about how you advance your power since the engine will make sure to not exceed operational temps and pressures.
The four-cylinder engine is a compact build. Using liquid-cooled cylinder heads and air-cooled casing, along with oil, the engine occupies a smaller footprint. It also uses advanced software to manage engine operation, using the optimal stoichiometry for the perfect combustion and leaving you without the worry of having to lean it out.
The engine also comes with an ECO mode. In ECO mode, which you can select, the moment the throttle is retarded down past 80% power, fuel flow is instantly adjusted to lean off-peak, without you having to adjust the fuel flow. Remember, your throttle does not measure fuel intake, but rather air intake. In a fuel-injected system, the system meters the fuel, and in this case, it is the ECU that meters the fuel automatically.
In normally aspirated planes in general aviation, we typically reduce the mixture to lower the fuel flow and measure its effect by monitoring the EGT. As the fuel is reduced the temperature increases because excess and unburned fuel cool the engine as it escapes out of the exhaust manifold. We typically find the point where it reaches the peak and then enrichen it because keeping the cylinders at peak EGT on an air-cooled engine will damage the rings and cylinders.
Because the Rotax iS cylinder heads are liquid-cooled, they can handle the extra heat, and operate efficiently when the heat is higher, essentially providing a complete burn of fuel and air. This results in a fuel burn of 8 gallons per hour at 15,000 feet while the ASI shows 150 KIAS.
Sling TSi Interior Design
As far as aircraft interiors go, the TSi’s is probably one of the most customizable I’ve ever come across. Available in four distinct color schemes - all of which are leather upholstered - give you the feeling of flying a much more expensive aircraft than the price the TSi commands.
The TSi comes with cabin heaters, tailor-made, sound-proof carpets and comfortably seats four (two front seats and two back seats) and a respectable luggage load of 77 pounds (35 kg) which all makes it perfect for light cross-country flying.
It has a glass cockpit powered by a variety of garmin instruments, which come with a ton of advanced workload reducing features. Much like in the Sling LSA, the flight display will adjust automatically to the natural light level in your cockpit as you fly, meaning there’s no staring to make out what words or numbers are which!
The Garmin G5 backup works by combining visual cues and data readouts into one area on the flight display, making it far easier for pilots to respond to whatever comes their way in-flight. Interestingly, the Garmin EFIS backup instruments installed on the TSi were purpose-built for the aircraft.
The powerful ADS B transponder emits a 406-MHz E-04 ACK ELT frequency, which is an industry standard, for search and rescue operations and makes it far easier to detect and locate aircraft both in-flight and in the unfortunate event of a crash of some kind.
In addition to this, the GTR 200 airband radio provides powerful comm capabilities, allowing you to communicate with both ATC and other aircraft in your vicinity in a far easier manner than on other kit aircraft.
Sling TSi Exterior Design
The exterior design of the TSi is effortlessly elegant. It is undeniably a “personalised dream aircraft”, as Sling Aircraft claim it is, as they allow you to give it whatever paint you want. I’ve personally seen everything from a simple all-white paint scheme to a mix-red, white, blue and black livery (which is the most complex paint scheme I’ve ever seen) with what looked to be flame stickers.
I can certainly see why many call the TSi the “sexy Sling TSi” and why it’s regularly featured as one of the best light sport aircraft out there, including by the likes of Plane and Pilot Magazine! It certainly shows that the dedicated engineering group specifically set up to design a sleek exterior did their job well.
Unlike most other aircraft designed for the light sport aircraft markets, the Sling TSi is all-metal. This means that everything from the rudder to the engine mount are metal (in this case, made from steel). Coupled with the TSi’s more modern engines, it offers exceptional performance.
In keeping with a traditional Sling Aircraft design feature, all exterior lighting on the TSi uses LEDs, which are exceptionally bright and are far more energy efficient than other types of lights typically used on other aircraft.
Interestingly, all the control surface hinges you see on the TSi use ball bearings as opposed to the traditional design used on everything from a Cessna 172 to a Boeing 747!
Unlike typical general aviation aircraft, you would have to think of the price of a Sling TSi a little differently. If you have the necessary resources - meaning the tools and machinery, to assemble the parts then you can purchase the kit that comes in crates, delivered to your doorstep.
The kit is inexpensive. Just $141,000 for almost everything. There are some options you can throw in, like the ballistic parachute, but other than that, all the avionics, leather seats, and plush carpeting are in the base price. You could upgrade the paint scheme if you like for a little extra.
It will take you 1500 hours to get the kit assembled. If you chose to have it built for you then you can choose to send the kit to a builder who will then put everything together and have it airworthy when it is delivered. This will, however, cost you an additional $160,000, on average. The build price depends on who you send it to.
There are completely built-up units for sale with low time available on the market. They are not necessarily categorized as used aircraft, but rather are the product of industrious enthusiasts who build them specifically for sale.
The thing you have to know about this is that this aircraft is flown in the United States under the FAA’s experimental aircraft rules. While the aircraft manufacturers design it to meet the standards of a normal category aircraft.
Before you purchase a Sling TSi, it would be wise if you contacted your insurer and got a quote on the aircraft. There are a handful of insurers that will take on the policy so it should not be too much of a problem.
You can either get hull and liability insurance or if you have fully purchased the aircraft, getting the Hull insurance alone will save you quite a bit.
A million-dollar liability cover for a Sling TSi averages about $800 annually.
On the other hand, hull insurance is a little on the expensive side for this model. For a qualified pilot, hull insurance for $250,000 - which is the replacement value of the TSi, and $1,000,000 liability courage works out to be about $8,000 annually.
To be considered qualified for this rate, a pilot would have to use the plane privately, and have over 1,000 hours of flight time, with more than 25 hours of time in the TSi.
Anything less than that, and the rate jumps up to $10,000 annually.
For simplicity in arriving at an hourly cost of flight, we will use 400 hours as a benchmark of annual flight time. Remember, if you fly more than this, the hourly rates will reduce since the fixed expense you incur will be stretched across more time.
We will also use Fixed costs to capture all the costs that you will incur regardless of flight time. This would be like insurance. And we will have a second category of costs that will depend on the hours you fly. This will be the Direct Operating Cost.
Direct Operating Cost
DOC will broadly include everything that you will spend each time you fly, like fuel. If the plane sits in the hangar it costs nothing in fuel.
For calculations of expenses, it is best to not use the low average of fuel burn. It is best to look at fuel from a slightly conservative value. In the TSi while fuel burn in ECO mode at altitude can be as low as 7 gph, it is best to use 10 gph for hourly cost calculations.
At $7.60 per gallon (the cost at my airport) that Direct Operating Cost per hour will be $76.
We typically also use engine oil burn in these calculations. The TSi runs clean and hardly burns engine oil more than a quart every five hours. That’s $2 per hour at the price of $10 per quart of engine oil.
There is one more maintenance issue that you should plan for, and that is the overhaul of the engine. The time between overhauls for the Rotax 915iS is 1200 hours. So if you are flying this 400 hours a year, you can do the math and be prepared for 3 years to schedule a TBO.
Depending on the condition of your engine you would either have to replace the whole engine which is about $25,000 or you could trade in the core of your engine and that would adjust your cost down to about $20,000. But for conservative estimates, let's assume your overhaul costs are $25,000 every 1200 hours. This works out to be $20.8 per hour.
Also, consider maintenance issues that crop up based on use. For instance, coolant flushes and change will cost about $20 for the TSi while an oil change is about $100. If in good condition, your TSi will not cost you more than $300 for each 100-hour inspection depending on your mechanic. That’s $3 per hour of flight.
With just these costs attributed to DOC, we find that the total is just $101.8 per hour.
As for fixed costs that we incur regardless of if the plane is flown, we know that insurance will cost $10,000 a year.
Hangaring the aircraft costs $3,600 a year, assuming a T-hangar, which is the cost of a T-hangar on my field.
You would also add any taxes that you would incur in the ownership of your aircraft here.
Then you have maintenance costs. This is an experimental plane, so it's unlikely that you are renting it out. As such you are only required to have Annual inspections and maintenance done, but for safety's sake, you should make it a habit to do 100 checks and oil changes to keep your aircraft in good condition (calculated in the previous section.)
An annual for a brand new Sling TSi would cost about $500 that’s if you do a 100-hour inspection during the course of the year.
You should also consider $1000 for incidental maintenance issues.
We have almost everything we need here and we can see that the fixed cost adds up to $15,100 per year. At 400 hours per year, that’s $37.75 per hour.
As such, in total it would cost you $37.75 + $101.80, or roughly $139.55 per hour of flight.
When it comes to the fast nature of the Sling TSi, remember that it is built to move quickly. But that’s not just about the engine. The engine is relatively small, generating 141 horsepower. The speed of the aircraft comes from two other factors that are often unnoticed.
The main contributor to the aircraft’s speed is the well-balanced nature of weight distribution in the aircraft. The second is the sleek, low-drag aerodynamics of the plane.
With low drag and a wing loading of just under 17 pounds per square foot, the Sling TSi is a very slippery plane and keeps going fast even with the power retarded. You need to think of this when coming into the pattern as you will be carrying a lot of energy.
The good thing about this plane is that the FADEC manages your engine health with the turbo and so if you need to back off the power on your descent, it's one less thing you have to worry about.
Flying this plane by the seat of your pants will become tempting, but don’t. It will get away from you when you least expect it. Fly the numbers.
The sling touches down a little below the stalling speed. You have to take that into consideration. Being a laminar wing so close to the ground, you’d have to arrive within one wingspan of the runaways at Vso, which in this case is 48 knots.
To do that, you would have to cross the threshold at 53 knots and begin your level out. You will still have good elevator, rudder, and aileron control, so not to worry.
The dirty stall speed for the Sling is 48 knots. While the flaps-up stall speed is 55 knots. For this reason, if you have to go around at this point, don’t drop the flaps first, power up till your engine is developing takeoff power and get your lane stable into the climb before you think of reducing your flaps.
The Sling doesn’t have a typical yoke or side stick, it has a WWII fighter-type center stick, which is an interesting feeling. But the one thing that you won’t get as obviously as in other planes is the buffet before the stall. The plane’s wings do a very good job of remaining even while it keeps flying right up to the point of the stall, then it’s a clean break.
Spins can be practiced in this aircraft and you should spend some time with an instructor to show you how to recover from stalls and spins. The spins are gentle and easily reversed if done early enough. There is sufficient control surface authority to break the spin.
Rotation happens at 55 knots and once off the ground accelerates quickly to Vx and then Vy. You have five minutes of take-off power, after which you need to reduce to climb power. At its sea-level climb rate that remains up to fifteen-thousand feet, it will take you fifteen minutes to get to 15,000 feet.
The sling TSi is typically flown at 15,000 feet. At this altitude, it will give you the best economic fuel burn while extracting the best True Airspeed.
100% power for the climb segment with engine RPM at 5500 will result in 11.3 gallons per hour. The first five minutes would therefore consume 1 gallon of fuel. Pulling it back to 90% power will burn 9.8 gallons per hour. That would result in another 2.5 gallons burned by the time you get to altitude.
Setting it to ECO power at this point will result in 85% power. You can choose to leave it here where you get the best speed for the lowest fuel used, or you can pull it back further to 75% power and burn just 7.3 gph.
At 75% power, you will have an endurance of 5.6 hours and a true airspeed of 155 knots.
About THE AUTHOR
After spending years watching every video I could find about flying, I finally scratched the itch and got my pilots license. Now I fly every chance I get, and share the information I learn, here.Read More About Joe Haygood