The Sirius TL-3000 is a light sport aircraft designed and manufactured by TL Ultralight, a Czech aircraft company. This aircraft is known for its sleek design and excellent performance, making it a popular choice among sport pilots and enthusiasts. The TL-3000 is constructed using high-quality materials, including a carbon composite airframe, which makes it both strong and lightweight. It is powered by a Rotax 912 ULS 100 HP engine and can be equipped with a range of avionics, including a glass cockpit display. The Sirius TL-3000 has a range of approximately 950 nautical miles and cruises at around 120 KIAS.
In 2021, the UK importer of TL Ultralight aircraft announced that the Sirius would be available as a factory-built 600kg microlight taking advantage of the increase in Maximum Total Weight Authorised (MTWA) for microlight aircraft. The aircraft was previously only available as an LAA kit-plane in the light aircraft category. I have always admired the design of this aircraft so I was naturally pleased to hear this.
A former student of mine who obtained their pilot's license a few years ago, recently made the decision to buy a Sirius aircraft, after having owned multiple Flight Designs in the past. The aircraft was custom-built to his exact specifications, predominantly featuring analogue instruments alongside a Garmin G5 attitude indicator and Garmin 507 autopilot controller. In my view, this setup is optimal. Whilst the aircraft can be configured with a full glass cockpit, this is not my preference. Call me old fashioned, but I prefer steam gauges with electronics only where necessary!
He also chose a simple fixed-pitch propellor although a constant speed unit is available. It is also available with the Rotax 912iS fuel injected engine, though he opted for the Rotax 912 ULS carbureted engine.
The ballistic recovery system comes as standard on the Sirius. This is a parachute for the whole aircraft and enables a safe landing in the event of a catastrophic failure. The BRS is installed in the fuselage of the aircraft and is activated by a rocket motor that propels the parachute out of its container. The purpose of the BRS is to provide an additional layer of safety for pilots and passengers and increase the chances of survival in case of an unexpected emergency.
This aircraft was delivered in early 2022 but it could not fly until the BMAA approved the type and issued a Permit to Fly. This took around six months, as the dealer’s demonstrator had to undergo stall and spin testing. The design specification also had to be thoroughly inspected. Consequently, the aircraft remained grounded in the hangar for most of the summer. However, the Permit to Fly was eventually issued in early Autumn, allowing us ample time to fly the aircraft under favourable weather conditions.
Having now gained around 30 hours flying time in the aircraft, I would like to relate my experiences about it for those who may be considering a 600kg aircraft in the near future.
Walking up to the aircraft.
My first impression of the Sirius was that it really showcases the potential afforded by the augmented weight limit. The aircraft boasts noticeably larger dimensions than most other microlights and presents a more robust and substantial appearance in every sense.
The Sirius has a well-thought-out design, with even the smallest details taken into consideration. A prime example of this is the clever incorporation of fuel tank dipsticks into the fuel caps, which eliminates the risk of them being accidentally dropped into the tank. This also allows for an instant reading of the fuel level as soon as the tank is opened.
Another example is that the engine is located well ahead of the firewall. Consequently, maintenance tasks such as sprag clutch replacement do not necessitate the removal of the engine, which is a common requirement in other aircraft. Such a setup results in significant savings on maintenance costs.
Payload.
This particular aircraft has an empty weight of 375 kg and a MTOW of 600 kg, giving a 225 kg payload. This allows for two adult passengers of average weight plus 80-100 litres of fuel. The fuel capacity is 130 litres with 65 litres in each wing, which is ample fuel for any trip.
I have heard of some aircraft that are closer to 425 kg when they are equipped with dual Garmin EFIS, a fuel injected engine and a constant speed unit. I’ve been told this makes the aircraft somewhat nose-heavy and alters the handling.
The cockpit.
The Sirius's interior boasts an elegant refinement that I believe will be widely appreciated among microlight pilots, particularly those accustomed to the austere design of earlier microlights which were limited by weight and often featured bare control cables visible in the footwells and unfinished composite panels. In fact, some have described the cockpit of the Flight Design as resembling a port-a-loo! By contrast, the plush trim of the Sirius substantially diminishes vibrations and engine noise, affording the aircraft a notably sophisticated ambiance.
One immediately noticeable feature of the Sirius is its yoke, a departure from the stick controls found on nearly all of the UK's current microlight fleet. This may initially deter some pilots who are accustomed to using a stick, but I am confident most would quickly adapt. Whilst training the owner to fly this aircraft, the most noticeable effect of the yoke has been that it stops pilots from overcontrolling the aircraft during turbulence or on final approach. This was a prevalent issue with the Flight Design CTSW, where some student pilots would feverishly stir the stick like a witch's cauldron. The yoke is responsive, yet less sensitive than the average microlight with a stick.
The aircraft also has a traditional cockpit layout with the throttle lever centrally located and differential toe brakes on both sides. The light switches and autopilot controller are located in the overhead.
Each door has a rotatable vent similar to the Ikarus C42 and there is a front windscreen vent, controlled by a hand lever conveniently located under the yoke, which further facilitates cabin ventilation. The cabin heater is more powerful than I have experienced on other aircraft with a noticeable blast of hot air when it is opened. Flying the Sirius during winter, I found that it consistently maintains a comfortable temperature, often prompting me to shed my jacket mid-flight.
The Sirius also comes equipped with ample charging options for personal devices, including USB sockets located under each seat and an additional socket on the top of the binnacle. A convenient armrest between the seats doubles as a storage cubby, making efficient use of the available space. The doors feature handy pockets for small items, while the luggage compartment situated directly behind the seats offers easy access during flight. Its design is reminiscent of the Cessna 152, providing a useful storage solution for pilots and passengers alike.
The seats in the aircraft are filled with thick foam and have proven to be very comfortable during long trips. Despite several hours of flying, I have not experienced the dreaded "numb bum" that can be common in other aircraft. Although the seats are not adjustable, the rudder pedals can be moved along a rail to accommodate pilots of all heights. However, some pilots may still choose to use cushions to improve their visibility ahead.
Compared to other microlights, the binnacle in this aircraft is notably larger. This provides ample space for all the avionics a pilot may want, but it does come at the cost of reduced forward visibility. This is similar to Group A aircraft such as the Cessna 172 or Piper PA28, and may take some getting used to for microlight pilots accustomed to a larger field of view. It's important to note that the aircraft takes on a slightly nose-down attitude during cruise, resulting in a good view ahead. However, pilots without experience on Group A types may need to adjust to the restricted view just before touchdown when the nose is at its highest.
The cabin width is 45 inches, which is one of the wider cockpits available, though not as wide as the Flight Design which is 49 inches. There’s still plenty of room and two adult pilots will not be rubbing shoulders.
In-Flight.
The Sirius take-off is spritely and uneventful. One point to note is that if the pilot has only ever flown with a stick, they might try to steer the aircraft on the ground using the yoke as if it is a car steering wheel! It takes some getting used to and is certainly a mind-over-matter process.
With two people on-board and 80 litres of fuel, the aircraft climbs at around 800 fpm. The Sirius lives up to its appearance and handles similarly to a Cessna with little adverse yaw. As a result, the pilot does not need to make as many rudder inputs and the aircraft feels more predictable. The trim lever is located near the throttle and moves freely, making it easy to adjust and fine-tune. The aircraft feels stable in turbulence, creating a sense of security and well-being. One of the aircraft's standout features is its quiet cabin, which is essential for touring. Noise fatigue can cause pilots to feel tired after a long flight, but the Sirius keeps it to a minimum.
During stall testing, the aircraft displayed good behaviour. To initiate the stall, we raised the nose and gradually reduced speed to around 36 KIAS. Maintaining the aircraft's balance required only a slight touch of rudder, and there was no indication of a wing drop at the point of stall. If the yoke is held fully back, the aircraft descends smoothly with the nose slightly nodding on the horizon. The stall speed with drag flaps deployed is 31 KIAS (Vs0) according to the manual, although the airspeed indicator may not be entirely accurate in this range. There is a slight buffet in the controls, followed by a moderate nose drop as the stall occurs. Recovery from the stall is immediate in both configurations.
The autopilot.
The optional autopilot has been a topic of debate in the microlight community, with some questioning its necessity. However, this particular aircraft boasts a cruising speed of up to 120 KIAS and a range of 950 nautical miles, making it an ideal choice for pilots who enjoy touring. Given this level of performance, there seems to be no good reason why an autopilot couldn't be a useful and reasonable addition. It greatly reduces the pilot's workload, freeing them up to concentrate on communication and navigation. However, it's important to note that proper training is essential before operating the autopilot, as understanding its functions and limitations is crucial. It's not simply a matter of turning it on and flying off.
The manufacturer fitted the autopilot to this aircraft and it is finely tuned. It can hold track and altitude with great precision, responding to turbulence and gusts more effectively and smoothly than a human pilot could. It doesn't react harshly to flight path deviations caused by turbulence and thermals, and over time I developed a strong trust in its ability to maintain altitude during critical moments, such as when entering controlled airspace.
The autopilot in this aircraft operates on two axes, controlling pitch and roll only, while leaving the rudder and throttle under pilot control. This is typical for single-engine aircraft. The autopilot's abilities rely on the data provided by the avionics. In this particular aircraft, it can establish and maintain a specific altitude and track, as well as other modes such as airspeed hold, vertical speed hold, and roll hold. If the plane is outfitted with the Garmin EFIS suite, it can also navigate in NAV and VNAV modes, automatically altering heading at preset waypoints and adjusting altitude in accordance with the flight plan. However, this level of capability may not be necessary for all pilots and requires a substantial investment in Garmin avionics.
The video shows a Sirius flying an automatic approach when equipped with Garmin EFIS systems.
One final feature I will mention about the autopilot is the LVL button. This button engages the autopilot and brings the aircraft back to a level flight attitude in a shallow climb. It can be used if the pilot inadvertently enters cloud or poor visibility and loses spatial orientation.
"I think the Sirius is the poster child for the 600kg microlight category"
Landing.
The Sirius is a breeze to land thanks to its straightforward design. The electric flaps are controlled in two stages and the aircraft approaches at 55-60 KIAS. The inherent stability of the airframe allows for a smooth and stable approach, and even with reduced visibility during the roundout, it is simple to execute a gentle flare without any tendency to balloon. The aircraft is also well-behaved in yaw during this phase of flight, which means there's no need for excessive rudder input. In crosswinds, the Sirius remains forgiving and handles exceptionally well. Additionally, the leaf-spring undercarriage offers extra cushioning, even for heavier landings.
Conclusion.
I think the Sirius is the poster-child for the new 600kg microlight category, being a true 600kg airframe and showcasing everything that is now possible in this class of aircraft. It’s an honest aircraft and flies exactly as you’d expect from looking at it. The price of all aircraft has risen sharply in the last 12 months, and a new Sirus of this specification will cost around £140,000 inc. VAT, so it is probably not financially viable for microlight schools, but for those who can afford the Sirius and want a capable and comfortable touring aircraft then I am not sure if there is anything better in the UK right now.
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