THOR 303

Product Description

Polini Motori presents the new THOR 303, a concentration of power and technology.
An innovative engine with important innovations which translate into reliability, power, low weight, reduced aerodynamic section and moderate overhang.

It is the Polini engine of the THOR family with the largest displacement and features a thermal unit, crankshaft, carburettor, air box, CDI and exhaust system entirely redesigned to guarantee greater performance and safety in flight.

With its 38 horsepower at 8000 RPM THOR 303 is capable of offering over 120 kg of static thrust with a 160 cm propeller *.

Consumption is only 3 liters per hour at 4500 rpm , which corresponds to approximately 30 kg of static thrust , average level flight value.

The THOR 303 is available in three versions :

  • THOR 303 with manual “flash starter” start
  • THOR 303 with both electric and manual “flash starter” starting
  • THOR 303 Dual Spark

 

 

The Dual Spark version is designed to meet the highest aeronautical safety standards . It is supplied with electric and manual “flash starter” and is equipped with 2 CDIs and 2 totally independent and redundant ignitions .

Safety in flight
The THOR 303 is the result of three years of work, design and testing in modern Polini test benches and in flight with our national and international professional pilots. Careful work that continues even at the moment of production, when every single engine is subjected to careful testing and verification in all its parts before being delivered to the customer .

The thermal unit
The cylinder was designed and created expressly for aeronautical use, exploiting the best modern technologies. Actual displacement stands at 281 cubic centimeters with a bore of 76 mm and a stroke of 62 mm .
The cylinder is equipped with 5 inlet ports to ensure precise and stable performance at all rpms, promising a smooth and powerful delivery capable of offering over 120kg of static thrust with a 160cm propeller *.
The head is designed with a special combustion chamber that speeds up the flame front.

 

The muffler The new exhaust system was designed
from the experience gained over the years with 2-stroke engines , designed to enhance performance and at the same time guarantee low noise . Compact and lightweight, it is the subject of extensive testing and research to find the perfect combination between expansion and gas flows. The result is a muffler that ensures stable and progressive delivery at all speeds . The suspension fixing and the ball joint system guarantee freedom of movement and at the same time eliminate any type of vibration, guaranteeing the durability of the drain over time .

The carburetor
The Polini THOR 303 is equipped with the 28 mm Orto VHST carburettor .
The carburettor technology makes the engine much less sensitive to changes in atmospheric pressure, humidity and altitude, ensuring greater stability and reducing any setting interventions to a minimum. This carburettor can be equipped with the Polini starter control, essential for starting the engine in total safety .
Thanks to all these advantages, combined with various setting possibilities, the Orto carburettor perfectly meets the needs of all pilots , thanks to the very high precision, fluidity and power delivery.
For transport: the carburettor is equipped with a special valve that allows all the fuel contained inside to be drained, also allowing a horizontal position to avoid petrol leaking from the vents.

 

Air box
The THOR 303 is equipped with an air box born from an in-depth fluid-dynamic study with the aim of optimizing the speed of the air inside it to guarantee the ideal pressure to feed the carburettor at every rotation speed. Reproducing an S-shaped circuit that stabilizes turbulence, the new air box allows linear, smooth and constant delivery . Completely openable and inspectable, inside there is a support frame for the new 30 PPI (pores per inch) open cell polyurethane foam filter mat : this support frame is designed to have a fixing capable of preventing over time to the mat from moving or collapsing on itself.
Furthermore, the filter box can be opened in two halves with just two screws, making it easy to replace during routine maintenance .

Cooling system and water pump
In the THOR 303, cooling is guaranteed by a compact 18-element radiator with dimensions of only 355X200 mm equipped with an expansion tank equipped with a cap with a 1.4 bar valve which allows the system to self-regulate the expansion of the liquid inside without weighing on the other components.
The circulation of the liquid is entrusted to a specific 30 mm mechanical pump housed on the countershaft . This system allows the temperatures of the thermal unit to always be kept under control even in demanding applications, allowing the engine to be used for a long time and under load without incurring overheating. With a view to greater attention to design , pre-shaped blue silicone tubes customized “Polini THOR” were chosen , which guarantee greater durability over time.
As standard, for greater safety, the engine is equipped with a thermostat, which prevents the liquid temperature from dropping below 60°.

 

Reed valve pack
The engine is equipped with a reed valve with direct entry into the engine crankcase . The reed valve pack, expressly designed by the Polini R&D department, is designed to maximize performance. This result is achieved thanks to the use of 6 carbon fiber blades with calibrated elasticity to react uniformly at all rotation speeds .

Engine crankcase
The THOR 303 crankcases are made of die-cast aluminum with a high silicon content . Thanks to this alloy and the production process controlled during all phases (foundry, painting, mechanical processing on sophisticated CNC machines) stable, long-lasting mechanical performance and low weight are obtained . The design of the crankcases has been optimized to be essential and reinforced at the points of greatest stress.

Crankshaft
The choice of the best steels and heat treatments , combined with perfect centering , eliminates parasitic vibrations due to unbalances which over time could lead to premature wear or failure. Thanks to the use of numerical control machines and latest generation measuring instruments, the dimensions are maintained within pre-established tolerances with maximum precision . The whole thing is completed by high quality bearings positioned on the connecting rod and in the engine crankcase .

 

Countershaft, reduction gear and clutch
In the front half crankcase there is the housing of the centrifugal clutch system , the mechanical reduction and the balancing countershaft , all in an oil bath .

The centrifugal clutch allows the propeller to remain immobile when the engine is at idle and to maximize pilot safety in the pre-flight phases.
The new THOR 303 is equipped with two different propeller reductions : 2.8 (recommended for propellers up to 140 cm) and 3.2 (for propellers over 140 cm) . The reduction is mechanical with helical teeth. This system reverses the direction of rotation of the propeller with respect to the rotation of the crankshaft, significantly attenuating the overturning torque.
The balancing shaft reduces the vibration resulting from the unbalance generated by the oscillation of the piston which, passing from the bottom dead center to the top dead center, shifts its mass with each rotation cycle of the engine, thus ensuring maximum flight comfort.

Electronic ignition
The ignition is capacitive electronic , governed by a CDI unit expressly designed for the THOR 303 engine . The CDI unit allows you to automatically adjust the engine advance degrees based on the rotation speed, allowing easy and smooth starting and always prompt and linear delivery.

 

Flash starter
The THOR 303 is equipped with the most updated version of the renowned flash starter , a system that guarantees immediate and simplified starting of the engine. In the latest version the critical points
have been reinforced and the centerings improved , improving operation and guaranteeing a longer operational life. Furthermore, an ergonomic handle allows a safer and more stable grip during the lighting phase.

THOR 303 Dual Spark
This version uses two completely independent electronic ignition systems , managed by 2 CDIs, 2 stators, 2 coils and 2 spark plugs completely redundant and independent of each other, guaranteeing better performance and greater safety during use .
The standard capacitive electronic ignition is combined with a second ignition which reads the signal via a dedicated pick-up and sends it to the secondary CDI, which controls the secondary coil and spark plug.

 

 

Fixing system
Polini Motori has decided to maintain the same fixing system on the entire range of THOR paramotors . Manufacturers can thus produce a chassis that can accommodate the entire range , significantly reducing both production costs and delivery times .
Riders can change THOR models without having to replace or modify the chassis.
Like the entire THOR range, the THOR 303 is also sold complete with all its parts, fully assembled and ready to be installed on the frame with extreme simplicity . Even in the versions with electric start or DS, the engine comes equipped with electrical wiring and plug and play battery as standard.

Use
Given the high power, the THOR 303 finds its maximum expression on single and two-seater trikes, delta trikes, three-axle single-seaters and UAVs (Unmanned aerial vehicles) .
As regards use in single-seater paramotors, it is recommended for expert pilots and is unparalleled in slalom races.

THOR 303 R.2,8 – 928,000,100
3,080.00 + VAT

THOR 303 R.3,2 – 928,000,101
3,080.00 + VAT

THOR 303 ELECTRIC STARTER R.2.8 – 928,000,110
3,490.00 + VAT

THOR 303 ELECTRIC STARTER R.3,2 – 928,000,111
3,490.00 + VAT

DUAL SPARK ELECTRIC START R.2.8 – 928,000,120
3,990.00 + VAT

THOR 303 DUAL SPARK ELECTRIC START R.3,2 – 928,000,121
3,990.00 + VAT

THOR 303

Polini engine 2 stroke single cylinder
Cooling down Liquid
Bore per stroke 76 x 62
Displacement 281 cm3
Power 38 HP at 8000 rpm
*Max. thrust 120 Kg with Ø 160 cm propeller
RPM max 8,400
Cylinder In aluminum with Gilnisil coating
Compression ratio 11.2:1
Piston Two trapezoidal chrome bands
Aspiration Reed valve in the crankcase
Carburetor Dell’Orto VHST 28mm
Air filter Air boxes
Power on Variable advance CDI electronics
Battery charger preparation Output power 40W at 5500 rpm
Candle cap With 5K Ω resistor
**Diet E5 or LL 100 AV GAS petrol – 2.5% with 100% synthetic oil
*Consumption 3 Lh 30 Kg of static thrust
Gear reducer Helical teeth in oil bath, reduction ratio 2.8 or 3.2
Goodwill Flash Starter (electric OPTIONAL)
Clutch Oil bath centrifuge
Muffler Expansion with aluminum silencer
Engine weight Starting from 20.5 kg (manual start version with radiator)
Propeller rotation Clockwise

THOR 303 DS

Polini engine 2 stroke single cylinder
Cooling down Liquid
Bore per stroke 76 x 62
Displacement 281 cm3
Power 38 HP at 8000 rpm
*Max. thrust 120 Kg with Ø 160 cm propeller
RPM max 8,400
Cylinder In aluminum with Gilnisil coating
Compression ratio 11.2:1
Piston Two trapezoidal chrome bands
Aspiration Reed valve in the crankcase
Carburetor Dell’Orto VHST 28mm
Air filter Air boxes
Switching on 1 Variable advance CDI electronics
ignition 2 Variable advance CDI electronics
Battery charger preparation Output power 40 W at 5500 rpm
Candle cap With 5K Ω resistor
**Diet Unleaded petrol E5 or LL 100 AV GAS – 2.5% with 100% synthetic oil
*Consumption 3 Lh 30 Kg of static thrust
Gear reducer Helical teeth in oil bath, reduction ratio 2.8 or 3.2
Goodwill electric + Flash Starter
Clutch Oil bath centrifuge
Muffler Expansion with aluminum silencer
Engine weight Starting from 22.3 kg weight complete with radiator
Propeller rotation Clockwise

* The values ​​reported were measured at sea level in standard atmosphere. The thrust and consumption values ​​may vary depending on the air temperature and the density level.

** E5 defines the type of petrol that can be used. E5= 95 octane green petrol with maximum 5% ethanol. This symbol is shown on all petrol pumps in Europe.

Open chat
Need Help?
Hello
Can we help you?