THOR 303 EVO
Evolution and reliability
Polini presents the new Thor 303 EVO engine, designed for those who demand high performance combined with absolute reliability, even in the most demanding flight conditions.
The Thor 303 EVO is the result of extensive work on every technical component, with the goal of further improving robustness, efficiency, safety, and combustion quality.
Advanced technical solutions increase performance and durability over time
- Completely redesigned cylinder, with enlarged exhaust port and transfer, and a new 5-screw mounting flange: more power, improved sealing, and total elimination of potential leaks.
- New optimized muffler, engineered to deliver strong, linear thrust across the entire operating range.
- Redesigned spherical joint, improving sealing and effectively isolating vibrations.
- Cylinder head with an evolved combustion chamber, developed in terms of compression and squish: faster, more complete combustion and lower temperatures.
- New ignition system with dual spark option, ensuring consistent spark delivery and maximum safety even in case of anomalies.
- Electric start as standard, with a new starter motor for immediate and reliable ignition.
The result is an engine that combines smooth power delivery, constant thrust, and optimized thermal management, key elements to face long flight sessions with complete peace of mind.
Reliability as an absolute value
In flight, there is no compromise: reliability means control, continuity, and confidence in your engine. Every design intervention on the Thor 303 EVO has been aimed at increasing operational safety and long-term durability. From the new cylinder configuration to the redundant ignition system, every detail is designed to minimize the risk of issues, even under the most demanding conditions.
With the Thor 303 EVO, Polini Motori reaffirms its philosophy: never-ending innovation to offer increasingly high-performance, safe engines ready to support every pilot in every flight condition.
THOR 303 EVO
| Polini Engine | 2 stroke monocylinder |
| Cooling | Liquid cooled |
| Bore for stroke | 76 x 62 |
| Displacement | 281 cm3 |
| Power | 38 HP at 8000 rpm |
| *Max thrust | 120 Kg with Ø 160 cm propeller |
| R.P.M. max | 8.400 |
| Cylinder | Aluminum with Gilnisil coating |
| Compression ratio | 9,5:1 |
| Piston | Two trapezoidal chromium plated rings |
| Intake | Reed valve in the crankcase |
| Carburetor | Dell’Orto VHST 28mm |
| Air filter | Air box |
| Ignition | Electronic CDI with adj. advance |
| Battery charger prearrangement | Output power 40 W at 5500 RPM |
| Spark plug hood | 5k Ω resistance |
| **Fuel type | E5 petrol or LL AV GAS-al with 2,5% synthetic oil 100% |
| *Consumption | 3 Lh 30 Kg of static thrust |
| Gear reduction unit | Helicoidal teeth in oil bath with 2,8 or 3,2 reduction ratio |
| Starter | Flash Starter and Electric starter |
| Clutch | Centrifugal in oil bath |
| Muffler | Expansion with aluminum silencer |
| Engine weight | Kg 21,5 including radiator |
| Propeller rotation | Clockwise |
*The values have been detected on the sea level at standard atmosphere. The thrust and consumption values may vary according to the air temperature and density.
**E5 means the petrol type that can be used. E5= unleaded petrol 95 octanes up to 5% of ethanol. This symbol is shown on all the petrol pumps in Europe.
