SP-28 CR Two-Stroke Engine
This two-stroke single cylinder SP-28 CR with 28 ccm is the longest standing engine in our lineup. It is particularly suited for fixed wing aircraft on the upper end of the below 55 lbs or up to 25 kg class UAS.
The 3W-International SP-28 CR engine is equipped in the standard configuration with one spark plug and a single ignition unit. The carburetor is rear (CR) mounted.
The cylinder and crankcase are casted aluminum and have been manufactured in this current form for over 10 years.
The carbureted version is the lightest and most robust engine in its class.
The carburetor adjusts automatically to the engine and environmental conditions.
Customers fly up to 24-28 hours with this configuration.
| Type | 1-Cylinder Gas Engine |
| Capacity | 28 ccm / 1.71 cu in |
| Power | 2.2 HP / 1.6 KW |
| Speed Range | 2500 – 10000 RPM |
| Weight | 2.95 lbs (1.34 kg) incl. ignition |
| Crankshaft | 3 ball bearings |
| Oil/Gasoline ratio | 1:50 / 2% mix |
| Operating Voltage | 6 – 8.4 V DC |
| Bore diameter | 1.42 inch (36.00 mm) |
| Stroke | 1.10 inch (28.00 mm) |
| Torque | 2.3 Nm @ 6600 RPM |
