Specification:
- Displacement(c.c. / cu.in.): 4.53 c.c. / .277 cu.in.
- Bore(mm / in.): 18.7 mm / .736 in.  
- Stroke(mm / in.): 16.5 mm / 0.65 in.  
- Practical R.P.M.(R.P.M.): 2,500 ~ 16,000 rpm 
- Output(BHP/RPM): 0.70 BHP / 15,000 RPM
- Weight(g/oz): 221.1 g / 7.80 oz

The Thunder Tiger GP-28 airplane engine is designed and developed under the ''Green Power" concept and feature a one-piece crankcase with an integrated carburetor body design to lower overall parts count.
No mounting screws are required for the cylinder head and backplate and a cast slot engine mount design simplifies the machining process.
Equipped with 3-chamber muffler, noise levels are greatly reduced while delivering excellent performance and lower fuel consumption.
Finally, the swept-back needle valve design and precision air bleed carburetor make operating the GP-28 airplane engine a safe, reliable and simple procedure providing you with years of trouble-free use.

Designed for sport airplane use
One-piece carb-crankcase structure
Bronze bushing support for easier maintenance
Aluminum piston with Nickel-plated brass cylinder liner
Air bleed carburetor design for easier adjustments
Swept back needle valve for added safety
CNC-machined aluminum heat sink head and backplate
Dual engine mount design
Forward side exhaust port
3-chamber muffler included
Redline R2 glow plug included