Specification:
- Displacement(c.c. / cu.in.): 6.90 c.c. / .421 cu.in.
- Bore(mm / in.): 21.5 mm / 0.846 in. 
- Stroke(mm / in.): 19.0 mm / 0.748 in.  
- Practical R.P.M.(R.P.M.): 2,000 ~ 15,000 rpm
- Output(BHP/RPM): 1.10 BHP / 14,000 RPM  
- Weight(g/oz): 357.2 g / 12.60 oz 

The Thunder Tiger GP-42 engine is designed to combine high performance with easy handling and maintenance using CAD computer technology. Major components of the engine are machined from the highest quality materials using state-of-the-art CNC manufacturing techniques, resulting in consistent-high quality and reliability.

The GP-42 engine is equipped with maintenance-free bronze bushings, Schnuerle porting, a special ABN type piston and cylinder sleeve, an easily adjusted air bleed carburetor, and a safe angular needle valve. The GP-42 engine has been specifically-designed to suit both beginners and experienced modelers.

Designed for sport airplane use
One-piece crankcase structure
Bronze bushing support for easier maintenance
Air bleed carburetor design for easier adjustments
Aluminum piston with Nickel-plated brass cylinder liner
Swept back needle valve for added safety during adjustment
Forward side exhaust port
Side exhaust
3-chamber muffler included
Redline R2 glow plug included