Ace Electronics

Thunder Tiger - Pro 39H Ringed

Pro 39H Ringed Heli Engine

Product No. 9604

The PRO series helicopter ring-type engines are equipped with dual ball-bearings, Schnuerle porting, one ring-type piston / cylinder assembly and two-needles automatic mixture control carburetor.

All Thunder Tiger engines have been designed to combine high performance with easy handling and maintenance using CAD computer technology, resulting in consistent high quality and reliability. Subjected to rigorous quality control check ensures that it will provide years of trouble free use.

The PRO-Heli series are manufactured by automated computer-controlled machinery, resulting in a product that looks and performs better. The displacement at .394 cubic inches is the largest displacement engine available in the popular 30-size helicopter class, and directly fit in all popular machines. Precision air bleed carburetor makes adjustments simple, and efficient mufflers keep things quiet at the field.

A Closer Look


  • Top grade CNC equipment, state-of-the-art technology are used.
  • Improved carburetor; swept back for safety, which makes adjustments simpler.
  • Forged aluminum connecting rod with dual bushings connects it all together.
  • Improved quality; ISO9001 Certified which guarantees the maximum power and performance.
  • Smooth running and long lasting power plant with front and rear ball bearings.
  • .394 cubic inches is the largest displacement engine available in the popular 30-size helicopter class.
  • Ringed-type piston.
  • Designed for both beginners and experienced modelers.



  • Heli blend fuel with 5-30% nitromethane and 20% lubricant content
  • Long type glow plug such as the O.S. #8
  • Glow starter
  • Plug wrench
  • Field equipment


  • Displacement: 0.394 cu in (6.45 cc)
  • Bore: 0.850 in (21.6 mm)
  • Stroke: 0.693 in (17.6 mm)
  • Crankshaft: UNC 1/4 - 28
  • Practical RPM: 2,000 - 22,000
  • Output: 1.35 hp @ 18,000 RPM
  • Weight w/o muffler: 10.22 oz (290 g)