ProBuild Aircraft Ltd are the original and longest-running Official UK Distributor and UK Service Centre for GP Engines, supplying genuine factory-direct products with full manufacturer support, expert technical advice and access to genuine GP spare parts and accessories.

GP-123 Twin Gas Engine – 123cc 12HP Twin-Cylinder Power for 35% Aerobatic Aircraft

When performance meets affordability, you get the GP-123 Twin Gas Engine, the ultimate power solution for serious aerobatic and 3D pilots.
Delivering 12 horsepower from its 123cc twin-cylinder design, the GP-123 combines precision engineering, smooth performance, and long-term reliability for the most demanding flight conditions.

Designed for 35% aerobatic aircraft, this powerhouse engine features a specially engineered crankcase that ensures equal fuel distribution between cylinders, reducing vibration and enhancing durability. Whether you’re flying extreme 3D or precision IMAC routines, the GP-123 gives you the consistent power and control you need.

Key Features

✅ 123cc displacement delivering up to 12HP
✅ Dual-cylinder configuration for smooth, balanced power
✅ Optimised crankcase for reduced vibration and improved efficiency
✅ Lightweight yet durable construction
✅ Walbro MJ-71 carburettor and NGK CM-6 spark plugs included
✅ Includes 2 mufflers and backed by a 2-year Probuild Aircraft warranty

Perfect For

• 35% aerobatic and 3D aircraft
  
• Pilots seeking high power with low vibration
  
• Builders upgrading from smaller displacement engines
  
• Those looking for professional-grade performance at a competitive price

Specifications

• Displacement: 123cc
  
• Horsepower: 12HP
  
• RPM Range: 1600–8900
  
• Compression Ratio: 9.2:1
  
• Fuel: 92 Octane Unleaded (40:1 oil mix)
  
• Recommended Propellers: 27x11, 28x10, 28x12, 29x9, 29x10
  
• Weight: Engine – 2300g | Ignition – 202g | Mufflers – 330g
  
• Warranty: 2 years (Probuild Aircraft Ltd)

Why Buy from Probuild Aircraft Ltd

✅ Official UK GP Engines Stockist
✅ 100% Genuine Products
✅ Trusted by Top International Pilots
✅ Fast, Reliable UK Shipping
✅ Supporting RC Pilots Since 1993