O.S. Max 105HZ-R DRS Helicopter Engine

O.S. Max 105HZ-R DRS Helicopter Engine
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This is the O.S. Max 105HZ-R DRS Helicopter Engine. The 105HZ-R DRS is the engine that precision aerobatic and 3D heli pilots have been waiting for! In order for 90-sized machines to nail huge maneuvers and hardcore, smack down-style 3D it's all about power, and the 105HZ-R have it in abundance. Displacement has been increased by 15%, and a huge venturi rams air into the carburetor, producing massive power, while remaining small enough to fit in a .90-sized mounting pattern.


  • Displacement of a 1.05 in the mounting space of a .90.
  • More displacement means more power, and these engines boost displacement by 15%!
  • Huge venturi boosts output even further.
  • The machined, blue anodized heatsink head is light in weight, and cools the engine efficiently.
  • Pressurized DRS (Demand Regulator System), ensures consistent fuel flow regardless of the heli's attitude.
Displacement: 1.048 cu in (17.17cc)
Bore: 1.442" (29mm)
Stroke: 1.024" (26mm)
Practical RPM: 2,000-16,500
Output: 3.75 hp @ 15,000 RPM
Weight: 21.46 oz (608g)
Verified Owner
Friday, Oct 2 2020 (5 months ago)
O.S. Max 105HZ-R DRS Helicopter Engine
Awesome engine, relentless power. I own two of these engines in two different machines. I plan on getting a third one when my reward points are available. The owner's manual does have a typo. Make sure you run your main needle to AND a half turns out for breakin.