O.S. GT15HZ: New Gas Engine

Apr 04, 2013 3 Comments by

Many years ago we tried using Zenoah gas engines in our helicopters, but there were several problems we could not overcome. First, they were not designed to be used in helicopters. Rather, they were designed for some type of commercial operation, such as powering a small blower. This meant they were unbalanced, so they had to sent away for balancing before we could even think of giving them a try. And, since they were designed for blowers, they could not be mounted in a standard helicopter, so designs had to be developed to specifically handle their size and mounting limitations. And, even if all these complications were addressed, then they failed to produce the needed power for anything but hovering and gentle forward flight.

Now the popular manufacturer for OS engines has decided to tackle all these problems, and to give us a gas engine that is specifically designed for our use. The OS GT15HZ gas engine was developed to be ideal for sport, 3D and scale pilots, and it fits most 90 size helis with minor modifications. It also uses the reliable and easy to adjust  O.S. Walbro pumper carburetor for consistent performance regardless of attitude, altitude, or fuel level, while the IG-05 ignition module is designed specifically for helis and is compatible with a wide range of battery chemistries including NiCd NiMH, LiPo and Life packs.

OS does offer the E-4051 standard muffer for use with the GT15HZ, but the polished aluminum PowerBoost pipe has been expressly designed for this engine, and can extract the full performance of the GT15HZ while producing stable and reliable gas engine operation.

Here are some of the engines statistics:

Displacement: 0.912 cu in (14.95cc) - Bore: 1.091″ (27.7mm) – Stroke: 0.976″ (24.8mm) – Practical RPM: 2,000 – 16,000 – Output: 2.76hp @ 14,000 RPM – Weight: Engine, 26.4oz (748g) IG-05 Ignition Module, 3.2oz (92g) with Power Boost Pipe and  7oz (198g) with E-4051 Muffler5oz (144g) – Gasoline/Oil Mix: 25:1

I’ll be converting one of my 90 size helicopters to take the GT15HZ, and will report back on its performance and flight characteristics. And, if you beat me too it, let me know how your works in your helicopter, and your detailed impressions.

Paul Tradelius, Uncategorized

About the author

A regular contributor to Model Airplane News, he is also the columnist for our “Rotor Speed” helicopter column. Paul has been flying RC helicopters since the early ‘80s and now enjoys all types of rotary machines, including scale and aerobatics, and he continues to experiment with modifications to improve performance.

3 Responses to “O.S. GT15HZ: New Gas Engine”

  1. Anthony says:

    Hi Paul, I know a few guys from my club who have change from Zenoah, they two had issues.

  2. Paul Tradelius says:

    I’s sorry I didn’t see your comment until now. You mentioned two issues. What are they and how were they handled?

  3. Tony Iannucelli says:

    I think Anthony meant they had issues with the Zenoah. But maybe not. Can’t imagine OS would put something out without thinking it through. Looking forward to your review.

Copyright © 2014 Air Age Media. All rights reserved.