top of page

2007 Todd Reick in Colorado built and flew the first Yamaha Genesis 3-cylinder (YG3) 120 HP aircraft conversion, installed on his Air Command single place gyrocopter.  It used a 3:1 Rotax C box and RK400 centrifugal clutch for soft starting, and his unique wrap-around, box-style PSRU adapter and aluminum tube engine mount.  It was very successful and Todd went on to sell several dozen copies, then retired in 2016. 

2010 Ernie Boyette, of Rotor Flight Dynamics (RFD) in Florida, built the first Yamaha Apex 4-cylinder EFI (YG4) aircraft conversion, mounted on a welded chromoly tube frame on one of his Dominator tandem gyrocopters.  It used an AutoFlight 3:1 gearbox, adapter, and prop-mounted sprag clutch for soft starts.  Although it flew, it was not successful and had numerous forced landings due to electrical issues.  It was the only one built.  


2012 Greg Mills built and flew the first Yamaha RX1 4-cylinder 140 HP YG4 in an Air Command Tandem gyrocopter near Atlanta. Mounted on an aluminum tube frame, it used an Arrow 2.58:1 gearbox with internal sprag clutch for soft starts. It was a complete success, with no re-designs or changes of any kind, and no forced landings or failures of any sort save for a loose wire spade that broke away from a carb heater while on the bench prior to assembly that came loose again in flight at 6 hours.  The electric carb heat was unnecessary since the carbs are also liquid heated, so the entire electric heating sub harness was removed.   

2013 Launch of Mohawk Aero (MAC) web site and store to sell RX1 conversion kits, including a modified wire loom.

2014 MAC moves from the Atlanta metro area to Savannah


2015 First purpose-built PSRU for a Yamaha is built by Greg.  It is a Hy-Vo inverted-tooth chain drive with a  slipper clutch for prop strike protection, not soft start, and is mounted to the existing YG4 on Greg's tandem Air Command.

2015 Tango Gyro, a business selling the first aircraft built around a Yamaha Genesis engine, is launched near Atlanta. It is a euro tub knock-off, semi-enclosed, gyrocopter kit built in Russia with a typical welded stainless steel tube frame; assembled with YG3 motors purchased in the USA; mounted with AirGearbox350 "Type B" 3:1 gearboxes; and an in-house, purpose-built, centrifugal clutch.


2016  MAC moves from Savannah, GA,  to Columbia, SC.   

2017 First successful 150 HP Apex YG4i wire looms and conversion kits are built by MAC, and Greg launches the Facebook group "Yamaha Aircraft Engines" to promote and augment the MAC website.  Although some YG4 kits use older, discontinued Rotax C boxes and RK400 clutches, most are sold with the newly-introduced AK7 "Russian" PSRU built to MAC spec by AirGearbox350 in Minsk, Belarus. These are beefier than the Rotax C and use the new soft-start MAC GT4 roller ramp clutch, GT5 sprag clutch, or GTF flex shaft coupling with BMW rubber donut.  It is determined that clutches are not necessary for the smooth running YG4's, and clutches are largely ignored for them from this point forward.  Rotax donuts are not sturdy enough for YG4 use, so Greg starts selling a Rotax-compatible version of the MAC GTF, using an adapter disk to mate the larger 78mm BMW donut to the 76mm Rotax drive flange.  

2019 First 80 HP Yamaha Phazer (YG2) wire loom and aircraft conversion kit is built by MAC.  It is sold to, installed and flown by Gil Audibert on his Quicksilver II float plane near New Orleans.

2020 First 165 HP Apex EXUP (model years 2011-2018) wire loom and conversion kit is introduced by MAC.  Greg does a ground-up installation on Geoff Resney's (Indiana) Air Command Tandem gyrocopter, and test flights begin in May. The build includes using Yamaha's stock titanium valve-controlled exhaust, AK7 3.47:1 gearbox, and GTF shaft coupling.  It spins a 3-blade, 68" Warp Drive (MAC is an authorized Warp Drive dealer) prop and 28' Dragon Wings rotor blades, and is affectionately christened "Godzilla". It is arguably the most powerful gyrocopter flying today.

















bottom of page