Merlin & HKS 700E Impressions

Finally I got around to making some video. Some day I will learn to edit it properly but don’t hold your breath…..

I am often asked if one can fly with the door off. I know it is possible but ’bout time I tried it for myself. 

I was impressed. The Merlin flies the same. 100MPH cruise, not much increase in noise, and not even much wind in the cockpit. I really liked it. Can’t wait for the next grapefruit drop competition!Some HKS impressions:

  • The engine starts quickly. A bit of a shake with only 2 cylinders and good compression. We installed an 18AH battery to spin the engine quickly and once it starts it smoothes right out. Takes a few minutes to warm the oil to 120F then it is good to go.
  • I have not accurately measured the fuel burn but I am sure it is close to the POH at 2.5-3.0 GPH. That provides some 5 hours endurance which is a lot longer than I plan to fly per mission.
  • Acceleration and climb is pretty close to that of the Rotax 582 Merlin. 
  • Cruise is 100 MPH or greater in the 5,500 RPM range. Prop is set in the middle for good climb and cruise, not optimized for either.  I would speculated that true airspeed at 7,000 feet with a prop set for cruise could exceed 115 mph.
  • The engine runs smooth throughout the throttle range. That is nice. And with the 3.47 reduction ratio that translates to a slow prop. This aircraft is exceptionally quiet and comfortable.

Watch here to see and hear the Merlin with the HKS:

Lots of touch & goes, some turns, and a few stalls, or at least flying with the power at idle and the stick in my lap.

Expect a few more Merlins with HKS 700E engines in the air soon!