Hi. Good news. I flew today my new RV-4 equipped with this NGH 9cc, in a field above 2,300 over sea level. Excellent capabilities to take off, climbing and good landing without flaps.
This engine surelly delivers more than 1 HP. Seems like an .50 IN nitro. I spectted more RPM'S... with an 11 x 6 prop I obtained less than 10,500.

Wich prop do you suggest to me?