ORIGINAL: billtulsa
APC has an 18.1-11 available as well as a new 18.1-12. I ran the 11 all last year and is very quiet along with some changes for the better in flight performance and feel compared to the 18.1-10. I am currently evaluating the 12 pitch. The engine has plenty of power to turn this prop also. I requested the blade be narrowed slightly so the engine would not load on the uplines since the pitch was increased. Only have 4 flights on the prop so more testing is needed before I can say for sure. Running a YS 170.
We were playing with Adrian Wong's DZ 170 in his ProLine last week - using a 17x12 we got it to measure 93db running on the rich side. Meaning that he only turned about 7900 rpm on the motor but still had more than enough power to fly through the P/F sequence. At one point we actually had him around 7500 rpm (91db) and he still had power to spare.