#### DrBenny

##### New Member

For cruise, I usually choose a 2100-2200 rpm setting for the 'Hawk at 2000-5000' MSL. These settings are at the bottom of the green line, but I like them the best. Anyway, here are some numbers for your perusal from the POH:

At standard temperature at 4000 feet we get:

2100 rpm - 46% pwr - 93 KTAS - 5.5 GPH

2200 rpm - 51% pwr - 99 KTAS - 5.9 GPH

2300 rpm - 57% pwr - 105 KTAS - 6.4 GPH

2400 rpm - 64% pwr - 110 KTAS - 7.1 GPH

2500 rpm - 71% pwr - 115 KTAS - 8.0 GPH

2550 rpm - 75% pwr - 118 KTAS - 8.4 GPH

IOW, If I went to full power, which at this altitude would be 2550 rpm and 75%, I would only get 118 KTAS and I would be burning 8.4 GPH. I would only be gaining 25 KTAS over the 2100 rpm setting. Put another way, I get a 27% increase in speed, but I pay the price of a 53% increase in fuel consumption. I am probably also lowering my time to overhaul since the engine is under more stress.

Opinions?