912 ULS engine wear at take off WOT RPM

Hei,

thanks for these great experiences, I have at moment the same issue, where fuel consumption seems 20-22 l/h (5,3-5,5 gph) for Rotax 912 ULS (Plane MTOW 600 kg SD4). And I get the following rpm: take-off 5320 rpm, climb 5200 rpm, cruise 3000 ft 5350-5380 rpm (WOT). You can feel that the engine seems overloaded. IT means I should try to decrease the pitch 0,75-1 degrees?

Regards
Erki

Hi Erki,

At 5320 WOT at take off you're not over pitched you're under pitched if you are running a ground adjustable prop. What's your WOT in level flight?

Hi, Roger

I got similar WOT's for different altitudes (from the ground, airport 250 ft). At some altitudes I believe I waited not enough for stable rpm at WOT, but roughly +75-75 rpm- sounds not very logical? When I read other posts, then take off 5320 rpm, should give as results higher rpm at level?:

Climb 5200 (MAP 920 mbar)

1000 ft level 5400 (MAP 890 mbar)

2000 ft level 5300 (MAP 860 mbar)

3000 ft level 5360 (MAP 830 mbar)

4000 ft level 5320 (MAP 799 mbar)

5000 ft 5250 (MAP 760 mbar)

Does it mean I should try to add ca 1 degree, I would reduce my take off performance, but would get better cruise performance? I will check on the weekend the current configuration, DUC recommendation is 20 or 23 degrees depended on the gear box.

Regards

Erki

Hi all

sorry WOTstands for?

thanks

Elias

WOT = Wide Open Throttle