What cruise settings do you use most often?

[Toobuilder]

Originally Posted by mannanj

...I generally run 23 squared till I'm above whatever altitude the manifold starts to drop, then it's full throttle, 2300rpm, LOP burning about 6.5 gph with about 165kts TAS...

What altitude do you fly where you can still pull 165 knots on 6.5GPH? I run WOT from takeoff until I "intercept" 23 inches on the way down at my destination, then I maintain that MP until in the pattern. Typically I'm at ~8000 feet and the best MP I see is 21 inches, with 2350RPM, 50LOP and 8.2GPH at 165+TAS.

165 @ 6.5 is impressive for an -8!

[rzbill]

Originally Posted by RV10inOz

OPTIMUM


Wide Open Throttle ALL the time except when in the yellow arc on descent or on downwind and landing. This is the maximum efficiency for the engine.

anywhere around 2400-2500 wherever it is smoothest. (2000-2100 on descent)

Ranging from 60-80dF LOP at high powers (approx 80%) down to 10-20dF LOP at higher levels below 65%. If in the flight levels and I want more power I will run 75+dF ROP, but that is not efficient.

Greg, check your PM's, I see you are down in Sale, Victoria.

+1. Pretty much this for me. WFO throttle at all times and RPM to set power level desired. I like 2400 or less but will run 2500 if I am in a hurry. Most of the time Peak or LOP. The only time the throttle comes back is if I am relatively low altitude and I don't want to run so darn far oversquare (lyc power charts allow about +4 inches but the OWT still gives me the willies). My CHTs have had good balance since the beginning but I continued tweaking and on a recent flight the total span was 5 F across all four. Made me smile.

[BigglesRV7A]

Some good feedback from regular travellers. As always it is a trade off between speed and fuel usage. 160KTAS at 29.5l/hr or 172kTAS at 38L/hr.

22% extra fuel usage for 7% extra speed. Still the application gives us a choice.

Please send in your settings and performance so that we can get a good cross section of what everyone uses on those longer trips.

Cheers, Greg

[brad walton]

Superior IO360 and Catto 3 blade. Cruise at 162 KTAS at 2450rpm an 7.8gph ROP at 6 to8 k DA. RV-8

[panhandler1956]

I tend to run around at 23 squared. If I'm going somewhere I'm up high and therefore I"m at WOT and 2300rpm and LOP.

[Neal@F14]

At altitude going cross country... Full Rental Power!

[roadrunner20]

I too am running Superior IO360 and Catto 3 blade.
Cruise at 165 kts at 2450rpm, 8.7gph LOP.
Seems to be my sweet spot.

[java]

O-360-A1A with Hartzell CS (non blended airfoil). Cruise at a typical 6500-9500ft is usually 23 squared (or WOT and what I can get for MP at altitude). 170kts +/- TAS @ ~8gph or 165kts +/- at ~7.5gph, but I don't have my fuel flow dialed in quite yet. Maybe a tenth or two gph higher than that. I'm carb'd so can't get to the -70 LOP that you injected guys seem to be able to without it getting rough, but the red knob can still make a difference in fuel and cruise speed.

Of note, if I lean aggressively (just under the point of it getting rough... around 30 LOP or so) it will seem to cruise along just fine, but every now and then feel like it misses on a cylinder. Disconcerting over the Rockies out here. I twist the red knob a bit and it likes it more, for a bit more gas.

[LettersFromFlyoverCountry]

would like to see some more responses from FP guys (the po' folk).

[Neal@F14]

Originally Posted by LettersFromFlyoverCountry

would like to see some more responses from FP guys (the po' folk).

As mentioned above... "full rental power", e.g. wide open and mixture peaked for highest rpm. With my original Aymar Demuth wood prop, at 8000' that would give me a bit over 2600 rpm and 195 mph TAS with full tanks and burning 8.9 GPH. Once the tanks ran down past 1/2 full and the CG would begin to shift aft, the TAS would creep up towards almost 200 mph. That prop seemed to be pitched a tad tall, but was a great flatlands cruising prop... not so good for climb while heavy or flying in the mountains though.

It's going to be curious to see what the new Sensenich ground adjustable prop will be capable of. It's supposed to arrive via UPS today