Cruise Performance

[John Hoffman]

I have a 1973 NA plane and usually fly 23x23 as high as I can, I expect to see 145K and burn a little less than 20gph. Since you are burning the fuel you must be making good power so my guess is somethings draging your speed down. I had some reriging done years ago after I bought the plane and believe it helped the speed. You might have someone take a closer look at the airframe for rig.

[Skymaster337B]

Do you keep your cowl flaps open after reaching cruise?

[tropical]

I have a 74 "G" and at 6000' running 23/2300 and 10gph/engine I average 155 to 160 KTS TAS.

[Tom]

Yes, cowl flaps are closed, gear up and wing flaps retracted

[edasmus]

I second "tropical." My 73G model (no turbo) does the same. I run 2300 RPM and whatever manifold pressure I can get depending on altitude. If I am low however, I will usually not run much more than 24 inches.

[Roger]

I fly mine non-stop between ART - SGJ typically 890-900 NM, and my average block to block is 5:50 - 6:10, for an average of 6 hours, at 150 Knots, 10.2 gals per hour per end. 7000 feet average 2300 rpm with throttle to the wall. 80 - 337-H.

[Skymaster337B]

Wow, isn't that pushing the gas....6.0 on a full tank?