What are your cruise fuel flow settings for your Turbo?

[mshac]

I've never given it the level of thought shown in your post, but I flight plan 26 gph total in my P337H. That's at 75% where I usually get pretty close to the book cruise numbers. Close enough anyway.

I do not have GAMIs.

I fly pretty much the way you described: I set FF via the JPI to about 13 GPH each initially, then "diddle" with it as the flight progresses. The JPI has a "Lean Find" feature that I find very un-intuitive, so I hardly ever use it. I will lean back as I get to altitude if I can keep my CHTs under about 380 and turbine inlet temps under 1500.

I just had the baffling repaired on the rear engine and haven't yet made any flights of consequence, but before I had to give the rear a bit more fuel in order to maintain the same CHTs. I would often fly with FF of 12.5 up front and 13.5 for the rear. We will have to see if the baffling fixes change that.

[Ryann]

Tangentially related, anyone else try seeing what the minimum possible fuel flow while staying aloft is for your plane? I needed to build a bunch of hours for insurance reasons while not going anywhere in particular very quickly, so I spent some time playing with this and got it down to about 12.5 GPH total (10500', 6.5 GPH front, 6 GPH rear at about 21" and 2250 RPMs). Couldn't get it much leaner without intermittent missing. 1975 P337G, no GAMI injectors on here. Photos attached showing EDM-960 display and airspeed.

Single engine with the front prop feathered at 10500' (while loitering over a rural airport with a 5000' runway) actually took more GPH to maintain altitude than with both engines running.

-Ryan

[mshac]

That's good info on the min fuel flow. I see you were doing C172 type speeds but with an extra 50% fuel flow (vs the 8 gph of the 172).

I have the EDM 760 FF gauge installed. My understand is the 960 is a plug-and-play replacement for the 760 (won't fit in the same mounting spot though!) I think with trade-in, the upgrade only costs about $1500! I would have already done it, but it would require almost a complete redesign of my panel, so I've held off. Would LOVE to have one though!

I bet you could cut it down even more by caging the front engine. I hear that the Skymaster is the only airplane that EXTENDS its range when operating on only one engine!

[Ryann]

Found the photos from my single engine minimum fuel flow test. Photos attached, looks like I ended up at 14.7 GPH on the rear engine to just barely maintain altitude close to Vx.

I'll try it again during the winter months sometime soon and see if I can get it down any further with cooler air available. And maybe see if I can maintain altitude at Vy for a little less drag.

[mshac]

Thanks for the pics Ryann! I always say, if there's no pics then it didn't happen!

[n86121]

Once upon a time, I heard that a three letter agency has a 337 that provides top cover comms coordination, during certain circumstances, that powers waaay back, with low RPM, and goes for hours and hours and hour