Most efficient cruise speed?

[AliceTBM]

Trying to get around the globe in the TBM and although I’m not quite there yet I need to figure out how to cross the Pacific from South America without running out of fuel. The longest flight on the trip looks to be 1620nm from Easter Island to French Polynesia (SCIR - SCIP).

I’ll have to pick a day with the wind in my favour but I’d rather conserve as much fuel as possible as it’s going to be close. How fast and what altitude is this bird most efficient?

[AliceTBM]

Spotted it on the Daher guide. 252knts @ 31,000ft.

[RobW05]

Almost correct, but you shouldn't consider airspeed as the determining factor. Depending on weight you  choose a power setting between 46-50% torque and accept whatever airspeed that gives you. You can look that up in the POH under the cruise performance section. Look for the long range cruise tables. 

[AliceTBM]

Brilliant, thanks

[EGT]

31000 ft and 50% torque will result in a fuel burn of about 35 gal./hr and 252 kts TAS. That gives an estimated range of 1800 NM with 1 hour reserve.

Edited October 20, 2019 by EGT