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Fuel efficiency in cruise

No actual numbers before I pick up the DA42-VI in a couple of weeks, but so far the test flights show:

DA42-VI, 70% power, FL130, KTAS 171, 46.2 l/hr Jet A (both engines); 0.27l/nm; 0.067l/nm/seat

(btw, hi Eduardo!)

My view has always been that the Cirruses are about the same as the TB20 in aerodynamics. They gain on the airframe and they lose about the same gain on the fixed landing gear.

And the DA42 is exactly the same as the TB20 too. From a flight I did a few years ago (Thielert 1.7s I guess) it was doing 140kt IAS (low level) at a combined fuel flow of 11 GPH which is what I get at low level.

And the Cessna 400 is exactly the same as the TB20 too. 140kt IAS at 11 GPH, measured on a flight a few years ago. This is perhaps not suprising since its airframe looks very much like a Cirrus.

There is no free lunch in physics!

Administrator
Shoreham EGKA, United Kingdom

My view has always been that the Cirruses are about the same as the TB20 in aerodynamics. They gain on the airframe and they lose about the same gain on the fixed landing gear.

Cirrus would claim that the landing gear is an airfoil creating lift

This whole comparison is pretty flawed. We all have about the same engines with the same SFC (besides the DA42) and the real differentiator is cabin size. This is what creates drag. No wonder the Vans and the Mooneys look good -- they have the smallest and slimmest cabins by far.

Pipstrel claim for the Panthera "typical cruise" of 202KTAS and "typical fuel consumption" of 37l/h which would be 0,18l/NM. Not realistic I'd say.

Cirrus SR22T = 0,33 liter/NM cruise

EDLE, Netherlands

SF260 FL80 170knots 48lph 0.28 l/nm and with 4 POB that's 0.07 l/pax/nm

Mooney M20F my normal cruise: 10,000ft 32ltrs/hr, 2500rpm wot, 10deg lop, 145ktas 0.22 ltrs/nm I get those figures every single time (adjusting for Density Altitude of course), pretty much 1 ltr for every 1000ft higher but lose 5ktas

F140 28lts/hr , 2500rpmwot, peak , 135ktas 0.21 ltrs/nm

2000ft bimble 2200rpm/22in 30deg lop, 24 lts/hr 115kt 0.21 ltrs/nm

Stock M20F with three blade , so I assume a nicely rigged M20J would add 10kt to these speeds.

ORTAC

Stupid question time.... What's "wot"?

EDHS, Germany

Wot? You don't know wot wot is ?

;-))

Couldn't resist......

Please wait while I stitch my sides back together :-) haha!

EDHS, Germany

haha
wot=wide open throttle, so throttle lever full in , and ram air selected at 10,000ft that brings about 21in manifold

lop= lean of peak

ORTAC
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