Could be the extra fuel for that last 3,000’ of climb isn’t won back in the cruise and extra 3,000’ descent.
Or the table is wrong.
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I did think climb could be a possibility, losing an extra 15-30 miles due to an additional 3000ft doesn’t sound unreasonable?
I need a PEGI 3 Prosecco cause there ain’t no way I work this hard during the day
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Okay thanks. I will give it a watch 
Maybe that’s where the best wind is?
Published range accounts for fuel use at climb power… like anything altitude/performance related, there is a point of diminishing returns…
For flight planning, range is moot… the concern is duration, as range is at the mercy of winds aloft.
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The problem here is you’re thinking in two dimensions.
Let me rephrase your question:
A rock trravels at TAS 253 in a straight line.
Another rock travels at TAS 263 at a 75 degree upwards angle.
Which rock will travel further along the ground in an hour?
This is why it can potentially be a shorter range for the “faster” plane - the difference in angle of attack does make a difference. Although both planes are moving “straight” through the air at their TAS numbers, the higher plane - as noted - has to have a higher angle of attack to maintain the same amount of lift. That changes the vector of the plane’s forward motion - the force that is moving the plane is not being exerted in a straight line parallel to the ground; it’s directed upwards by the number of degrees of the AOA.
Think of triangles. The planes as they fly are actually moving along the hypotenuse of a triangle. But that triangle is getting pulled towards the ground because of the reduction in lift at that altitude. A lower plane has more lift, and the triangle isn’t getting pulled down. So the higher plane has to move faster in real terms through the air to keep up with the lower plane, because its frame of reference is different.
I have dim, probably faulty memories of the math underlying this - it’s basically ballistics in the end - so I think it can be described mathematically. But I’m not the one who will be able to do it. 
I’m pretty sure this is the answer, though.
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what was your speed ?
it require few seconds to actualise speed data cause I think it s calculating differential from a instant / point A to point / instant B
I don’t remember but it was like this all the way to the VOR/DME.
Looks like a bug to me. If the data is invalid as in this case those displays are meant to blank. Interested why if just flying to a real VOR why you are using the RNAV rather than one of the Nav radios. Are you virtual VOR’ing here?
It’s set to NAV 2.
Ah right looks like RNAV in the picture and I missed thd little number 2 on the display. Probably a bug then. Shouldn’t be showing that.
I would suggest as workaround to try and to take full advantage of KNS-81, using that nav 2 frequency on the KNS-81, maybe then the KDI-572 once set on RNAV will display accurate number from the kns ?
I remember having done that multiple time in king air when I had inaccurate reading due to DME showing 9999 or 0 error from nav 1 or 2 stack, the KNS 80 was always a great alternative to get those values
The king air caps the displayed values on the DME indicator in a similar way to a real unit would but that’s a different model. This implementation of the KDI clearly doesn’t handle out of range data.
I think it has more to do with the fact, that you have to climb 3.000 ft higher. As you climb those 3.000 ft from 25k to 28k the other aircraft at 25k can already cruise with a low power setting, while you are climbing with a climb setting and burn more fuel at this time.
With ever diminishing gains in efficiency, the effort to climb wipes out any potential gains.
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Just in the Turbine:
ISA and no wind, 50% fuel
FL250, Torque 880, Prop 1800
TAS= 266
GS= 266
FF= 32.5
FL280, Torque 840, Prop 1800
TAS= 268
GS= 269
FF= 30.7
Both true airspeed and ground speed are faster at FL280 and fuel flow better.
The only factor remaining must be either the climb or incorrect published figures.
And as others have stated fuel flow also seems to be higher than the figures stated in the manual.
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well not to throw a rock to them, but people were mostly refeering to tablet range and flight with max power setting (ITT limit)
in manual there is various table
(this table giving more or less value people met)
someone shared this other table on a related topic on JF forum
Hawkeye said
for the normal power setting tables, you are getting exactly the range the tables describe. If you want to push the plane to maximum range, you need to use the maximum range table. Here’s the tables
note that torque is much lower, allowing better range.
edit : apologize just noticed you shared some data to compare, I didn’t doble check those values, possibly in game indeed FF is slighty above.
I guess jayDee may relate, I have been monitoring a lot the analog caravan and king air FF values, sharing a little note from this experience, in a simulator, it’s not easy to perfectly match POH values. It becomes very tricky when taking into account air density and various changes in flight level.
No problem
In the flight I just did I was going by this table- my fuel flow seems higher
I dont know if these match closer to the piston maybe? I only have the Turbine, and this is from the Turbine manual.