Performance calculator, HondaJet and high temperatures

[Rodeo314]

Because of the very high temperature at KLAC (43C) I seemingly cannot takeoff from a 14,000 foot runway:

Departure:
KLAS/LAS  REID INTL
  SA  262156  18006KT 10SM FEW120 FEW250 43/11 A2982 RMK AO2 SLP061
              CB DSNT NE T04280106

If I reduce the temperature to 37C, I get V1 177 Vr 228 V2 272:

The conditions are a bit extreme, but surely that can’t be accurate? Vmo is 270 for the HondaJet.

Regards,

Tim

[Rodeo314]

For comparison, an A320 with a reasonably high takeoff weight:

Regards,

Tim

[SimBrief]

Thanks Tim, definitely a bug.

Should be fixed now, please let me know next time you have a chance!

Cheers,

[Rodeo314]

I don’t know enough to determine if the values are accurate or not, but they’re certainly more plausible now.

And at 41C it has to takeoff with flaps up to make the minimum climb gradient whereas if the temperature is lower, it can make the gradient with TO flaps, nice

Out of curiosity, what was causing the issue before?

Regards,

Tim

[SimBrief]

@Rodeo314

Out of curiosity, what was causing the issue before?

Just some bad math on my part. Due to the runway being so much longer than the typical values for the HDJT, combined with the fact its v-speeds don’t change much with weight. Some of the extrapolations were not working as they should, and the errors got further compounded by the high/hot temperature corrections afterwards.

Cheers,