SkyDemon Forums

How is the endurance computed

http://forums.skydemon.aero/Topic37293.aspx

By lhe - 7/26/2024 7:35:25 AM

A sample fuel plan computed by SkyDemon looks like this:

Taxi/Takeoff          4,2 ltr
Enroute      2h 17m  73,6 ltr
Holding Time    45m  18,5 ltr
Landing               2,5 ltr
Contingency (10 %)    7,4 ltr
Minimum             106,1 ltr
Planned       3h 8m 106,1 ltr

How is the endurance 3h 8m calculated? No time is given for the contingency fuel, but clearly it contributed to the endurance. At the fuel flow for the chosen power setting (31.7 l/h), the contingency fuel would contribute 14 minutes for a total of 2h 17m+45m+14m = 3h 16m – 8 minutes more than the total computed by SkyDemon. (The times for enroute and holding are correct.)

Am I missing something or is there an error in how SkyDemon computes the endurance? (If there is an issue with SD, now would seem a good time to address it as the fuel plan calculations are about to be reworked anyway to include Final Reserve Fuel.)
By Tim Dawson - 7/30/2024 9:46:55 AM

Thank you, it's a suggestion that clearly has merit. Before making such a change though I would be interested in the other contributors to this thread weighing in also. One of the uses for the calculated endurance is on flightplans, where search and rescue want to know how far the aircraft could have got to if contact has been lost.