On the Morane Saulnier 760 Paris jet (4 seater, two Maboré

IV turbojets) it makes quite a bit of difference:

At an N1 cruise setting of 19500 RPM at standard atmospheric conditions under similar climbing and descend conditions (climb: N1 at 21500 RPM,

IAS 200 kts up to 20,000 ft, then - 10 kts each 3000 ft / descend: N1 at 17000 RPM air brakes out ,

IAS 180 kts) I´ll get the following values:

Cruise altitude___________Range___Time to TOC______Time from

TOD to GRD_______Total flight time

10,000 ft________________560 mn_______5´_________________6´______________________1h57´

20,000 ft________________720 nm______11´_________________9´______________________2h30´

25,000 ft________________810 nm______16´________________11´______________________2h50´

30,000 ft________________860 nm______21´________________12´______________________3h05´

To account for taxi and circuit fuel subtract 100 - 150 nm from each range figure

Also from the manual:

at 19000 RPM both engines together use 400 l/h at 30.000 ft while they use 640 l/h at 10.000 ft (the manual and aircraft are from the 1950s, they gave fuel consumption in litres per hour)

at 21500 RPM (highest power) fuel consumption is 625 l/h at 30.000 ft and 1075 l/h at 10.000 ft.

The manual advises to climb as high as possible as fast as possible.

Jan

[Edited 2012-08-08 07:28:27]