View Full Version : Jet cruise speeds...at what RPM percentage

August 23rd, 2011, 03:30
I am working on the Alphasim freeware Jaguar packages and trying to give them a new FDE set. I "borrowed" the FDE files from the KBT F-1 (and have sent an e-mail seeking permission to use their files in this manner), which is the Japanese built licensed version of the Jaguar. The plane is much better behaved now...other than the speed...the plane is freaking FAST. I am trying to dial in the speed. The Jag has a posted max speed of 917 knots/1,056MPH at 36,000 feet.

Given that top speed, which is most likely for a Jag in clean trim...what would be a good cruise speed to shoot for and at what RPM percentage? I'm guessing something in the 550 to 600 MPH range for cruise....but I am not that jet savy.


August 25th, 2011, 14:46
Not having flown or worked with the Jag, I a only commenting in a general way. For this type of aircraft, a cruise somewhere in the M.90/550 knots TAS range might be correct, with Long Range cruise depending a lot on weight and altitude. Speeds down in the high 400's and M. 078-85 might be appropriate.

Turbine engines cram all of their power into the top RPM ranges, it's not linear. The Jag and it's contemporaries get the high speed out of afterburning. Typical RPM for high speed cruise might be say 92%, just as a WAG.

Cheers: Tom