Landing gear drag

[Fox One]

The test (track attached):

 

With 30% fuel and no external stores, I fly horizontally at 240kts. The required engines rpm is 74%.

Then I lower landing gear and increase the rpm to 94% to keep the speed constant at 240kts.

So in order to compensate for landing gear drag the engines rpm must be increased by a shocking 20%.

 

For 2 engines in this class, an increase in rpm of 20% means an increase in thrust for both engines of SEVERAL TONS. You need something like a Concorde landing gear to have a drag of several tons.

 

MiG-21 in reality typically extends landing gear and fly the circuit at 500Km/h. If the F-18 with gear down needs 94% rpm to fly horizontally at 450Km/h, the MiG-21 should need afterburner to fly horizontally at 500Km/h with gear down.

 

The good thing is that for F-18 in simulator at typical approach speeds landing gear drag seems resonably low.

 

Out of curiosity I performed tests with Su-33 and F-15, I extended landing gear in horizontal flight at 500Km/h and increased rpm to keep the speed constant. For both aircraft the required rpm increase was about 5%.

gear drag.trk