Speed Brake automatically Retracts when Flaps Lowered

[Igor4U]

The Hornet's Speed Brake automatically Retracts when the Flaps are Lowered

 

Anyone know if this is Normal Operation ?

 

Couldn't find any info on it in the F/A-18C Early Access Guide.pdf

 

THANX ! :pilotfly:

[muehlema]

If I recall right my memory, thats correct behaviour ;)

[Igor4U]

Copy - Thanx !

 

Many other Jets want the Speed-Brake out in Landing Config to keep RPM Up in case a Go-Around is Needed. That way you can get:

 

- Rapid Throttle Respond (already spooled up)

- Rapid Reduction of Drag by retracting SB

 

But I did Notice that Full-Flaps put a Lot of Drag on the Hornet. That alone probably keep the Engine RPM Up - and the F-18 GE 404 Motors seem to accelerate very quickly

[Dangerman]

[Fast jet QFI on]. Extended airbrake will move the form drag curve to the left for a given IAS, thus the total drag curve is shifted slightly left, thus you have more margin for IAS excursions as you remain in the speed-stable section of the curve before dropping to the back side of the curve .....where lift induced drag at inadvertently slow approach speeds will cause even further loss of IAS ... other reason....for older types with blown flaps such as the banana jet, higher RPM due airbrake gives more blow over control surfaces... all in addition to the the reasons given above. [Fast jet QFI off]

[FightsOn]

Yes, the F/A-18A-F all retract the speedbrake when the flaps are lowered (when the flaps actually start to move below 240 kts, not when the switch is lowered). But in the A-D you can hold the speedbrake out manually. As long as the switch is held aft the board will extend. In the E-F it cannot be extended in PA mode at all until Weight on Wheels.