My Hawk is powered by a Jetcat 160 derated to 120 standards so the idle thrust is unchanged. There is no problem with excess thrust at idle on approach, in fact, power is required.

The Hawk flaps are small but effective, but do produce strong downwash on the stab. and it is possible to stall the stab. If this happens and the machine pitches down I guarantee the pilot will KEEP the stick back until impact so the stab is never unstalled. Include the mods. and settings I quoted and I doubt you will have a problem, they have been flight tested. Although they are small the flaps DO make a worthwhile contribution to lift and drag and it should not be forgotten that they also "wash out" the wing, making flight at low speeds safer. If you want more drag just use aileron upset as Ali suggests (crow), that also adds to safe flight at higher angles of attack at low speed.

I use flight modes and the flap system on the 10X. This allows the flap angle and stab angle to be set to maintain trim. This trim can be fine adjusted in flight using the normal trim switch and the flight mode system will memorise them, makes life very easy.

Two more points:

Limit max stab. travel to 15 degrees to protect agianst stab. stall. (I will measure mine when I get my transmitters back from calibration)

Set the Tx so that flap movement is slowed, giving you more time to correct if things go wrong. If an uncontrollable pitch down ocurrs retract the flaps immediately.

Redesigning the flaps on the SM Hawk MAY be exactly the WRONG thing to do. The problem is not the amount of air over the stab. but the angle at which it flows onto the stab. with flap deflection. A slot may re-energise the boundary layer over the flaps increasing the downwash. Without putting the thing in a wind tunnel there only one way to find out, good luck !


Regards,

David Gladwin.