May I suggest you gentlemen take a look at my review article on the SM Hawk in RCJI . I made some suggestions, and flight tested them and my Hawk is totally docile., throughout the flight envelope. My suggestions were based on fullsize practice and the experience of Duncan Simpson during early flight test of the real Hawk, when control was temporarily lost during stalling trials with flaps extended.

In short, :

Use two powerful servos on the stab.

Mass balnce the stab.

Limit flap angle to no more than 1 inch of depresssion at full flap, half that for take off and approach.

Set the stab. trim slightly up about 1/8th inch for take off/ approach flap , about 3/16th inch with landing flap.

Set up like this the model is a delight to fly.

The results of early problems with the Hawk can be seen by the deletion of about two feet of the outboard section of the secondary flap.

The problem was the strong downwash created by the flaps on the tailplane. In addition flap extension caused a nose down pitch, (probably due to C of P shift) which required uptrim on the stab. the result being a stalled satb.

The model seems to replicate this extremely well !

Regards,

David Gladwin.