Plane: add flag to disable wp speed scaling on heading and groundtrack

ArduPlane/quadplane.cpp

@@ -280,6 +280,7 @@ const AP_Param::GroupInfo QuadPlane::var_info[] = {
     // @Bitmask: 20: Force RTL mode-forces RTL mode on rc failsafe in VTOL modes overriding bit 5(USE_QRTL)
     // @Bitmask: 21: Tilt rotor-tilt motors up when disarmed in FW modes (except manual) to prevent ground strikes.
     // @Bitmask: 22: Scale FF by the ratio of VTOL to plane angle P gains in Position 1 phase of transition into VTOL flight as well as reducing VTOL angle P based on airspeed.
+    // @Bitmask: 23: Disable waypoint speed scaling based on heading and groundtrack angle difference
     AP_GROUPINFO("OPTIONS", 58, QuadPlane, options, 0),
 
     AP_SUBGROUPEXTENSION("",59, QuadPlane, var_info2),
@@ -2998,7 +2999,7 @@ float QuadPlane::get_scaled_wp_speed(float target_bearing_deg) const
 {
     const float yaw_difference = fabsf(wrap_180(degrees(plane.ahrs.get_yaw()) - target_bearing_deg));
     const float wp_speed = wp_nav->get_default_speed_xy() * 0.01;
-    if (yaw_difference > 20) {
+    if (!option_is_set(QuadPlane::OPTION::DISABLE_WAYPOINT_SPEED_SCALING) && yaw_difference > 20) {
         // this gives a factor of 2x reduction in max speed when
         // off by 90 degrees, and 3x when off by 180 degrees
         const float speed_reduction = linear_interpolate(1, 3,

ArduPlane/quadplane.h

@@ -604,6 +604,7 @@ class QuadPlane
         FS_RTL=(1<<20),
         DISARMED_TILT_UP=(1<<21),
         SCALE_FF_ANGLE_P=(1<<22),
+        DISABLE_WAYPOINT_SPEED_SCALING=(1<<23),
     };
     bool option_is_set(OPTION option) const {
         return (options.get() & int32_t(option)) != 0;