Raising speed limit on fixed wing vehicle

I changed the FW_THR_MAX to 100, the FW_AIRSPD_MAX to 35, EKF_ASPD_MAX to 35, and at max throttle in offboard. I am unable to fly faster than 25 m/s air speed or ground speed. This is in a gazebo SITL simulation with the classic_plane model. What parameter am I missing?

@John_smith_1 What you have changed are the parameters of the autopilot.

Setting the parameters does not influence the model of the simulation.

Does the simulation have a set speed limit? How can I increase the speed by changing parameters in the .sdf?

I checked and I send thrust of 0.99 in /mavros/setpoint_attitude/thrust but when I look at /mavros/setpoint_raw/target_attitude the thrust is only 0.38.