def METHOD_NAME(self):
    """load rotor aircraft envelop, all unit in SI"""
    limits_rotor = {}
    for mdl, ac in self.acs_rotor.items():
        limits_rotor[mdl] = {}
        limits_rotor[mdl]["vmin"] = ac["envelop"].get("v_min", -20)
        limits_rotor[mdl]["vmax"] = ac["envelop"].get("v_max", 20)
        limits_rotor[mdl]["vsmin"] = ac["envelop"].get("vs_min", -5)
        limits_rotor[mdl]["vsmax"] = ac["envelop"].get("vs_max", 5)
        limits_rotor[mdl]["hmax"] = ac["envelop"].get("h_max", 2500)
        params = ["v_min", "v_max", "vs_min", "vs_max", "h_max"]
        if set(params) <= set(ac["envelop"].keys()):
            pass
        else:
            warn = f"Warning: Some performance parameters for {mdl} are not found, default values used."
            print(warn)
            bs.scr.echo(warn)
    return limits_rotor