It is 60-8004 which is the fourth aircraft of ASF-X. This ASF-X-04 is used for weapons testing, etc.
Thanks to Ostrich (@SuperOstrich) for creating the ASF-X template.
ASF-Xのテンプレートを製作してくださったOstrich氏に深く感謝します。
ASF-X Template
Moddb.com
Codename VANILLA -Template Repository-
Moddb.com