Named after Lieutenant Colonel James Doolittle of the United States Army Air Forces, this design by Epic Engineering is intended as a tribute to the vintage medium bomber design. Armed with 4 turrets with 2 guns each, this plane is capable of defending itself. Use of Activation Groups 1 to 4 is intended for the separate turrets, Group 5 is the emergency release for the internal bombs, and AG 6 is required for the use of the propeller pitch control Be sure not to overspeed the propellers for more than 3 seconds. Thank you for your interest in our products. Aftermarket upgrades and modifications are encouraged. If you have any questions, feel free to ask.