You can find that drawing on the book "Queen of the midnight skies" by Pape and Harrison. Ed Schiffer. ISBN 0-88740-415-4. Page 29. Text under the pic is : "Early conceptual design of the P-61. This four crew, two turret design does not indicate the presence of radar on the drawing and the nose is of metallic construction. (Balzer Collection)"
From Page 28-29
Northrop Specification 8A. November 5th 1940
Original Night Interceptor Pursuit Airplane data was: tricycle landing gear, 2xDouble Wasp engines, twin tail boom configuration, crew of three (gunner for the nose turret, pilot and radar operator/rear turret gunner), span = 66 feet, lenght = 45 feet, weight = 16,245 pounds empty/22,654 pounds gros.
An interim design of a single tail shoulder wing design was shortlived (no drawings :'()
Mid November 1940 re-design: additional gunner station added. Nose and tail turrets deleted and in their place was a .50 cal machine gun in the belly and four .50 cal machine guns in the top turret. The crew now consisted in two gunners, pilot and radar operator. In the nose was located the airborne intercept radar with the structure of the nose now being fabricated from non-metallic material.
November 22nd 1940 re-design: The crew once again to a three man configuration: pilot, gunner and radar operator. The armament changed once again also. It now consisted of four 20 mm cannon in the wings, the lower turret had been deleted with the top turrer being retained.
I have seen other drawings about P-61 early conceptual design but I can remember where...probably on Northrop P-61 Black Widow - WarbirdTech Volume 15 (WarbirdTech) by Warren E. Thompson (http://www.amazon.com/Northrop-P-61-Black-Widow-WarbirdTech/dp/0933424809/ref=sr_1_3/104-6982050-1731157?ie=UTF8&s=books&qid=1192527531&sr=1-3).
Lark, do you remember it?
