Justo,
would you please post Model 2 picture? I'd love to see it.
Model 3 and 4 were both fighter projects from 1937.Both were preliminary proposals submitted by Bell to Army Air Corps specification X-609 issued on March 1937 for a single- seat, single-engine (V-1710 with turbo-supercharger) high altitude interceptor.
It would have been a complementary type to the winner of X-608 (Lockheed P-38) for 1940-45 USAAC fighter force, according to US aislacionist policy from that years.
Armament for Model 3 consisted of a single 25 mm cannon and 2 0.50in machine guns (option for 2 more 0.50in MG) in forward fuselage. The engine was placed between the nose and the cockpit. It progressed to full-scale mock-up only because of poor visibility. It latter influencied the design of Model 32/XP-77
Tech Data: Span: 10,67 m, Lenght: 9,04 m, height: 3,61 m, Wing Area: 27,78 m2, Loaded weight: 2,446 Kg.
Model 4 reversed Model 3 cockpit/engine position. It was selected as winning design and further develoment resulted into Model 11 (XP-39) and Model 12 (YP-39).
Source: Bell Aircraft. A J Pelletier. Putnam
More info here:
http://www.secretprojects.co.uk/forum/index.php/topic,183.0.html
On post #82 you can see Apophenia's superb Model 3 render.