The fuselage was largely fabric covered but the central part containing the wing support structure was plywood skinned.
In some photographs the three sloping struts that connected wing and fuselage, a distorted N arrangement most easily visible on the BS.7, were faired in as on the Biancone, but others show them exposed.
The new fuselage, deeper at the tail than the Biancone's tailboom, required a less tall fin to maintain the tailplane's position with respect to the rudder but otherwise the empennage was unchanged.
A wooden landing skid with rubber springing, deep like the one on the BS.11 Milano and assisted by a small tail bumper served as its undercarriage.
[1] In July 1934 a Bigiarella set an endurance record of 2 hrs 50 min, flying at Vigne di Valle near Rome.