The SAB AB-20 was a large four engine twin boom French bomber built in the early 1930s as a development of the Dyle et Bacalan DB-70 airliner.

The latter was built around a thick, wide chord airfoil centre section which provided generous internal space for passengers.

Both aircraft had conventional undercarriages with pairs of mainwheels widely separated on V-struts attached to the lower longerons of the centre section.

[1] The new central crew pod was flat-sided and tapered forwards to a complicated cylindrical nose, formed by a simple lower part with an overhanging, windowed cabin for the navigator/bombardier and an open gunner's cockpit, fitted with a machine gun ring, directly above.

Firing trials were halted after damage was caused to the lower wing skin by blast from the gun muzzle.