Martin chose the always wise “walk before you run” approach with their innovative XB-48’s bicycle landing gear. They used a household TB-26G-25-MA with its original tricycle landing gear replaced by a pair of tandem retractable wheels placed in the fuselage and small outrigger wheels installed in the engine gondolas. Nicknamed the “Middle River Stump Jumper”, this Marauder opened the door,not only to the obscure XB-48, but also to the seminal B-47 and B-52.
Still a beauty, even with its somehow makeshift undercarriage and generous external stiffening. Certainly prettier than the plain horrible XB-48: