What was the "Big Belly" modification?

Short answer

It was a modification of the B-52D begun in late 1965 to increase its bomb capacity for carpet bombing. Internal load rose from 27 to 84 bombs of 500 lb (230 kg), or from 27 to 42 of 750 lb (340 kg). In total, 60,000 lb (27,000 kg) with 108 bombs.

Published: November 1, 2026 · Updated: November 1, 2026 · Edited by Above Ten Thousand · Editorial policy

A B-52 Stratofortress flies near the North Pole

A B-52 for conventional warfare

In late 1965, several B-52Ds underwent the Big Belly modifications, designed to increase bomb capacity for carpet bombing. Work began in December 1965 and was completed in September 1967. An unmodified B-52D could carry only 27 bombs of 500 or 750 pounds. After the modification, the same aircraft could carry 84 bombs of 500 pounds or 42 of 750 pounds.

What changed inside and what stayed outside

The change was concentrated in the internal bomb bay: capacity rose from 27 to 84 bombs of 500 lb (230 kg), or from 27 to 42 bombs of 750 lb (340 kg), while the external load remained at 24 bombs of 500 lb (230 kg) or 750 lb (340 kg). Combined, this gave a total of 60,000 pounds (27,000 kg) with 108 bombs. That was 22,000 pounds (10,000 kg) more than a B-52F carried.

Arrival in the Pacific

The first B-52Ds with the Big Belly modification arrived in Guam in March 1966. The modified B-52Ds entered combat in April 1966, flying from Andersen Air Force Base, Guam.