The airframe of the HP81 Hermes IV formed the basis of these proposals with the intention of extending the production life of the type. The HP89 was proposed as a freighter version of the Hermes and had a ventral door which hinged down to form the loading ramp.
Both the HP91 Hermes VI and HP92 Hermes VII were proposed in 1950 as structurally lightened versions of the Hermes IV. Both were to operate at 85,000 lb all-up weight, the Hermes VI being otherwise like the Mk IV, but the Mk VII having four Rolls-Royce Griffon engines.