|LONG-RANGE HEAVY BOMBER||Virtual Aircraft Museum / United Kingdom / Bristol|
An unsuccessful contender for a 1917 large bomber requirement, the Bristol Braemar triplane formed the basis of the Pullman, an equally unwanted airliner with a large cabin and enclosed cockpit. The Pullman's crew distrusted this feature and took to carrying axes with which to hack their way out in an emergency.
The Royal Mail Steam Packet Company showed interest in a version called the Tramp to be powered (naturally) by steam engines. By 1919 this was pretty eccentric and a considerable challenge. Two Tramps were built, each with four piston engines in an internal engine room while a light and powerful steam powerplant was developed. This proved impossible, as did making the system that transmitted power from engine room to propellers work reliably, and thus neither of the Tramps ever flew.