The central ducted propellor provides the majority of the thrust, the outrigged props can be rotated independently to enable manouvering. The outriggers have no engines - they are powered by crankshafts coupled to the main steam plant which is inside the body of the ducted fan. Steam is generated using a catalytic reaction of Tetra-lithium crystals (magic, basically
) and most of it is captured, condensed and re-circulated.The baloons are long elliptical rigid-framed zeppelin types, extending considerably in front of and behind the cabins, not spherical hot air balloons. They should actually be considerably larger than those show - at least 3 times the diameter, probably more. As such, they are riddled with a number of gangways and ladders, the ideal place for a running chase/ suspenseful game of hide and seek (just don't take any naked flames, or cause any sparks).
The front hatch opens downwards, draw-bridge like, creating a passenger ramp. There is a larger cargo ramp at the rear of the vessel, which leads into the rear cargo hold, and there is a central belly-hatch for mid-air pickups. There are also maintenance hatches - one on each side, leading onto the outrigger booms, and one on the top to give access to the engine inside the duct.
The glassed area at the front is the flight deck, which protudes a little bulbously above the main body of the vessel to give some limited rearwards visibility - not much, because of the main engine, of course.
Not shown are the numerous stay-cables that attach the outriggers, the balloons and the main body together. Imagine the criss-cross wiring of a suspension bridge or a WW1 Biplane and you will not be far off.
Its a cargo vessel (with some room for passengers), and unarmed. An armed version might replace the forward lockers with gun emplacements, add gimbal-turrets to the forward holds, bomb racks in the central cargo bay and billeting for assault troops in the rear cargo hold.
***
Yes, I know it is impractical - but its steampunk, its not supposed to work. Even so, the gas-bags probably ought to be larger.
