The Flying Kettle Project has as its fundamental premise, the use of steam as the lifting gas for lighter-than-air craft.

There are two types of lighter-than-air craft: balloons (which are unpowered) and airships (which are power-driven). Thus this Project has its two aspects: the Steam Balloon and the Steam Airship. These ideas at first sight appear whimsical if not comical - which can only be beneficial to this Project from the publicity point of view. However they are quite serious proposals, we believe solidly founded in technological feasibility.

See here for a digression upon the philosophy of technological development....


The Steam Balloon is a sort of hybrid between a hot-air balloon and a gas balloon. It is our contention that a steam balloon will have certain definite advantages over the hot-air balloons that are in common use today. It must be admitted that it also will exhibit certain disadvantages. What the balance between these turns out to be, in various circumstances, can only be properly assessed after much experience in actual operation.

In fact, there will be several quite different ways in which a Steam Balloon can be flown, depending on whether a flight boiler and/or an insulating jacket are carried. The concrete and quantified details of how we propose to fly in these modes can be seen here.

As compared to hot air, the basic advantage of steam as lift gas is that the lift per cubic meter is more than double. This means that it becomes practical to carry an insulation jacket upon the envelope, which is quite out of the question for a hot air balloon. Heat insulation will greatly prolong flight times. However a special boiler will be required for initially filling a Steam Balloon on the ground, and handling and packing the insulation jacket will be quite troublesome.

As compared to helium or hydrogen, the advantage of steam as lift gas is that it is much cheaper and also is easier to provide in the field, and that lift control is easy; however, its lift is less, and of course it progressively loses heat, so for long-term flight it must be kept hot.


A Steam Airship will definitely require an insulating jacket and a boiler to keep the steam lift gas hot during flight. This means that it will be very advantageous indeed to use a steam engine to power the airship as well. This aspect of the Flying Kettle Project is more ambitious than the Steam Balloon side, and the extrapolation extends further. Current speculations can be seen here. It is obvious that we must get a lot of experience with flying Steam Balloons before even attempting to build a Steam Airship.

At this stage our assessment - speculative! - is that, first, there is no potential in a rigid Steam Airship, but only in a non-rigid with an envelope which can be deflated and re-inflated, because the chief advantages of steam lift gas are its cheapness and convenience, which make it practicable to deflate the envelope after every flight and to re-inflate for the next. We think that, while such a non-rigid Steam Airship certainly does not have the potential to compete with the helium airship in every application, it will have its niche. Specifically, we think that the Steam Airship can succeed in satisfactorily filling the niche that hot-air airships try to occupy but fail. Consider the following very typical mission requirement:

On a day when the weather is likely to be reasonably fine, to fly over a major sporting event and maintain station for some time, displaying an advertisement or carrying cameras. To be able to contract to do this in advance, with a good chance of actually being able to fulfil the engagement.

Now a hot-air airship cannot meet this requirement. Theoretically it might be able to do the job, but actually, when it comes to the question on the day, virtually always the wind is too strong. In reality, hot-air airships are too floppy and large and underpowered and slow to fly in any wind above the slightest feeblest breath. That is why they are typically only flown very early in the morning or at dusk - basically not the times when aerial advertising or camerawork is required....

At present the helium airship is the only possibility for this mission, and helium airships are extremely expensive to operate, fundamentally because they must be kept inflated more or less indefinitely.

I believe that, with development, a Steam Airship of moderate size will eventually be able reliably to:

Arrive from base, deflated and packed in a single large vehicle, at a launch site in a park or other site within a few kilometers of the target event location;

Be inflated with steam from a boiler carried on the vehicle, by a small ground crew;

Fly to the target event and hold station over it for several hours;

Return to the launch site; and

Be deflated and packed back into the vehicle and returned to base.

And all at a cost perhaps double that of a hot-air airship, but much less than a helium craft. And I think that the upwind performance of such a steam airship will be sufficiently decent for this mission to be possible in the prevailing weather conditions on, perhaps, 80% of days.

In fact for a limited mission such as the one specified above the full abilities of a helium airship - such as long-term endurance, high airspeed, and poor-weather flight capability - are not actually needed. The steam airship will have the most important qualities necessary for publicity and camera platform work: hover capability in moderate winds, and large conspicuous size. And I think that the low cost and the convenience in ground handling of a Steam Airship will, in this restricted operational context, more than make up for its deficiencies.

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