George Stokes

Tail fin bleed holes

Rip panel actuation lines

Inside view of nose ring

Overpressure vent flap anchor (on inside roof, 3 half-gores off centerline)

Unknown anchor point

Tail fin bleed hole detail

Nose ring

Inflation tube?

Superpressure burner opening?

Inside view of gondola roof area.
Right is fore, left is aft.

Forward rip panel
(on top centerline)

Rear rip panel (on top centerline)
(Note both overpressure flap anchor points fore of rip panel)

Tail fins and rear rip panel

Nose view

Forward rip panel actuation

The bag, approximately 600+ pounds

Little is known about Mike Caldwell and this thermal airship he designed and built. This section will hopefully grow in size as more information is available. If you have information to provide, please share by emailing me.

Caldwell Balloons was a company headed by Mike Caldwell in Southern California in the late 1970's and early 1980's. Caldwell may best be known for the two hot air balloon systems which were built for Coca-Cola, loosely resembling some design features of then-current Raven balloons.

This "mystery airship" was apparently built for the Great American Bank but never finished, as evidenced by this email I had received from an anonymous tipster:

Yes, this airship was built by Mike Caldwell, in the very early 80s, perhaps around 1980 - 1981. It was built for Great American Bank, which defaulted on the contract and eventually went out of business. The airship was in storage for some years while Caldwell was living in Australia. He probably lost track of it while pursuing other more compelling business ventures.


What may be most interesting about this airship is that it was allegedly the first instance of silicone-coated fabric used in the balloon or airship industry, predating Colt's early 1980's introduction of HTN90. The 1.9oz ripstop nylon used in this airship envelope was obtained from Noah Lamport, where it was finished with a custom silicone coating.

This envelope is approximately 200,000 cubic feet and 160 feet long. The maximum diameter is just over 50 feet. Five small fins were apparently used for directional stability, with no rudder or control surfaces present. Steering was said to have been intended to be accomplished by way of airboat-style vectored thrust from the propeller behind the gondola, which may not ever have been built.

This anecdote from Dr. Fred Barnes may add more to the story of this airship:

Hello Jon Radowski:
This Ship looks very familiar. This goes back to the late 70's or early 80's and my memory is weak on those days, so I hope I'm right. I believe that this was one of the last (unfinished) projects of Mike Caldwell, owner of the now defunct Aerostatic Rainbow Wagons Balloon Company. I was ballooning and living in San Diego then (live in NY now), and we were driving up to a very foggy morning launch site near Perris. When we came to the field, there was a very large red and blue airship looming in the mist. Obviously, we stopped to watch. The scene became comical, when they somehow put a burner in it and it gently righted. It must have been an oversight, that there were too few ground handling line and persons, because the hot bubble rocketed to the tail and the while thing stood on its nose. And it stayed there for quite a while before slowly settling. The crew quickly bagged it and we went on to our passenger meeting spot – I never saw or heard of it again. Aerostatics was purchased shortly there after by David Bradley, a young balloonist from Kansas who moved to the San Diego area and set up a ride business. Caldwell built several special balloons: a super-pressure Great American Bank, the green and yellow balloon that appeared on the old US postage stamp back then, and several Coke balloons, white and red, to name a few. There may have been more (including this "mystery airship") that didn't get included in the inventory of the sale, and were lost in storage. Things may have been chaotic for Caldwell back then. In years past, I flew the old stamp balloon many times. Like your airship, it was over built (a Caldwell trademark); heavy fabric and load lines. So heavy in fact that if you let it get away, it would generate an impressive descent rate. It was an AX 7, but in the bag, weighed as much as a 9. I hope I'm giving you good information, and not dead-end. But, I can't think of anyone else that could have built it. I've been around balloons and airships for a while and know others that might have more information and better memories than mine. If this sounds worth pursuing, we can keep digging.

Profile view showing overall shape of envelope