HMS Indefatigable: Airship

Lord Monty Zarknell was not a man with a vast sense of humor. Thus when he suggested building a flying ship in 1905 this was seen as a sign of insanity so he was promptly discharged from the RN. In all actuality they probably were right, but insane or not, Zarknell used his vast fortune to build a prototype himself rather than give up on the idea.

Six months later HMS Indefatigable was the result. While it was only one tenth the size of what he originally had in mind, it proved how sound his concepts actually were. Capable of speeds in excess of 250km/h (155 mph) and ranges of around 500km (310 mi) fully loaded, she was useful as well.

However when he presented his creation to Admiralty they were not impressed… and neither was he. Determined to prove his concept despite them, he flew to the site of a naval exercise, he proceeded to use the dual 4.5 inch guns to destroy all the targets before the ships could. What happened next? The history is unclear, but most reports indicate that while finally impressed, Admiralty were not amused…

Enough history; more facts! The envelope was filled with hydrogen and provided enough lift to offset about 95% of the total loaded weight. This meant that the rotors could use most of their power for movement rather than lift, and also that Indefatigable was stable on the ground. The rotors themselves were steam driven; inside each nacelle was a steam turbine running at a constant speed with the rotors using the revolutionary technique of varying pitch to control power. There was a single main boiler inside the rear of the upper fuselage which fed both turbines. In the case of steam failure a secondary boiler could be used to restart the primary, but if height and terrain permitted it was safer to just autorotate and land, and then restart on the ground. (Rotor damage at height would have resulted in crash.)

As a reduced scale prototype HMS Indefatigable was lightly armed, but it certainly wasn’t defenseless. Two 4.5 inch guns were designed for attacking ground targets (they couldn’t elevate up) and for local air defense there were 4 0.303 inch machine guns. The latter could be rotated but not elevated.

4 crew were carried, but it wasn’t designed for their comfort. The lower gondola did carry bedding and provisions for longer trips however. Their uniform (and flag) was non-standard; another sign of Zarknell’s insanity?

I’m king of the world!

Buoyant Power!

When I was younger a TV show called Beyond 2000 ran a story about the Helistat Piasecki PA-97 prior to it’s testing. I never saw the episode, but I do have the book! For years I looked at this interesting concept, wondering if it was successful or not.

This was obviously before the internet and this was one of the first bits of research that I did once I had access. To my disappointment it was a failure, and a rather complete one at that. After only a few trials there was a ground handling mishap due to a gust of wind, and everything was destroyed. Sadly even the test pilot died.

This seemed to have the had the effect of killing the concept for some time, even though the fault was mostly attributable to the rough nature of the prototype; the frame was inadequate and all other parts were re-cycled. Even the name “helistat” has become a dirty word. But the concept of the hybrid airship is too appealing to resist. By combining the neutral buoyancy of a blimp/zeppelin with the lifting power of a helicopter allows you to cancel out most of the vehicle weight leaving you with a long range craft with the vast aerial lifting capabilities. Many industries need this; especially logging. But the advantages don’t stop there. The PA-97 disaster aside, “hybrid airships” would be much easier to handle on the ground due to reduced buoyancy, which also means that the ballast issues that make zeppelins and blimps impractical become a non issue. Also, unlike ships and aircraft, all they need is an roughly-prepared open area to load and unload.

Thus it’s hardly surprising that the idea has been revived. This is the SkyHook JHL-40, a joint Boeing – SkyHook International project that is aiming to achieve a 40 ton lift over 320 km (200 miles). No prototype is ready as yet; in fact nothing is likely to even be in the air until 2014. Hopefully it’s the first of many. I must confess that it’s a dream of mine that zeppelins have a revival in my lifetime; I think they have a potential to replace some aspects of sea and air transport, especially with odd shaped cargo.

DARPA are actually researching this right now, with a project referred to as Walrus HULA, but details are scarce on the project. (It may even be canceled.)

But for now it seems that the concept will just have to live on as a favourite Sci-Fi / Steampunk concept!