Last weekend at the Pi-Con convention, James L. Cambias gave a fascinating talk on historical airships.  This is a summary based on my notes and my memory. DISCLAIMER: I MAY HAVE GOTTEN STUFF WRONG OR MISSED IMPORTANT POINTS. I’M NOT AN AEROSPACE ENGINEER AND DON’T CLAIM TO UNDERSTAND THE PHYSICS OF FLIGHT.

Airships are a staple of steampunk and speculative fiction. Their aesthetic is immensely appealing but their mechanisms are rarely discussed. Cambias’s talk was a refreshing and fascinating look at real historical airships and touched on the engineering challenges of lighter than air flight. For example, burning fuel changes your weight.

The historical highlights began with Henric Giffard (http://en.wikipedia.org/wiki/Henri_Giffard) who created the world’s first airship in 1852 and ended with Zeppelin and his creations in the twentieth century. Along the way, Cambias discussed other significant figures. Santos-Dumont was particularly interesting. He not only created a number of airship’s between 1898 and 1905 but he actually used them to fly around Paris. (Santos-Dumont eventually turned his attention away from airships to airplanes.)  La France created by French army captains Reynard & Krebs was also mentioned. It was the world’s first fully controllable flying machine and used an electric motor which drove it at 12 mph.

Cambias discussed some 19th century American attempts at airships. Dr. Andrews’s Aereon built in 1863 was documented in newspapers at the time. However, modern scientists say its design would not have worked. The speculation is that it functioned as a balloon rather than an airship and that the Andrews got lucky with the wind giving the illusion that the craft was steerable. Marriott’s Avitor was an airship that sadly never came to be. A prototype was built in California in 1869 and flew on a tether.  But, alas, a full sized version was never made. In the 1890’s, there were reports of a mystery airship in American newspapers. The stories even included reports of cows being stolen. In all likelihood this was an elaborate hoax started by bored telegraphy operators and perpetuated by newspapers that freely stole each others articles and cared little for the truth.

The Giffard dirigible
Source: http://en.wikipedia.org/wiki/File:Giffard1852.jpg

It’s been hot this weekend and since I don’t have air conditioning in my apartment I need another way to keep cool. It is good weather for ice cream but ice cream is high in saturated fat and sugar so I made a healthier alternative using what I had on hand. A homemade fruit sorbet the perfect healthy ice cream replacement.

Here are the instructions if you want to make own.

Ingredients:

1 frozen banana
1 half fresh avocado
frozen tropical fruit mix
frozen mango
1 tbsp organic blue agave syrup

Equipment: High speed blender such as a vitamix.

First add the avocado, then add the frozen fruit, final finally add the agave syrup. Start blending on low and then increase the speed to 10 then to high. Using the tamper push down the fruit to blend it. Continue blending and pushing with the tamper until the desired consistency is achieved. Scoop out of the blender. The sorbet can be eaten immediately or stored until later.

One thing, I like about this recipe is that it lends itself to experimentation and adaptation. For example, I normally use ice but — perhaps because it was a hot day — the stores I went to had none left in stock. No problem, I simply made sure that I used plenty of frozen fruit.

Feel free to experiment but I recommend using bananas and avocado if possible. These help give the creamy consistency that makes this such a good ice cream replacement.

Disclaimer: I’ve only tested this recipe with a Vitamix. I don’t know how the recipe will work with another blender but if you try it please let me know how it goes. The recipe above is my creation but I’m not the first person to suggest using a blender to create a healthy ice cream replacement. Numerous other people have their own recipes. I’m sharing mine here because I hope it will be useful for those who are also looking for a healthy way to beat the heat.