1973: Maynard Hill invents the electrostatic autopilot

Google has recently scanned and posted all of Popular Science's back issues (and they go WAY back), and there are some gems in there from the early days of autopilots. One of them is this, which describes an autopilot the legendary Maynard Hill (yes, the guy who flew a hobby UAV across the Atlantic in 2003) built that uses minute electrostatic differences with altitude to create an analog autopilot.

Here are some other pictures from the article, but you should really read the whole thing. Anyone know what went wrong with this approach and why he abandoned it?

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Comment by Grahame Algar on April 12, 2010 at 12:47am
I remember reading this article (was it really 1973 seemed like yesterday!)

I think the reason why this project was not taken any further was that the electrostatic sensors were made of radio active material banned in Germany at the time and probably throughout the world by now! I also believe the autopilot was confused by hills and terrain.

This concept is still valid if suitable sensors could be investigated and designed. With all the knowledgeable folks here I bet someone could come up with a solution!

Comment by Morli on April 12, 2010 at 1:25am
May be we could ask him , a good candidate for Podcast :-)
Comment by Mike on April 12, 2010 at 4:17am
You will need some of this: http://en.wikipedia.org/wiki/Polonium
Comment by Mike Bakula on April 12, 2010 at 6:18am
You could probably do it with pairs of field mills, but they're going to be a lot heavier.
Comment by Tj Bordelon on April 12, 2010 at 6:44am
You can use an alpha particle source from a smoke detector to "tap in" to the voltage reading. I'm not sure why but this supposedly ionizes the air and provides a connection point.
Comment by Lew Payne on April 12, 2010 at 9:33am
Polonium can be purchased off-the-shelf. In the 1980's, we were using it to do x-ray photography of small objects, along with piezoelectric Kirlian photography. The polonium was obtained from StaticMaster Brushes(the refill cartridges), and for the piezo generator we used a Radio Shack device that generated a needle-point static charge when you squeezed its handle, and was designed to remove dust and static from LP's and 45's.
Comment by Stephen McAmis on April 12, 2010 at 10:44am
Isn't Polonium the same stuff that was used to kill the Russian diplomat in England a couple of years back? Seems they got the stuff from those brushes too.... not sure, just curious.
Comment by Lew Payne on April 12, 2010 at 12:35pm
@Stephen - Regarding the Russian diplomat who was poisoned with polonium... are you implying they tricked him into thinking the StaticMaster was a moustache grooming tool? :)
Comment by bGatti on April 12, 2010 at 12:57pm
I suspect this design is no better than thermopiles in any case, and far more complicated to deploy. It wasn't used (in article) because metal airplanes would have distorted the readings, and because electrical storms were a suspect problem - among other problems...
Comment by Stephen McAmis on April 12, 2010 at 6:07pm
lol Lew.
Nah, more or less I was saying that if someone uses the stuff... they shouldn't inhale! ;)


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