Friday, July 20, 2007

Another book?

I've often threatened to write a book about my time in industry, particularly the nearly seven years I spent in aerospace development. For an inkling of the kind of stories it might include, take a look at “Sarge, Is This Another Bug Hunt?" by Michael John Smith.

"The hardest thing about bug impact testing is dealing with the crickets. It was not too difficult modifying an air gun with top useful speed of three hundred miles per hour to operate at five to six hundred miles per hour. All it took was replacing the old solenoid valve with a larger one, upping the operating pressure from twenty or thirty psi. to one hundred and fifty psi., making Styrofoam sabots, developing a compressed Styrofoam wad for stopping up the chamber, and making custom tools for packing the chamber. All pretty standard stuff. And it is not as if the crickets are physically difficult to work with. They fit in the 1/4² barrel nicely. Their weight is not such that the gun has a hard time pushing them. They take special care to use, being delicate and all, but that is no big deal. No, the part I did not like was killing them. Even though they are just bugs and I put them out painlessly with cold before they knew what they were in for, I just did not like it. So I was not disappointed when it turned out that even at speeds in excess of five hundred and fifty miles per hour they do not damage an F-18 windshield. For that, I had to call in a stunt double...

Everyone has been under a lot of pressure over this bug thing. It is this month¹s big emergency. Even the head salesman for the F-18, Chuck Seagle, has come into to town to add his personal touch. Chuck is a Texan, and loud of it. The chemists have been getting a little tense lately. Fortunately for me, I just have a hard time taking bug impact testing seriously.

With crickets out of the running for bug damage simulation I had to cast about for a replacement. Obviously, the impact part of the bug damage (if any) is caused by hard bodied insects like flying beetles instead of soft bodied insects like crickets. I decided to try one of my very first ideas which I had discarded in favor of crickets. So on Monday morning on my way to work I opened up the Kellogg¹s Raisin Bran and sifted out five raisins. The way I figure it, raisins are squishy like a bug, but not bouncy like rubber or silly putty. They are not hard on the outside, but I did not have any Raisin-Nut-Flakes, so there you go. (Raisin-Nut-Flakes have raisins which are coated with chopped up nuts.) However, they do hold together a lot better than soft bodied insects.

I went to work with my raisins early in the day. My air gun is loaded at the breach end through a hole in the side of the barrel. To get fast shots I shove the projectile down into the barrel from the chamber, and then pack in compressed Styrofoam behind it. The Styrofoam holds back the in-rushing air just long enough to get really high pressure, then disintegrates and flows easily down the barrel. (Now don¹t go stealing my techniques. As someone pointed out, I am probably the only person in the world working on this problem right now, and I don¹t want to be scooped.)"

Thanks to my old colleagues Bernie and Wayne for the pointer. We didn't ever get round to firing bugs or raisins at our windscreen (and other structural) test pieces but we did fire a range of other things including hand-crafted hailstones in a variety of sizes...

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