Path: utzoo!attcan!uunet!decwrl!shelby!rutgers!att!cbnews!military From: argosy!freeman@decwrl.dec.com (Jay R. Freeman) Newsgroups: sci.military Subject: Re: SR-71 congealed oil Message-ID: <1990Oct11.051057.29887@cbnews.att.com> Date: 11 Oct 90 05:10:57 GMT References: <1990Oct8.220953.7541@cbnews.att.com> <1990Oct10.000645.444@cbnews.att.com> Sender: military-request@att.att.com Organization: MasPar Computer Corporation, Sunnyvale, CA Lines: 46 Approved: military@att.att.com From: argosy!freeman@decwrl.dec.com (Jay R. Freeman) The "solid oil" problem crops up in more conventional aircraft in wintry temperatures. Only a few people can afford heated hangers for lightplanes, so pilots and the industry have come up with ingenious alternatives. External oil-sump heaters are common -- it is said that a light bulb on an extension cord works well, if you put it under the sump after shutdown and leave it on all night. Bush pilots are known to drain the sump into a large tin or drum, and warm up the oil over a campfire when it is time to get going again. They say that on particularly brisk days you just drain the sump into the snow, and pick the oil up in one piece after it sets. Tended airports in cold places have "preheat" devices, which can be sent round to chilly airplanes to blast hot air into the cowl for a while. These gadgets resemble the offspring from a long night of passion between a flamethrower and an industrial vacuum cleaner. I recall one amusing personal experience. In December 1971 I ferried a Bellanca Decathlon from the factory in Wisconsin to the Pacific Coast. (That's a 180-horsepower two-seat tandem aerobatic aircraft, with high wing, tailwheel gear, and fabric-covered surfaces (except for the cowl).) I stopped in Huron, South Dakota, where the plane cold-soaked at nearly minus 30 Farenheit, all night long. In the morning I asked for a preheat, but started my preflight inspection while waiting for the cart to come around. All went well till I checked the oil. The dipstick was attached to the inside of the oil filler cap, which screwed on. It was reluctant to turn. "Thermal contraction and congealed oil," I thought, and twisted harder. Presently it unstuck, and I unscrewed it a turn or two. But when I let go momentarily, to shift my grip to keep turning, the cap screwed itself back up! The oil in the sump had congealed around the half-inch-wide dipstick, and was applying enough torque to turn the cap! I finally got it to where I could pull the dipstick out, and when it broke loose it did so with a most unusual "pthook" sound. The congealed oil sticking to the dipstick had about the consistency of red "licorice ropes" or of pretty well-hardened caramel. It looked delicious, but I had already had breakfast ... -- Jay Freeman