| Author | Message | ||
     Jim Butler (Unregistered Guest) Unregistered guest |
For the last 6 years I have been wondering how the Express would handle a bird strike. Now I know. I was at 11,000 feet crossing the Appalachians, which at that point put me at about 4000 AGL. I looked down at my charts, and when I looked up there was a spot on the windscreen about 1 1/4" in diameter, with goo trailing up the windscreen. I didn't hear or feel anything. Upon closer inspection, it had hit about 3 inches forward of the lower edge of the windscreen and again about 3 inches back of the lower edge of the windscreen. After landing, I cleaned off the debris with water and there was no evidence anything had happened. How it got through the prop I'll never know. I always suspected the angle of the windscreen offered a greater level of protection and it turns out in probably does. Jim | ||
| John Harlow New member Username: Jharlow Post Number: 29 Registered: 10-1999 |
Jim, Glad to hear you had no damage. Another may be the design choice to use the very thick plexeglass. Dana said it was designed for a 200 mph bird strike and it turns out he was correct. Keep your prop spinning. John | ||
| Ted Gaston (Unregistered Guest) Unregistered guest |
There's a legend that says the thickness of the windscreen was determined by hurling 12 pound turkeys at a test article at 200 mph until it no longer would break. Years later it was revealed that the turkeys were frozen, but by then the decision to go with 5/8" acrillic was already made.  The rest is history. | ||
| Chris (Unregistered Guest) Unregistered guest |
That sounds like the old "rooster booster" test the FAA developed to test bird strikes on windshields and jet engines. The British copied it to test a high-speed train windshield, but couldn't understand why all their test articles were easily destroyed. Only after checking with the FAA did they discover they should use thawed turkeys instead. Go figure... - Chris | ||
| Jim Ward New member Username: Jehward Post Number: 38 Registered: 02-2000 |
Jim: On aother web-chat area, there was discussion of the possibility of a bird strike getting into the intake air (without a screeen or filter). One guy did the calculations: "...Actually, a bird has pretty good odds on getting to your air intake without encountering a prop blade. The odds would be somewhere around 3 1/2 to 1 of success (although I'm sure that the bird wouldn't see it as successful) depending on your speed, rpm and the size of the bird. At 180 knots, you're traveling about 18,216 feet per minute. At 2500 rpm a blade is passing by the intake at the rate of 5,000 blades per minute (for a two blade prop). That means that the airplane travels over 3 1/2 feet between blade passes. A 1 foot long bird would have better than 3 to 1 chance of getting through. ..." So, if you have a 3-bladed prop, the odds are reduced to 2.4 to 1 chance of getting thru the prop.  Jim |