Message posted by greatguess on March 31, 2012 at 3:41:52 PST:
Good "noisy" morning from Lancaster Ca near Plant 42 home of the Lockheed Skunk Works and Northrop. A couple of facts first -- The sky is clear, there is no (like zero) wind, humidity is high for here (55%), air temp is 58 deg f, and the moon set at 0225 today. the temp is the highest it has been at night since last summer and we may have a temperature inversion going on which would make the sound travel further. At 0212 i was awakened in east lancaster by the loud rumble of an aircraft at plant 42 running up it's engines. It didn't sound like one I had heard before but the weather conditions are quite unusual today so the sound may have been a bit unusual also. the engine runs occurred from 0212 to 0228 with a couple of three or four minute high power runs. there were some very short engine runups and chops also. When the engine(s) were pulled back to idle i could not hear them at all but they must have been running because the "quite" times were usually less than 30 seconds between louder events which is not enough time obviously to shut down and restart the engine(s). at 0228 it went quite again. the engine sounds seemed to be coming from the direction of site 4 (northrop). at 0237 the engine noise again increased but it wasn't as loud and didn't seem to be coming from the same place as before. my guess is that whatever was making this noise had now taxied out to the runway which is more to the west (for an east departure) and a bit further south. if the aircraft were sitting on the msin runway it's tail would have been pointed pretty much away from me so the sound would have been less. the aircraft did a very short engine runup and chop to "quiet" and about 10 seconds later ran it's engines up again and i assume began it's takeoff run. i could hear the sound level reducing for the next 3 minutes or so as whatever it was took off and left the area toward the east. i think somebody is getting a new toy today.
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