This is the recording that my grandpa made on Tuesday, September 8, of the Thunderbolt 1000T at PRP VFD #1. As you'll hear, this Thunderbolt is literally a half octave lower than it should be, and the chopper motor sounds very underpowered. This is the only recording I have this time, because I was out of town, and I had both of the other recorders with me.
http://www.fileden.com/files/2008/2/3/1 ... -08-09.mp3
For comparison, here's a recording of the same Thunderbolt from April 2008, when it sounded like it's supposed to.
http://www.fileden.com/files/2008/2/3/1 ... FD%201.mp3