0.5 flight time, 1 ldg. Short flight to check out the radio. Need to up the intercom squelch, otherwise good. Flew over to the I-10 project, then over to the ultralight field then return. Engine running really smooth. Slowed down by the ultralight field to listen for airframe rumble. Airframe starts to rumble at about 85 mph indicated, and gets louder as it gets slower. Pulling the flaps adds to this noise.
