On August 17, 2004, at 0831 eastern daylight time, a Piper PA-28-151, N6816J, was substantially damaged when it was struck by another airplane, a homebuilt RV-6A, N181A, while both airplanes were taxing at the North Philadelphia Airport (PNE), Philadelphia, Pennsylvania. The RV-6A received minor damage during the collision. There were no injuries to either the certificated commercial pilot of the Piper, or the certificated commercial pilot of the RV-6A. Visual meteorological conditions prevailed, and no flight plan was filed for either airplane. Both airplanes were on local flights conducted under 14 CFR Part 91. According to the pilot of the Piper, he had contacted the ground controller and was cleared to taxi from the Jet Center ramp area, to runway 24. Shortly afterwards, the pilot heard the pilot of the RV-6A contact the ground controller. The RV-6A pilot was instructed to taxi to runway 24 and that he would be taxiing behind another airplane. As the Piper pilot continued to taxi, he passed the RV-6A, which subsequently taxied into the left wing of the Piper. According to the RV-6A pilot, he contacted the ground controller to request taxi instructions, and was instructed to taxi to runway 24, following a Piper. The RV-6A pilot looked out his left window and directly ahead, and did not observe the Piper. As the RV-6A began to taxi, the propeller struck the left wing of the Piper as it passed in front of the RV-6A from the right.