On May 27, 2001, at about 1635 eastern daylight time, a Piper PA-25-235, N6667Z, registered to and operated by Airscape Inc., as a 14 CFR Part 91 glider tow flight experienced a reported loss of engine power between 2,500 to 2,800 feet. The pilot released the glider and crashed during a forced landing at the Spartanburg Downtown Memorial Airport, (SPA) Spartanburg, South Carolina. Visual meteorological conditions prevailed and no flight plan was filed. The airplane sustained substantial damage. The commercial pilot reported no injuries. The flight originated from Spartanburg Downtown Memorial Airport about 5 minutes before the accident. The pilot stated during the preflight inspection of the airplane that he did not visually check the fuel tank and relied on the fuel float for the amount of fuel in the fuel tank. He flew eight flights before departing on the accident flight and no fuel was added to the airplane. He departed SPA at about 1630, made a left turn, circled to mid field and climbed to between 2,500 to 2,800 feet when the engine started running rough. He informed the glider pilot that he was going to release him and that he turned direct towards SPA. was returning to SPA. He informed all aircraft on the UNICOM frequency that he was declaring an emergency. At about 2,000 feet he heard a Learjet pilot state that he was going to take the active runway. He immediately called the Learjet on UNICOM frequency and informed him to hold his position, but no response was received from the Learjet pilot. He observed the Learjet taxi out on runway 23. He immediately made another call on the UNICOM frequency and began a turn towards a closed runway. The Learjet pilot did not respond to his call. He crossed over the center line of runway 05 at about a 1/4 mile final at about 1,000 feet. He turned base and turned final to runway 27 when his landing gear collided with trees, and he crashed on the apron of the closed runway. When asked what caused the loss of engine power, he stated he ran out of fuel. The glider pilot being towed by the accident pilot verified the accident pilot statement about the Learjet pilot not yielding the right of way to an aircraft in distress. The Learjet pilot was not identified.