UDRI Conducts FAA Testing for Airplane With Propellers on Both Ends

It was a snowball fight like never before -- a government agency and the University of Dayton Research Institute versus an airplane manufacturer and its propeller.

In tests performed by UDRI and observed by the Federal Aviation Administration, Hartzell Propeller Inc.’s airfoil propeller on the Adam Aircraft’s A500 survived as 3.25-inch diameter ice balls pummeled it at speeds of up to 520 miles per hour using a compressed-gas gun. The testing simulated ice impacting the propeller while the aircraft is in flight.

The A500 is different from conventional twin-engine aircraft with propellers on the wings as it has a propeller at the plane’s front and rear.

By passing the propeller test, Adam Aircraft’s A500 moved one step closer to achieving complete FAA certification and landing on customers’ runways. The test was part of one of the FAA’s most strenuous certification processes to ensure that aircraft with rear-mounted propellers are capable ingesting any ice accumulations that could break loose and subsequently strike the rear propeller.

“This test program was performed to demonstrate that ice impacts would not create a hazardous condition and the propeller would meet new FAA flight safety regulations,” said Kevin Poormon, UDRI’s impact physics group leader. “The propeller took its shots pretty well, and everything looked good. It’s by far the biggest ice ball I’ve ever shot.”

Adam Aircraft says its design, along with new composite materials, help ensure stability should one of the engines fail in flight.

“Until the introduction of the A500, there was a large gap in the new twin-engine aircraft market,” Adam Aircraft officials said in a press release. “Since the mid-1980s, nonpressurized light twins and pressurized turbine twins have been the only new aircraft available. For many customers, the light twins do not deliver enough performance over their single-engine counterparts, while the turbines are outside of a reasonable price and operating cost.”

by Shawn Robinson, UD Public Relations

February 1, 2005