HILTON HEAD ISLAND, S.C.—Tires for aircraft and aeronautical use were prominent on the agenda at the 29th annual Clemson University Tire Industry Conference.
Aircraft tire manufacturers are hard at work developing tires that are quieter, safer, more economical, more intelligent and more environmentally friendly than previous tires, according to Jacob Peled, executive chairman of the Israeli firm Pelmar Engineering Ltd.
“Aircraft tire manufacturers don't like to talk about themselves,” Mr. Peled told the Clemson audience. “It's always a sensitive subject when you discuss the causes of accidents, or the fact that retreaded aircraft tires do much better than original ones. Retreaded tires get 30 to 50 percent more landings than new ones—and landings, not mileage, are the measure for aircraft tires.”
Aircraft tires, in fact, are the only segment of the tire industry that is dependent on retreadability and whose requirements for retreaded tires are often more stringent than those of new tires, according to Mr. Peled.
The average number of landings for civil aircraft tires is 250 to 300—a level most commercial Boeing 737s will reach in one to three weeks, Mr. Peled said. For military fighter planes, tires generally last 20 to 50 landings.
The effort to build an intelligent aircraft tire is of utmost importance, he said.
“Having more intelligent aircraft tires means it will be possible to get information off a tire at any time as to whether it needs to be changed. That is very critical in this industry.
“The complete history of a tire can be determined by a trans-mitter installed in the tire.”
The most common cause of aircraft tire failure is abrupt braking during takeoff or landing, according to Mr. Peled. Ruptures are second, though those are extremely rare.
“There are very few aircraft tire failures in any year,” he said.
“The exact number is highly confidential, because no one likes to talk about it.”
Goodyear is the largest producer of aircraft tires, followed closely by Michelin Group, Dunlop Aircraft Tyres Ltd. and Bridgestone Corp., according to Mr. Peled. Together these four tire makers account for 85 percent of annual aircraft tire production.
Attesting to the high quality of aircraft tires, he said, Goodyear recently won an award from Boeing as its supplier of the year—out of 8,000 suppliers from every field.
Bobak Ferdowsi, American systems engineer at the National Aeronautics and Space Administration's Jet Propulsion Laboratory, could speak at the conference only through the good graces of advanced technology. Because of the sequester put in place by Congress and signed by President Barack Obama, NASA canceled all business travel for its personnel, so Mr. Ferdowsi spoke at the Clemson conference's April 25 luncheon via Skype.
Mr. Ferdowsi detailed his work in designing the six wheels on the Mars Science Laboratory “Curiosity.” One of the challenges in designing those wheels, he said, was making sure they had the lightness and traction not to sink into the sandy soil of Mars.
“There's no good way of predicting soil composition on Mars,” he said. “In our previous mission, the front wheel sank into the sand, and we couldn't extract it. We changed that in this mission.”
Because of the problem of outgassing, the wheels contained no rubber or other polymers, Mr. Ferdowsi said.