THE stealth qualities of the futuristic F-35 Joint Strike Fighter on order for the Royal Australian Air Force are overrated and the plane's combat performance greatly exaggerated, a defence lobby group has claimed. The complaints by Air Power Australia, longtime critics of the $16 billion JSF acquisition, were made last night before a public hearing of parliament's defence sub-committee. Latest-generation Russian fighters such as the Sukhoi T-50 would easily defeat the F-35 in air-to-air combat, Air Power's Peter Goon said, referring to recent modelling tests by his organisation. "The aircraft we are planning to buy is carrying over 2000 pounds (900kg) of dead weight," Mr Goon said, referring to the JSF's big jet engines. New Russian and Chinese air defence radars would also have little trouble detecting the JSF, a craft touted for its stealth qualities, he added. The RAAF says it wants 100 US-designed JSFs to replace the decommisioned F-111 strike aircraft, with the first squadron supposed to be operating by 2018. But the program has been mired in cost overruns and delays. Last month US Defence Secretary Leon Panetta ordered the purchase of US JSFs to be delayed to allow Lockheed-Martin time to resolve production and technical shortcomings. The company is contracted to deliver the first two training aircraft in 2014 with another 12 scheduled for 2015-17. Defence Minister Stephen Smith has said he is now considering an option to order additional F/A-18F Super Hornets to fill any capability gap created by further JSF production delays.