Aircraft engine maker Rolls-Royce said Thursday that first-half net profits had soared on rising revenues, a bumper order book and the sale of its stake in US-based International Aero Engines. Earnings after taxation surged 24 percent to £1.19 billion ($1.84 billion, 1.52 billion euros) in the six months to the end of June, compared with £842 million in the same part of last year, Rolls-Royce said in a results statement. Pre-tax profits meanwhile rallied to £1.31 billion, from £1.14 billion last time around. The company\'s order book increased by 4.0 percent to £60.1 billion, while underlying revenues swelled five percent to £5.8 billion in the reporting period. \"Rolls-Royce has delivered solid growth in underlying revenue and underlying profit in the first half of the year,\" said Chief Executive John Rishton. He added: \"For the full year, we continue to expect good growth in underlying profit with cash flow around breakeven, excluding the positive impact of the Tognum acquisition and the sale of our equity stake in IAE.\" During the first half, the group completed the sale of its 32.5-percent holding in US-based joint venture International Aero Engines AG (IAE) to Pratt & Whitney -- a division of United Technologies Corp. -- for $1.5 billion. IAE makes V2500 engines which power the Airbus A320 family of aircraft and the Boeing MD-90. \"We remain an essential supplier to IAE and will benefit from a revenue stream from the current installed fleet of V2500-powered aircraft for the next 15 years,\" the group added on Thursday. \"Rolls-Royce remains committed to the mid-size aircraft market, to IAE and to its customers.\" Last year, meanwhile, Rolls-Royce and German automaker Daimler clinched a joint takeover of Germany\'s industrial engines group Tognum.