I doubt the engine's a TF-34. Just an assumption though it might be a williams fj-44. The RQ-3 darkstar flew up to 45,000 feet using this engine.And I told you that it is NOT a 35 year leap. Such engines have been around for a long time. The Bae-146 aircraft that first flew in 1978 and was designed to operate from city airports has a very high bypass ratio along with similar noise deadening features to allow it to meet regulatory levels. The engine rumoured to be in the RQ-170 that is the TF-34 also has a very high bypass ratio and has been around since 1971.. add sound deadening and certain performance improvements and you have a Quiet and smokeless engine.
NO 35 years leap.