A log powered gas-turbine is a relatively simple endeavour. Yes logs, not sawdust or wood gas. A gentleman constructed an automotive turbocharger based turbine engine. In place of the conventional short combustion chamber between the compressor and turbine sections he routed the compressed air quite a distance to to the bottom end of a 55 gallon drum. This was filled with a matrix of logs, and exhausted through a similarly lengthy pipe that routed the gases past the turbine. Once ignited it was self sustaining, and generated as many revs as it's propane powered equivalent.