Thanks for the info. Did the company simply fold after a short time? Do you recall any specs about the model? I think it may be possible to convert it to a single large fan, say a byro jet with a 91. I am not about to get two DF units whirring in the same model. Too much trouble. Out of curiosity, what was the mode of operation at the company. At Byron it was Engineer a prototype around the byron component group, test fly, correct for unsatisfactory performance, reengineer, second prototype, test fly, re-evaluate and so on until the project succeeded.