As I remember, the magazine ad was not at all specific either in general details or specifications, and neither were the plans, but the ad did infer that two of them could be used on the ends of a helicopter blade. I think that there was no hint as to thrust, materials to be used, spark starting, and etc. Maybe it was just a scam. I built one out of mostly welded mild steel sheet metal of about .050" thickness but have been to afraid to try it.
I wonder if anyone visiting these forums has built this and got it to working. I would be interested in any and all info or comments. DBene
"If it ain't no fun,... it's no fun!"