HI THERE GUYS,

I dont even know if this is the correct forum. If not let me know and I will change it. But, I Really would appreciate your thoughts. I am building a 6 ft span A10 Warthog, which makes the engine pods about 6 or 7 ins diameter. Now I want to keep costs down, so my question is this. I can easily get 6x4.5 3 blade props and fit them inside the given engine cowlings, or ofcourse go the ducted fan way ( which would be more expensive) I have no experience with fans, but as far as props go, usually the diameter decides the thrust, and pitch the gearing. I might even be able to cheat a little ( its only a sport scale model) and fit 7 in diameter 3 blade props. So, Which between the 3 blade 7in prop and the Fan would provide better thrust? keeping in mind the cost equasion. ( I was thinking of the HET 6904 70 mm diameter fan unit)

Also, I have a program which calculates the static thrust if you know the rpm of the prop, but is there a program which would tell me how many rpm for a given prop I would get depending on motor used and voltage supplied etc


Anyway, all help appreciated.

regards, John