TLAR, remember the best line in the movie "The Karate Kid" where the old Japanese guy (Pat Morita) says to the young street kid (Ralph Macchio) "I promise teach Karate... you promise learn."
When you do get a proper real live engineer to run your numbers and help you design something, understand that there is a reason for whatever they are telling you. If it is not what you are hoping to hear, don't get angry at the engineer because you were hoping for another answer.
If you have minor engineering problems, try posting them here and some of the qualified engineers may help you out for free. If you are looking for more involved engineering calculations expect to pay engineering rates. Since aircraft design can involve many different engineering disciplines it would be helpful to know a littler more about the aircraft and what you need done.