Opening a RC Related Hobby store
I believe the key to running a hobby shop and being successful is either having a large enough inventory to compete with Tower or doing something that no one else is doing. Get set up with manufactuers other than Great Planes - who are willing to work with you on volume purchases. Next, have a marketing plan. Most people I see in the hobby shop business have no clue how to market products. They rent a building, put $5,000 or $10,000 in inventory into it and expect the products to sell themselves. You need to advertise - newspapers, hobby magazines, internet, etc. If you have no advertising or graphic design experience, that puts you at a disadvantage right away because now you have to hire someone. Also, you need a good internet website with an easy to use shopping cart. I see a lot of hobby shop websites that are very poorly designed.
Do something like selling your engines at cost in order to draw people to your store. People will walk in to buy an engine and probably leave with many other items.
And finally inventory. Why would I want to buy items from you, if it takes you a week to have them shipped in? I might as well order directly from Tower or Horizon, save a few bucks and have it shipped to my door. Products are really hard to sell when you don't have them in stock. Advertise only what you have in stock and ship every order complete, the same day.
Like Flyboy said, you have to be good with people. Overly friendly on the phone - every day - all day! Handle every problem right away and don't hassle anyone. Make people want to order from you because they like you.
Don't let the naysayers get you down - find a niche and run with it! There's plenty of room for good hobby shops.