I have been asked by my son and one of his friends to financially back the start up of a maintenance shop. They have a good business plan and the competition in the area seems vulnerable. His friend has all the certifications and about 10 years in the industry woking on everything from light A/C to commercial jets. My son is a CFI with a lot of experience doing work on our airplane under the direction of his friend. They have some good contacts ,but they are going to have to build a clientel. Anybody had any experience in start-ups? How long does it take to build a decent clientel? Everything looks good and I can afford to take the risk, but I don't know much about the industry. Your advice/opinions pro and con would be appreciated.