Creating deals with private investors?

[Robert Mckenzie]

I am a new real estate investor. I currently have one vacation rental condo and a single family home that I bought to flip, but am currently living in. I am looking towards my next move and have an interested private investor. He is going to provide capital for the down payment, renovation and fixed costs. I am a construction project manager and will be handling 100% of the renovation. My question is this: how should, or can we structure this deal, and how is this situation typically handled in this industry? Since he will only be providing capital, I proposed that we structure this like a loan- he puts up the money, then upon sale of the house, I return his money with interest (I was thinking 15%ish). His proposal was that we buy the property, he provides the money, I do all the work, then we split profits 50/50. Him and I have been great friends for a long time so we both want what is fair. Any advice on how to structure this deal and profit sharing guidelines is greatly appreciated.