Whether you are dealing with business acquaintances or friends there needs to be a legally binding agreement and all roles need to be clarified from day one. Many joint ventures start in a very balanced and encouraging fashion only to hit trouble with confusion about day-to-day management and the roles of the various parties.
A clear and concise document covering every detail of the joint-venture is a must have from day one.
Yes absolutely right... make sure the nature of the agreement is written down and a full "partnership agreement" is drawn up detailing the terms and roles of each partner. This is a must to avoid bad feeling later down the line if one party isn't pulling their weight for example...
Our JV agreements are much simpler as we just require finance JV partners so ours are more like loan documents with the funds fully secured on the assets we're buying so it's less about roles as our partners are mostly "silent" partners.
Whatever the nature of the agreement there needs to be some sort of contract though.