Flip financial advice/question

[Steve Sauro]

I have several rentals but have never tried a flip.  I'd love to hear from anyone that has FINANCED the purchase and then had a contractor to the the work - then sell it and split the profits.  I just want to make sure all of my math and finances are accounted for so I can start to look for potential properties.  My thought was:
1 - I put the down payment and assume the mortgage.

2 - Contractor (no skin in the game at this point) buys materials to complete the necessary upgrades

3 - When it is done we sell the property and subtract the down payment, material cost, mortgage payments, utilities, settlement costs - and then whatever is left we split.  

Am I missing anything?  Am I oversimplifying this?

Thanks!!