I have a short term rental that I self manage and am considered a real estate professional based on material participation rules.  

Purchase price: $250,000 Cash invested: $14,000 I purchased and managed a rental property in Chicago, focusing on strategic improvements and tenant satisfaction to increase both its value and profitability.

He get's principal and simple interest payments over a number of years.I'll manage the deal and the property.Looking to create a proforma for this that would fit a typical rental analysis but insert the detail of having private money cover the DP.

Are you accounting for everything—taxes, property management, maintenance, insurance, reserves—and still hitting your target returns?

You should consult with local property managers and find what the average DOM would be to lease your home and rental rates etc. this would be a good starting point. 

The big pros are the strong job market (lots of major employers), good population growth, and still-reasonable entry prices.

What is killing me is after factoring in property taxes of about $9000 for the year and 10% of the rents $6.720 for property management as well as insurance factored at another $2400.

If there is a property manager, your success rate is going to be very low.   

My property manager says there was no indication that the tenants are at fault.

However, they approach financial health from different angles.The 50% Rule is a quick estimate that suggests operating expenses (excluding mortgage principal and interest) will roughly equal 50% of the property's gross income.The DSCR is a more precise calculation (Net Operating Income / Total Debt Service) that determines if a property generates enough income to cover its debt obligations.Deal example:- Class C middle class neighborhood- 4bd / 2ba single family house- ARV: 190k- Purchase: 105k- Rehab: 35k- Market rent: $1,400-1,525- Section 8: $1,475- Property manager: 10%- Taxes: 125 month- Insurance $1250 yr- HOA: $55 month- purchased and rehabbed with all cash.