I am sure that I am not the first to have this idea so I am just wondering if people have been successful with this in the past or if it is not recommended.

So in essence I would still be adding to the heloc.I can flip it and clear 30k to pay down the heloc as planned, but lose a potentially good rental property.I am conflicted....flip or plan as cash out.I also have another rental that I could do a cash out and reduce some on my heloc(interest only) and still cover note/expenses.I do not like the idea of a balance on a heloc since it is interest only and is currently up to 6.5%Cash out and reduce some of the 6.5% interest only to a fixed 4.77% and paying down with each payment.

In fact, I'd also recommend trying to catch one of those weekly webinars that Brandon Turner does - he usually goes through analyzing a deal in each one, and it may give you a better idea of how to calculate how much of a mortgage you can take on. 

@Michinori Kaneko I really like that idea!

It is somewhat upsetting to see how topic starter pushes this idea of investing.

He has this idea of the perfect deal, He is still looking for that perfect deal that fits the formula that he came up with.

Maybe more.So between down payment, closing costs and repairs, I'd have to front somewhere around $50K - $60K, which I don't have.The strategy that I am considering is finding a hard money lender for this initial costs, with the idea that I pay back all at once when I refinance.On paper, it seems a good prospect for which may be worth to due a solid due diligence but I want to make sure my strategy is entirely doable and be aware of the risks I have to keep in mind. 

I like that you're thinking about several exit strategies and ideas.

Although I'm a fan of Dave's, he's not for me either (as per his debt ideas).

If it's permissible, it's a fantastic idea.