I'm a cash flipper but need to scale

Hi all-

I'm new to BP and this is my first post, hopefully I am in the right forum. I am currently on my 4th flip. I have been doing them one at a time, because I am using my own cash to purchase the property and fund the renovations. This works great for one house at at a time, but is posing a challenge for shorter term scalability.

What are your thoughts on using a line of credit at a local credit union for this? My understanding is that the loan should be secured by either cash or a property, in order for the loan to be more realistic. Does anyone have an opinion with this strategy vs using hard money from a wholesale company for example?

I should note that in Austin, simply applying for a loan will not cut it. I need to have cash available due to the competition. 

Any creative advice? For example, secure the line of credit backed by a property I currently own (even though it will be sold before the loan expires)?

Thanks!!

Nathan