Guidance on finding investors for drone tech (I will not promote)

My cofounder and I have a drone startup but we are in the very early stages. We have a patent pending and a rough 3D model design that needs tweaking. We ran out of money further development but we believe strongly in the tech. For drones, the development stage is capital intensive: you need a good 3D model (few thousand each iteration), then do a simulation ($5-7k each iteration), and after several iterations (usually around 10), you have results good enough to create a working prototype. Where would we go about finding investors for this niche tech? We are based in DC and Los Angeles, if that matters.