Douglas DC-6 (N500HP)

Sorry that's no Douglas product, it's a Howard 500 based on a Lockheed airframe.

Jim, Based on the L37?

In the 1950s and 1960s, Howard Aero was re-constructing military aircraft (Lockheed Lodestars and Lockheed Venturas) for the executive market. The Howard 500 is similar to these aircraft with a new design and a new fuselage.
The outer wing panels from the Lockheeds were used but the rest of the new wing was designed to be "wet" and the new fuselage was designed with pressurization in mind. The gear is from a PV-2 Harpoon, and the engines are Pratt and Whitney R-2800/CB-17 and rated at 2500 HP.
Both of the flyable Howard 500's are based 3 miles from me, and I get to see and hear them regularly.

Jim, this the other one u know of?

http://flightaware.com/photos/view/171364-39c16c5c1817f979c4ee1bdd7804a6f707cd6151/user/paviation07/sort/date/page/6

Yes Sam, both of the Howard 500's, N500HP and N500LN, and the Grumman Albatross N98TP are all owned by TP Aero at Anoka County airport in MN.

Here's their web site, check out some of their great videos.

http://tpaero.com/

Beautiful birds