Late in 1936, Ted Wells and the Beech engineering staff initiated a major upgrade program to keep the Model 17 in production, and make it more competitive. The result was the improved E17-series and the more robust and heavier D17-series. The D17-series incorporated the most salient changes. Four versions eventually were developed, including the D17A (320-hp and 350-hp Wright R-760E2), the D17S, the D17R (420-hp Wright R-975), and the more powerful D17W (600-hp Pratt & Whitney R-985-SC-G).

To improve elevator authority for three-point landings, the fuselage structure of the D17-series was lengthened 13 inches to 229 5/8 inches compared to 216 5/16 inches for the B17 and C17. The airfoil was changed to a NACA 23012 section and the ailerons were relocated to the upper wing panels. Electrically operated plain flaps were installed on the lower wing panels. To compensate for the lengthened fuselage and maintain center of gravity limitations, negative stagger of the wings was increased to 25 19/32 inches from 23 inches on the earlier models.

Beechcraft D17S NC20753 was originally delivered to Hangar Six, Inc. in San Antonio, TX. Restoration was completed in July, 1972 by Donald Blue, while owned by Dr. Eugene Blumberg. In 1976, Stephen and Diane Parker of Odessa, TX, acquired NC20753, and subsequently donated the airplane to the Staggerwing Museum in memory of Steve’s father, Mr. Alvin H. Parker. Mr. Parker was a true pilot who not only taught Steve to love flying, but also held many records including soaring’s highest award, the Lilienthal medal. He was inducted into the Soaring Hall of Fame, and his sailplane now hangs in the Smithsonian Air & Space Museum.