HBD HBD!!! That stands for Happy Birthday Hall Bulldog!
On this day, August 15th, 88 years ago the Hall Bulldog was wheeled out of the hangar at Bowles airport and presented to the world. Just 3 weeks later it was retired after only one race and around 20 hours of total flight time. A test flight was planned for this day in 1932 but was canceled due to a flat tire, incurring a penalty of “more than $1,000” to the team building the plane under contract to Marion Guggenheim. A substantial penalty that in today’s dollars would be around $20,000.