Boeing 247

The Boeing Model 247 was an early United States airliner, considered the first such aircraft to fully incorporate advances such as all-metal (anodized aluminium) semimonocoque construction, a fully cantilevered wing and retractable landing gear. Other advanced features included control surface trim tabs, an autopilot and de-icing boots for the wings and tailplane.

"Ordered off the drawing board", the 247 first flew on February 8, 1933 and entered service later that year. Subsequently, development in airliner design saw engines and airframes becoming larger and four-engined designs emerged, but no significant changes to this basic formula appeared until cabin pressurization and high altitude cruise were introduced in 1940, with the first pressurized airliner, the Boeing 307 Stratoliner.

Design and development

Boeing had eclipsed other aviation manufacturers by introducing a host of aerodynamic and technical features into a commercial airliner. This advanced design, which was a progression from earlier Monomail (Models 200, 221, 221A) and B-9 bomber designs, combined speed and safety. The Boeing 247 was faster than the U.S. premier fighter aircraft of its day, the Boeing P-12, which was an open-cockpit biplane. Yet its flight envelope included a rather docile 62 mph (100 km/h) landing speed, which precluded the need for flaps, and pilots learned that at speeds as low as 10 mph (15 km/h), the 247 could be taxied "tail high" for ease of ground handling.

C73

C73 or C-73 may refer to :

List of County-Designated Highways in Michigan

The County-Designated Highways in Michigan comprise a 1,241.6-mile-long (1,998.2 km) system of primary county roads across the US state of Michigan. Unlike the State Trunkline Highway System, these highways have alphanumeric designations with letters that correspond to one of six lettered zones in the state. The CDH system was created in 1970 in response to the business concerns of a woman from Saugatuck. Her one-woman crusade in the 1960s started after the highway in front of her motel was turned over to local control as a county road and removed from state highway maps when the nearby freeway opened. After nearly a decade of efforts, the first two test highways were designated, one each in the Lower and Upper peninsulas of the state and included on the 1970 state highway map. The CDH system was created and expanded in scope c. October 5, 1970, after it was approved by the County Road Association of Michigan and the State Highway Commission.