The first airliner to reach supersonic flight was not the Soviet-built Tupolev Tu-144 or the well-known Concorde, which wouldn’t break the sound barrier until a test flight in October 1969. Instead, it was a modest DC-8
The DC-8 was the first aircraft powered by a Douglas jet. On September 18, 1959, it went into service concurrently with United Airlines and Delta Air Lines. The DC-8 could reach speeds of over 600 mph (966 km/h) as it was powered by four jet turbine engines. The DC-8 saw seven distinct versions throughout its 14-year production run, totaling 556 aircraft in all.
Even more, a DC-8 became the first airliner to fly supersonic on August 21, 1961. It was a modest DC-8, specifically no. N9604Z, rather than the renowned Concorde, which wouldn’t break the sound barrier until an October ’69 test flight, or the Soviet-built Tupolev Tu-144.
William Magruder, a Douglas test pilot, planned the test flight, which was scheduled to depart from Edwards Air Force Base (AFB). As flight test engineer Richard Edwards told Air & Space Magazine, the idea was to “get it out there, show the airplane can survive this and not fall apart.” Commercial carriers had been using the DC-8 for roughly three years, competing with the Boeing 707 at the time. The DC-8 wasn’t intended to reach supersonic speed, but the importance of being the first to do so made the effort worthwhile.
The jet needed to be in a dive to reach Mach 1. This entailed taking it up to 52,000 feet, a record altitude, according to Mentalfloss.com.
As Edwards tells Air & Space Magazine, “We took it up to 10 miles up… and put it in a half-a-G pushover. Bill maintained about 50 pounds of push. He didn’t trim it for the dive so that it would want to pull out by itself. In the dive, at about 45,000 feet, it went to Mach 1.01 for maybe 16 seconds, then he recovered. But the recovery was a little scary.”
The stabilizer was overloaded, and the plane stalled when Magruder tried to pull it back.
“What he did, because he was smart, is something that no other pilot would do,” explains Edwards. “He pushed over into the dive more, which relieved the load on the stabilizer. He was able to run the [stabilizer] motor…and he recovered at about 35,000 feet.” The crew successfully turned a mass-produced airliner into the world’s supersonic commuter jet. (Right by their side the entire time? Chuck Yeager, the first person to ever go supersonic in 1947. He escorted the DC-8 during its test in an F-104.)
“That’s an unofficial supersonic record, payload record, and of course an altitude record for a commercial transport,” Edwards points out.
Following the test, Canadian Pacific Air Lines received DC-8 no. N9604Z, which it operated for over twenty years until retiring. Unfortunately, this piece of aviation history isn’t housed in a museum. Following its decommissioning, Canadian Pacific sold DC-8 number N9604Z for scrap.
Photo by Douglas and Eduard Marmet via Wikipedia