Aircraft – Boeing 720B

With its fleet and service issues of the 1950s resolved and a solid business footing restored, Northwest moved into the 1960s with technical acumen, a well-balanced route network, and a strong cash position. NWA’s objective now would be to acquire jet aircraft that would be both economical to operate and that would deliver high standards of service for passengers and freight.

The Pacific routes needed jet service immediately and the DC-8 was available immediately, but NWA only acquired enough frames to cover those long-haul services. Lockheed Electra 188 turboprops took over for the Stratocruisers and some Douglas propliners on the domestic side from the late 1950s, but this was also a ‘bridge’ strategy – as Northwest was aware of new jet offerings coming from Boeing.

Boeing’s 720B, derived from the longer-range 707, featured a turbofan engine which was a technological step up from the original “pure-jet” powerplants on Northwest’s DC-8 aircraft, with better fuel consumption and thrust. The 720B gained the nickname “Renton Rocket” from the city it was built in and the exciting performance it offered. Its range and performance was ideal for domestic sectors, and fit NWA’s needs perfectly.

Delivery of a fleet of 17 aircraft began in 1961 and ended in 1964. Seating was configured for 107 passengers in its original layout; later modified to 30 first / 81 coach. Deployment of the 720Bs allowed the Electra 188s to push out the company’s DC-6 fleet and most of its DC-7s, while the 720B handled the high-traffic flights. The 720B was used from Miami to Honolulu and its tail became the basis of the carrier’s 1960s logo. While the 727 would take over the 720B’s role in the mid-1960s, the final two frames in the fleet did not leave until 1974.

If you use these photos, please credit the Northwest Airlines History Center – please also contact us to let us know how you’re using them and if we can be of further help!

Cover illustration for Northwest’s 14-page introductory brochure celebrating the launch of Boeing 720 services, from the James Borden Collection. Click here to open the document in a new tab!
Cover to a 1961 brochure explaining the Pratt & Whitney JT3D turbofan engines on the Boeing 720B. From the D. Scott Norris collection. Click here to open the document in a new tab.
Construction of 720B Ship One. Boeing photo, NWAHC archive.
Construction of 720B Ship One – just behind the cockpit. Boeing photo, NWAHC archive.
Construction of 720B Ship One – wiring and hydraulics feeds in the cockpit. Boeing photo, NWAHC archive.
Construction of 720B Ship One – fuselage section aft of cockpit – the galley door is at left. Unusual to find a photograph of women working on the assembly line! (Of course they were there, just rarely what a photographer wanted to record…) Boeing photo, NWAHC archive.
Construction of 720B Ship One – wing box section with port and starboard roots. Quite a difference from how fuselage and wings are assembled today! Boeing photo, NWAHC archive.
Construction of 720B Ship One – preparing window frame seals. Decals on the windows say “MEASLES” in bold and “do not remove protective covering from glass surface” in fine print. Boeing photo, NWAHC archive.
N721US coming together, March 1961. Boeing photo via the James Borden Photography Collection.
Construction of 720B Ship One – just about to bring the forward sections together. Boeing photo, NWAHC archive.
N721US with fuselage joined, awaiting painting and engines. Note the 1950s “compass” logo rather than the Imperial Eagle. Boeing photo via the James Borden Photography Collection.
Construction of 720B Ship One – weight applied to pylon to approximate the mass of an engine, to ensure all joins are true once the real thing is hooked up. Boeing photo, NWAHC archive.
N721US with fuselage joined, awaiting painting and engines. Boeing photo via the James Borden Photography Collection.
N721US under construction – engines not yet attached. Boeing photo, NWAHC archive.
N721US under construction – engines not yet attached. Boeing photo, NWAHC archive.
N721US under construction – engines not yet attached. Boeing photo, NWAHC archive.
N721US getting pre-delivery control system inspection. Boeing photo via the James Borden Photography Collection.
Three-by-three coach seating on N721US. We are all used to the seat width after sixty years, but legroom per row was noticeably farther apart than we are used to in the 21st Century. No meaningful overhead storage, although overhead automated oxygen masks were standard in April 1961. Boeing photo via the James Borden Photography Collection.
N721US under construction – engines not yet attached. Note the mass attached to the left inboard pylon. Boeing photo, NWAHC archive.
Resplendent in the Seattle sun, April 1961, N721US. Boeing photo via the James Borden Photography Collection.
Engines mounted on N721US in April 1961, with some testing still being conducted (note the open panels under the wing roots, cable around the vertical tail, and hoses coming out the intake side of both port-side engines, leading down to small black boxes…) Boeing photo via the James Borden Photography Collection.
Engines have been mounted and testing is underway on N721US, April 1961. Boeing photo via the James Borden Photography Collection.
Engines have been mounted and testing is underway on N721US, April 1961. Boeing photo via the James Borden Photography Collection.
N721US, assembly complete, waits in the April 1961 darkness to be handed over for delivery. Boeing photo via the James Borden Photography Collection.
N721US antenna being examined prior to flight. Boeing photo via the James Borden Photography Collection.
Looking down the vertical tail from the inspector’s position! Boeing photo, NWAHC collection.
N721US in a Northwest publicity photo over the Cascades, April 1961. Via the James Borden Photography Collection.
N721US delivery publicity flight, April 1961. Boeing photo, NWAHC archive.
N721US delivery publicity flight, April 1961. Boeing photo, NWAHC archive.
N721US in a Northwest publicity photo over the Cascades, April 1961. Via the James Borden Photography Collection.
N721US delivery publicity flight, April 1961. Boeing photo, NWAHC archive.
N721US in color on her delivery publicity flight, April 1961. Boeing photo, NWAHC archive.
Company-issued postcard. NWAHC collection.
Post-delivery view of the flight deck, with Northwest ship # 721 above the right-side instruments. From the James Borden Photography Collection.

With a large pool of pilots trained on the 720B, it was natural for NWA to bring in the long-range 707-320 sister ship to replace the small DC-8 fleet in 1963. With this move, Northwest proudly advertised itself as the “all fan-jet airline.” The Pratt & Whitney JTD3-1 turbofans on the 720B fleet were also updated in 1963 to the JTD3-3 series, allowing 720Bs and 707-320s to swap engines as needed, saving on spare inventory and making maintenance more efficient.

N728US on the pre-delivery line at Renton in the fall of 1961. Another Northwest jet and four for Eastern are getting engines installed. Boeing photo via the James Borden Photography Collection.
Cold ground with a dusting of snow, and N727US taxiing by could place this in November 1961. The photo credit is to Logan Coombs so we assume this is Minneapolis-St. Paul. Via the James Borden Photography Collection.
1960s shot of N722US on the ramp at Minneapolis-St. Paul before construction on the new terminal completed. Photo by Dick Phillips, NWAHC collection.
N727US looks to be at Seattle-Tacoma in the early to mid 1960s. The aircraft was delivered to NWA in October 1961. There is a flight display board next to the “Gate 3” sign, but the writing is not clear – nor is the placard next to the boarding steps. Shadows suggest a late afternoon / early evening departure? No photographer noted, via the James Borden Photography Collection.
Boarding is underway via airstairs for N726US at Minneapolis-St. Paul in the spring of 1962 (leaves have not yet appeared on the trees). Old terminal building is in the far upper left corner. Electra N129US is to the left, and a Braniff DC-7 appears in the upper right. Also note in the upper right how the end of the Blue Concourse (today’s E concourse) is only one level high. Photographer unknown. From the James Borden Photography Collection.
N724US at Minneapolis, summer 1962. Photo by Logan Coombs, via the James Borden Photography Collection.
N722US getting catered and using a jet bridge at the newly-opened Minneapolis-St. Paul International Airport in summer 1962. Photographer unknown. From the James Borden Photography Collection.
NWA publicity photo by Forde, early 1960s. NWAHC collection.
N723US at Detroit, July 28, 1962. Jon Proctor photo used with permission – available through Wikimedia Commons.
1960s shot of N723US at probably New York JFK (big TWA hangar in the background.) Photo by Dick Phillips, NWAHC collection.
N734US in Atlanta, March 28, 1967. Jon Proctor photo used with permission – available through Wikimedia Commons.
N730US in its final colors, in this photo from the Noel Allard collection. Date and airport undetermined.

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