Northwest’s fleet update plan from the mid-1950s recognized that most of its domestic airports did not have the population or cargo demand capable of supporting pure-jet service, but also concluded that piston engines were not going to be able to power a mainline fleet reliably or efficiently in the future.
Allison’s model 501 turboprop engine offered impressive fuel efficiency and much longer time-on-wing figures than piston powerplants. Lockheed was so impressed with its performance they designed two aircraft around them at the same time: the military C-130 transport, still ubiquitous around the world, and the civilian L-188 Electra (which would also see military use). Northwest ordered ten Electras for delivery in 1959, and a follow-up order for eight for delivery in 1961. The first aircraft received arrived on July 25, 1959.
Seating 90 in pressurized comfort, and with a cruise speed of 400 mph, the L-188 ushered in Regal Imperial service and sported the Imperial eagle on its tailfin – the only Northwest aircraft to do so. It quickly assumed flagship duty on many domestic sectors, including new routes to Florida. It became a favorite of flight crews as well, thanks to its “hot rod” performance compared to the earlier Douglas propliners.
Two aircraft were lost in accidents due to the Electra’s harmonic design flaw: N121US at Tell City, Indiana, in March 1960, and N131US at Chicago in June 1961. After the type’s grounding and modifications, NWA’s remaining L-188s continued to serve with distinction through the 1960s, with the last four not leaving the fleet until 1972!
The knowledge base and parts availability for the Allison 501 engine in the Twin Cities was reinforced with the local Air National Guard wing basing a small fleet of C-130s at MSP, and was an important factor in North Central deciding to use the engine for its Convair-Liner CV-580 upgrade project. Truly, the drone of the Allison 501 became a signature sound of the Northland from the late 1950s all the way into the 21st Century.
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!
First of the fleet, N121US, on the assembly line in this Lockheed photo from early 1959. From the James Borden Photography Collection.First of the fleet, N121US, on the assembly line in this Lockheed photo from early 1959. From the James Borden Photography Collection.First of the fleet, N121US, on the assembly line in this Lockheed photo from early 1959. From the James Borden Photography Collection.N121US on pre-delivery flight in early 1959. From the James Borden Photography Collection.N124US at MSP, probably 1962. Shot by Logan Coombs, from the James Borden Photography Collection.N129US being serviced at Milwaukee in winter 1960. Photo shot by Dick Magnusen, from the James Borden Photography Collection.N131US at Minneapolis-St. Paul with the freshly-completed main hangars, probably circa 1962. (The Western Airlines hangar is at far left.) From the James Borden Photography Collection. N131US at Minneapolis-St. Paul, probably circa 1962. From the James Borden Photography Collection. N130US over California in a Lockheed air-to-air photo shoot, 1959. From the James Borden Photography Collection.N130US over California in a Lockheed air-to-air photo shoot, 1959. From the James Borden Photography Collection.N130US over California in a Lockheed air-to-air photo shoot, 1959. From the James Borden Photography Collection.N130US over California in a Lockheed air-to-air photo shoot, 1959. From the James Borden Photography Collection.N130US over California in a Lockheed air-to-air photo shoot, 1959. From the James Borden Photography Collection.Promotional postcard from the early 1960s.Unknown fleet number, unknown photographer. From the James Borden Photography Collection.Promotional postcard by the L.L. Cook Co. featuring N125US at Milwaukee in 1960.N136US coming in to land at Minneapolis-St. Paul, August 5, 1967. Shot by Charles Mayer; from the James Borden Photography Collection.Capt. Harlan G. Knauf in the flight deck of N134US in 1967. The size of the cockpit is very similar to the C-130 transport made by Lockheed at the same time, with which it also shared its use of the Allison 501 turboprop. Harlan & Delores Knauf have the photographer credit; picture donated by daughter Joyanne Meta.Capt. Harlan G. Knauf posing with N134US in 1967. Note the deletion of the Imperial Eagle on the tailfin – done as Boeing jets came on-line for the domestic network, as those types took the marketing spotlight. Harlan & Delores Knauf have the photographer credit; picture donated by daughter Joyanne Meta.
