A Third (And Last) Tri-motor

By John Dorcey

I consider myself to be pretty well heeled in aviation history and while I freely admit that I am not aware of every aircraft ever made, this one was a real surprise… and a real find. The Kreutzer Model K-5, 'Air Coach' is today's Plane of the Day. Never heard of Kreutzer before? Good, that makes at least two of us.

As an overview there were 47 different tri-motor aircraft models built by 24 various manufacturers during the design's heyday during the 1920s and 1930s. Of course, that discounts the relatively more modern Boeing 727, Lockheed's L1011 and the Douglas DC-10/11 and other modern examples of the tri-engine design.

The Joseph Kreutzer Corporation, located in Venice (CA) built its first model, the K-1, in 1928. The design termed a 'light transport' was planned to fill the void between the typical two seat aircraft and the large airliner of the day with 10 seats or more. This model had four seats, the ultimate goal was six, and was powered by three Velie 55-horsepower (HP) engines.

That airframe was then modified to the six-seat Model K-2. This model was powered by a single 90 HP, LaBlond 7-cylinder engine in the nose and two 60 HP LaBlond 5-cylinder engines on the wings. The K-2 was certified as NX-612. The K-3 model featured three LaBlond 90 HP engines, significantly improving performance. The K-2 and K-3 were certificated in the summer of 1929.

The 'Air Coach' was an outgrowth of the K-3, in fact this airframe was the same one used in all models K-1, K-2, K-3, and finally modified to a K-5. The K-5 design was approved in September 1929 and featured 3 Kinner K-5 engines of 100 HP.

A planned model using Warner 'Scarab' engines of 110 HP never left the drawing board. The Kreutzer Corporation built a total of 14 aircraft - 6 K-2s, 2 K-3s, and 6 K-5s. By 1930, like many early aircraft manufacturers, struggling under the effects of the depression closed its doors.

This aircraft NC612 was purchased by its third owner, Navajo Airways, and was based in Winslow (AZ). Navajo acted as a feeder to Transcontinental and Western Air. Its next owner, Willard Hellman, would convert the aircraft to model K-5 by upgrading the engines to the Kinner model.

The Kreutzer K-5 'Air Coach' held Aircraft Type Certificate (ATC) 223, and according to that document the aircraft has a cruise speed of 130 mph, landing speed of 45 mph. The service ceiling was a mountain scaling 17,000 feet with a range of 520 miles. The 1929 price, FOB Venice, was $18,500. Today's price is higher.

NC-612A is owned by Greg Herrick and is the only remaining example of a Kreutzer aircraft. The airplane, as one might expect, is immaculate; having undergone an extensive and exhaustive restoration.

FMI: www.airventure.org