STILL FLYING AFTER ALL THESE YEARS
OX-5 Powered WACO 9
It could be argued that a major factor in the birth of civilian aviation was the Curtiss OX-5, 90hp, liquid-cooled V-8 engine. That wasn’t because it was such a wonderful engine. In fact, it was heavy for its power and crude in every design detail, and it took some tinkering to keep it running. Reliability wasn’t its strong suit. Pilots of the day, many of whom were barnstorming from farm fields, said that they flew OX-5s from emergency landing to emergency landing. It was the seed of 1920s’ aviation simply because thousands were available on the military-surplus market for next to nothing at a time when aircraft manufacturing was in its infancy.
How available was the engine? It was designed and built by Glenn Curtiss and company for the original JN series, culminating in the JN-4 “Jenny” in 1915. By 1919, Curtiss had built more than 6,800 Jennys, with approximately two engines for every airplane. The Jenny and the surplus engines were the backbone of 1920s’ barnstorming, and the OX-5 engine powered many new designs. Iconic aviation companies, such as WACO (Weaver Aircraft Company), Travel Air, and many others, all of which were working on shoestring budgets, got their start building affordable airplanes around that engine.
WACO, which began business under the banner of Advance Aircraft Company and was renamed in 1929, fielded its first mass-production airplane as the OX-powered WACO 9 in 1925. In the best WW I Fokker D.VII fashion, it had a welded tube and fabric fuselage, with the wing structure being rag-covered wood. The slowturning (1,400rpm) OX-5 swung a big 8-foot-plus prop, which, only having 90hp to work with, produced enough thrust—barely! Combined with the nearly 30-foot wing panels and light wing loading (1,320 pounds empty;
2,100 pounds gross), the WACO 9 could haul a pilot and two passengers out of a wheat field—barely!
By the mid-1920s, the OX-5’s days were severely
numbered. It had established the aviation market as being a viable source of revenue, so a number of companies, including Pratt & Whitney and Wright, were formed to manufacture radial engines that produced two and three times the horsepower for the same weight. Equally as important, the new engines didn’t have the irritating habit of depositing pilots in remote fields or in the trees when they quit. Still, approximately 270 OX-powered WACO 9s were built before the WACO 10 superseded it, of which an incredible 1,600 were built. Only the first WACO 10s were powered by OX-5s. Production had barely begun before they were replaced by Wright J-5s and similar, now-legendary, radials. General aviation now had reliability on its side.
Only a small number of OX-5 powered aircraft of any kind still ply the airways. Most are Jennys, but a few WACOs still sport the wonderfully streamlined nose that cleaves the air aside, letting the usually blunt OX-5 through. One is WACO 9, NC1536, owned by Scott Glover as part of his private collection, Mid America Flight Museum in Mt. Pleasant, Texas. As serial number 9, it is one of the very first aircraft to be built by Advance Aircraft/WACO. It is also flown regularly, often with Kelly Mahon at the controls.
Kelly says, “This airplane was originally restored by Frank Pavliga. He started with a fuselage and three wings that were good only for patterns. It is essentially a new airplane. But it is a true antique in every way. It has no normal airspeed indicator, no brakes, a tailskid, no carb heat, only one mag, a rudder bar rather than pedals, and on and on. The way it handles in the air is pretty well summed up by a line in the handwritten pilot’s handbook that says, ‘The ailerons are only a suggestion to the airplane.’ It is leisurely in the extreme.
“Mechanically,” he continues, “it is, shall we say, ‘unique.’ Rigging the wings, for instance has more to do with the phases of the moon than angles and measurements. The engine has to be constantly monitored and pampered. The valve train has no internal lubrication, so we grease it every day or every 45 minutes of flight time. You can see the rocker arms jiggling around out there while they are throwing grease back over the airplane. It cruises at 65mph while turning 1200rpm.”
NC1536 keeps company in Glover’s museum by aircraft that show how quickly airframe design progressed in the ’20s and ’30s. They include the first DC-3 taken into the U.S. Army Air Corps (a heavily documented C-41), a Mustang, a Corsair, an A-26, a Grumman Duck that survived Pearl Harbor, and a wide variety of other historic aircraft.
The WACO 9, however, shouldn’t be denigrated for its shortcomings. It was a pioneer in the birth of civil aviation and was in production only seven years after the end of WW I, a time when civilian aero design and manufacturing were just getting on their feet. Given its historical importance, it’s a wonderful thing to see one of the breed still in its element.
Above: The WACO 9 used an abundance of wing area to make up for a lack of horsepower. Left: Cruising at a leisurely 65mph, the “9” could barely get the rudimentary airspeed indicator off the peg.
Below: The life span of an OX-5 was often as short as 50 hours. Gilmore was an early oil company that sponsored many racing and airshow airplanes in the 1920s and ’30s.
Above: The WACO 9 pictured was one of the very first aircraft manufactured by the legendary company.