August 2, 2013 - The Mono Aircraft Corporation was proud of its success winning air races with its early Monocoupe design. But then, as often happens with rapidly developing technologies, it started to lose to the competition.
"They only had 60 hp and everyone else had 100 hp," said Glenn Peck, an aircraft restorer for the Historic Aircraft Restoration Museum at Creve Coeur Airport near St. Louis, Missouri. "They needed a faster airplane so they tried putting the 100 hp motor on that airframe and it did not work.
"They enlarged the airframe, put some modern features on it like the elliptical wing tips and different style landing gear, and bigger motors. So they were back in the winner's circle again."
The result of Mono's modifications was the Monosport, a two-place, side-by-side airplane a bit bigger than the earlier coupe. Ultimately 16 of the type were built before other technological advances made the design obsolete.
The museum's 1929 Monosport, which is here at EAA Oshkosh for the first time since its restoration to flying condition, is a Monosport 2 and was the fourth produced. It is the only known example remaining in the world.
The airplane was acquired mostly intact and had been restored to a static display condition. So Peck believed it would be a relatively straightforward effort to get it into the air.
"Turns out having all the parts meant that we had all the big pieces," Peck said. "Ten or 15 boxes of small pieces had vanished into the wilderness. So it ended up taking a year and a half instead of the eight or 10 months I had planned."
One interesting aspect of the project is that the engine and the propeller carry the exact same serial numbers listed on the original 1929 factory bill of sale.
One possible minor difference between the restoration and the original may be the wing.
"The original was rotted out because it had been stored outside," Peck said. "The person who bought the airplane had someone rebuild the wing for him, but he used the modern Monocoupe airfoil."
Original drawings do not exist so an exact template of the original airfoil is not available. But based on some internal parts, and drawings of other Monocoupe designs, Peck believes the rebuilt wing may be a small departure from the original type.
"It is all serviceable and is close enough," Peck added. Once the restoration was complete, getting an airworthiness certificate turned out to be a challenge.
"The FAA didn't have a type certificate in their database for it," Peck said. "And they weren't going to certify it even though we had an original airworthiness certificate dated from 1952.
"The database they had was dated 1943. But it left out about five pages with 60 airplanes on them. They are not common airplanes so nobody really noticed.
"I happened to have a 1938 book that lists all the type certificates up to that date. I showed them the book and gave them some photocopies of the pages they were missing. [The Monosport was on those pages] so we got our airworthiness certificate."
As it was with many early airplane types, the Monosport had some quirks.
"The landing gear geometry was rather strange," Peck said. "That explains to me why there were so many landing accidents with this particular model.
"The shock struts were too long and let the wheels get at an angle that looked like a P210 Cessna about midway through gear retraction."
Peck says the airplane lives up to the Monocoupe reputation for being very maneuverable and squirrely on the ground.
"With not having everything adjusted properly yet, I would say it flies quite nicely," Peck said. "It is a relatively docile airplane, but at this point it is not anything you can let go of and sightsee. I don't know if it will ever be like that."
The Historic Aircraft Restoration Museum is open to the public and has a collection of 60 airplanes. According to Peck most are either ready to fly or can be restored to flying condition.