Page 30 - Volume 18 Number 1

28 • TWIN & TURBINE JANUARY 2014
From The Flight Deck by Kevin R. Dingman
How I met my Motors
(and the zero-turn-radius lawn mower)
over the years – including two Dukes. I say was, because, to the sorrow of everyone that knew him, and at a truly significant loss to the flying and engineering communities, his passing occurred
this past August, 2013. As a young man on the teaching and research staff at Princeton, Dane declined an offer of tenure, and later also turned down the position of Director at the newly-opened Fermi National Accelerator Laboratory. These two lofty assignments would not suffice, because Dane had a hankerin’ for tinkerin’.
He accepted a position with Allis-Chalmers, a diversified manufacturing company, where he designed high-energy X-ray machines. Later, he was named vice- president of research at McGraw- Edison Company, where he first tinkered with commercial lawn mowers. And this is likely why you recognize the name Scag – as in Scag lawn mowers. Dane struck out on his own with the purchase of Bob Cat snow throwers and soon introduced the first commercial, self-propelled, belt-drive lawn mower. Scag eventually sold the $15 million company and began his next venture, Scag Power Equipment, Inc. Scag mowers became recognized as the most technologically-advanced, efficient and reliable machines on the market. As it grew into a $20 million company, Dane sold it to Snapper. His next invention, a tight- turning mower, evolved into Great Dane Power Equipment. He again built the company to around $20 million and sold to John Deere. Through all of the growth, Dane used GA to enhance his businesses.
Show me the money
Dane’s reputation was well known in the Duke community, so when I heard he was selling his engines, my deposit was on its way to him in minutes. I later flew
The trepidation from a ticking Hobbs meter as it climbs towards the time for a hot section inspection or an overhaul is like no other ticking – except maybe the time-bomb kind of ticking. There is no way to avoid the inconvenience and expense. For some, it can precipitate the sale of their machine. Fortunately, such expensive maintenance events are rare. We can only hope that when the moment arrives, we are ready.
A few years ago, the Duke’s Lycoming TIO-541-E1A4’s engines were at TBO. I had been replacing cylinders as the compressions weakened, but then oil analysis declared that the camshafts and lifters were very rudely beginning to deposit their metallurgical DNA into the oil samples. I say rudely, but I am grateful; it was quite unselfish of them to provide the warning before grinding to a spectacular halt in flight. It was time to think about a complete overhaul: the moment had arrived – and I was not ready.
A Drop in the Honey-Bucket
At the time, the going overhaul rate was about $50k per side. After you add the cost of removal and installation, a couple of prop overhauls, new starters, turbos, mags, and hoses and baffling, you’re talking some serious bucks. About $130k for a couple of overhauled motors, props and accessories. If I were an airline pilot from the olden days, this may be a drop in the proverbial honey- bucket, but, alas, I’m not. I had to hope that the cams and lifters would behave themselves until a suitcase full of money floated up on the beach – which would be just as likely as that hot place freezing over, or Sharon Stone calling me for a drink.
Around one hundred hours past TBO, something wonderful happened; she called me for that drink – no, not really. Darwin Conrad of Rocket Engineering in Spokane, Washington, started putting turbines on Dukes: P&W PT6A-35’s flat rated to 550 shaft horsepower, capable of a climb to 25k in nine minutes. Although I didn’t have the million bucks for a turbine conversion, another Duke owner did, and he elected to become the very first to get the Royal Turbine Duke conversion. This meant that the relatively low- time Lycomings and props from his Duke would soon be available.
I got wind of the sale from my friend and Duke training pilot, Bob Hoffman. By happenstance, Bob had introduced me to the owner of these soon-to-be-available engines at a Duke fly-in a couple of years earlier. Having previously met the man and knowing of his background, I was excited about the potential quality of the engines. His name was Dane Scag, familiar from an article written by editor Dianne White (March 2001 T&T). A little memory jogger and tribute to Mr. Scag is in order, before we continue with the engine-replacement story.
Hankerin’ for Tinkerin’
Dane Scag was a brilliant physicist, engineer, inventor and pilot who owned several airplanes