I was folding up the Cincinnati sectional and reaching for the Charlotte edition when the generally smooth-running Continental engine in the Beech Bonanza began a slight but persistent rumble. Associate Editor Al Marsh, sitting in the left seat, and I traded deer- in-the-headlights glances and immediately started through the emergency checklist. Switching fuel tanks, turning on the boost pumps, and checking the mags had no effect. The vibration continued. Engine gauges were in the green; airspeed and altitude were steady.
What to do? The rumble didn't seem to be getting any worse, and our scheduled fuel stop was just 30 miles ahead. On the other hand, we had just passed an inviting airport with a 5,000-foot runway set on the east side of the Appalachian Mountains. I punched up the nearest-airport function on the GPS. It told me the airport was Wilkes County Airport in North Wilkesboro, North Carolina. "Let's find out what's wrong," I suggested to Al. He wracked the airplane to the right, toward Wilkes County, accepting my suggestion to maintain altitude until over the field. I called on the unicom to see whether there was a mechanic available. The response was affirmative.
Within a few minutes the mechanic had the cowling open and the borescope in the number four cylinder. He peeked around inside while uttering enough ummmmms and uhhhhuhs to make a surgeon proud. We knew our flying for the day was over when he muttered, "You ought to be able to see that one from the outside," and started poking around on the bottom of the engine. Sure enough, a crack was visible at the base of the exhaust port. "About another 30 minutes and you'd have put a cylinder right through the side of the cowl," the mechanic predicted as matter of factly as if he'd looked at the sky and said it might rain tomorrow.
We retrieved the airplane a week later, after he'd replaced the cylinder. And within a few weeks we'd installed an Insight Instrument Graphic Engine Monitor (GEM) to better monitor the engine's cylinder-head and exhaust-gas temperatures. I'm convinced that some anomalous readings would have shown up on the GEM prior to that flight — readings that would have led us to the maintenance shop for an investigation.
The GEM uses stacked bars to depict EGT and CHT for each cylinder, making it easy to see when one changes relative to the others. Since having the GEM installed, I've learned to rely on it, giving it a quick glance while rolling down the runway. If the CHT and EGT displays don't match those I've become accustomed to seeing, I can easily abort the takeoff. The GEM also makes mixture leaning easier and more precise than the factory-installed single- probe EGT that is supposedly on the first cylinder to reach peak.
The GEM is the brainchild of John Youngquist, president of Insight. As anyone who has dealt with Youngquist will tell you, he has an opinion on everything and an interesting story or three to back up his view.
While Youngquist was first to market with the graphic engine monitoring concept, he is quick to give credit for the EGT gauge itself to another aviation icon: Ed Swearingen. Swearingen is best known for developing the Merlin business turboprop and the Metroliner turboprop airliner. He currently is developing the SJ30 and SJ30-2 business jets in cooperation with some Taiwanese investors. His company, Sino-Swearingen Aircraft Corporation, plans to certify the sporty little jets in early 1998.
Swearingen does take credit for introducing the concept of using exhaust gas temperatures to measure fuel efficiency in the aviation world, but that was not his plan when he first began tinkering with the notion.
In the late 1950s and early 1960s, Swearingen was employed by a company that was modifying Lockheed Lodestars. Among the modifications the company wanted to introduce was a propeller autofeather system for the Wright radial engines. Swearingen hired on as a subcontractor to develop the autofeather system.
The biggest challenge for him was not the development of the autofeather system itself. Instead, it was determining how to tell the autofeather system when an engine had failed so that it could do its job of increasing propeller pitch on the dead engine to reduce drag. Swearingen decided a drop in EGT was a good indication of an engine's failure or impending failure.
Though he spent months perfecting the design, the company modifying the Lodestars never did adopt his auto-feather system.
Swearingen then put his "combustion detector," as he called it, on a Bonanza and found it to be a great aid in precise mixture leaning. He attempted to patent the device but learned that the same principle had been patented in 1914 for use in automobiles. Nonetheless, Swearingen received an award from the FAA for the design.
Swearingen later sold the design to Van Dusen, where it languished for a number of years before Alcor started marketing an EGT gauge. Alcor went on to become a leader in the EGT gauge market.
The idea for the GEM actually came to Youngquist during the many hours he spent staring at the Alcor EGT gauge in his Bonanza. Youngquist was a computer designer back in the days when a "personal" computer weighed about half a ton.
He began his quest for better engine data by installing scientific thermometers in the Bonanza's engine to measure and display the temperatures. He quickly decided that the raw numbers were not very helpful in flight. What he needed was a pictorial display. In 1981 he had prototype gas plasma displays built and a gauge completed in time to make it to the American Bonanza Society's annual convention. He worked the booth himself and found great interest among the aircraft owners.
He set up a manufacturing shop in his garage and, as the business grew, moved to a small office complex. He has since bought the building and is now drawing up plans for a new, larger facility.
"The first few hundred instruments have only my fingerprints on them," Youngquist says.
Insight's office building is easy to recognize along a side street in Fort Erie, Ontario. It's the only one with a Hughes 500 helicopter on the roof. Youngquist keeps the aircraft there for his own amusement and for business trips in the region. He still has the Bonanza that he used for the GEM development. When not flying one of those two, he can be found traveling around the continent in his Mitsubishi MU-2, visiting dealers and attending trade shows.
Insight's product line has grown beyond just the GEM, to include the Gemini, a sophisticated EGT/CHT gauge for twin-engine aircraft. The Gemini stores engine operating parameters that can be downloaded by the aircraft owner or maintenance shop via an infrared datalink. The information can then be charted by a computer for trend monitoring and troubleshooting.
Insight has also ventured into an entirely new type of avionics with the Strike Finder lightning detector. As the GEM did with its pictorial display of EGT/CHT, the Strike Finder caused quite a stir when it was introduced.
Insight began marketing the Strike Finder in 1991. But BFGoodrich, the maker of the Stormscope, succeeded in shutting down Strike Finder shipments in early 1992 by claiming patent infringement. Insight fought the charges. The patents in question eventually expired, and so did the injunction preventing shipments. Today, the Strike Finder has captured substantial market share, and Youngquist is back at work on other innovative products. No telling what new device his fertile mind will dream up next.
