|P210 Makeover: Faster, Higher, Cooler|
|Written by Bill Cox|
|Monday, 16 January 2012 15:22|
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These days, many readers might speculate that last investment is questionable, but Vitatoe is confident he can translate his personal enthusiasm for the project into another successful business. Vitatoe Aviation, a division of Vitatoe Industries on Pickaway County Airport near Chillicothe, Ohio, is one of the newest companies in the business of solving problems that are too expensive for manufacturers to address.
Vitatoe has been a pilot since 1975 and bought his first airplane, a P210N, several years ago. He went through the usual highs and lows of operating Cessna’s premier, high-wing, piston single. “It was a comfortable airplane with a large cabin, and it made a wonderful cross-country machine. The pressurization was great - low differential but very uncomplicated, set it and forget it,” says Vitatoe. “The bad news was the airplane had lethargic climb, hot CHTs, lots of early cylinder overhauls, a low TBO, and high fuel flow.”
Another significant problem was unenthusiastic cruise. Vitatoe discovered the P210 took considerable winding of the big key on its back to reach a reasonable cruise number. “I couldn’t come anywhere near book performance, because I couldn’t keep the cylinders cool,” Vitatoe explains. “Several CHTs would charge up well above 400 degrees, and that wasn’t acceptable.”
The best speed he could maintain in his stock airplane with acceptable CHTs was about 180 knots at 17,500 feet, burning about 20-21 gph. That’s probably the most popular altitude for the P210, as it maintains a cabin altitude of 8,000 feet while operating in clear air and sunshine above 90 percent of the world’s weather. Some owners do operate in the flight levels, but the relatively low pressurization differential (3.35 psi) discourages true high-altitude operation.
After purchasing his P210, Vitatoe checked with a number of other Centurion pilots and found his operating experience was typical. “I remember reading some comments on P210s by Richard Collins, now retired but a former writer for Flying magazine,” Vitatoe explained. “Collins acquired one of the very early Pressurized Centurions and kept careful track of his performance data over the next 25 years. He reported an average cruise speed of 156 knots, and that agrees with my experience in the airplane.”
Vitatoe already possessed more than his share of aviation smarts, and when it came time for engine overhaul on his P210, he wasn’t eager to spend $55,000-$60,000 and still have the same problems. Accordingly, he began looking for alternatives.
A former NHRA hot rodder and a competent engineer in his own right, Vitatoe knew his way around a shop and established a modification company on the local airport, hired Robert Bobo to run it, and started on the road to FAA STC approval.
He consulted with some of the brightest folks in the aircraft engine business, George Braly and Tim Roehle of Tornado Alley Turbines in Ada, Oklahoma. Braly and Roehle own a number of STCs for IO-550 applications on aircraft ranging from the Beech 33/35 Bonanza to the Baron and Cessna 185. Tornado Alley Turbines also developed the initial turbonormalizer utilized on the Cirrus SR-22T. In this age when avgas costs more than reasonably priced Chablis, Braly has been the industry’s strongest booster of lean-of-peak operation, a procedure that can save as much as 15 percent of fuel burn.
“Braly knew I was working on a project similar to his that might someday compete with him, but he was extremely generous in sharing the results of his R and D on the Continental IO-550 engine and the principles of lean-of-peak management,” Vitatoe commented. “I attended his weekend engine seminar in Ada, and learned quite a bit.”
The Ohio businessman wasn’t looking to reinvent the wing, but he was hoping to find a solution that would allow him to utilize the full capabilities of his airplane. He determined that the IO-550P would fit into the existing cowl and could be adapted to accept the standard Air Research TEO6 turbo in turbonormalized mode, incorporating dual intercoolers. He also did some research into propellers and found that there were a pair of new Hartzell semi-scimitar props that could add climb and cruise while reducing noise.
The engineer also adapted the Atlantic Aero six-point engine mount, intended to more firmly secure the 550 to the aircraft and provide smoother operation.
Vitatoe began his development program in 2008, flew the first modified airplane in March 2009, and put the airplane on display at Oshkosh AirVenture the same year. “There was tremendous enthusiasm at Oshkosh, and that convinced me to go ahead with the project,” Vitatoe remarks.
The company was awarded its STCs in June of 2011. They include installation of the aforementioned Hartzell props for the Cessna 180/182/185/206/207 and 210; a cross flow tuned induction system for the Cessna 206/207, and the P/T210 turbonormalized IO-550 engine swap.
“Our primary goal was to reduce normal engine CHTs to the 360-degree range for climb and to maintain temps below 380 degrees at cruise,” says Vitatoe. “That would allow us to operate at a max cruise power of 262 hp. That’s 84 percent of the P210’s normal 310 hp, but it’s only 74 percent of the engine’s max rating of 350 hp.”
Vitatoe achieved his goals and more. When he flew his first tests in his P210, he set the mixture to full rich (36 gph) for climb, launched from Pickaway, and was surprised to average nearly 1,000 fpm for the climb to 23,000 feet. Better still, all CHTs remained well below 360 degrees. He ran four more climb tests to FL230 in the same day and saw times averaging 25 minutes, right at 900 fpm. That’s considerably better than anything he’d ever done in his stock P210.
Cruise performance at 23,000 feet also combined avgas and sky with surprising efficiency. Trimmed and level with the big 550 set to roughly 50 degrees lean of peak, Vitatoe logged 208 knots TAS on 17.6 gph. “The airplane was cruising right at the bottom of the yellow arc, something I never even came close to with the old 520.
“That’s well ahead of book,” says the engineer, “but it’s not a surprise, considering the engine was running so cool. Our flight tests yielded cruise speeds consistently 12-20 knots quicker than the POH, purely a function of being able to run in the cooler range on the lean side of peak.”
I flew with Vitatoe in a converted 210 owned by Terrell Clampitt of Clearwater, Florida, and saw proof positive of the difference the turbonormalized 550 makes. During a four-hour delivery flight from Ohio to Florida at max cruise power of 30 inches and 2,500 rpm, the Cessna performed better than any 210 I’d flown, except for O & N Aircraft’s Silver Eagle Rolls-Royce conversion. Centurions of any description have always been great cruisers, heavy, smooth, and durable, stable as a table and possessed of a locomotive’s sense of straight ahead.
After departing Pickaway airport and climbing to 10,000 feet, we trimmed and leveled for max cruise and eased the mixture back to 18.0 gph; then, reduced further, seeking the magic 17.6 gph. Eventually, the numbers were there, and we were making 182 knots at 10,000 feet. (Later tests by Clampitt at 16,500 feet over Central Florida yielded 202 knots.)
During the ferry trip, CHT was the primary concern. If the CHT began to rise, we had three choices to keep temperatures in check – open the cowl flaps a notch, reduce manifold pressure, or go slightly leaner. Opening the cowl flaps would obviously add slightly more drag and cause a slowdown, so running leaner was the method of choice.
For pilots unfamiliar with the 550’s operating procedures, the last alternative flies in the face of convention. Remember, we were operating on the lean side of the EGT curve, probably about 50-75 degrees below max EGT. If you’re flying rich of peak, adding fuel (richening mixture) reduces temperature. Operating on the lean side, it has the exact opposite effect, and EGT climbs back toward peak as you richen mixture.
Vitatoe has obviously been experimenting with the 550 for some time, as he played the engine like a Steinway. He made slight adjustments of manifold pressure, mixture, and cowl flaps to keep temperatures in check while maximizing speed and minimizing fuel burn.
Inevitably, someone’s bound to ask about weight and cost. The extra 30 cubic inches of engine displacement only adds a maximum of 10 pounds to empty weight, a negligible addition considering the benefits of the 550. The whole premise of the Vitatoe conversion is that Cessna P210 owners facing an engine overhaul are looking at something between $54,000 and $60,000 for a factory-remanufactured Continental TSIO-520P. After overhaul, the 520 will feature a 1,600-hour TBO.
In contrast, Vitatoe’s TSIO-550 conversion sells for $94,760, including a new Hartzell prop. Sounds a little like apples and grapefruit, but it turns out to be more equitable than you might imagine. “On the face of it, that seems a significant difference, but remember, we’re burning about 2-3 gph less than the stock TSIO-520. At $6 per gallon and a typical 2.5-gph savings, that’s $15 per hour less operating expense, or $30,000 over the life of the engine (which, incidentally, is 400 hours longer than the stock, remanufactured 520).”
The conversion includes a long laundry list of new pieces, some of which are new Slick pressurized magnetos, all hoses, ducts, baffles and seals, the aforementioned twin intercoolers, and all associated hardware. The conversion is compatible with air conditioning and dual vacuum systems.
Also, remember that the Vitatoe package includes a new Hartzell prop. That’s probably at least another $15,000. Add it up, and it all adds up. The 550 conversion costs about the same as a remanufactured 520.
As this is written, there are four Vitatoe 550 conversions flying, with another half dozen in work. Vitatoe Aviation shop manager Robert Bobo says, “In the beginning, we were hoping to complete a conversion in 9 to 10 weeks, but it soon became obvious we needed more like 12 weeks to complete the new engine, mount, and prop.” Build time will probably be reduced as Vitatoe’s mechanics slide down the learning curve.
Larry Vitatoe recently acquired a late-model, normally aspirated 210, and he hopes to use it to develop the turbonormalized 550 installation and make a heavy breather out of a standard Centurion.
In 30 years of production, Cessna built just under 8,000 normally aspirated and turbocharged Centurions and another 900 Pressurized Centurions. At this early stage, there’s no way to tell if Larry Vitatoe has his fingers on the pulse of so many Centurion owners, but in the current down economy, this enterprising Ohio aviation enthusiast just may have conceived a conversion that offers more than enough for less than too much.
|Last Updated ( Monday, 16 January 2012 15:30 )|