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Cessna 310R: Building the perfect twinCessna 310R: Building the perfect twin

Twin Cessna owner’s longtime labor of love

In 72 episodes of the Western adventure series Sky King, which debuted on American television in 1951, fictitional Arizona rancher and pilot Schuyler “Sky” King captured criminals with the help of Songbird, his trusty twin-engine Cessna, initially a Cessna T–50 Bobcat.
Photography by the author
Photography by the author

He also captured the imagination of John Bowman, then a youngster in Wichita, Kansas.

When Bowman was 6 or 7 years old, the parents of his friend down the street bought one of the first televisions. “It was a big deal,” he recalled, but the first shows they watched didn’t impress. “Then Sky King came around. This guy fought crime—he was kind of like Superman. That plane would bank down, and he would catch the bad guys. But they always showed him in the plane. And I was fascinated with that.”

When Sky King came on, Bowman was in front of that black-and-white TV. Eventually the Bobcat gave way to a Cessna 310B. “I just thought it was the coolest-looking airplane. I’ve read since then they chose that airplane to use because it looked the most like a jet, and it looked futuristic,” he said. “I know for a fact that it influenced me.”

Bowman grew up, earned a pilot certificate, and was co-owner of a Cessna 152 before buying a Piper Lance. “But I always wanted a 310,” he said. “I knew it was because I watched that TV show.”

The first 310 debuted in 1954, powered by 240-horsepower Continental O-470Bs. It pioneered the signature tip tanks, boasting a short, rounded nose and squared-off vertical stabilizer. Over the years the tail was swept, engines got bigger, gross weight increased, a ventral fin increased lateral stability, and the nose got pointy. The biggest changes came at the end, with the 310R in 1975, which had 285-horsepower IO-520Ms; a 5,500-pound maximum takeoff weight; and a 32-inch nose stretch to accommodate more baggage and avionics.

In fall 1986, Bowman and his wife, Cynthia, bought their 1975 Cessna 310R without his ever flying one. It was the 223rd 310R off the assembly line. And his background in art and graphic design becomes apparent as soon as he begins to describe Cessna’s first postwar twin. “We’re biased by the looks of this. We really liked the tail and the angle of the tail relative to the fuselage.”

Checking out in a 310 while his new purchase was in the shop, Bowman was surprised by how difficult it was for him to land. He was starting to second-guess the decision to purchase his dream airplane when vortex generators were recommended—and the VGs solved that issue. “Vortex generators on this airplane are an amazing thing,” he said. “The stall is below the VMC rollover when you’re taking off. [VMC rollover can occur if a twin slows below minimum controllable airspeed after one engine fails, and it can be abrupt.] This makes a substantial safety improvement flying a twin-engine airplane, and it increases the useful load.”

Exterior

The Cessna 310R was built in 1975 and represents the final iteration of the venerable twin, with a 32-inch nose stretch to accommodate more baggage and avionics. The 310R’s main fuel tanks are its 10-foot-long, 50-gallon tips; with up to 300 pounds on each wing tip, balance is important. Art educators who ran a visual merchandising company, the Bowmans obsessed over the paint scheme. “This may not be the best 310 in the world. But I can assure you it’s the most expensive.”—John Bowman

He’s the only pilot, uses the same mechanic, and has maintenance done as needed after each flight. As a result, he’s never surprised during an annual. “There’s no big bills, only a bunch of little bills, which I can handle,” he explained. Bowman is a big fan of his ECi nickel-coated cylinders, and a believer in borescoping them during inspections. All the current cylinders have compression readings above 75 after more than 1,000 hours of operation, he noted. He’s also an advocate of low-thrust detectors.

Over the years, and more than 7,000 flight hours, Bowman rebuilt the original Continental IO-520 engines, upgraded to Hartzell three-blade propellers, then upgraded the engines to Continental IO-550s with the Coleman supplemental type certificate conversion—and, subsequently, rebuilt those engines. “We bought it for looks. Like a Corvette,” he laughed.

The biggest performance improvement came when Bowman switched to the 300-horsepower IO-550s under the Colemill STC; the upgrade is now available from Mike Jones Aircraft in Murfreesboro, Tennessee. While the bigger engines burn more fuel per hour, he said his overall consumption actually dropped because he’s going faster, spending less time en route. “The biggest thing I noticed after the conversion is the rate of climb. It climbs like crazy,” Bowman said. His cruise speed also increased, to 203 knots.

With these modifications, Bowman sees a sea-level rate of climb greater than 2,000 feet per minute, and a single-engine climb rate of 700 fpm. And the VGs add 180 pounds to the maximum takeoff weight, giving him a useful load of more than 2,000 pounds.

The 310’s fuel system demands some respect. “When you buy a 310, you’ve got to sit down with a cup of coffee and figure this out,” Bowman said. You must take off and land on the main tanks, which are the 10-foot-long wingtip tanks. And return flow from the fuel injectors goes into the mains so if you switch to the auxiliary tanks too soon, the return fuel will vent overboard—reducing endurance. He said the auxiliary fuel pump is very effective; put it on Low for takeoff, landing, and when switching tanks; and on High only if the engine-driven fuel pump fails.

As Bowman contemplated retirement, he decided to restore the Cessna, but the effort soon shifted from refurbishment to making it better than new. The 310 got new paint and interior in 2016.

Bowman and his wife are art educators who later ran a visual merchandising company, so he knew that creating the right paint scheme wouldn’t be easy. “Before we came up with this one, we probably looked at 50 other schemes. Some of them were hideous,” he said.

In preparation for the paint job, he flew to see Ken Kaminski, president and owner of Flying Colors Aviation in Benton Harbor, Michigan. “I told him I had this 310 that had been in the family for years, and I want to make it the best 310 in the nation,” Bowman recalled. “I said my wife and I are designers, and I showed him some designs. He rolled his eyes.”

Interior

Cynthia and John Bowman purchased their Cessna 310R, N310CJ, in 1986. Owner Bowman finds the interior much more capacious—and therefore more comfortable—than that of a Beechcraft Baron. He said that the Baron, which has been in production since 1961, is the only twin currently being built that comes close to matching the capabilities of his 310. The throttle quadrant is standard, but annunciators for the low thrust detector system are mounted on the panel. If you see Bowman’s Cessna 310, the panel will not look like this. As this issue went to press, he was preparing to install a new panel built around a touchscreen Garmin G500 TXi; the ADF receiver, WX-10 Stormscope, and other equipment will go.

Jonathan McCormick of Plane Schemer started the design, and the Bowmans worked with No Coast Design LLC to finalize the scheme. “They were really into this—not just a little bit.” Both designers and painter Kaminski pushed back, offering suggestions, Bowman said. And Kaminski was very accommodating while the Cessna was being painted. “He agreed to let me come over any time I wanted, and be as involved as I wanted. As time went on, I went over less and less.”

They settled on a white, black, and red scheme. “[Kaminski] talked me into this metallic black. We had chosen a charcoal gray,” Bowman said. “Cynthia and I beat our brains out to find the right red. Some are too orange and some are too maroon.” Kaminski added mother of pearl to red paint. “I never would have known to do this,” Bowman said.

To get the best results, Kaminski took a lot of the airplane apart. “As much as you can disassemble an airplane, we did,” Bowman said. Many fiberglass and plastic parts were replaced, as was the hinge to the cabin door. Computer-designed stencils were used to align the complex curves. “We spent weeks on this,” Bowman said. “It was fun.”

Painting led to some surprises. “When we looked at it and it was all white, from a visual perspective there are some things that look cool,” Bowman said, like the tail and the tip tanks. And there were some he didn’t like—such as the hump on the nose. The Bowmans flattened the paint scheme’s curve on the nose to deemphasize that hump, then used the computer to match the curve on the engine nacelles. “Now when you look at it, the hump goes away. I’d like to change the slope of the windshield, but I can’t do that.”

The interior was created by Dennis Wolter of Air Mod in Batavia, Ohio. While the airplane was in his shop, Wolter noticed that the cabin entry step was not retracting properly. That was repaired, as well.

Next on Bowman’s agenda is the panel. “The airplane’s a work in progress. It’s never done. The goal is better than new,” Bowman said. “I understand now why some guys at my airport spend two or three years building an airplane. They fly it for six months, sell it, and start over. It’s kind of a fun process.

“This may not be the best 310 in the world,” Bowman added. “But I can assure you it’s the most expensive.”

He’s been trying to schedule the installation of a touchscreen Garmin G500 TXi since last fall, but his avionics shop was swamped. The work will be done this spring. Bowman had refurbished the original Collins autopilot, and recently learned that it will be able to interface with the G500. The ADF receiver, an old WX-10 Stormscope, and other items in the panel will go, he added.

Only its second owner, Bowman has flown N310CJ more than a million and a half miles. “I believe that as far as general aviation, if you want to get into a twin, this is the way to go,” he said. “I’m certainly not a wealthy person, but I’m not going to miss a meal. I’ve been justifying this by comparing it to the cost of a new Baron—and then I justify it because I don’t fit in a Baron,” he laughed. The 310 has a better useful load, “and I think it’s better looking, too. There’s nothing else I’ve found to pour money into.”

Bowman estimated he’s invested about $300,000 into upgrades of the 310, not including the engines. “When it’s done, you have something that’s better to use and better to own than buying a brand-new airplane. I don’t want a new airplane, I want it better. And you can do it economically. You can have a 200-knot airplane.”

If a Baron is the most comparable twin in production, and with a new Baron knocking on the door of $1.5 million, Bowman’s numbers make a lot of sense. “As far as operating costs, and the payload, and the quality of the airplane—I think I have a great deal,” he said. “Considering they haven’t been made since 1982, the legacy fleet is doing very well.”

Future use of the airplane hinges on Bowman’s wife. He has retired and their children run the family advertising business, where Cynthia still works. “She’s an integral part, she was there from day one,” he said. “Her retirement is perpetually just over the horizon.”

Although it may seem like the Bowmans have been through a lot with the airplane, he’s not complaining. “We knew there’d be issues but we love the looks of the plane,” he said. “I’m 70 years old but if I live to 95, I know this plane will still be going strong.”

Email [email protected]

Mike Collins

Mike Collins

Technical Editor
Mike Collins has worked for AOPA’s media network since 1994. He holds a private pilot certificate with an instrument rating.

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