Royal Turbine Conversion for Beechcraft 60 Duke

Duke. The four-blade Hartzell props, even at their highest rpm, are smooth and quiet, negating the need to reduce rpm unless maximum range is needed. On the convenience side, owners of Royal Turbines don't have to fret about thermal shock issues and unrealistic climb or descent requests from con- trollers like owners of stock Dukes do. In addition, engine preheat is simply not an issue with the turbine in all but the most severe climates. Just fire it up and go. One Royal Turbine owner, who is also an airframe and powerplant me- chanic, says his annual inspections are a snap without the piston engines tak- ing up some 80 percent of the labor re- quired to complete the job. Out for a spin I had the pleasure offlying the Royal Tur- bine from Northwest Turbine's home A very special Duke mechanic By Michael Maya Charles At 89, when most octogenarians are choosing the color of their rest home walls, Dane T. Scag is finishing up his Inspection Autho- rization (IA) class at a mechanic school near Nashville. He was the oldest student to ever take the FAA test at the school and scored better than some of the young bucks in his class. Although he holds graduate degrees in both physics and math, Scag says, "I became a mechanic the day I was born." His love of design and engineering, and desire to work on his own airplanes, led him to get his A&P license in 1982. Scag bought his first aircraft, an Ercoupe, in 1946. He used It to cover a huge territory as a product development engineer at Allis Chalmers. He flew the little Ercoupe "everywhere," he says, including over the western mountains. An early Beech Bonanza followed in the early 1950s, followed by a Rajay turbocharged Piper Apache in 1959. Looking for a new challenge after he retired from AC in the early 1970s, he bought a struggling Wisconsin snow thrower com- pany called Bob Cat. "I didn't know anything about manufacturing or snow throwers •••••• But he turned the company around by de- signing a new commercial lawn mower to complement the product line. An English company bought him out several years later. Not happy with Idle hands, Scag started another company, named it Scag Machine, invented a better commercial lawn ma- chine, built the company to $40 million in sales, and sold it, too. Over time, the twin-breasted Piper became a Beechcraft B55 Baron, then a pressurized Baron SSP, and finally, a new Duke In 1982. He owned that airplane for almost 25 years. this long-term ownership ex- perience led to his becoming a technical guru for the Duke Ayers Ass0- ciation, where he offers his vast Duke experience with wit and humor. base at Spokane's Felts Field. The mis- sion of the first flight was to get some photos of the airplane over nearby Lake Pend Oreille in Northern Idaho. With three people and 140 gallons offue!, the Royal Turbine was off the ground in less than 1,000 feet and climbing at about 3,500 fpm. In this airplane, there's no ex- cuse not to go high-even for short trips. The climb rate is so good that you'll be at altitude in no time. The fuel burn drops off precipitously up there while true air- speed increases just as quickly. Finally, with pressurization, nobody's battling the ear-popping climbs and descents that the Royal Turbine is capable of. After a neck-twisting, eyeball-searing job of getting the photos you see with this story, Conrad took over and demon- strated the single-engine capabilities of the Royal Turbine by sliding a power lever to idle and feathering that engine's propeller. Once trimmed up, the autopi- lot was flying the airplane hands- and feet off. At altitude, Conrad says it'll fly at 240 KTASon one engine. At our relatively light weight, the airplane mustered a 1,200-fpm climb on one engine through 8,000 feet. With the engine back online, Conrad demonstrated an approach into a busy airport with a demanding con- troller and flew the airplane at 190 knots indicated to the outer marker and made the first turnoff from the runway without any heroics. One unfortunate drawback of con- verting any piston airplane to a turbine is the fact that the max structural cruis- ing speed (the bottom of the yellow arc The jets will have the speed advantage, but the Royal Turbine will out perform any VLJ in runway performance, opening up thousands more airports for potential use. on the airspeed indicator) becomes the new never-exceed speed (the redline) in a turbine airplane. The Royal Turbine's new redline is 198 KIAS, which is easy to exceed at lower altitudes, reinforcing the need to get the airplane to altitude quickly. Our second flight found me in the left seat of the Royal Turbine for a quick trip to altitude to verify speed claims. Start- up is standard PT6, watching for oil pressure, ignition, fuel flow, and light off while monitor- ing temperatures. On takeoff, like many twin turbo- props, the spool- up time of the Pratts is not at the same rate, so Conrad suggests holding the brakes until at least 400 foot/pounds of torque is reached on both engines. Early in the roll, you'll still need to jab the brakes for directional control as the power is fed in until the rudder becomes effective. Unfortunate- ly,you can't just push the power levers to the stops or you'll over-torque the en- gines. Takeoff power is 1,200 foot! pounds of torque and trying to finesse the power levers while keeping the cen- terline under the nose-as well as sim- ply hanging on for the ride-can be- come a chore for the uninitiated. Things happen very fast in this airplane. In about 900 feet and a scant nine seconds from brake release, the Royal Turbine reaches about 90 knots and is clawing for altitude at a 25-degree deck angle and better than 3,500 fpm. Our uninterrupted climb found us at FL280 in a short 12 minutes, for an aver- age climb rate of 2,200 fpm. Fuel re- quired to climb to FL280 was 16 gallons total, and the density altitude that day was almost 30,000 feet. We topped out at 280 KTASon 66 gph at FL280. Cabin alti- tude at FL280 is a high 12,000 feet, so I wouldn't spend long at that altitude without supplemental oxygen. At FL260, speed was 287 KTASon about 70 gph on this warmer-than-standard day. With cooler temperatures, the magic 300- knot number appears realistic. Following another toss-out-the-an- chor, flight-idle descent, I flew an ILS approach while slowing from the red- line speed back to approach speed. The Duke's high gear and flap operating speeds are complemented by the fact that trim changes are minimal. I couldn't duplicate Conrad's "first turnoff from the runway" trick, but even on my first try, we didn't use more than 1,200 feet of pavement. Unlike in a stock Duke, I'd be com- fortable flying this airplane in and out of 2,500- foot runways-paved or not. Required for the conversion are vor- tex generators, winglets, and aft body strakes made by Boundary Layer Re- search. These items combine to raise the maximum takeoff weight of any Duke to 7,000 pounds from the stock airplane's 6,725- or 6,775-pound MTOW. Since the new engines are lighter than the original Lycomings, the airplane gets a useful - • • load increase of about 350 to 400 pounds depending on the donor airframe. Con- rad says most airframes roll into the shop weighing about 5,000 pounds empty and leave weighing about 4,600 pounds. The test airplane has a useful load of 2,485 pounds and a full-fuel pay- load of 1,782pounds. In a perfect world, one could find a well-cared-for, late-model Duke with low airframe time and run-out engines for $250,000 to $300,000, depending on avionics and equipment. After the con- version, you'll have a 290-knot twin turboprop with new engines for a total investment of about $1.3 million. Cabin size and cruise performance is about on par with an EADS Socata TBM 700, although the Royal Turbine handi- ly outclimbs the single-engine TBM. Comparative twin turboprops would be the Cessna Conquest I, Piper Cheyenne, and Beechcraft King Air C90, all of which are quite a bit slower and use more fuel, but have larger cab- ins. Most interesting is how the eco- nomics of the Royal Turbine will com- pare to the uber-hyped very light jets that are coming to market. If the VLJs can keep prices in the $1.5 million range, it will be an interesting compari- son. The jets will have the speed advan- tage, but the Royal Turbine will outper- form any VLJ in runway performance, opening up thousands more airports for potential use. So far, ] 5 orders have been placed for the Royal Turbine and a few are from folks who've never owned a Duke. Individuals and owners of small businesses are attracted to its small size and economy compared with the larger turboprops like King Airs and Conquests. Owners we talked with have praised the entire operation at Northwest Turbine and report excel- lent post-sale support. They too wish that the pressurization system had a little more oomph and that the air- plane could carry more fuel. For now, the airplane holds 266 gallons of Jet A, which provides about 3.5 hours offuel at high-speed cruise. If you can get a direct climb to altitude, keep the power back in cruise, and start your descent 10 minutes from your desti- nation, the Royal Turbine can stay air- borne for about 4.5 hours with re- serves. Remember, the Duke has no potty, though. There are some flies in the ointment, however. Because it's so new and lacks a history, the insurance for the airplane could be a deal breaker for some pilots lacking in multiengine turbine time. In addition, to maximize its efficiency, the airplane must be flown high. In the Northeast, where controllers and traffic flow determine altitudes to be flown, the Royal Turbine pilot may find him- self stuck at less-than-optimum alti- tudes where the airplane is nudging the airspeed redline and slurping copious amounts of Jet A. In the end, however, Northwest Tur- bine has given the Duke a much-need- ed performance makeover to match its dashing looks. The Royal Turbine is simply a hoot to fly. Its abundance of performance and nimble flying charac- teristics, combined with its comfort and efficiency, make it a superlative turbine airplane for a pilot with a fami- ly or small business. M:a Peter A. Bedell is a first officer for a major airline and co-owner of a Cessna 172 and Beechcraft Baron. CB For more information about the Royal Turbine, /lisit the Web site (www. royalturbine.com) or call Northwest Turbine at 509/535-0187.