And that’s what we examine this month: converting to turboprop power from a piston airplane - or from one propjet brand to another. Northwest Turbine- a relative of JetPROP- LLC- did for the Duke what its corporate cousin did for the Malibu: give it the benefits inherent in a turbine engine. Currently you have JavaScript disabled. Besides the great equalizer of human stupidity (insufficient fuel, improper procedures, flying into bad weather, etc) the piston twin doesn't have a lot going for it. Since turboprops generally have much more power than piston engines, however, they still tend to outperform turbocharged piston aeroplanes at most altitudes. In this process- the package must usually show that it first does no harm- or introduces no negative issues into the aircraft’s use. Subscribe to the Flight Safety Australia news site by entering your email address below. As we’ll see near the end of this article, despite their famed engine reliability, you still need to be ready for engine failures in turboprops. But the 3-600-hour engine overhaul cycle for the P&WC powerplants is more than twice as long as the Duke’s original engines. The advantage at altitude is what gives turboprops such appeal. I'm also familiar with some of the drawbacks that are generally associated with piston to turbine airframe conversions, and while I don't dispute that those drawbacks often do exist, I'm not particularly concerned with generalization drawn from the whole of the turboprop conversion fleet. For decades, the drumbeat has been steady—turbine airplanes are unobtainium as private aircraft. An aeroplane with a wide range of allowable CGs will have changes in performance and handling depending on how it is loaded. With that mastery you should be able to avoid accidents, right? Downtime during aircraft conversion “There’s also the downtime of the aircraft to be considered,” Nel explains, saying that If the operator is converting from an older model turboprop to a newer turboprop that’s roughly the same physical size, it usually takes about a month to conduct the conversion … A Colemill conversion is much more than an exchange for more powerful engines. It operates at much higher temperatures, and the turbine spins as fast as 45,000 rpm, so a turboprop engine must be constructed of extremely heat-resistant metals and be very well balanced to handle rotational forces. This permits you to direct thrust forward, instead of rearward, to dramatically shorten landing distances. By comparison- the Bonanza with its piston engine can cover only about 730 nautical miles in the same time needed by the Tradewind-converted Bonanza to fly 900. Compare that to the Malibu’s 350 maximum horsepower- which drops about 20 percent at cruise altitude. A turbopropeller engine (turboprop) is similar to the piston engines with which you’re likely familiar, in that both types are internal combustion engines. With their abundance of power, both airplanes are bucking against their respective redlines at lower altitudes. The Bonanza does need considerably more fuel capacity- and Tradewind accomplishes that with a set of distinctive tip tanks with integral winglets for efficiency. THE CONSIDERATIONSFor decades back- aircraft engineers and designers recognized that putting aircraft in higher- thinner air offered the potential to fly faster. Following- we’ll look at three of the betterknown and longer-running conversions on the market- recognizing that others exist – and that more will be coming in the future. In 2002, Conrad and Sadler launched into a development program to replace everything from the firewall forward on the prototype Duke. You’re about to transition into a single-engine turboprop (SETP). Familiar piston aeroplanes have fairly narrow CG ranges. Click here for instructions on how to enable JavaScript in your browser. Performance achieved with a Rolls-Royce Turboprop Engine conversion by Soloy Aviation. Both types of pressure-aspiration enhancements show up in piston aircraft across the years. While not something widely embraced- the customer-base has proven large enough over the years to support some long-term programs. Nope, only corporations and the well-to-do can burn Jet A. In simpler terms, a steam engine utilizes heat to create stream pressure, … The piston engines on the Duke are expensive maintenance hogs. Turboprops come in two basic designs: fixed shaft and free turbine. Going to turboprop from piston involves some interesting balancing acts because of different aspects of the engine going in and the engine coming out. By using our site, you consent to our use of cookies. The Cessna 172, for example, has a 16 centimetre range in allowable CGs, from the forward to the aft limit. Original designed and built during the WWII era and equipped with radial engines, it was converted to turboprops some 40 years ago . The problems that have befallen others are likely to be the issues you’ll face as well. Click here for instructions on how to enable JavaScript in your browser. Performance with the 250 turboprop engine marks a dramatic break from that of the piston-powered Bonanza. And if a twin-engine piston is more what you were thinking O&N offers those same Rolls-Royce turboprops in a pairing on the Cessna 340, converting the piston twin … I found some of the article misleading with ref to the exhaust of a piston engine being wasted compared to a turbine, they are both ‘wasted AFTER the charge has done it’s job in both instances! For the pilot without a Malibu- the cost can vary and still beat those of a new Meridian by several hundred thousand dollars – though the panel of a new Meridian may have the JetPROP devotee thinking about spending some more to gain similar technology and capabilities on top of the basic DLX package. An issue piston and turbines also share involves fuel efficiency. But, too much is asked of the big piston engine on the Duke. Finally- the time to overhaul for piston aircraft generally comes far earlier than in turbine engines- adding a significant attraction to the appeal of turbine engines. Tradewind picked the highly regarded- light and compact Rolls-Royce Allison 250- flat-rated to 420 horsepower- and since the Bonanza lacks pressurization- Tradewind focused on providing a performance increase with the Rolls-Royce Allison due to it's low fuel consumption at non-pressurized altitudes. For example- climbing to the Tradewind Bonanza’s optimal altitude will take the Bonanza more than 15 minutes- while the converted airplane needs less than five. Even without converting this to distance in centimetres, you can visualise a wide variety of performance and handling with variations within the allowable centre of gravity envelope. Single-engine turboprops put a dent in that theory starting in the 1980s with the introduction of the TBM series and Piper’s Meridian in 2000. Lower air pressure reduces the efficiency of engine-inlet pressures- which cuts power output. ( SHP ) at about piston to turboprop conversion fpm different type provides the same benefits them! Generally weigh less per horsepower because of different aspects of the differences in performance and handling on! Setps are pressurised other auxiliary storage option- or using more of what may be unused existing can... From 1970 to 1984, Frakes converted 8 Mallards while in Texas by manifold pressure, RPM! 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