Pratt Prepares To Reboot the PT6 Yet Again with New Technology
As it seeks to prolong the legacy of its 50-year-old PT6 engine dynasty, Pratt & Whitney Canada (P&WC) is laying plans to refresh the epic product range at the top, middle and lower ends. Speaking with AIN ahead of this week’s NBAA show, P&WC president John Saabas confirmed that the manufacturer intends to cap the PT6 portfolio with a 2,000-shp version of the turboprop but indicated it is not yet ready to target a specific launch date.
“We need one more larger size, a 2,000-shp turboprop that could fill a niche,” he said. “We have a lot of advanced design concepts for this but we have to build a business case around this. We need to be sure what the minimum [power] volume would be for this, and what electronics it would need and how it would be retrofitted. Right now our priority is to enhance what we have and keep people in the [PT6] family. This big investment will come in time but not in the next year or so.”
At the same time, P&WC (Booth No. C6518) continues to work on PT6 product enhancements. At the smaller end of the family, the focus is on providing more modern turboprop alternatives to piston engines powered by avgas, which is facing obsolescence as an aviation fuel. “We’re working on revolutionary technology to make big changes at the small end,” said Saabas.
Meanwhile, the Montreal-based group is seeking to further upgrade the middle of the product family. “There are things that we have to do to adapt the engines to the needs of more modern avionics,” Saabas explained, suggesting that the second half of the PT6 century (see box) will amount to a continued mix of evolution and revolution. He stressed that P&WC will continue with its long-standing philosophy of making technology developed for one engine available to other family members to the fullest possible extent.
By year-end, P&WC expects to have delivered more than 100 of the latest 867-shp PT6A-140 engines, which are powering Cessna’s new 208B Grand Caravan EX. “This engine has pushed the limits of new compressor technology and blade materials to give more flexibility for operating in hot-and-high conditions,” said Denis Parisien, P&WC’s general aviation vice president.
According to Parisien, the PT6A-140 and the latest PT6T-9 turboshaft for helicopters are prime examples of how P&WC has continued to apply the latest technology to get yet more performance and versatility out of a engine that first flew back in 1963 and that has retained fundamentally the same architecture over the past five decades. What has changed is that the PT6 is now delivering almost four times as much power from the same basic shell as the 500-shp PT6A-6 back in the 1960s, and, as importantly, 20 percent leaner specific fuel consumption (SFC). “We’re constantly looking for where the next 5-, 10- or 20-percent improvement can come from,” said Parisien. “We will always strive to push the needle as far as we can.”
Given the rising price of fuel and its direct impact on the economic viability of general aviation, SFC improvements have been one of the P&WC’s main goals for PT6 product development. But the company has also focused on adapting the engines to deliver ever-greater versatility to the extent that the family has achieved some 136 different aircraft applications in its history.
These span platforms as diverse as Beechcraft’s latest King Air 350i twin turboprop (powered by a pair of PT6A-60As), which is challenging the role of light jets in the executive transport market, and the rugged Twin Otter operating in extreme subzero temperatures in the Antarctic. “The PT6 effectively created the single-engine commercial IFR market since operators are willing to operate this way due to its reliability,” said Parisien, referring mainly to the latest single-turboprop workhorses such as the Pilatus PC-12 and the Daher Socata TBM700/850 series.
Last year, P&WC established its new general aviation division as the focal point for its efforts to ensure the continued longevity of the PT6, and it has regularly made annual research-and-development investments of between $300 million and $400 million to keep the competitive edge. “We’re still delivering the maximum technology for the price and were always looking at what we can provide for the various markets we support,” Parisien told AIN. “It’s always a trade off in terms of what technology is affordable and it ultimately comes down to what an OEM wants to get from its aircraft.”
In addition to mainstream general aviation applications, the PT6 is powering activities such as agricultural support and the market for single-engine military trainers and unmanned air vehicles. Saabas pointed out that the variety of applications for the engine has itself been a driver of product improvement. “We can compete in all these different markets and we continue to learn things that we can take from one to another,” he said. “For instance, things we’ve learned from helicopter operators have fed into [greater operational efficiency] for engines serving the regional airlines and fractional operators.”
In the agricultural sector, PT6-powered aircraft have boosted farmers who are constantly under pressure to feed the world more cost-effectively. “The use of turboprop aircraft has resulted in much greater efficiency to crop-spraying,” Parisien told AIN. “Aircraft started off being able to carry a 300- to 400-gallon spray payload and now this is up to 800 gallons and soon 1,000 gallons, and it has also increased the area of land that can be sprayed in one day.”
The same benefits also have reaped dividends in the specialist field of aerial fire fighting. “The market is using aircraft in ways we never expected and we been pleasantly surprised at how this has happened,” said Parisien.