New turboprop singles for business aviation

 - December 17, 2007, 11:02 AM

In the past, turboprop singles used for business flying typically did not offer the speed, load capability or systems redundancy of turboprop twins, though singles have amassed a comparable safety record. But the differences between them are disappearing with the advent of new breed of turboprop singles destined to enter the market in the next two or three years.

While their engines might be familiar, with a majority powered by the venerable Pratt & Whitney Canada PT6, the latest business turboprops–namely the Epic LT, Extra EA-500, Grob G160 Ranger, Ibis Ae270 Spirit and Farnborough F1 (the Vulcanair VF600W and Grob G140TP were excluded from this list because they lack pressurization)–have an extra edge because they were designed using state-of-the-art engineering software. The Epic LT, Grob G160 and Farnborough F1 are all-composite designs, which make them even lighter and more aerodynamic.

Despite some industry analysts’ dismissing turboprops as several very light jets (VLJs) close in on certification, it’s not likely that these propeller-driven aircraft will go the way of the dinosaur. Not every pilot–no matter how much money he has in the bank–will be able to meet the stringent training and flight experience requirements that the insurance companies are dictating for VLJs. Just because they can’t have a compact jet doesn’t mean these pilots don’t need or want a faster aircraft, and this is where the newer turboprop singles will come into play. Additionally, others will find that these aircraft fit their mission profile better than any VLJ could.

The new breed of turboprop singles, like any aircraft, has its pros and cons, and some offer better value than others. Not all of them outperform the existing pressurized turboprop singles–the Socata TBM 700, Pilatus PC-12 or Piper Meridian, all of which have been in production for several years–in every category, but the newer airplanes generally have an advantage when it comes to price, short-field performance and avionics. Some also offer greater speed, range or both.

Epic LT
If the Epic LT performs as promised, it could very well redefine the turboprop-single market. Las Vegas-based Epic Aircraft started flight testing the all-composite turboprop single in mid-July, with certification expected in early 2006. It claims that the aircraft will be able to cruise at more than 350 knots while carrying six people, baggage and full fuel.

With an NBAA IFR range nearing 1,400 nm and a maximum certified ceiling of 31,000 feet, the $1.9 million Epic LT will be able to fly above or around most weather. The company said the Epic LT’s cockpit will have the latest avionics, including large-format EFIS displays, traffic, weather and terrain information, synthetic vision displays, GPS and integrated autopilots. However, the company has not yet chosen an avionics suite.

According to CEO Rick Schrameck, the cabin of the LT will be similar in size to the Citation Mustang’s, although the turboprop is expected to fly 10 knots faster than the 340-knot twinjet and have a capacity for six-people, full-tanks, NBAA IFR range of 1,396 nm (it will be able to fly 1,608 nm at its 289-knot economy cruise speed). EASA certification of the 6,330-pound-mtow Epic LT is also expected in early 2006.

Extra EA-500

The all-composite EA-500 obtained European Aviation Safety Agency approval in July, and FAA certification was pending at press time. The company maintains that the $1.545 million, six-seat turboprop single is the most economical (in terms of both acquisition and operating costs) in its class. As proof, it noted that the aircraft consumes only 130 pph of fuel while cruising at 230 knots at 14,000 feet.

When EA-500 deliveries begin later this year, the cockpit will sport Honeywell EFIS 40 displays and Garmin GNS 430/530 navcoms. But starting in early 2006 the airplane will come with the Honeywell Apex avionics suite, and a slightly higher price tag. The Apex system, which will include two 10.4-inch-diagonal LCD screens, should be flying aboard an EA-500 test airplane in the first quarter of next year. Apex will add avionics options, notably EGPWS and weather datalink. In a rare move, Honeywell will retrofit Apex–at its cost–to the EA-500s delivered without the advanced avionics.

In the cabin, passengers will appreciate the roominess afforded by a high-wing configuration that avoids any spar intrusions. While its cabin-payload capacity of 437 pounds is on par with that of other turboprop singles at full fuel, the EA-500, with its 1,250-foot takeoff run, offers the best short-field performance, hands down, of any turboprop single in its class.

G160 Ranger
The G160 Ranger is a larger seven-seat derivative of the four-seat G140TP. As with the G140TP, the fuselage and wings of the G160 will be made from carbon-fiber composites, but the seven-seat version will be powered by the 850-shp Pratt & Whitney Canada PT6A-42A instead of the G140TP’s 450-shp Rolls-Royce 250-B17F. Certification is planned for the second quarter of next year.

Projected performance of this $2.56 million turboprop single includes a max cruise speed of 270 knots and range with six occupants of 1,800 nm. Lightly loaded, the aircraft has a maximum range of 2,060 nm and will carry a maximum useful load of 1,588 pounds.

Grob said the G160’s cabin, at about 16 feet long, 4.7 feet high and just over five feet wide, compares favorably with the interiors of small and midsize business jets. The cabin will feature such amenities as individual reading lights, folding tables, an optional refreshment center, lavatory and power connections for laptops. The company plans to fit an electronic flight information system (EFIS) on the G160’s flight deck.

Ae270 Spirit
The 850-shp Pratt & Whitney Canada PT6-66A-powered Ae270 Spirit is a multirole aircraft that can fill executive, commuter, aeromedical or cargo roles. Czech and U.S. certification of the turboprop is expected before year-end.

In its typical executive configuration, the Ae270 will carry six passengers 1,544 nm at a 218-knot economy cruise speed. Its top cruise speed is 270 knots. At $2.2 million (fully equipped in commuter configuration for nine passengers), the Ae270 competes with the Pilatus PC-12, which is priced at about $3 million similarly equipped.

The Chelton FlightLogic system is the Ae270’s standard avionics suite, and the Honeywell Apex system is available as an option. FlightLogic is the first-ever flight display system certified with synthetic vision, which offers a virtual-reality view of terrain.

Farnborough F1
In a change of direction, Farnborough Aircraft has put its search for financing on hold and is again working on developing the F1. First flight of a proof-of-concept, non-conforming prototype is planned for the first half of next year, with certification slated for late 2008.

The six-seat, all-composite turboprop’s design has been optimized to provide fast and flexible doorstep to destination travel for intra-continental trips of up to 1,000 nm. The company estimates that the F1’s operating costs per mile will be similar to those of an executive car service.

Farnborough Aircraft said the F1’s cabin is large for its class and is designed to allow passengers of above-average stature to adopt natural postures while aboard. A full IFR panel will round out the aircraft, though Farnborough has yet to announce its choice of avionics suite.