Taking advantage of the big stage at the NBAA Convention last month, Piper Aircraft introduced its evolved and renamed PiperJet Altaire, showing a mockup of the redesigned fuselage and cabin interior and describing the aircraft as “the next step” in the evolution of its single-engine very light jet program.
The PiperJet Altaire is based on the proof-of-concept PiperJet, which has been flying since 2008. That airplane uses the fuselage of the single-engine turboprop Meridian and, according to Piper, this fuselage did not lend itself to the company’s long-range plans for scaled-up future generations.
“We wanted to give our jet customers an even roomier light jet that incorporates a scalable design, paving the way for a future family of competitive business jets,” said Piper CEO Geoffrey Berger.
At first glance, the Altaire appears quite similar to the proof-of-concept PiperJet, with its single engine mounted in the vertical stabilizer. A closer look, however, reveals a larger, 61.5-inch-diameter circular fuselage (nine inches taller and four inches wider) and round cabin windows replacing the rectangular windows of the Meridian. A still closer look shows an expanded-chord wing and a shorter vertical stabilizer.
The Altaire cabin (211 inches long, 55 inches wide and 55 inches high) is dramatically different from the cabin in the proof-of-concept airplane. The new design eliminates the through-the-cabin wing spar intrusion and allows for a 12.5-inch-wide and six-inch-deep drop aisle. There are an additional four inches of headroom and more elbow room with a nine-inch-wider cabin. Behind the main cabin is 20 cu ft of baggage space, which will be accessible in flight. In the nose is an additional 20 cu ft for baggage, heated but not pressurized.
The Altaire typically will be configured for one pilot and five passengers (one of them riding in the cockpit right seat), with a storage cabinet directly across from the main door that can be replaced by another passenger seat. The four seats in the cabin will be arranged in a club configuration. Other options for that space include a lavatory and a cabinet containing a mini-galley or entertainment center. An optional modular design allows the relatively easy swap-out of those features to meet mission requirements.
A three-foot-wide cabin door includes a built-in stair for ease of entry and exit.
Performance Promises Unchanged
Up front, the PiperJet Altaire will carry Garmin’s G3000 avionics suite, featuring what Piper describes as “the first touchscreen-controlled glass cockpit ever designed for light turbine aircraft.”
Performance projections announced with the proof-of-concept airplane have not changed. Powered by the Williams International FJ44-3AP, the Altaire is expected to have a range of 1,200 nm with four passengers (800 pounds). Max range with a lighter load is expected to be 1,300 nm. Max cruise speed is projected at 360 knots at a cruise ceiling of 35,000 feet.
Flight controls for the Altaire will be control yokes, replacing the sidestick controls tested in the proof-of-concept model. Handling will be enhanced by the Williams International FJ44-3AP engine’s Exact “passive vector changing exhaust system.” The design allows three to five degrees of vectored thrust, which is particularly effective in countering the nose-down pitch tendency in aircraft with an engine mounted above the centerline.
This thrust vectoring is achieved not by movement of the exhaust nozzle, but by way of shaping the throat on one segment of the nozzle. When the flow through the nozzle is subsonic, typical at takeoff speeds, it conforms with the curvature of the shaped throat, thanks to the Coanda effect (the tendency of a stream of air to be attracted to a nearby surface), thereby achieving some upward thrust deflection to compensate for the high thrust line of the PiperJet Altaire’s fin-mounted engine installation. But when the pressure ratio becomes supersonic in cruise, the over-expanded stream pushes away from the extended surface, reducing the vector.
According to Williams, the result may be shorter takeoff field length and reduced trim drag.
Piper claims the total variable operating cost per hour for the Altaire will be $727.36, compared with $867.16 for Cessna’s Mustang and $972.88 for Embraer’s Phenom 100, at average speeds of 320 knots for the Altaire, 310 knots for the Mustang and 324 knots for the Phenom 100.
The $2.6 million (typically equipped) airplane will be produced in Vero Beach and fly in 2012, followed by certification at the end of 2013 and deliveries in early 2014.
According to Groom, the company currently has orders for more than 150 airplanes backed by $75,000 refundable deposits. The next payment is not due until first flight of the first conforming prototype.
According to Piper, pilot transition from the Meridian turboprop single “should be seamless,” aided by the Altaire’s simplified glass cockpit.