Flight Test: Highlight on the PT6A-67P Powered Pilatus PC-12NG

The New Generation model builds on the PC-12’s established reputation as the bizjet rival that takes unprepared strips in its stride

Words: Dave Unwin

As the propeller blades slow, feather and stop, I can’t help but be impressed. I’ve done quite a lot of gliding over and around mountains, but never in an aircraft with a MTOW of five tons! As you approach a Pilatus PC-12 the initial impression is that − for a single-engined aircraft − it really is a big machine. Standing 4.26 metres tall and with a wingspan of 16.28m, it towers over most other aircraft, even twin-engined ones.

The Swiss have always had a reputation for quality engineering, and as Pilatus production test pilot Jan Schatteman and I walk around the gleaming PC-12NG I can see immediately that it is beautifully made.

A top-end Turboprop | f_ocused, Flickr CC2.0

Starting at the spinner, it is powered by a Pratt & Whitney PT6A-67P turboprop. This engine can produce up to 1,845shp, but is flat-rated to 1,200shp. All that power is converted into thrust via a four-blade (five-blade for the 2016 version) Hartzell prop, which is both fully feathering and reversible.

As I inspect the wings it occurs to me the single-slotted Fowler flaps cover a large proportion of the trailing edge (67%, to be precise), not leaving much room for the ailerons. The reason for the big flaps is to keep down the stall speed, but as small ailerons often result in reduced control authority, spoilers are often fitted to augment lateral control (as they are on the TBM series).

The PC-12, however, doesn’t have them and I make a mental note to check the roll rate. The wings feature elegant winglets, and I wonder if perhaps these contribute to the aileron efficiency, possibly by constraining span-wise flow.

The Honeywell weather radar is housed in a neat pod at the starboard wing tip, while de-ice protection is provided by Goodrich pneumatic boots on the wings and tailplane, and engine bleed-air to the intake. The windscreen and prop are heated electrically − a much better method than ducting engine bleed-air onto the screen. Bleed-air windscreen heating systems are always noisy, and less efficient at reduced power (like during the descent and on the approach, just when you need them). Using electricity to heat the windscreen is a far better idea, which is why most airliners use similar systems.

Read the rest of the article at Pilotweb.com.

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