Tuesday, September 24, 2013
Caravan With Enthusiasm
Blackhawk modifications of Waco, Texas, converts basic caravans to Super Caravans
Blackhawk's Caravan conversion upgrades practically everything forward of the firewall. The stock Pratt & Whitney PT6A-114A is replaced by a PT6A-42A, which increases shaft horsepower from 675 to 850.
Blackhawk's conversion upgrades practically everything forward of the firewall. The stock Caravan's Pratt & Whitney PT6A-114A turboprop is replaced by a PT6A-42A, increasing shp by 25% from 675 to 850. This is the same engine used in pairs on the popular King Air 200 for years, and it's proven to be one of corporate aviation's most reliable powerplants.
Any airplane that's the beneficiary of a 25% power increase is bound to score better cruise performance, and while that was definitely one of the goals of the power-up, Blackhawk CEO Jim Allmon feels the upgrade has changed the whole personality of the Caravan I.
"When we began working on the conversion," says Allmon, "we were looking primarily at the corporate and utility markets. We spent thousands of man-hours developing the initial upgrade, plus probably 250 hours in flight test. We felt the extra performance would be especially attractive to charter and business operators, companies that have a need for medium-range travel with five to 10 passengers.
Predictably, the extra horsepower resulted in even better performance on the 208A "little" Caravan than it did on the stretched 208B Grand Caravan. The upgrade itself was very similar. In addition to installing the more powerful -42 engine, the upgraded Caravan features a four-blade wide-chord Hartzell prop, trimmed back from 106 to 100 inches in diameter. This provides slightly better ground clearance (and water clearance on the floatplane), as well as a marginally reduced noise level. The four-blade will be the standard prop on the Caravan conversion, but Blackhawk is continuing testing of a more efficient three-blade.
The conversion also incorporates a pair of stainless-steel Frakes exhaust stacks in place of the single right stack on the standard airplane. The Frakes exhausts are the result of extensive R&D into reducing back pressure in the larger engine. They're also the beneficiary of research into the optimum design and mounting position to avoid noise, vibration, fumes and possible heat waves corrupting image quality on air-to-ground photogrammetry missions. Many Caravans have been pressed into service for aerial photo-mapping work, and the additional stand-off of the Frakes exhausts helps direct the burned gases away from the airplane. A fringe benefit is the reduction of exhaust soot on the nacelle and wing. This is a big benefit for those in the cabin, as well. In the process, the Frakes stacks are streamlined to minimize drag.
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Labels: Turbine Singles