December 19, 2017
Daytona Beach, FL - Sometimes it’s the simplest things that make the biggest difference. Case in point: the Exhaust Fairing developed by Power Flow Systems in conjunction with their ground-breaking Tuned Exhaust System for the Cessna 172 aircraft.
This fairing was originally conceived of solely as an aesthetic improvement. It softens and streamlines the rather “distinctive” appearance of the company’s first design which featured a long tailpipe protruding from the cowling and then angling back to run parallel to the belly for about 18”. Power Flow calls this their “Classic” design (which does sound a whole lot more appealing than “UGLY”) to differentiate it from the more conventional appearance of the Short Stack design which evolved a few years later for both the Cessna 172 & 177 series airframes.
In the course of the flight testing required to obtain an STC for the fairing, though, Power Flow soon discovered an un-anticipated benefit to the design: the device actually lowered the CHT’s on the test aircraft (particularly during climb) by an average of 10O to 15O F.
A quick look at the aerodynamics involved shows how this happens: the drag of the fairing in flight creates a bulge of high pressure on the leading edge of the fairing with a burble of relatively low pressure occurring on the downwind (open) side of the fairing. This is the aerodynamic equivalent of a large venturi system and the vacuum thus created naturally draws air from the only available source: the lower half of the engine compartment. The improved air flow through the cowling results in significantly lower CHT’s.
This beneficial effect is most pronounced during climb-out when the high deck angle made possible by the additional 10 – 20 HP generated by the company’s tuned exhaust system would normally impede engine cooling.
When the company originally obtained their STC for the exhaust fairing, the Short Stack version of their tuned exhaust was not even on the horizon, so their STC was limited to Cessna 172 airframes equipped with the original (long tailpipe) tuned exhaust system. When the Short Stack version was introduced a few years later, Power Flow was fortunate to find that an STC’d exhaust fairing was already available for both the 172 and the 177 airframes. Designed by well-known aerodynamicist and entrepreneur Roy Sobchuck and manufactured by Maple Leaf Aviation in Manitoba Canada.
Rather than re-invent the wheel, Power Flow quickly signed-on as a reseller for Maple Leaf. As a result, they can now offer the above benefits to ALL owners of Cessna 172, 177, & 177RG aircraft.
The Power Flow exhaust system is an FAA Approved tuned exhaust system that provides an increase of 30 to 130 additional RPM, an additional 100-250 feet per minute in climb and the ability to go the same airspeed for up 2.2 fewer gallons per hour.