Redbird Shows Off Diesel-powered ‘RedHawk’

 - July 29, 2013, 8:25 AM
RedHawk Aero’s new diesel-powered Skyhawk is sure to turn curious heads at EAA AirVenture Oshkosh.

On July 28, the day before the opening of this year’s EAA AirVenture Oshkosh show, EAA chairman Jack Pelton and Mac McClellan, director of publications, flew a specially refurbished Cessna Skyhawk from Fond du Lac, Wis., to Oshkosh. The Skyhawk has been turned into a “RedHawk Training Aircraft” in a new venture by simulator manufacturer Redbird Simulations and its flight training division Redbird Skyport. AirVenture visitors can see the RedHawk at the exhibit near the main gate. The airplane’s paint job, which will be replicated on all future versions, features humorous but educational labels for various parts and systems festooning the airframe and adding some levity to what’s usually a serious endeavor. “It trains while it’s standing still,” said Redbird and RedHawk Aero chairman Jerry Gregoire.

The RedHawk is now powered by the Centurion diesel engine formerly manufactured by Thielert, a company that was purchased a week ago by Continental Motors. The airframe looks new, with fresh paint and interior including all plastic, sidewalls, headliner and seats and Aspen Avionics Evolution 2000 glass displays, Bendix/King KAP 140 autopilot and other new avionics, which will include Bendix/King’s new KSN 770 GPS/navcom after it is certified.

The idea is to create an airplane that costs far less for flight schools to operate, and also a leasing, financing and insurance structure that will help flight schools prosper. Partners in the RedHawk program include Aspen Avionics, Bendix/King, Brown Aviation Lease, Continental Motors and Starr Companies (insurance).

Gregoire has worked with Continental Motors president Rhett Ross on Continental’s Zulu Flight Training effort, which uses Redbird simulators. Continental’s purchase of the Thielert diesel engine program included the supplemental type certificate (STC) for installation of the 135-hp Centurion 2.0 engine in the Skyhawk. Cessna had announced plans to build a diesel-powered 172 using the Thielert engine in 2007, but that program ended when Thielert went bankrupt.

An Experiment

Gregoire got the partners together to work on the RedHawk program and take advantage of the many used Skyhawks available at a low price and the low operating costs of the Centurion engine. For a flight school needing new training aircraft, a new Cessna 172 at about $340,000 makes it difficult to run a viable business, Gregoire explained. [Manufacturers] have left us no choice,” he said. “We can’t make a $340,000 airplane work in training.” But a used Skyhawk with all-new engine, avionics, interior and paint should make a difference, especially when the diesel engine burns lower-cost jet-A and uses far less fuel.

During the flight to Fond du Lac, for example, Redbird Skyport chief pilot Roger Sharp saw fuel burns of 4.9 gph at 113 ktas and 6.5 gph at 127 ktas. This is gallons less per hour than a normal Skyhawk at those speeds. And jet-A is much more readily available all over the world than avgas.

Pelton said he enjoyed the simplicity of flying the RedHawk, especially the pushbutton startup. “That’s a big plus for people who are not feeling mechanically comfortable,” he said, comparing the RedHawk to the mixture and throttle controls that must be manipulated exactly right for a gasoline engine to start. Engine runup is simple, too, just push one button to test the Fadec. The entire experience felt like flying a truly modern airplane, he explained, not like a 1940s-vintage design. The noise level in the cockpit is much lower and Pelton felt he almost didn’t need a headset to protect his hearing. The engine responds quickly to throttle movement. “At 80 knots [in the pattern] I was able to pull back and hit speeds just like a normal recip engine.”

The idea for the RedHawk experiment–like all Redbird Skyport projects, this is a test–is to put the RedHawk into the flight training environment and see how it performs and holds up to typical student abuse. And to seea whether the cost projections are accurate and make sense for a flight school.

The cost savings are more than just the price of the RedHawk, which has not yet been established, and the fuel savings. Project partner Brown Aviation Lease is working on a power-by-the-hour leasing program that includes all costs, so a flight school can start flying quickly and without having to line up a leaseback owner or putting a lot of money at risk on a new airplane for the training fleet.

The Centurion engine is a big part of the RedHawk experiment. Everything forward of the firewall is replaced, including the engine mount. Wings must be removed and fuel tanks and lines are all replaced. The Centurion engine is turbocharged and liquid-cooled, with a constant-speed MT composite propeller. A Fadec is used to control the engine; the pilot has just one control to move and there are no limits on how much power can be applied, nor worries about shock-cooling when descending at idle power. Starting is simple, just hold the brakes and push one button. The pilot has a propeller rpm gauge (the engine has a reduction gearbox) and a percent power indicator plus fuel flow gauge.

The cost of the diesel engine upgrade package is roughly equivalent to a firewall-forward piston engine replacement, if everything were swapped out, including the engine mount, according to Ross. The Centurion engine has a 1,500-hour TBO and the gearbox currently needs to be overhauled every 300 hours, although a higher time interval for the gearbox is in the works and nearly ready. Continental is also working on a TBO boost for the Centurion, and there is plenty of operational data to back that up, with some 2,600 engines in the field, mostly in Diamond airplanes.

Ross pointed out that regions without reliable avgas supplies are ideal customers for a training airplane like the RedHawk, including China and Africa.

RedHawk Aero is currently modifying three more Cessna 172s and results of the training experiment at Redbird SkyPort will be revealed the annual Redbird Migration Flight Training Industry and Design Conference at the Skyport’s San Marcos, Texas base from October 28 to 30.

Gregoire and the RedHawk partners believe that it’s time for another disruptive move to help general aviation grow again and that the RedHawk can help achieve that. “I consider this the same situation as simulators,” he said. Six years ago, Redbird launched low-cost (around $60,000) motion-base simulators for the GA training market, and since then has sold 700 of its flagship FMX simulators. Now Redbird also makes King Air simulators that sell for well under $200,000. Aircraft manufacturers have had plenty of opportunities to figure out how to create airplanes for the training market that don’t cost more than $300,000 each. “They’re crazy tone deaf,” he said. “We feel like they left us no choice. Somebody had to do this.”


It's about time somebody started to seriously tackle the problem of "entry-level" airplane prices soaring, and the problem of avgas availability outside the US. Great to see older Skyhawks being refurbed with diesel power!

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