DeltaHawk unveils diesel engine for certified aircraft

If avgas, also known as 100LL, disappeared tomorrow, what would you use to power your airplane?

The folks at DeltaHawk Engines have an answer to that: A diesel engine designed for aviation.

During AirVenture the company showed off the new design mounted in a Cirrus SR20. The Cirrus is the proof-of-concept model and during the show it had a steady crowd around it.

Dennis Webb, the president of DeltaHawk, notes that the engine would not have been feasible as little as 10 years ago.

“There is a lot of innovation in it,” he said. “This engine took a lot of hard-core research and development. In the past 10 years materials and technology have changed and now we have computer-designed engines that we never could have done in the 1960s. This is not a rehash of automotive diesel technology.”

Webb said the Cirrus was chosen to be the proof of concept airplane for several reasons.

“It was in the right horsepower class and certainly the Cirrus is well known,” he said. “It is a well understood and well respected airplane.”

Previous to the Cirrus, DeltaHawk did a great deal of testing in a Velocity. “It is a great aircraft, but also an experimental,” he said. “The certified crowd wants to see you flying an aircraft that is more familiar that they can relate too, so we went with the Cirrus.”

According to Webb, the new engine is a little bit lighter than the Continental IO-360 it replaces.

“When most people think about diesel, they think heavy,” said Webb. “We get people asking ‘how much weight did you add?’ but we did not add any weight to this airplane. The new engine weighs about 335 pounds. With the installation kit, it weighs about 400 pounds, so we actually saved weight — not much, just about 10 pounds — by removing the Continental.”

“The new engine is about 35% more efficient than avgas burning engines,” he continued. “From a cost standpoint you can fly further on less fuel for less cost. Also, since it is a turbocharged engine, so you can maintain 100% power up to 18,000 feet.”

Webb describes the engine as futuristic, burning tomorrows’ fuel today. That’s important, he says, because Jet-A is more available than avgas around the world as many countries are phasing out leaded fuels.

“We all know what is happening with avgas. It has become more difficult to get,” he said. “I was talking to a man from Frankfurt, Germany, who said even in Germany they are having trouble getting low leaded aviation fuel.”

And if it is available, it’s more expensive. In Seattle, for example, in early August a gallon of avgas was $7.88 while a gallon of Jet-A sold for $5.87.

The Cirrus is the tip of what could be called a growing iceberg, according to Webb, who notes there is a lot of interest in diesel technology for general aviation aircraft.

“We are developing kits for various aircraft right now,” he said, noting the engine is being tested on 41 different aircraft. “Some are experimental, some are certified. We also have six twin-engine projects in the works. Twins are coming back because people like the safety of the twins, but they are so expensive to operate, until now — we are bringing back affordability.”

For the next few months DeltaHawk with continue flight testing the new engine. Webb noted the new engine had about 15 hours on it when it arrived in Oshkosh.

“That was enough to make the FAA happy,” he said. “Our own test program will include testing combinations of propellers and and adjustments to the air scoop to get optimization of performance. The plan is to finish our flight testing by the end of this fall.”

Webb predicts DeltaHawk will achieve Type Certification for the engine in mid-2015 with an Supplemental Type Certificate for the Cirrus to follow soon after.

The price of the new engine has not been released yet.