Turbines Spinning Up

Want to confuse the heck out of the line boys? Imagine the look on their faces when they see you pulling up in an RV-8, but they hear the whine of turbine power.

Innodyn began making its first production turbine engines just in the last few days. These engines are based on conventional small turbine technology, but with advanced manufacturing methods and proprietary systems used by Innodyn. Formerly named Affordable Turbine Power, the company changed its name in June 2004.

The turbine engine will burn slightly more fuel than a piston engine of comparable power. It weighs significantly less, only 188 pounds for the engine and reduction gearbox. With only one moving part in the turbine, and 11 in the gearbox, there aren't many things to break. The company is working on several different firewall forward kits for experimental aircraft.

"Reliability is our goal," said Chuck Nearhoof, president of Innodyn, in an interview with ANN. Chuck and his brother Charlie have operated a machining business in Pennsylvania for over 30 years. They designed the mechanical and gear systems for the turbines and developed and patented an advanced fuel system.

The engine itself can range from 165 to 255 horsepower with the installation of different diffusers, injectors, and nozzles. Prices range from $26,500 to $34,500. "If you don't need the horsepower, why pay for it," asked Nearhoof.

The engine is a radial inflow turbine with a centrifugal compressor on an overhung design. With the overhung design there are no bearings in the hot section. This leads to easier manufacturing and lower cost. The turbine shaft goes directly into the dual planetary reduction gearbox where 61,000 rpm is reduced to a more prop-friendly 2,750 rpm.

The gearbox uses gearing that is several grades higher than a person might find in a car, for example. Nearhoof pointed out that the gearbox is rated to take 500 HP continuously, 600 HP peak, with a 10,000 hour TBO. Most of the weight and size of the engine package is in the gearbox.

The fuel control system uses Pulse Width Modulation electronic fuel injection for a lower manufacturing cost and better engine fuel economy. Nearhoof explained that it atomizes the fuel at the injectors regardless of engine rpm. The company holds the worldwide patent for the technology.

The company has gotten a fair amount of press in the past, flying around in an RV-4 which had a prototype engine installed in 2002. They began flight-testing on an RV-6AT in July of 2004.

Now, an experimental Super Cub is being fitted with a production engine and is expected to fly in the next few weeks. In addition, their trusty RV-4 will also be fit with a production engine. Innodyn also expects to acquire an RV-10 that they hope to have on display at Oshkosh sporting a shiny new turbine engine. The production engines are being tested on a helicopter as well.

The company expects to begin delivering engines to customers later in the Spring of 2005. Nearhoof said they had could be shipping engine within 30 to 120 days. Their backlog schedule can fluxuate as some postion holders may not be ready for their engine yet.

What else is in work? The company is experimenting with using bleed air for heating and cooling. Although it is working in the test cell, it has not been flight tested yet. Innodyn is planning to produce a higher power turbine in the future, and a "twin pack" which may be on display at Oshkosh.

Aware that there has been frustration with delays, Nearhoof said, "Just be patient, it took us eight years to get this far. Give us another couple of months. We want nothing more than a good quality turbine engine for the experimental market."

FMI: www.innodyn.com