Ameritech Industries: American Propeller and Eagle Engines

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April 2014-

Propellers take a beating. During operations that range from the instant takeoff power is cranked on to power-off stalls and descents, blades continually flex due to changes in aerodynamic loading. Props endure years of light damage due to rock, ice and rain impacts.


In spite of being within degrees of separation from the top spot on the most highly stressed parts on an airplane, props are so dependable it's probably no stretch to say that the average GA owner pays as much attention to his prop as he does the ground below his feet.


The FAA considers propeller maintenance to be so critical that even the most knowledgeable FAA certificated airframe and powerplant mechanic isn't allowed to do any propeller maintenance, save smoothing out minor rock nicks and removing and replacing one. All other maintenance tasks must be done by an FAA certified propeller repair station.


One such repair station is American Propeller in Redding, Calif. Established and under the same ownership since 1976, American Propeller is a full-service prop shop.


The early days


Kerry Dawes and Dennis Praegitzer started American Propeller together. Praegitzer was working in a prop shop and wanted his own shop; Dawes met him through friends, and a deal was struck. In October 1976 the FAA issued a propeller repair station certificate to American Propeller in Redding.


At times the going was rough. After setting up shop, the airport authority wanted to build a new terminal on American's site. It moved. Then on Sept. 25, 1995, Dawes and Praegitzer got a call at 2 a.m. saying the business was on fire. Due to the firefighters' belief that the shop contained toxic and explosive chemicals, efforts were restricted to protecting surrounding properties. The building, 19 years of tooling and equipment and 160 propellers were lost.


Due to excellent insurance and the fact that all records survived the fire, every prop and every prop blade that was destroyed in the fire was replaced to each owner's satisfaction.


With American's customers taken care of, it was time to restore the business itself. Todd Marinkovich, the service manager of American Propeller, found an existing propeller shop at Dallas Airmotive that was for sale. He surveyed it, bought it and loaded everything in the back of two semitrailers for the trip back to Redding.


Within four months, American Propeller had relocated to its present off-airport place of business and was again up and running. Despite the complex logistics of recreating the entire business, American's management took a people-first approach. "The hardest part was making sure that all our technicians were taken care of," said Dawes.




"We used to be able to provide removal and reinstallation services and prop balancing service when we were based at the airport. Now we utilize our vast network of Ameritech Service Centers throughout the West to provide those services," said Bob Honig, corporate sales manager at Ameritech Industries.


Ameritech Industries (comprised of American Propeller and Eagle Engines) sends three trucks on the road every week to pick up and deliver propellers, governors and engines. These trucks cover five western states—California, Oregon, Washington, Nevada and Arizona—and are beginning to cover Idaho and Utah.


The Ameritech pickup and delivery trucks eliminate shipping charges for engine and prop overhauls in those states. Ameritech also pays one-way freight charges for engines and props shipped in from out-of-truck regions when the shipper coordinates shipping with Ameritech.


Todd Marinkovich, when asked about the state of American Propeller, said, "Volume-wise, we're the largest prop shop on the West Coast."


Eagle Engines takes care of the shipped-in engines that require overhaul. The engine segment of the business was established by Dawes in 1990.


When Lou Pierard, a highly qualified and well known piston engine technician and builder became available, Dawes decided the time was right to go into the engine building business.


Pierard moved to Redding and set up shop. He has since retired, but not before establishing Eagle Engines' reputation as a top-notch engine overhauler. His son Bobby is now working as shop foreman.


Family connections


The Lou-and-Bobby family connection is just one of the family ties that run throughout Ameritech. Kathy Dawes, Kerry's sister, came to work at American Propeller before marrying Praegitzer; they still work there. Tony and Tracy are Todd Marinkovich's brothers, and Tyler is a nephew and Tracy's son. They all work in the prop shop.


One factor in the success of Ameritech is its stable workforce. Mike Crowell is the Chief Inspector; he's been at Ameritech since 1999. Chris Dishong has been with the company since 1984; Todd Marinkovich since 1986; Chuck Baist since 1989; Tony Marinkovich since 1990.


Doug Booth, the PPG trained and certified painter who cranks out the FAA approved, customized paint schemes for Ameritech's Designer Prop, has worked at Ameritech for 14 years.


The new guy in the prop shop is Travis Drake. Drake has been aboard for 16 months and is in training to take a place next to Kevin McGuire—the "Blade Master"—who goes at damaged and out-of-spec blades with a grinder and files to get compromised blades back into compliance with the manufacturer's requirements for width, thickness and twist.


Grinding and filing is dirty, noisy work. "Nobody wants to cross-train for that job," said Drake as he manipulated the probe of an eddy current tester to check for corrosion and cracks in the bore of a blade.


Each propeller is evaluated for damage upon receipt. Then it's disassembled, cleaned and further inspected.


New equipment


Ameritech has invested in a lot of new equipment in the past year including an AeroScan machine in its prop shop. The AeroScan makes short work of measuring each blade for angle, thickness and twist. It completely eliminates tedious hand measuring.


After McGuire "tunes up" divergent blades, the result is a closely matched blade set in each overhauled propeller. Matching like this generates equal thrust profiles from each blade; this creates a smooth prop.


In addition to the capital investment in the AeroScan, Ameritech has also recently installed blade airfoil shot peening equipment. Shot peening is a mechanical process applied to the surface of propeller blades that strengthens the metal and increases fatigue life.


"Since we can do shot peening in-house, that, plus our pickup and delivery service presents a substantial reduction in shipping charges for some customers," said Honig.


He also pointed out that this capability often relieves customers of the need to buy new blades when more powerful powerplant retrofits are installed, since some propeller manufacturers allow the existing blades from the lower-horsepower installation to be used, provided they have been shot peened.


American Propeller sends its technical team and a truck with propellers to the Reno Air Races every year to provide on-the-spot propeller changes and minor maintenance for racers.


Eagle Engines


Eagle Engines has moved on from initially offering two boutique engine upgrades and now offers one high-quality engine overhaul with a limited menu of options and upgrades. "Today's overhauls feature all the best we can offer at a very competitive price," said Honig.


Every engine that goes out the door at Eagle Engines is built to new engine tolerances. Every engine part is inspected using state-of-the-art nondestructive testing (NDT) on ferrous and non-ferrous parts.


Every part listed in the engine manufacturer's "required new parts at overhaul" bulletins is new, although Eagle Engines does substitute parts built by specialty companies such as ECI and Superior Air Parts. These parts are all FAA approved under Parts Manufacturer Approval (PMA). The list of new parts always includes camshaft, lifters, pistons, all valve train parts and all bushings, bearings, critical fasteners as well as gaskets, seals and hoses.


All engine case halves are lapped and line bored. All crankshafts are dynamically balance-checked; reciprocating components such as piston sets and connecting rods are also balance-checked.


Hydraulic lifters are matched by bleed-down rate and cylinders are port matched and checked for efficiency to exceed factory-new engine specifications.


In addition to these quality and experienced-based standards, Eagle Engines has the ability to flow match cylinder sets to within one percent and to balance reciprocating components to within 0.5 grams. These two services are available upon request and result in further charges on the final bill.


During my visit, Pierard told me that the engine shop was awaiting delivery of two new pieces of equipment. A SuperFlow 600 is currently in use but will soon be replaced by the faster SuperFlow Pro SF-1020. According to the SuperFlow website, the SF-1020 "measures and records air flow at OEM engineering accuracy, faster than any other flowbench on the market."


The second new item is a Serdi 2.0 machine. This device simultaneously and automatically cuts three angle valve seats that optimize airflow past the valves. The machine delivers valve seats that are 100 percent concentric every time.


Pierard told me that the Serdi machine will eliminate what he calls the "Barney Rubble"—the old valve seat grinding practice that is somewhat variable since its success is entirely dependent on a technician's skills and well maintained tooling. "I'm like an expectant father waiting for that machine to come in," said Pierard.


Others in the engine shop include Bill Orr (15 years); Chris Hasley (2.5 years) and Lance Tomblinson (19 years).


Every engine is test run on the Eagle Engine test cell for one to 1.5 hours with an actual propeller instead of a test club. Using an actual propeller loads the engine during testing, and this insures more thorough pre-release testing. During these break-in runs, a small amount of dye is added to the oil to detect oil leaks. No engine is released until Eagle's strict requirements are met.


Owners' cylinders can be overhauled, but it costs only a little more to install new cylinders. Honig told me that 90 percent of the engines the company overhauls go out the door with new cylinders.


James Bridgeman, the service manager at Eagle Engines, worked up a quote for the overhaul of the Lycoming 180 hp O-360 A1A engine in my Comanche.


According to this quote, it would cost less to install new Superior steel cylinders than to overhaul my existing cylinders. If I wanted new Lycoming cylinders? $963 more. New ECI Titan Steel cylinders? $243 more. How about new ECI Titan Nickel+Carbide cylinders for added corrosion protection? $664 more. Those charges are to replace all four cylinders.


Typical engine overhaul turnaround time is four weeks unless the crankshaft is in such bad shape it needs to be reground. Due to California's environmental laws, the nitriding process that's required after each crankshaft regrind can't be done at Eagle. Crankshaft regrinding must be sent out of state.


Electroair electronic ignition


Ameritech Industries is also bullish on the advantages gained through the installation of an Electroair electronic ignition system.


The majority of certified airplane engines are still equipped with magnetos; magnetos, with regular maintenance, are dependable—but electronic ignition means starting is easier due to a much hotter spark. In addition, an Electroair system actively advances the spark timing to reflect changes in manifold pressure and engine speed.


Electronic ignition also supplies a much longer duration spark that results in more complete combustion. The result is a better running engine and fuel savings. Some users report a 10 to 15 percent reduction in fuel burn.


The Electroair system does depend on aircraft electrical power; a magneto runs fine without any electrical power. One Electroair system and one magneto is the perfect setup: a single electronic ignition system for smoother starting and optimized operation, combined with a tried-and-true backup system that automatically supplies spark in the unlikely event of a complete electrical power loss.


Electroair systems have been installed on thousands of noncertified aircraft and are now approved for installation on hundreds of four-cylinder engines installed in FAA certified airplanes. Approvals for six-cylinder applications are increasing.


Since each Electroair system has a 2,000 hour TBO, it makes a lot of sense to install electronic ignition at engine overhaul. In my experience, your engine will run better and you'll start saving money immediately.


Keys to success


It's gratifying to find an aviation services company that has weathered the industry's storms so well for so long. When asked about the secrets of success at Ameritech, Dawes answered, "The two things that we made it on are quality and customer service."


This was echoed by Honig when he told me that when a customer calls with a problem, "that problem or that warranty claim becomes our number-one priority."


Other keys are Ameritech's stable management team and workforce, and its recent capital investments in equipment that will further increase quality and better serve customers. That's a winning combination.


Steve Ells has been an A&P/IA for 39 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He's a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation ( and lives in Paso Robles, Calif. with his wife Audrey. Send questions and comments to .