27,000 Feet in an RV-7

Taking a kit plane to the top

BY MIKE KERZIE, EAA 1039380; CHANDLER, ARIZONA

ON APRIL 26, 2011, I attempted to climb to 27,000 feet in my Van’s RV-7 Top Secret. My goal wasn’t just to set a record, but also to research new technologies that optimize aircraft performance. The story goes back a ways.

My sons David and Kyle, along with my good friend Mark, helped unload my quick-build kit in October 2007. I wanted my RV to exceed Van’s performance numbers, so my goals were to increase horsepower, minimize drag, and keep weight to a minimum. Thanks to my dad, I had the skill set necessary to build my RV-7 after helping build his beautiful RV-6 N22XK.

From my bachelor’s degree in aerospace engineering I learned in Aero 101 that to maximize aircraft performance, you optimize lift and thrust and you minimize weight and all seven types of drag. It all adds up. For example, I have the Whirl Wind 200RV prop/carbon spinner, which is approximately 18 pounds lighter than the Hartzell prop. It provides another 27 fpm climb just from its lower weight.

In the end, N77XK weighed in at 1,025 pounds. It would have weighed less, but my painter, Mike Rosales, insisted on a good paint job.

THE PEOPLE BEHIND THE FIRST FLIGHT

When it came time to choose the engine, my friend Mark pointed me to Steve and Tina Thomas’ Poplar Grove Airmotive, located at C77, just outside of Chicago.

Dave Allen, Dave Mitok, and the rest of the team are accomplished engine experts; they all came to the rescue. We discussed every conceivable combination and engine parameter in detail. We considered a narrow deck to reduce weight and ruled out an angle valve because it’s 30 pounds heavier. ECI cylinders are lighter, tapered, and effectively run cooler. In the end, we chose an experimental Lycoming IO-360 parallel-valve engine with NFS 10-to-1 pistons for light weight, power, and reliability.

One of the keys to maximizing horsepower at altitude is the engine monitoring system (EMS), which takes care of timing advance and fuel/air mixture. While most data is confidential, reading about the Eagle EMS on www.PrecisionAirmotive.com should answer most laymen’s questions.

It weighs essentially the same as the Bendix fuel-injection system. For safety, a backup battery weighing 2 pounds is recommended.

Help came from many others, including my wife, Cindi; my three children, David, Kyle, and Kristen; and friends and neighbors, who were always there to help with the bucking bars. Stoney Burke from DeltaHawk Engines helped glue the canopy with Sikaflex to prevent cracking during extreme temperature changes. Jon Sharp and Kevin Eldredge, Reno Sport Class pilots, provided expertise in canopy carbon fairing, engine, and cockpit panel layout. Electrical geniuses Ole Moyer, Jim Henderson, and the Advanced Flight Systems (AFS) technical representatives, especially Trevor Conroy, were all very helpful in integrating the Eagle EMS with the engine, the AFS EFIS, and the laptop. Rich Reno, a longtime Army friend from Texas, flew to Arizona several times to help install the engine, prop, and many other accessories. Even one of my coworkers, Freddy Usoltseff, spent countless hours polishing. I would like to give special thanks to all those who provided their expertise and time in making this dream possible. Top Secret made its first flight on October 2, 2010. You can watch the video on www.SportAviation.org.

EXPERT TESTING

On Easter Sunday last year, I asked my dad if he would go flying with me. The scary part is that Dave Kerzie, besides being one of the greatest fathers anyone could have, is an American hero, a distinguished fighter pilot, and a former president of the Society of Experimental Test Pilots. He received the Iven C. Kincheloe Award (outstanding experimental test pilot) for his flutter tests on the U-2, and I’m sure there are other accomplishments that remain top secret (thus my aircraft’s name, in his honor).

The engine started on the first blade as it always does, despite being cold or heat soaked, thanks to the Eagle EMS.

Top Secret came off the ground before I could get the throttle halfway in, and off we went. I was lucky the takeoff was halfway straight, and of course, the RV was climbing like hell! I transferred the controls to my dad, and he proceeded to conduct a 40-minute engineering flight-test course far surpassing my 20 years of maintenance test-flying instruction.

DON’T TELL DAD

Two days later, without my dad’s knowledge, I took off from Stellar Airpark (P19) and attempted to climb to 27,000 feet. At

12.000 feet, I requested 27,000 feet, or as high as I could get. Bill Kline, ABQ controller, told me I was cleared to 28,000. At

18.000 feet the RV was still climbing at 1,200 fpm. Twenty miles east of San Carlos, I turned straight into the forecasted winds at altitude.

I had already decided I was not going to go above 27,000 feet. The oxygen mask is certified for 25,000 feet, and the Aerox engineers had advised me that the system has one hour’s duration at that altitude.

At 25,000 feet everything slowed down; my groundspeed was only 18 knots as we continued to climb at 75 knots indicated.

At 26,900 feet, I couldn’t climb any more, though the aircraft handled rock solid (thank you, Van). I took some quick pictures of the curvature of the Earth, my EFIS, and the transponder. The Eagle EMS provided a very hot, long duration, variable ignition advance, as well as that efficient 12-to-1 air/fuel mixture for max allowable horsepower. The engine developed 9.4 inches of manifold pressure at this altitude. But no matter what I did— level off or zoom climb—I was unable to gain any more altitude.

For my descent, I’ve learned enough about Lycoming engines to know that cylinders would crack by shock cooling them too rapidly. I also was concerned about inducing flutter by coming down too fast.

I advised ABQ that I was out of 27,000 feet (it sounds better than 26,900) and descending. I pulled the throttle out halfway and ensured that the cylinder head temperatures did not cool more than 10 degrees per minute. In addition, I kept a watchful eye on the calculated true airspeed on the EFIS and settled in for a 180-knot descent.

I landed in front of a small crowd and was very happy to be back on the ground. Cindi informed me that she had called my dad, who then tracked my flight on FlightAware. Bad mistake. When I called, he congratulated me on the flight, then proceeded to lecture me on Air Force rules about pressurized cabins, pressure suits above 25,000, partial pressures, etc. He made me promise I would never do that again.

Someday I plan to enter and fly this RV-7 in a CAFE race with its combination of speed, carried weight, and fuel efficiency. I feel this is where Top Secret would excel. It starts immediately, regardless of the temperature, continually burns fuel at the max horsepower settings, and can be leaned out to an economy setting. At full lean, one full turn of the knob will make the EGT go exactly 100 degrees hotter and decrease the fuel flow by 0.5 gallons per hour at

8,000 feet cruise. During my max altitude test it only burned an average of 7.2 gallons per hour.

I have many more test flights planned for this aircraft, but taking my wife on trips has moved up to the top of the list.

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