November 1, 2008

Mooney Acclaim Type S: A Piston Rocket

As a former executive at Columbia Aircraft, I read Ian Twombly’s story on the Mooney Acclaim Type S with interest (“ Mooney Acclaim Type S: A Piston Rocket,” September AOPA Pilot).

Obviously, keeping that number-one speed ranking for the Columbia 400 was important to us but the simple reality was that aircraft we were building during 2006 and beyond were not meeting book specifications, so we had already (privately) lost that race before the Type S came to market. Whether Cessna has been able bring the 400 back up to the 237 KTAS book number or not is unknown. (Perhaps AOPA should give it a test.)

Twombly did touch on an even more important issue than raw speed, however, and that is efficiency. In order to fly the 400 at peak speed, it took roughly 28 gph (rich of peak) to keep turbine inlet and cylinder head temperatures within limits. According to Twombly, he saw 21.7 gph at 239 knots, which is nothing short of spectacular, as is 16.5 gph (lean of peak) to get 232 knots. This aircraft is not just the fastest, but its ratio of speed-to-fuel burn is far beyond the Columbia 400 as well as anything else I’ve seen in general aviation.

Of course, the Acclaim does have to pick up its gear to achieve this performance, which adds some complexity (and higher insurance rates) versus the 400, and crosswind landings in a Mooney (not mentioned in the article) are certainly unique. The 400 also has the roomier cabin—certainly up front. Overall, though, the Acclaim is very impressive, especially when the cost of fuel is a consideration and that certainly has become a much bigger issue of late.

Richard Belzer, AOPA 893808
Bend, Oregon

I fly an older Mooney, so I went to see the new Type S at EAA AirVenture in Oshkosh. In an airplane that shouts “IFR in the flight levels,” the back-up instruments were a real disappointment. They are located on the far right on the panel. I tried to imagine flying with them. Could I get down with a failed Garmin G1000 that takes all the attitude instruments, com, nav, and autopilot with it? Could I fly with my handheld in one hand looking over my right shoulder? The added difficulty in an already difficult situation was not a pretty picture.

Steve Hurst, AOPA 5177094
Tucker, Georgia

The key to ownership

I enjoyed Ian Twombly’s article about different ways to enjoy flying while sharing expenses (“ The Key to Ownership,” September AOPA Pilot). I have been in a four-person partnership for 23 years with a Piper Arrow. We purchased the airplane with cash, established a corporation and wrote bylaws to spell out the operations. In the 23 years the other partners have changed, but it has been an excellent way for four pilots to share the expenses and be able to own and fly for pleasure and some business. Scheduling is done online and there have not been any conflicts in the 23 years.

We bought the airplane with 6,300 hours and it now has 10,250 and still gets compliments wherever it goes. The airplane has been painted twice and has had two complete interiors, including a full leather interior last year. One month the airplane went from Austin, Texas, to Seattle and then to the Bahamas. A partner flew it to the southern coast of Mexico this year.

What a great way for four middle-class pilots to be able to afford the thrill of owning and flying when and where they want.

Ron Butler, AOPA 415596
Austin, Texas

Last of the Tomcats

I was pleased to read about the F-14D Tomcat Felix 102 (“ Pilot Briefing: Last of the Tomcats,” September AOPA Pilot). Ford Island is a fitting place for the great dogfighter. I would like to inform readers that the other Tomcat that took part in the last flight ceremony, Felix 107, is also safe and proudly on display as the centerpiece of the Hickory Aviation Museum at Hickory Municipal Airport (HKY) in North Carolina. Felix 107 was the standby aircraft at the ceremony, and flew the farewell flight when Felix 102 developed mechanical problems.

The Hickory Aviation Museum is operated by the Sabre Society of North Carolina, a group of pilots and buffs who work to honor veterans and the jet aircraft they flew. The group was founded almost 20 years ago when they saved a rare FJ-3M Fury from the ravages of a public park in nearby Taylorsville, North Carolina. The collection has grown to include an F-105B Thunderchief, F-4B Phantom II, A-7A Corsair II, F-5E Tiger Aggressor, A-4L Skyhawk, T-33 Shooting Star, and an F-27 Friendship freighter donated by Federal Express. There is more to see at the Web site.

Jeff Willhelm, AOPA 1113742
Hickory, North Carolina

How slow can you go?

What Barry Schiff says in his September column, “ Proficient Pilot: How Slow Can You Go?” about reduced engine power settings giving increased range and fuel miles per gallon is true. However there is one thing that he did not say about running aircraft engines at 55 percent and below power settings is that you will be cleaning the lead balls out of the bottom spark plugs a lot more often. If you are paying a mechanic to clean the spark plugs then you may not be saving money because of the reduced fuel usage.

Each engine is different so results may vary. I found years ago running a Cessna 172M at 55-percent power during cruise that I had to clean the bottom spark plugs a lot during run ups and sometimes I got an intermittent engine miss after flying a few hours at the low-power setting. After just a few hours the bottom spark plugs were full of lead balls. At 65- to 70-percent cruise power it is rare that I have to clean the plugs between annuals.

I think that the problem was that the reduced power setting resulted in a much lower combustion gas temperature and more lead vapor from the fuel would condense on the cooler cylinder walls and the piston top. This would form lead balls that were electrically conductive, would bounce around in the cylinder, and would finally fill up the gap around the bottom spark plug center electrode insulator and cause either a intermittent misfire or a shorted plug that would not fire at all.

At higher power settings such as 70 percent the lead vapor would not condense at as high of a rate since the gas temperature was hotter, the piston and cylinder walls were hotter and instead the lead would remain as a gas and go out the exhaust pipe.

John Frerichs, AOPA 679741
Gurley, Alabama

Test Pilot

I’ve just read Barry Schiff’s “ Test Pilot” column in the September AOPA Pilot and I am responding to question number 8, “Who or what was the Mercury 13?”

I am one of the so-called Mercury 13, an unfortunate name lightheartedly coined by a Hollywood producer, which leaves the impression that these women were involved in a NASA Mercury astronaut program. Not true. Parsing the answer: “NASA” (NASA knew nothing about this program while it was under way) “trained” (we tested, not trained), “13 women astronauts” (25 women pilots were tested of which 13 passed and we were never astronauts—maybe astro-nots would be correct) “in secrecy” (true) “at the same time of the Mercury 7” (the Mercury 7 were selected in 1959, we tested in 1961).

Dr. Lovelace of the Lovelace Clinic in Albuquerque had contracted with NASA to do the medical testing on the Merc 7. He was interested in finding out if women could also pass those tests and possibly become astronauts, his subsequent secret female testing program being paid for by the Lovelace Foundation. The 13 women who passed were advised that they would undergo two weeks of further tests by the Navy in Pensacola, Florida, at which time I had to quit my job teaching flying at the University of Oklahoma to participate. The Navy, apparently deciding that they needed some justification for the expense asked NASA to bless it, which NASA declined to do. In fact, there was eventually a congressional hearing asking if NASA was prejudiced against female astronauts, which of course they were (John Glenn testified that men flew the airplanes and women raised the children), and it would be 20 years before our country had women astronauts. In the meantime, I became employed by the Beech Aircraft factory as a sales demo pilot, the dream job of all time for a young woman in 1962.

Gene Nora (Stumbough in 1961) Jessen, AOPA 183662
Meridian, Idaho


An article in the October AOPA Pilot titled “ Solo!” contained a photo identifying a student as Lt. Anil Nathan. The officer shown writing on a knee board is Lt. Tandon Mardis. AOPA Pilot regrets the error.

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