Letters

Prime time for the Jabiru

August 1, 2011

I enjoyed the article about the Jabiru J230-SP in June’s AOPA Pilot (“ Prime Time for the Jabiru”), but am at a loss to understand the 104-degree-Fahrenheit operational limitation. Is there a degradation in airframe 

strength when heated? Is the expansion rate of the dissimilar materials likely to cause delamination? Will this be a problem if the aircraft sits on the ramp when it is up to 120 degrees in the sun? I used to fly a Mooney out of Chico, California, where it often was more than 104 degrees F. 

Robert R. Corradini, AOPA 1562493
Palmetto Bay, Florida

Prime time for JabiruAl Marsh mentioned two rather large shortcomings, but did not expand on them—a recommended 1,000-hour top overhaul and the maximum air temperature of 104 degrees F for aircraft operations. At a price of $152,072, to not be able to utilize the airplane in temperatures easily found throughout the U.S. in the summertime, and to have to plan on a top overhaul at 1,000 hours, who do they expect to sell these aircraft to? The article gives the reader the idea that this is a great aircraft but glosses over these issues.

Tim Bailey, AOPA 1170209
Clackamas, Oregon

Al Marsh responds: The 104-degree F ambient air temperature limitation on the Jabiru composite airframe is actually the same as the 140-degree F limitation on many other brands of aircraft made of fiberglass or, in Jabiru’s case, a composite sandwich. Jabiru determines the critical internal temperature differently. Jabiru does not have an internal temperature probe so it uses NASA calculations. The top overhaul is because of running cast-iron rings in steel cylinders. Ring wear will take end-gap clearance beyond limits in about 1,200 hours; Jabiru picked 1,000 hours as the target for top overhaul.


A soldier’s best friend

I enjoyed the article “ Cessna L–19 Bird Dog: A Soldier’s Best Friend” (June 2011 AOPA Pilot). However, I believe there is one minor error in the article: The author states: “Cessna began work by mating the tail of a Cessna 195 and the wings of a Cessna 170B with a newly designed fuselage.” The part about the Cessna 195 tail may be correct (although I would like to know if there is any difference between the 170B’s and the L–19’s tail group), but I understand Cessna actually started with a 170A wing, added Fowler flaps, and three degrees of dihedral; they then used the L–19 configuration to produce the 170B. Although I have not been able to confirm this, it seems to make sense as the 170B did not enter production until 1952, well after the production and first flight of the L-19 (Cessna Model 305, December 14, 1949).

Richard Wegener, AOPA 5695959
West Hartford, Connecticut

Barry Schiff responds: It is possible you are right. I have six sources. Three state that the Bird Dog used Cessna 170 wings, while the others say 170B. I assumed that B was correct because the 170B wings were in development when the Bird Dog was cobbled together. I wouldn’t bet on it, though. I’m sorry that I can’t confirm this one way or the other. No one currently at Cessna seems to know. Matter of fact, they get glassy-eyed when you just mention a Cessna 305.


Pressurization points

The Piper Mirage recently reviewed for AOPA Pilot seems to be equipped about the same as the one I currently fly (“ Piper Mirage: Pressurization Points,” June 2011). The useful load was interesting as I have found the aircraft to be one of the more difficult to plan in terms of weight and balance. Short stage-lengths are especially problematic when required to carry an IFR alternate and the associated fuel reserves as part of the zero fuel/max landing weight. My typical flight takes 22 gallons to destination and 45 minutes to fly; the closest IFR alternate is our departure point. To optimize payload, my typical fuel load is 60 gallons, so in order to land at maximum landing weight, my maximum takeoff weight has to be restricted to 4,255 pounds. My aircraft’s empty weight difference is only 28 pounds from the aircraft Tom Haines had the privilege to fly. He might be quite surprised to see where the center of gravity falls with two people and the pilot in the seats and 120 gallons of fuel.  I religiously run a weight and balance calculation every flight.

 The Piper Mirage is indeed a beautiful airplane to fly, especially when flown within the envelope. I just wish Piper would get busy with raising the maximum landing weight.  This in itself would increase its utility and make it a superior airplane.

Calvin Mjolsness, AOPA 5427509
Victoria, British Columbia


Aeronautical dinosaur

Amen, Amen. I couldn’t agree more with Barry Schiff (“ Proficient Pilot: Aeronautical Dinosaur,” June 2011 AOPA Pilot).

I firmly believe that not everyone is cut out to fly an airplane. I use the analogy of a motorcycle a lot. Airplanes need quite a bit more concentration than a car.  Just like a motorcycle. It seems the new generation of folks (who want it now) with the likes of Cirrus, Piper, et cetera, want to buy an airplane and learn how to fly it in a month. Well, you and I both know one can’t pick up what you need to fly an airplane in a month. Get people in a Cub or a Champ and they’ll be hooked. All the schools do is try to teach ATC and glass and no common sense flying. That is where our problem is. What is the saying, “If you can fly a Cub, you can fly a 747, but the opposite can’t be said?”

There is a large feeling of dislike of the Sport Pilot category.  If it is used correctly, it would be such a great first step into aviation.

Bob Bible, AOPA 6330346
Johns Creek, Georgia

Barry Schiff’s column brought to mind how the natural pilots of the world (birds) are really far superior to the unnatural ones (us). My wife and I were staying at a place on the ocean in southern Carlsbad, California, and we watched groups of pelicans flying along the beach, all staying in perfect formation and holding altitude and heading with no problem. Never have I seen a bird make a hard landing or overshoot a landing area. Last I checked, birds are not equipped with glass panels or even steam gauges or communications gear to ask ATC for help. I hope VORs and ILSs stay around for a while. I’ve been resisting glass for my 172 for a long time.

John Davidson, AOPA 1248992
Porter Ranch, California

Barry Schiff is right on the mark! Seat of the pants, feel, being one with the aircraft, makes for a better pilot. And, even though flying a turbo Bonanza with all of the stuff now is very nice, I still miss flying an airplane instead of managing it from point A to point B. 

John List, AOPA 0363724
Glenbrook, Nevada

Teaching pre-solo students in a G1000, I have both screens as a PFD. No moving maps, weather et cetera. Basic flight and engine instruments only. I typically set the G1000 and don’t allow the student to “play” with the G1000 except for tuning radios and choosing which transmitter to use. Otherwise they spend too much time fiddling with the G1000. I prefer to block the altitude indicator as they [students] spend way too much time on it. The negative is that the “ball” is also masked.

I run into students with hundreds of hours with Microsoft Flight Simulator. They have a very good understanding of pitch and power relationship and general aeronautical knowledge.  But two problems: even less use of rudder and a fixation on the instruments without looking outside. So the worse combination for a student is flying a G1000 (or other glass cockpits) with a few hundred hours on Microsoft Flight Simulator.

Luca F. Bencini-Tibo, AOPA 384103
Weston, Florida


Tools for wisdom

Tom Haines’ article “ Waypoints: Tools for Wisdom,” (June 2011 AOPA Pilot) both opened my eyes and reminded me of my past. I am a retired Navy helicopter pilot with fixed wing thrown in. Post-Navy, I worked for Evergreen Air involved in hospital Airevac ops as well as highline construction in southern Arizona. I purchased a Flight Design CTSW and proceeded toward 6,000 accident-free hours. I am nine hours short of that landmark and proud in advance of that goal being complete. At 71, I look forward to many more hours of safe flying.

 My eye opener was the Aviators Code of Conduct. Never heard of it and probably would not have had Haines not mentioned it in his article. However warm and fuzzy the code may make some people feel, one-on-one by technology or in personal conversation is the answer to wisdom transfer. Our bad nights and near misses are the stories that need told only because we had the wisdom and skills to make that flight successful.

Thank you for the wisdom: Haines does a great service to all aviators.

John A. Morse, AOPA 905047
Chesapeake, Virginia

Haines’ article brings to mind the old flying adage spoken to me by my primary flight instructor: “There are old pilots, and there are bold pilots, but there are no old-bold pilots.” Stay within your limits and that of your airplane, thus you will log the same number of takeoffs as landings.

Ed Buehler, AOPA 709656
Rosenberg, Texas


Erratum

In “ Waypoints: GA Makes it Possible,” (July 2011 AOPA Pilot), the photo caption incorrectly identified Mike and Jeanie Ferguson. AOPA Pilot regrets the error.

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