AZ Scholarship Winner Takes Flight in the Backcountry 


By Rick Bosshardt 



As many of you who attended the “sold out” Arizona Pilots Association’s Annual Meeting on May 13th know, we awarded three Scholarships to deserving young pilots-to-be.  From these immensely talented and motivated high school students, who are also involved in extra curricular education in aviation related fields, the Scholarship committee of the APA selected three for this honor.  Being one of the members of the Scholarship Committee, I can attest to the difficulty in selecting these three from the 9 outstanding candidates that put forward their applications.

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To this end, all three of the Scholarship Committee members offered airplane rides in their planes to any of the applicants and winners that wanted a ride.

I had already given one of the winners a ride during an early spring Young Eagles event at Falcon Field, but I was contacted by the other two winners subsequent to the scholarships being awarded.   I managed to get one flight done before I sold my demo plane, and I promised the other a ride as soon as I get my new, and “upgraded,” Carbon Cub in the fall.

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So on May 31st I had the distinct pleasure of taking Kayla Phillips, one of our scholarship winners, up for her first flight in a true “backcountry” plane. I wanted her to experience the different kind of flying that such a plane can offer, and to show her that even though her goal is firmly set on being a Captain for an airline in the future, that there are a myriad of different types of planes, and thus many different missions that can be flown!

We started off with a low and slow flight up the Verde River Valley, being sure to keep a bit offset because of the current Eagle nesting period.  We opened both the window and door, and were on a “mission” of spotting wild horses!  I was truly amazed that for the very first time on my many flights up the Verde, we didn’t see a single one!

It was super great to see that Bartlett Lake is almost full again. As we flew from there to Horseshoe Lake, we saw the water level was just low enough to see the Indian Adobe ruins on the northeast side.

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From there we climbed up and over the Four Peaks range, and headed for our destination, Buzzards’ Roost.  As the new “caretaker” for the strip/field for the APA, I wanted to land and check out the conditions.  The ground was nice and dry, although a bunch of 1-2’ weeds had sprouted up from the recent rains on the meadow that we landed in.  The tundra tires made quick work of it, and Kayla experienced her first (voluntary!) off-airport landing!

The return flight took us on a low pass over Grapevine (88AZ) to show her the handiwork of the APA volunteers, and then back to Falcon.

Its really great to feel the passion and excitement from a young person today who loves all things aviation, and Kayla promised to come out with her dad (they are both camping enthusiasts) to our next fall Grapevine event, to camp with all the pilots and to meet more APA members.

Congratulations to Kayla and all the winners and applicants. May your aviation careers be long and rewarding! 

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Now that you have reached your cruise altitude, you can switch off the fasten seatbelt sign and take a moment to relax. If you are in a technologically advanced airplane, or carrying a tablet, you are probably looking at multi-colored LCDs throwing all sorts of information at you. My Electronic Flight Information System has readouts of fuel flow, range, miles-per-gallon and indicated/true/ground speeds. Is there a way to minimize fuel flow, maximize MPG, and maximize airspeed all at once? Probably not, but we will explore the factors effecting each and some other performance metrics that we may not normally think about.


Maximum Time Aloft

The airplane's time aloft or endurance is its fuel on board (gal) divided by fuel flow (gph). To maximize time aloft, one must maximize fuel capacity and minimize fuel flow. Fuel flow is minimized by using the least amount of power to sustain flight. This is the bottom of the power required for level flight curve. On an endurance flight, as fuel is consumed and the airplane weight decreases the minimum power required will decrease and the throttle can be reduced. To fly for maximum endurance, you will be flying really slow, at or near your Vx speed, so this is rarely done in general aviation. An example of when this would be useful is on an observation mission where the airplane needs to remain on station for the longest possible time.


Best Miles per Gallon, Best Range Speed

This probably gets your attention because now we are talking about saving money. The best miles per gallon will result in the maximum range of the airplane. Another way to express it is that this cruise speed will use the least amount of fuel for a given trip distance. The fuel used on a trip depends on fuel flow and the time it takes to make the trip. So now we need to minimize fuel flow (keep power low) but make the trip fast enough to use as little fuel as possible (keep power high!). The middle ground is found at the bottom of the L/D curve of the airplane and is close to, if not the same as, the Vy speed. In the interest of saving fuel, we get to fly a little faster but still at a relatively slow airspeed.


Best Speed per Gallon

Optimum cruise speed was derived by B.H. Carson of the U.S. Naval Academy in 1980. For those of you that can remember back that far, this was after the oil embargo. Suddenly the country was focused on the fuel efficiency of cars and airplanes. Carson addressed the question of using miles-per-gallon as the optimizing metric for airplanes. He noted that for airplanes the speed for optimum fuel efficiency was quite slow and utilized only a small percentage of the airplane's available horse power. Instead he derived a new metric, the optimum cruise speed which maximizes the speed of the airplane relative to fuel flow. It is the best speed per gallon-per-hour ratio that can be achieved. The optimum cruise speed that he derived is 1.32 times the best miles-per gallon speed. It is a bit more practical than flying at best range speed.


Here are the V speeds discussed in this article derived from the performance charts I measured during the flight test period of my RV-10. The blue line is the thrust required for level flight and is read from the axis on the left in pounds. The red line is the power required for level flight and is read from the vertical axis on the right in horsepower. The maximum endurance speed is a very slow 70 KIAS and only requires 57 horsepower from the 260 horsepower engine. The maximum range speed is 90 KIAS and requires about 100 horsepower. The optimum cruise speed is 120 KIAS, still somewhat slow, but better, and requires around 120 horse power - still only 46% power.


Next month we will discuss how to determine these performance curves for an airplane through flight testing.


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