Plane & Pilot
Tuesday, October 23, 2012

Fly Cheap (Or At Least Cheaper)


It’s getting tougher to fly cheap, but there are still a few tricks you can use to reduce the cost


I have a friend who owns a 36 Bonanza, and though his airplane has always been a dozen or so knots faster than my LoPresti Mooney, he's consistently envied my airplane's lower fuel burn. At max cruise settings, Bob's A36 will truck along at a comfortable 166 knots, while the best I can do under the same conditions is about 154 knots.

We were trading lies the other day in his hangar in Long Beach, and he was complaining that the recent upswing of fuel prices has driven fuel cost on his Bonanza to nearly $100/hour. Bob makes a good living as a roofing contractor, but even he has difficulty justifying that kind of operating expense.

I hear that a lot these days from pilots across America and around the world. European pilots have been paying $7-8/gallon for years, but they're now feeling the pinch as petrol prices have risen to $10 or more. If you travel overseas in a private aircraft, you'll see fuel prices you won't appreciate.

I'm lucky in that I occasionally get to fly on someone else's nickel. Regardless of who's paying the bill, however, I've developed a few habits designed to minimize the expense. These won't make your airplane fly faster, but the bottom line may be less costly travel. Some of these suggestions are obvious; others are more obscure.

First, I've gotten out of the habit of flying at lower altitude on short trips, say, 75-125 nm. Time was, if I needed to fly from Long Beach to Palm Springs, Santa Barbara or San Diego, I'd level at 5,500-6,500 feet, reasoning that it was just too time consuming to ascend to 9,500-10,500 feet.

Not any more. While it's true there's a point where the extra fuel consumed in climb makes it unwise to fly tall, you can usually offset that with the more efficient burn and better cruise speed on high, not to mention the improved safety margin and ground clearance at two-mile altitudes. Also, remember that higher is usually smoother and cooler for the airplane and passengers. Any airfoil is more efficient in smooth air than in a choppy sky. Similarly, a longer climb usually means a longer descent, and that should partially offset the high climb.

Using my Mooney as an example, I can pick up about four knots of cruise by climbing to 9,500-10,500 feet rather than bouncing along in the low-level chop at 7,500 feet. At 10,500 feet with the ram air door open, the book suggests I can see 145 knots on 70% at 10.1 gph. Down at 7,500 feet, I'm scoring more like 142 knots on the same power at 10.4 gph.

Everyone knows that normally aspirated engines are more efficient at lower power settings, so I've started using 60% most of the time at 10,500 feet. My airplane does slightly better than book because of LoPresti's and Power Flow's modifications, but if I use book numbers, that reduces speed by about eight knots and cuts fuel burn to 9.2 gph, nearly a full gallon less. That's a 5% speed reduction in exchange for a 10% improvement in fuel burn, a pretty fair trade.



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