Not the most fuel-efficient ride.

I had a conversation with a friend of mine the other day about the fuel burn rate and “mileage” of my helicopter. It’s actually an interesting calculation.

First, consider my “best range” cruise speed. According to Robinson Helicopter Company (RHC), the best cruise speed for a Robinson R44 Raven II is 100 knots or 115 miles per hour.

Now consider the fuel burn rate. RHC claims 14 gallons per hour, but I’m getting closer to 16 these days. When you do the math (115 ÷ 16), you come up with 7.19 miles per gallon.

Now that doesn’t sound very good, but there’s another calculation to do to equate this to car miles. That’s the “straight line” factor — as I like to call it. RHC, in its Operating Costs document, estimates that because a helicopter can fly in a straight line and roads over long distances are seldom straight line routes, each air mile is equal to 1.5 road miles. I think this is pretty reasonable as an average. On certain routes, that number would be smaller while on other routes, it would be much larger. So if you do the math (7.19 x 1.5) you come up with 10.79 miles per gallon.

This isn’t much worse than my redneck truck, which gets about 15 mpg.

Of course, 100LL fuel, which the helicopter burns, costs anywhere from $4.50 to $7.00 per gallon. Regular gasoline, which my truck burns, is currently about $3.50 per gallon.

I just flew from Wickenburg, AZ to Seattle, WA by way of the California coast. We covered the estimated 1,500-mile distance in about 13 hours of flight time. I spent over $1,000 on fuel. Not exactly a cheap trip, but with highlights like an overflight of the Golden Gate as the marine layer moved in, it’s one I’ll remember for a long time.