Avgas Alternatives

I blurted out, "Three dollars and eighty-eight cents?!" and my expression must have looked as if a lifetime of cheeseburgers had just found my aorta because she quickly said, "But the pump price is $4.08." As if that was going to make me feel better.

Every six months or so, I make it a point to ask the same psychologically damaging question, and the last number to stick in my mind was something like $2.45. Now, it's nearly a buck and a half higher! Hey, folks, something has to give here. At those rates, every nine hours of flight, I pay more for fuel than I paid for my first airplane when I was in college. Okay, so it wasn't much of an airplane (a not-quite-dead L-3), but what do you expect for $350? When your gas tank holds only 24 gallons, as mine does, it's easy to think that fuel is a minor cost until you multiply the "only 24 gallons" by four bucks and get choked up at the result.

So, what are we going to do about it? Obviously, the oil companies aren't going to take pity on us. That's like expecting the phone company to give you a discount just because they like the way you sound. So, what do we do? I'm all for finding an alternative to avgas.

My first exposure to the now-popular phrase "alternative fuel" was in my grandmother's house on her farm in southeastern Nebraska. It was the early 1950s, and she had this wonderful old cast-iron cook stove that had been converted to burn corncobs. That's right, corncobs, which explained the huge (nearly as big as the house!) pile of cobs outside the door. The old stove gave off a rosy glow and made the kitchen a warm memory from my youth.

So, how about a corncob airplane? Engines run by converting fuel to BTUs, which magically turns a propeller, which, even more magically, gets us off the ground. We can grind up corncobs, maybe let them ferment---no, that's wrong; it's the corn that does the fermenting, isn't it? And then, there's the problem of the huge cob pile. Bad idea.

Okay, how about propane? Some of the buses and government vehicles around here run on it. Let me see, I have 24 gallons of storage, the burn rate for propane is much higher than avgas, and I don't have enough space for a larger tank, so my range may be limited. I crunch a few numbers on the calculator and, voilà, I have the answer: I couldn't stay in the air long enough to fly out of sight!

When your wallet starts squeezing your brain, it sometimes gets a little goofy as you look for ways around costs. The primary requirement for all fuel is that it has to burn and be plentiful. Hey, how about Listerine? Nah, it just feels like it burns. How about vodka? That, we know, burns. Yeah, but even I have enough pride that I wouldn't make my little airplane drink $4-a-gallon vodka, and I'm pretty certain Smirnoff or Stoli won't come down to that level.

Okay, so forget about my airplane. What about a totally different airplane, one with light wing loading and lots of wing area that can get by with less power? Surely someone out there is experimenting with something like that.

The first power source for a super-light airplane that pops to mind is electricity. Huge strides have been made in electric motors---oh, wait, there's the power cord; maybe it would have to be too long. But what about batteries? My Milwaukee hand drill seems to go forever on one charge. How many of those power bricks would it take to drive a motor big enough to get off the ground? Or maybe we should just line the entire belly of the airplane with easily available D cells. I'm certain that we can get a good deal on them from Costco. I do a few more quick calculations, and it looks as if it will take a dump truck-load of D cells to generate any worthwhile power. Back to the corncobs.

Hey, remember those balsa airplanes from our youth, the ones with a stick for a fuselage and a rubber band running down the bottom? They flew like crazy. Maybe we could just scale that up. In fact, I saw an article on someone who's doing exactly that. If I remember correctly, he has a carbon-fiber "motor tube," which is precisely what it sounds like---a long, fuselage-sized tube that has the rubber band in it, and the cockpit, such as it is, is built around that.

Why a motor tube, you may ask? Why not run the rubber band right between the seats and down to the tail? If you asked, then you've obviously never seen a rubber model that's over-wound when the rubber band lets go. I certainly wouldn't want a couple hundred pounds of Pirelli's best flailing around in the cockpit. Besides, picture a Bonanza with a gigantic, knotted rubber band running between the passengers. Our professional image would slip a little in that situation.

I wonder how many rubber bands (or corncobs) it takes to generate 180 hp? My calculator doesn't know how to figure that out.

So, is there an answer for expensive avgas? Not at our level. We're at the mercy of the fuel companies and the world economy in general. The best that we can do is run smaller motors and get really good at leaning our machines. Plus, it should be an absolute rule that we never look at the price on the pump. If we don't know what something costs, it always seems less expensive.

Budd Davisson is an accomplished aviation writer and photographer, CFII & A, aircraft owner and builder. He has authored two books and lectured at the Smithsonian and NASA's Langley Research Center. Check out his Website at www.airbum.com.