Can ethanol be an aviation fuel?

Share

A few months ago I bought an engine for the Cozy that is a 200 HP version of the Lycoming IO-360. This engine produces about 20 HP more the standard 180 HP O-360 engine. In order to get to 200 HP, it has higher compression ratio and that requires the use of 100 octane fuel. Today, 100 octane fuel is available at most U.S. airports, but I worried about its continued availability in the future. Aviation fuel, or 100LL as it’s called, uses tetraethyl lead to increase the octane rating of fuel. Adding lead to auto fuel to enhance its octane used to be quite common but fell out of favor when it was found to distribute the lead, now recognized as a poison, into the atmosphere. Just about all countries in the world have discontinued the use of lead as an octane enhancer for auto fuel.

I began to wonder what I might use for fuel in the future should leaded aviation fuel be outlawed, and my attention turned toward alcohol, ethyl alcohol, to be specific. It’s also called ethanol or grain alcohol and is used as an octane enhancer. It also makes gasoline burn more cleanly. Ethanol is the form of alcohol that you find in alcoholic drinks. Because of this, it is subject to liquor taxes. The only way to avoid paying liquor taxes is to add poison to it. If fuel was drinkable and available for a few dollars per gallon, it’s assumed that no one would bother buying beer, wine, or spirits. With that logic, it’s hard to understand why anyone would buy an 18-year-old bottle of scotch for $75 when Everclear can be had for $10. 🙂 This poisoning is called ‘denaturing’ and as long as it makes the alcohol undrinkable, just about anything can be used.

It’s not unusual for auto fuel in the U.S. to contain 10% alcohol since most cars can run on fuel with this concentration of alcohol. It’s beginning to become available at 85% concentrations, called E85, but that requires that the fuel system is compatible with that level of alcohol concentration. Only a small number of vehicles manufactured over the past 10 years or so claim compatibilty with E85 and you can look up whether yours is compatible by searching for “E85 compatibility” on the Internet. Each year, more vehicles are introduced that will run on E85 or regular gasoline and these are referred to as ‘flexible-fuel’ vehicles. There’s even an effort underway to make an aviation grade ethanol called AGE-85 that is not without controversy.

Back in the 1980s and 1990s when aviation fuel cost about twice as much per gallon as auto fuel, several efforts to qualify auto fuel in aircraft were conducted. They were targeted at older aircraft with low compression engines which were able to run on an aviation fuel called 80LL whose octane rating was close to regular unleaded auto gas. Quite a few aircraft were eligible to burn auto fuel, provided they purchased a placard called an ‘STC’ for about $200. Some airports actually began carrying it as a less expensive alternative to 100LL after 80LL went out of production. However, the tests to get approval for the STC were conducted before alcohol became a common additive to auto fuel. After it became commonplace to use alcohol as an additive, it was found that some aircraft had problems with it attacking the rubber seal materials in the fuel system. The entities that granted the STC, namely Peterson Aviation and the EAA, do not allow the use of auto fuel that contains alcohol. The octane enhancer of choice back in the 1980’s was MTBE, methyl teriary butyl ether, and it had no issues with fuel system compatibility. But it has subsequently fallen out of favor because it has environmental and health concerns. It has largely been replaced by ethanol. Adding ethanol has now become so common with auto fuel, and the difference in price between auto fuel and avgas is not as significant as it was in the 1980s so the popularity of using auto fuel in aircraft is beginning to wane.

The IO-360 engine I mentioned earlier would not be a candidate for an auto fuel STC anyway because the octane rating of auto fuel available in the U.S. runs about 85-91 octane which is much too low and would damage an aircraft engine designed to run on 100 octane fuel. To get a fuel that had an octane rating around 100 would require using some additive. Otherwise, engine knock, also known as auto-ignition, would create multiple flame fronts that collide in the engine’s cylinders, increasing pressures and temperatures that over stress and damage the engine.

It would appear that a solution to my concern would be to make the plane compatible with ethanol because it has an octane rating of 105. I recall seeing a group of experimental aircraft showing up at Oshkosh for many years now that all run on ethanol. They are known as the Vanguard Squadron and are shown in the image above. I tracked down one of their members, Dick Pearson, and he generously allowed me to pick his brain regarding his experience of using ethanol in an airplane. Dick has nearly 14 years of experience of using ethanol in 2 separate experimental aircraft that he flies as well as that of the other 4 aircraft in the Vanguard Squadron. He is quite a proponent of the fuel. He told me that there is a lot of controversy and misinformation floating around regarding ethanol. For example, there is a persistent belief that the energy that it takes to grow corn and convert it into ethanol exceeds the energy content of the resulting ethanol, giving it a negative energy balance. This is not true. The reason that this misconception persists is because natural gas is often used in the conversion process to provide heat for making alcohol from corn. But there’s a good reason for using natural gas for heat. The value of natural gas per BTU is much lower than it is for ethanol per BTU. It’s about a third the cost per BTU as ethanol. So even though one could use a portion of the ethanol to provide heat in the process that makes it, it’s not as economical as using natural gas for heat. It’s this business of using a fuel other than ethanol to help make ethanol that leads people to believe that it has a negative energy balance. It actually has a positive energy balance widely accepted to be around 1.34, or getting a third more energy out of the process than is put into it. That takes into consideration the energy required to fertilize, plant, irrigate, spray, harvest, transport, and convert the corn into alcohol.

Energy balance is only part of the equation, since when you talk about energy you must consider more factors that the energy balance or cost/BTU. It’s also important to consider factors such as energy density, convenience, and fuel compatibility. This is particularly true when it comes to transportation fuels since there is high value to having a fuel that is compatible the existing engines. If energy balance and cost/BTU were the only measures of concern, we might see coal-fueled vehicles since its cost per BTU is about 10% of what we pay for gasoline.

In Brazil where they make alcohol from sugar cane, they are able to burn the waste parts of the sugar cane called bagasse to generate the heat needed for the process. As a result, they get 10 times more energy from the sugar cane than is required to grow and convert the sugar cane to ethanol. This is similar to the energy balance expected with cellulosic alcohol.

A number of companies are working on deriving ethanol from cellulosic plants instead of corn kernels. These materials include waste products such as wood chips, corn and wheat stalks, and other organic waste materials that have limited use today. In most cases, you have to pay someone to dispose of them. The processes that convert cellulose to alcohol are currently not mature enough to be cost competitive with making ethanol from higher-value materials like corn. However, there are a number of companies working to improve the processes and if they become competitive, it could reduce the cost of ethanol to be lower than gasoline in a direct fuel mileage comparison, and when that occurs, it has the potential to change everything.

Some cellulose-to-alcohol processes are based on enzymes that can unlock the sugars in cellulose and convert it into alcohol using conventional fermentation. There is an ethanol plant in Canada already doing this as well as a few more under construction. There is a also a non-fermentation process developed by Range Fuels of Broomfield, Colorado that can convert cellulosic materials to alcohol. Range Fuels is building a cellulose-to-ethanol plant in Georgia that will be capable of producing 100 million gallons of ethanol a year from wood chips. I think this will substantially change the perception that ethanol is nothing but a farm subsidy, which is the view a lot of people have about it today. Can you imagine a lawn service where they reduce the fee if you let them take away the lawn clippings, leaves, and other yard waste? I think that would be a huge step in the direction of energy independence because recovering energy from local waste materials would reduce an energy supply chain that currently extends around the globe to a short loop within your own neighborhood. It would also reduce CO2 emissions because plants generally release their carbon back into the atmosphere in a relatively short time, and so instead of digging up carbon that has been buried for millions of years, we’d be able to use carbon that was essentially on its way back into the atmosphere anyway. [UPDATE 2014-02-26] Range Fuels burned through $234M in capital, about a third of it from taxpayers, before shutting down operations in 2011.

There are a lot of competing and complementary renewable energy technologies under development including wind, solar, and biomass. I don’t think that there will be a single winner in the race to replace our convenient yet exhaustible fossil fuels. I feel a lot more optimistic about it after doing my own investigation of alternatives like ethanol instead of listening to pundits arguing for or against it, because it doesn’t take long for people to get emotional about their point of view when it comes to renewable energy. I guess that’s because mixing politics with science can be such a volatile combination. Now if only that volatility could be converted into usable energy our future would be secure!

Cozy MKIV trailer

Share

A few guys made a 15 minute DVD for Aircraft Spruce, the company that now owns the plans for the Cozy MKIV. I saw the DVD at Oshkosh and it’s amazingly well made with lots of great aerial footage of the Cozy in flight. There is a short (~2.5 minute) downloadable trailer on the Cozy MKIV website of the DVD. You can also see it on YouTube:

Learning to fly

Share

My friend Chris, who is 14 years old, asked me how to get started in aviation. When I was a kid, it was possible to go to any small airport and hang out there and chat with pilots and instructors who often spend their spare time at the FBO. I didn’t know that when I was young or I would have spent time there learning about airplanes and flying. FBO stands for ‘fixed base operator’, and it’s a business that takes care of things at the airport like selling fuel, managing a flight school, and may also have an aircraft repair operation. On larger airports, there may be several FBOs. On really small grass airstrips, you may not find any.

Over the years, security at airports has become a concern, especially if it handles any commercial traffic so they’ve been fenced in. However, it’s still possible to get through the fence, usually by walking through the FBO’s office. Then you can walk out on the ramp looking at the airplanes if it doesn’t look like you’re up to something. You might get chased off, but if you tell them you love airplanes and just want to look around, they usually won’t bother you. Sometimes you can wander over to the hangars and chat with the pilots who like to tinker with airplanes in their spare time. This is especially true with pilots who build and fly experimental airplanes.

I’ve heard stories about kids who paid for flying lessons by exchanging labor washing airplanes for aircraft rental and instructor time, although I’ve never personally met anyone who has done that. The cost of an hour’s plane rental can be as much as $100/hour or more and along with an instructor at another $40/hour, it would take a lot of minimum wage labor to work one’s way through pilot training. I’m not saying it’s impossible, just that it would take a lot of hours. When I was training nearly 20 years ago, the costs were about half of what they are today. Something that doubles in 20 years is increasing at an annual rate of around 3.5%, which the average rate of inflation. So the real cost of learning to fly hasn’t changed in all that time. I think you’ll find that to be the case for as far back as you look when it comes to flying expenses.

If I were to give advice to someone today to minimize the cost of learning to fly, the first thing I’d recommend is to be born into a family that owns an airplane and have a dad who is an enthusiastic flight instructor. Failing that, I’d say to look for a local EAA chapter and find out when they have their meetings and attend one of them to meet some pilots. EAA people are the friendliest in aviation because they typically fly for the love of it and most of them are not rich. If they were rich, they’d probably just buy regular airplanes and not spend so much of their lives working on building them to save money. You can find EAA chapters in every major city in the U.S.

EAA also sponsors a program called Young Eagles where members take kids ages 8-17 up for an introductory ride in an airplane for free. So far, more than 1.2 million Young Eagles have been flown. Each EAA chapter generally sponsors several Young Eagles rallies a year. You can also request a flight on the Young Eagles website.

The minimum number of hours of training required to get a private pilot’s license in the U.S. is 40 hours, half of which must be flown with an instructor. There is no age limit on how early you may start your flight training and logging hours. However, you must be 16 to solo and 17 to receive your pilot certificate.

If you do the calculations using the numbers I mentioned previously, namely $100/hour for aircraft rental and $40/hour for an instructor, you will come up with a minimum cost of around ($100*40) + ($40*20) = $4800 if you were able to finish in the minimum time. There will be other incidental costs too, like the study materials and the check ride fee. However, most people take more than 40 hours to be ready for a check ride. The last time I checked, the average was around 72 hours, so if you multiply $4800 by 72/40, you get about $8600. That’s a lot of money any way you look at it.

A way to reduce this would be to get a Sport Pilot certificate, which was a topic of a previous blog post. That training requires only half the hours that a private pilot certificate requires. The only issue with the Sport Pilot is that it’s so new that Light Sport Aircraft and instructors who understand the rules may be hard to find. Still, it would be worth looking into it.

To get a pilot certificate, you need to pass a written test and a practical (i.e., a flying) test. The preparation for the written test is often called ‘ground school’, because you can learn the material and pass it without every stepping into an airplane. I learned this material at the same time I was learning to fly. In retrospect, I think it would have been more efficient to have done the ground school first and passed the written test before I started flight training. You can do this for next to nothing because all the questions are available on the Internet and there are good study guides available from Jeppesen and Gleim to help you understand the material and test questions. You might also consider a ground school class at a local community college or flight school, especially if you think you’d benefit by having the material presented to you by an instructor.

You can also stop at a flight school and ask for some old sectional maps. The ability to read and understand aviation maps is an important part of learning to fly. So studying aviation maps is time well spent. These maps expire every 6 months. The expired maps are usually available for free from an FBO or a pilot friend.

I’d also spend as much time as possible using a flight simulator such as Microsoft’s Flight Simulator. You don’t need the latest and greatest version. The older versions are available for next to nothing and are very good for training yourself to be familiar with handling an airplane. A flight simulator will familiarize you with the instruments such as the Tachometer, Airspeed Indicator, Altimeter, Directional Gyro, and Artificial Horizon. Being able to hold an altitude and heading are critical piloting skills and with a simulator, it will teach you to scan the instruments to make sure you’re not climbing or descending or veering off course. It will also teach you how to properly trim an airplane which is absolutely vital for holding a heading and altitude.

Having the written test under your belt and a lot of time in a flight simulator could help to prepare you for the practical test in the minimum time, potentially saving thousands of dollars.

That’s probably enough for one posting. I will follow up with some other advice and tips on flight training in another posting…

GA renaissance and Light Sport Aircraft

Share

In looking over my posting of 14 years ago mentioned in my previous blog entry, I don’t find my predictions too embarrassing because most of the things that I cited turned out to have had an important effect on general aviation. The arrival of GPS and moving maps has ushered in the biggest change to the way people fly airplanes, greatly enhancing their convenience and safety. The glass panels I alluded to have also had a major impact on the design of aircraft instrument panels, although with the advent of color LCD displays, we don’t call them CRTs anymore. The DUAT (direct user access terminal) has been enhanced with web-based weather, complete with graphical weather maps. Flight planning is something you do by keying in a few waypoints to your GPS/moving map.

On the other hand, the primary category never took off, with only 2 aircraft ever being approved in that category. However, one can argue its successor, the Light Sport Aircraft initiative, is gaining a lot of traction. The primary category sought to reduce the complexity of getting an aircraft certified by the FAA and would have allowed the owner to perform more of the routine maintenance. Aircraft maintenance is very expensive because shop rates are in typically in excess of $75/hour and you need to have an annual inspection done once per year. The annual inspection typically requires a minimum of 8 hours of labor and could easily escalate into thousands of dollars if something is wrong with the plane or if a new Airworthiness Directive has been issued against the plane or engine.

The Light Sport Aircraft category carries the concept of the primary category further and shares some features with the experimental category when it comes to maintenance. If you take an approved maintenance class, you can get a ‘repairman certificate’ for the airplane which means you can maintain it yourself, similar to an experimental airplane. But, unlike the experimental category, you don’t have to build it yourself, unless you want to, of course. You can purchase it fully assembled and still qualify for the repairman certificate.

Light Sport Aircraft have the following features/restrictions:

  • Maximum gross takeoff weight of 1320 lbs. (or 1430 pounds for seaplanes)
  • Maximum stall speed of 51 mph
  • Maximum speed in level flight at max power of 138 mph.
  • 2-seat maximum
  • fixed landing gear
  • single engine
  • fixed propeller
  • unpressurized cabin
  • The last 3 restrictions aren’t really necessary because the alternatives wouldn’t be practical on an aircraft that met the first 3 restrictions.

    There are a number of ‘old school’ tube and fabric aircraft that meet these conditions such as the venerable Piper Cub and Aeronca Champ. Those are very simple, low and slow flying aircraft, made with 70 year-old technology. There is also a newer category of modern planes designed explicitly for the LSA category with sophisticated technology and modern construction materials. That class of LSA aircraft is the most interesting to me. A few examples include the Evektor SportStar and the Flight Design CTSW. In addition, over the past year, well established, reputable aircraft companies like Cessna, Cirrus, and Van’s Aircraft have all introduced new aircraft targeted specifically at the LSA category.

    In addition to the LSA aircraft, a new type of pilot certificate has become available called the ‘Sport Pilot’ that is a match for these new aircraft. It should be much less expensive to get a Sport Pilot certificate because there is less training required. Only 20 hours of training is required vs. 40 hours for a Private Pilot Certificate. I should mention that the minimum hour requirements are not realistic for everyone so you may need to double them before you’re ready for a check ride with an examiner.

    Here are the privileges/restrictions for the Sport Pilot certificate:

  • Visual Flight Rules (VFR) only (this means no flying inside or on top of clouds)
  • Daytime flying only
  • No flying above 10,000 feet
  • Can carry one passenger
  • Solo flight is restricted to the LSA category of aircraft
  • No flying into controlled airspace unless trained to do so (with a logbook endorsement)
  • No business/commercial flying
  • No periodic medical exam required
  • The last issue is the big one. I’m sure that many pilots would consider restricting their flying to LSA aircraft if they had a medical condition that didn’t hamper their piloting abilities, yet jeopardized their ability to get an FAA medical certificate.

    There are plenty of ways a pilot can lose his medical certificate. For example, my friend takes a sleep medication that is on a list of ‘cannot fly if taking this medication’ because it’s also used to treat people who have seizures. He’s actually safer taking the medication because it makes him feel more rested. Although he has never had any seizures, if he tried to get a medical and reported that he was taking that medication, he would be denied his medical and might never be able to fly again. The Sport Pilot certificate has a kind of catch-22 in that regard. If you’ve ever been denied an FAA medical certificate, you cannot get a Sport Pilot certificate. However, if you simply let your medical certificate lapse when you have a medical condition that could get you denied, then you can automatically become a Sport Pilot.

    Of all the people who start to learn to fly nearly 70% quit, primarily because of the amount of time and money required to get a pilot’s certificate. Of those who do finish, many stop flying for cost reasons since owning or renting aircraft can be quite expensive.

    So perhaps the GA renaissance has merely been delayed, or at least that is my hope. I will revisit this posting in the future and see if the LSA category for aircraft and the sport pilot certificate has reversed the downward trend in the number of people holding pilot certificates. In the 1980s, we had over 800,000 pilots in the U.S. and now it’s just slightly under 600,000. Judging by the age of the average pilot, reversing that trend is going to be quite a challenge but reducing the cost and time to obtain an entry level pilot certificate is a step in the right direction.