Replacement fuel for leaded avgas will have to accommodate the airframe which is more of a problem (and could be more costly) than the engine modifications. Who is going to pay for all the testing in each and every current airframe so as to be able to use an alternate fuel? Seems to me like a lot of planes will be useless/worthless without certified fuel to operate them? Imagine what alcohol will do to a "wet wing" after a few years ?

 

Revolutionary answer-GAMI formulates unleaded piston-engine aircraft fuel

Justin Lofton Staff Writer

Ada — George Braly and Tim Roehl may have solved a problem that’s been plaguing the aircraft industry and the Environmental Protection Agency for years. Braly and Roehl, owners of General Aviation Modifications, Inc. at Ada Municipal Airport, say they have formulated an unleaded piston-engine-aircraft fuel that may revolutionize the industry because it produces the same octane rating as leaded fuel.“We have one of the finest test facilities in the country for being able to evaluate the octane performance of various fuels,” Roehl said.In November 2007, Friends of the Earth — an international network of environmental organizations — petitioned EPA in attempt to get "avgas," a high lead fuel regulated. Roehl said due to a court case with Friends of the Earth the EPA must finally force a removal of lead from avgas.“Having been familiar with a lot of the formulations that have been tried in the past, we decided to formulate our own fuel,” Roehl said. “After about a month of testing, we feel confident that we have, in fact, come up with a fully 100 Motor Octane Number unleaded avgas fuel that meets essentially all of the requirements that avgas will need to meet.” The new fuel is called G100UL. Roehl said they have filed for a patent and have applied for certification with the FAA. He said representatives with the FAA, The Aviation Consumer magazine, and General Aircraft Manufacturers Association have come to Ada to look at the fuel they’ve developed. No ingredients in their formula should drive the cost of avgas up significantly, Roehl said.

“Our goal here is to preserve the opportunity for today’s aircraft engines to not only maintain existing aircraft performance levels but also to be able to raise those performance levels and improve the efficiency of those engines on a new unleaded high-octane fuel,” he said. Roehl said the fuel has been tested in their testing facility, as well as in one of their airplanes. After more testing, he and Braly hope the formula can be licensed to world-wide avgas producers. “We hope this fuel can be adopted as a replacement for 100LL and should serve to help the environment while maintaining the performance of our aircraft today,” Roehl said. “For 15 years since the lead was removed from automobile gas, the EPA has given an extension to the general aviation industry to allow them to continue to try to find some additive to try to replace tetra-ethyl lead which would allow for the removal of lead and yet the retention of the 100 octane rating of the fuel.” Roehl said no substitute could be found that provided the same octane rating. Roehl said there are approximately 200,000 airplanes currently flying in the world with piston aircraft engines—typically smaller single and twin engine airplanes. The standard fuel for these engines is called avgas, also known as 100LL (Low Lead). Roehl said tetra-ethyl lead is a major ingredient in the fuel. “It’s the last remaining leaded fuel allowed by the EPA,” he said. “As airplanes and engines are certified by the FAA (Federal Aviation Administration), the engines’ horsepower and performance is based upon the octane rating of the fuel. If you decrease the octane rating of the fuel, the engines cannot make the rated horsepower and the engines and the airframes in combination can’t perform according to their certification basis.” Roehl said they’ve tested several unleaded fuels others have formulated to try and solve this problem.

 

Embry-Riddle Tests Biofuel For Switch To "Green Fleet"


2/22/10. Mary Grady, Contributing Editor. Embry-Riddle Aeronautical University, which operates the nation's largest fleet of airplanes in a college training program, said on Monday some of those airplanes will soon be burning lead-free renewable fuels produced by Swift Enterprises. "We believe this effort by Embry-Riddle and Swift will guide the way to a large-scale switch by the general aviation industry to alternative fuels," said Richard Anderson, associate professor of aerospace engineering and chief investigator in the research project. Engineers at ERAU's campus in Daytona Beach, Fla., will perform the certification testing needed to enable more than 40 Cessna 172s, nearly half of the university’s fleet of 95 aircraft, to use Swift fuel. Embry-Riddle chose to partner with Swift because the company's non-leaded fuel has passed an FAA detonation test and gets more miles per gallon than current aviation fuel, the university said in a news release. The fuel can be synthesized from sorghum.

Small aircraft, which burn nearly 190 million gallons of aviation fuel a year, contribute 45 percent of the lead emissions in the nation's air, according to the Environmental Protection Agency. Removing lead from airplane fuel has been technically challenging, because lead prevents detonation in airplane engines, according to ERAU's news release. AVweb editorial director Paul Bertorelli recently tested another candidate for the fuel that will replace 100LL, G100UL, under development by General Aviation Modifications, Inc. Click here to read his report and his opinions about the fuel.

 

SwiftFuel powers Seminole at Sun 'n Fun

4/13, Mike Collins, AOPA: A twin-engine Piper Seminole, registered as an experimental aircraft, is burning SwiftFuel during daily demonstration flights at the Sun ’n Fun International Fly-In and Expo. The 100SF fuel, developed by Swift Enterprises Ltd. in West Lafayette, Ind., uses biomass such as sorghum and switch grass—instead of oil—to produce a high-octane fuel the company says could replace leaded avgas in piston-engine airplanes (see “Grass for Gas,” September 2009 AOPA Pilot). Erik Lindbergh, grandson of Charles Lindbergh, is serving as guest pilot on the flights, along with staff from Embry-Riddle Aeronautical University. “The future of general aviation is quickly evolving toward alternative aviation fuels,” Lindbergh said. “I’m delighted to be working with Swift Enterprises and Embry-Riddle to help solve the leaded fuel challenge for general aviation.” SwiftFuel does not use lead, ethanol, toluene, or oxygenates, and produces fewer pollutants than 100LL fuel—while providing 15 percent more volumetric energy, the company said. The fuel does not require any additives or stabilizers, and the company believes it could be “a near drop-in replacement” for today’s 100LL fuel.

Embry-Riddle Aeronautical University plans to phase in lead-free renewable fuel for its training aircraft, the nation’s largest collegiate fleet. Engineers in the Eagle Flight Research Center, a laboratory in the College of Engineering at Embry-Riddle’s Daytona Beach, Fla., campus, will perform the certification testing needed to enable more than 40 Cessna 172s, nearly half of the university’s fleet of 93 aircraft, to use Swift fuel. "Having Embry-Riddle come with us to Sun ‘n Fun, one of the premier airshows in the United States, brings credibility and attention to what we have been doing to ease the pressure general aviation has been under not only to get rid of leaded fuel but also to reduce the need for crude oil in the United States," said Mary Rusek, president of Swift Enterprises.

FAA targets 2015 for unleaded aviation gasoline

4/14 John Croft. CharterX. The US Federal Aviation Administration is planning to spend $10 million over the next five years to develop an unleaded aviation gasoline to replace the 100 octane low-lead (100LL) fuels used in piston-powered aircraft. The effort comes as the US Environmental Protection Agency prepares to issue an advance notice of proposed rulemaking to reduce lead emissions in avgas, the only remaining mobile source of lead in the USA, according the General Aviation Manufacturers Association. Included in the FAA's 2011 budget request, which has not yet been approved by the US Congress, is $2 million in research funding that will include engine ground testing of candidate unleaded fuels at the agency's Atlantic City technical centre. The FAA and industry partners, including GAMA, fuel companies and two universities, will also begin research into ways to modify high performance general aviation engines to run on unleaded fuels. While many smaller engines have been cleared to burn automobile gasoline, higher-performance engines require the tetraethyl-lead additive in 100LL to prevent detonation problems that can lead to engine failure. The FAA's ultimate goal is to develop a replacement fuel that will be transparent to the pilot, in terms of its delivery and use, with equivalent performance to 100LL.

 

EPA to comment on 100LL

4/09, AOPA ePublishing. The Environmental Protection Agency (EPA) is expected to publish an advance notice of proposed rulemaking this month about the environmental impact of leaded avgas. The notice will address a 2006 request by Friends of the Earth (FOE) that the agency propose emissions standards for lead from general aviation aircraft. The EPA will publish information about the use of leaded avgas and its effect on air quality, and will request comments on that information. The GA industry has been actively involved in developing a plan to transition to a new, unleaded avgas for piston-engine airplanes and will continue to work with the EPA on plans that are practical for GA. The FOE petition requested that the EPA find that lead emissions from GA aircraft may reasonably be anticipated to endanger public health and welfare—conditions that make those emissions fall under the Clean Air Act and give the EPA the authority to regulate them—and propose emissions standards under the Clean Air Act. In 2007, the EPA issued a Federal Register notice seeking comment on the FOE's petition. The agency said that it has concerns regarding lead exposure, particularly during childhood, and that leaded avgas is used at almost 20,000 airport facilities in the United States.


Industry groups prepare for unleaded future

4/22, AOPA eBrief. The Environmental Protection Agency has formally begun the regulatory process that may ultimately lead to standards mandating general aviation's transition to unleaded avgas. The EPA issued an advance notice of proposed rulemaking (ANPR), a preliminary step in the process required by the Clean Air Act for the EPA to establish standards for lead emissions from avgas. The ANPR gives the GA community an opportunity to comment regarding the possible new environmental standard and the development of a plan for identifying, evaluating, and ultimately transitioning to an unleaded fuel, several industry groups said in a joint statement April 21.

 

You guys might want to check a thread I started about electric/hybrid aircrafts at the Pprune forum last year. It has some interesting postings.

Here's the link: I can't wait for electric/hybrid aircraft. - PPRuNe Forums

But just in case you might not care to go there, here's my initial posting and some added facts:


And here's a bit more meat:

Food for thought. I'm am absolutely certain that electric is the future for aviation.

 

Thanks for sharing your interest in this topic, I love tech topics also. I keep up on the technical news and occasionally I have thought about including electric topics here as well. They seem to have an application to certain unmanned science and surveillance aircraft and to light sport airplanes, for which they are ideal. The immediate future is in unleaded gas and possibly biofuel. My understanding is the pure electric is ideal for use in light sport airplanes. It's a lot like the choice you have with surface electrics: electric works and works well as long as you stay a limited distance from power. It has numerous positive qualities like reliability, responsiveness, quiet, and so on. But you also have to trade speed for endurance in a severe balance. You can go fast with lots of acceleration, or you get enough endurance to go some fraction of the distance of gas. Therefore it is not mature technology until a better battery is designed. Electric is very good for use in light airplanes for flying without the roar of the engine. Electric powerplants have many other great qualities as you know. The future is bright for electrics, no doubt about that. However, there needs to be a breakthrough in battery technology before they are competitive with combustion.

The hybrid is an attempt to alleviate the battery limitation by letting some gasoline ride along with higher energy density. It's not a bad idea for small airplanes and it certainly could be done, but hybrids will have to go through an enormously expensive development-certification cycle, one the GA consumer cannot support. We first need to solve the unleaded gasoline problem then we can think about other engines. Cheap gasoline motors brought the wonder of flight to the average working person but even without the cost of developing a new powerplant GA airplanes have gone beyond the reach of the average consumer. The light sport airplane is an attempt to remedy this problem. So, while it may be technically possible to engineer a hybrid airplane and we already actually have electric LSAs, the hybrid-electric GA airplane in 4 to 6 seats would almost certainly be a miss owing to cost. Engineers have to look at cost in order to propose a development program. You would have to sell many more airplanes than GA manufactures in a given time to make back the cost for development.

 

Thanks.

It's a topic close to my heart.

You're absolutely right that the technology is all there - all we need now is the energy storage capacity in batteries. As I mentioned, that progress is happening and battery capacity doubles every 5 years. Even being very conservative (not considering the newer patents for nanowire and equivalent high density storage) with the 400Wh/Kg that we have today, it would only be about 20 years until we're in the region 3200Wh/Kg. That's enough to start hammering the nails into the coffin of fossil fuels.

Let me just give you some examples:

Fuel has about the equivalent of 12000-20000Wh/kg in theoretical energy density per litre. But since combustion and turbine engines are so inefficient in turning this into thrust, only about 20-30% get to actually work. That's about 3600-4000Wh/Kg. Electrical however turns about 90% of the power stored into work, so they meet around here in figures.

However, in the meantime and until the power storage has been solved, hybrid is an interesting bridging technology. And in my view the development and certification obstacles should be less stringent than a certification for a new engine. Because, after all, with a hybrid system you have redundancy. If the batteries fail - you power the electric props/fanjets or whatever directly from the APU. Likewise, if the APU fails, you have enough juice in your batteries to make your safe alternative or deviate to another airfield.

 

Just let us know when those batteries can equal the energy of 350,000lbs of JetA1 at the same weight. I suspect that is a very long way off, perhaps never. Using electrical energy to produce high density hydrocarbon liquid fuels is currently both possible and a more likely alternative.

 

In a macro perspective drilling for oil, shipping it across the world on boats, pupming it into refineries and ground transporting it out to aircraft who then turn only 20% of it into actual working power, is just about as inefficient as you can get. The infrastructure for electrics is already there and readily available. What's even better, it's already been paid for.

There's been a lot of talk of electric taking over for the last 100 years and not much has come of it. But i truly believe we've now turned a corner. 1 million sold Priuses and hybrids in every manufacturers pipeline is a sign of that. Just look at the R/C field where electric power has totally trashed all records in both speed and performance. Gas powered doesn't stand a a chance and can't even compete in the same category. Granted, endurance is not what's needed in R/C flying at the moment, but that will come with better capacity.

If it can happen there, it will happen in GA.