I think the diesel like the Delta Hawk is the way to go, and it appears more cost effective over the life of the engine than it's gasoline counterpart.

 

I tend to agree that gasoline should be phased out in favor of diesel engines such as the DeltaHawk. Better aviation diesels are slowly being developed by firms that realize there are efficiency gains to be had through in high-pressure combustion that cannot be had with lower pressures. Perhaps they also want to offer a solution to the issue of oil dependence from natural reserves located in foreign lands which is a big issue to consider. There is also the possibility of an eventual depletion of natural reserves although the latter is not certain. In the meantime there must be a renewable non-leaded gasoline substitute for existing engines when 100LL is banned due to environmental rules. Clean turbo-diesel is a wonderful technology whose time has come in my opinion. The main barriers are high upfront investment figures and the slow sales of engines of this size. Here is a new aviation turbodiesel to add the the list:

500 hp [Raikhlin] diesel tested in Germany

(AOPA ePilot, 11/26, A.K. Marsh) "Raikhlin Aircraft Engine Developments (RED), a new venture founded by Wladimir Raikhlin and his associates, has flown a 500-horsepower diesel engine on a modified Yak 52. The propeller for the water-cooled, twelve-cylinder engine called RED A03 is gear driven. It was built by RED Aircraft GmbH in Adenau, Germany. The engine generates 500 hp for takeoff at 3,900 rpm. The engine weight at the moment is 705 pounds, according to diesel engine consultant Andre Teissier-duCros. The company brochure does not give the weight, marking that specification as “to be announced.” The weight includes two alternators, a starter, an engine/gearbox oil heat exchanger, and a prop governor..."


Thielert [maker of biofuel-compatible GA turbodiesels]: Profitable, Seeking Investors.

(AvWeb, P. Bertorelli, 11/30) "Thielert Aircraft Engines GmbH says it has returned to profitability, improved its engines and is now seeking investors to continue its revival... After its initial reorganization in 2008, Thielert’s attempt to find investors yielded no results because of the global financial crisis. Further, the company’s sales dipped as Diamond Aircraft, the principle civil buyer of its engines, turned to its own engine supplier, Austro, to provide engines for the popular DA42 light twin. Thielert has a significant military market in supplying engine for UAVs... As of last September, said Thielert, 3000 of its engines were operating worldwide, making it the most successful aircraft diesel in history. The lifetime of the Centurion 2.0 engine was recently increased to 1500 hours and clutch and gearbox lifespans were extended to 600 hours. Although the gearbox and clutch lifespans still fall short of what Thielert promised two years after the engine was introduced, the company now claims net operating costs and efficiency are better than ever..."

 

Seems like this topic has slowed back down lately, but here is something.

Committee to advise on avgas transition

(AOPA, 02/04/11) FAA Administrator Randy Babbitt has signed a charter establishing an aviation rulemaking committee (ARC) to advise the agency on the move toward an unleaded fuel.The ARC will be a joint government/industry committee tasked with identifying key issues relating to, and providing recommendations for, the development and deployment of an unleaded avgas. The move comes in response to a request by the General Aviation (GA) Avgas Coalition, which includes AOPA, the American Petroleum Institute (API), the Experimental Aircraft Association (EAA), the General Aviation Manufacturers Association (GAMA), the National Air Transportation Association (NATA), the National Business Aviation Association (NBAA), and the National Petrochemical and Refiners Association (NPRA). “This is a much needed step in the process that will ultimately determine how the aviation industry reaches an unleaded fuel solution,” said Rob Hackman, AOPA vice president of regulatory affairs and liaison to the GA Avgas Coalition. “While the move toward an unleaded aviation fuel has been spurred by an Environmental Protection Agency action, it is the FAA that must approve new fuels, ensuring they provide adequate safety...


Avgas Alternatives

(S.Ells, 2/15/2011, Flying) In April 2010, the Environmental Protection Agency released an announcement that it was proposing to gather data to determine if leaded avgas is an environmental health hazard. The announcement in the form of an advanced notice of proposed rule making (ANPRM) has created reactions that range from a willingness to move forward in the search for the new lead-free avgas to alarm at the idea of government mandated changes and outrage due to what some see as a misguided plan to replace one boutique fuel with another. Regardless, the ANPRM served as a wake-up call to GA that 100LL is on the way out and the aviation community needs to figure out what to do next. Responders to the ANPRM questioned whether the tiny amount of lead in the GA fuel supply, which accounts for one-10th of 1 percent of the transportation fuel used in the country each year, presents a credible threat to health. Some bemoaned that scant attention was being paid to the fact that supplies of ethanol-free premium auto gas — a viable and FAA-approved fuel for more than 150 piston-powered airplane types and approximately 70 percent of the airplanes plying the skies — are rapidly shrinking due to congressional mandates to increase ethanol usage, a state of affairs that actually required more pilots to use 100LL instead of a viable unleaded auto-gas alternative...

A New G.A. Engine From Austro

(AvWeb, 03/03/11, M. Grady) Austro Engine, best known for its work supplying powerplants for Diamond airplanes, announced this week it plans to develop a new 280-hp six-cylinder diesel engine for the general aviation market. Austro will work in partnership with Steyr Motors to develop the engine, based on the Steyr Monoblock Motor M1. That engine features an integral crankcase and cylinder head that has proven robust in marine and special-vehicle applications around the world, according to the company. The new engine is intended to power two Diamond aircraft now in the works: the DA50 Magnum, a single-engine five-seat airplane, and the twin-engine Future Small Aircraft (FSA) intended for personal and utility applications...

 

Diamond getting [Austro] 280-hp jet-fuel engine
New aircraft in the works

(AOPA, 3/04, A. K. Marsh) Two of Austria’s key engine development companies, Austro Engine and Steyr Motors, signed a cooperation agreement to develop a 280-hp, six-cylinder aircraft engine. It will be used on two new Diamond Aircraft airplanes. Austro Engine is developing the engine for the DA50 Magnum (single- engine, five-seat aircraft) and the FSA (Future Small Aircraft) twin-engine private and utility aircraft. Development, certification and production of these programs will take place at Diamond’s Wiener Neustadt facility in Austria...

 

Here's their 250hp 6 cylinder. So, I'm guessing that they hook two of these together in a V-12 for the 500hp version.

http://www.steyr-motors.com/products/images/256.pdf

 

This is what bothers me a lot. Ethanol is completely pointless for cars (worse fuel economy, takes more energy to make than it produces, uses valuable food resources, and drives up the cost/gallon), and now it's hurting the aircraft industry as well.

 

House R&D bill would continue unleaded-fuel research

(AOPA Online, 3/26/11) The House Science, Space, and Technology Committee has sent to the full House a bill containing language to authorize FAA research on an unleaded aviation fuel. The bill reauthorizing FAA research and development calls for continuing R&D activities “into the qualification of an unleaded aviation fuel and safe transition to this fuel for the fleet of piston engine aircraft.” It would require the FAA administrator to develop a plan for carrying out the policy within 120 days of the bill’s passage.


Avgas research funding support urged

(D. Namowitz, AOPA, 5/23) A $2 million FAA budget request for research into an alternative to leaded avgas is an “absolutely critical part of the process” of switching the general aviation fleet to a lead-free fuel. That’s the message leaders of five GA associations sent in a letter urging members of a House committee to support the funding.The May 17 letter from the presidents of the GA associations urged members on the Appropriations Committee’s transportation subcommittee to support the funding proposal in the FAA’s fiscal 2012 budget. The funds would support research on the safety of different avgas formulations and development of airworthiness standards for engine modifications at the FAA’s William J. Hughes Technical Center in New Jersey. “This is an absolutely critical part of the process to identify and transition the general aviation piston fleet to a new unleaded avgas..."

 

Unleaded Swift fuel tested in radial engine

(S. Brown, AOPA, 10/26) An unmodified Pratt & Whitney R-2800 Double Wasp engine running on Swift Enterprises’ high-octane unleaded fuel 100SF showed no signs of knock in an informal round of testing, Purdue Research Park announced Oct. 25. High-powered radial engines, designed to run on 115/145-octane fuel, present a significant challenge to any developer of an unleaded fuel. These engines already must run on reduced power settings on today’s lower-octane 100LL, and losing the knock protection provided by lead could further shrink their operating margins. The testing was part of an effort to prove that the fuel can meet the needs of engines that demand high-octane fuel, like the radial-engine aircraft that play an especially critical role in transporting people and supplies in Alaska—a question that Swift Vice President of Renewable Fuels Jon Ziulkowski said frequently arises during meetings with industry. “Everybody says, ‘Yeah, but will it work in a radial engine?’” he said. Now, the company can say, "Yes," he added. “It turns out it’s at least as good as 100LL."..

 

I've flown the austro diesel quite a bit now, and it is impressive how little fuel they burn, but there is a HUGE problem with diesel...

For every barrel of crude, you can TWICE as much petrol as diesel. And actually, it's supposedly 20g of petrol, 10g of diesel, and 4g of jet-fuel. So while it's nice that diesels are more efficient, the fuel has more energy, and so on, it's always going to be more expensive and you can't run everything on it, far from it...

I remember the article lycoming gave to AOPA about how you really have to use 100 octane leaded fuel, and while some alternatives might work some of the time, you just can't get these fuels certified and have them run nicely with all the engines. When you read the article harder, it just seems like it's lycomings 1920s technology that's really holding them back. We really need to see some better engine designs, smaller displacement turbo engines. Auto engines have improved dramatically IMO, to the point where it just makes aviation technology laughable.

100, 110, 115 octane...seriously? This is why the diesel engines are a huge step forward. They are simply new technology. Something designed IAC with modern engines, high pressure fuel rails for atomization, direct injection, etc.

Lycoming and others need to invest in new technology. Of course, the problem is "it won't fit into a bonanza/cirrus" and all that, but seriously, something has to change.

I've always thought we have a unique nich with aviation, as there seems to be a whole lot more planes still in the air from 50 years ago compared to cars on the road from 50 years ago. At some point someone has to pay the price to keep an airplane going (you could easily argue that they already do, many times over). No one likes the idea of replacing an engine, but I think that's just what's needed; suitable replacements that can burn regular automotive fuel. Think about how much we pay for avgas in the first place, $5/gal, 6, how much more? 2000hr tbo x 8gph average x 5.5$/gal=$88,000 2000 x 7(more efficient engine) x 3.5=49000, that's a $39,000 difference...that's huge. I just don't see any viable solution that can be mass produced for a reasonable amount of money that will meet the needs of these outdated (but still perfectly functional) engines.

At the very least, we need to seriously consider significant modifications IMO.

 

You know that diesel and jet fuel aren't that far apart, right? If there were no demand for petrol (gasoline), then they wouldn't make it.

I'm not sure what you're proposing, but there are bunches of planes using dinosaur Lycoming and Continental engines, that are burning regular car gas. I was burning car gas (with a legal STC) in my 1974 Cessna 172M with Lycoming O-320-E2D over 20 years ago. Nothing new.

Higher compression and turbocharged engines need more octane. That's just a fact. Any fuel that replaces what those engines were certified for would require modifications or power reductions, or both.

My utopia would be all airplanes would burn one fuel; jet A / diesel. Then, when jet fuel replacements become price acceptable (or we run out of cheap oil), then all planes would switch over to that synthetic oil replacement.



Figures are based on 1995 average yields for U.S. refineries. One barrel contains 42 gallons of crude oil. The total volume of products made is 2.2 gallons greater than the original 42 gallons of crude oil. This represents "processing gain."