a64pilot wrote: I'm pretty sure 100LL is actually refined "illegally" as there is a law banning the refinement of leaded motor fuel, but it obviously isn't enforced. As I understand it Avgas wasn't considered back when the law was passed, I guess it would have been in the late 70's or early 80's.

As I understand it, AvGas is refined straight from the crude and alkylated to achieve the desired stabillity, high octane, and low sulfur. From there it can either become auto gas or avgas. To make avgas, they just blend it with toluene and other additives. I don't think this blending qualifies as refinement, which involved further vaporization.

1SeventyZ wrote:

a64pilot wrote: I'm pretty sure 100LL is actually refined "illegally" as there is a law banning the refinement of leaded motor fuel, but it obviously isn't enforced. As I understand it Avgas wasn't considered back when the law was passed, I guess it would have been in the late 70's or early 80's.

As I understand it, AvGas is refined straight from the crude and alkylated to achieve the desired stabillity, high octane, and low sulfur. From there it can either become auto gas or avgas. To make avgas, they just blend it with toluene and other additives. I don't think this blending qualifies as refinement, which involved further vaporization.

OK, I'm pretty sure Avgas is being blended illegally as it is a motor fuel containing lead

maules.com wrote:The M9 with Lycomings is months close, I have deposits in hand from buyers willing to wait. The SMA 305 diesel being introduced by Maule and SMA is aimed at close to Sun n Fun dates and I hold deposit here too.
SMA is a division of Sagem of the large European consortium SAFRAN, much like Lycoming is to Textron.
The SMA 305 is already flying in 17 older C182s, the Trinidad by Aerospatial, the Partenavia, testing being done in Piper 235s. It burns JetA and JetA1 which is available anywhere turbines, jets, and helicopters go. I did'nt count the 585 parts, that was SMA's claim. I suppose if each and every screw, washer, wire crimp fitting etc were added it is possible.
Jeremy

Jeremy,
I'm not beating on them. Just the other day a little bird blew through the plant and when I asked he told me that they had a conforming wing on the M9. (We share the same ACO of course)That wasn't a month ago. I think that was the biggest hurdle. Now of course comes the test plan, company tests and certification flight tests, usually done by a DER of course, but now it's a matter of making the paperwork stack up until the FAA is happy. The M9 will happen, but certifying an airplane is like eating an elephant. It's not done all at once.
I would be astonished if they had the assets to even start on the Diesel until after the M9 was wrapped up. It'll happen, and I would like to see the Diesel certified by Sun-N-Fun, but I'll bet lunch it won't be. For a little family owned and run business, they are performing miracles, certifying aircraft as fast or faster than the giants with deep pockets like Cessna and Cirrus. My hat is off to them.

a64pilot wrote: OK, I'm pretty sure Avgas is being blended illegally as it is a motor fuel containing lead

I found this on the EPA website. This is an interesting topic, because I looked into it a few months ago while arguing with a guy on another forum about the percentage of lead contamination in the environment that GA is responsible for.

From: http://www.epa.gov/EPA-AIR/1996/February/Day-02/pr-1326.html

February 2, 1996

40 CFR Part 80 wrote:C. Availability of Gasoline Containing Lead or Lead Additives for Uses Other Than as Motor Vehicle Fuel

Section 211(n) bans the use of gasoline containing lead or lead additives for use as a motor vehicle fuel but does not restrict other potential uses of gasoline containing lead or lead additives. The definition of motor vehicle is limited to self-propelled vehicles designed for transporting persons or property on a street or highway. 42 U.S.C. 7550(2). The regulations of 40 CFR Part 80, which are amended by this rule, apply only to fuel that is sold for use in motor vehicles. See 40 CFR 80.2(c). The petroleum industry may continue to make and market gasoline produced with lead additives for all remaining uses, including use as fuel in aircraft, racing cars, and nonroad engines such as farm equipment engines and marine engines, to the extent otherwise allowed by law.

Is there newer legislation that I'm missing?

No,
Older apparently http://www.epa.gov/history/topics/lead/02.htm
It had been allowed on the sly so to speak apparently until what you qoute in 96? I may be wrong here, but what you qoute I think is a ruling, which I think does not necessarily mean the law has been changed. But hey, I'm way outta my league here with legal stuff.
I had been told that Avgas is being made technically against the law, but as there was no viable alternative and it is such a tiny fraction of fuel, the EPA was essentially ignoring it, but the law had not been changed to allow it. They had chosen to allow it without going to the bother of changing the law that forbids it. Being the paranoid type that if true worries me.
on edit: Your link is CFR and in the federal register, that makes it law doesn't it?

Bump for a video about the Centurion 2 motor. ^^

The early Thielerts have, as a64 noted, a time between replacement. They cannot be practically overhauled, according to their literature. They are based on Mercedes automobile engines. I suspect they are working to resolve that issue at present, and maybe the higher hp newer model will have it resolved.

I believe the Thielert is certified for Jet A.

MTV

My understanding is that Chevron will be the only company that will be certified to make avgas in the future.

Great give a huge company like that a monopoly, Great damn idea.

I've got stock, sounds good to me .

Sorry, couldn't resist.

And, by the way, Tesoro still blends avgas in Alaska. Chevron ships it to AK as well.

MTV

This didn't exactly pan out, as Thielert folded. Bummer.

Avweb.com wrote:Thielert Aircraft Engines has thrown in the towel after its share prices dropped to near penny stock levels as the crisis over its financial reporting practices deepens. Thielert filed for insolvency on Friday as its share price dipped to .35 Euros. It's traded as high as 25.22 since it went public in 2005. The very existence of the company is now in question as the insolvency process begins. "The going concern of Thielert Aircraft Engines GmbH can only be ensured permanently by restructuring activities with the support of investors, due to the fact that the Holding Thielert AG is not capable to do so anymore," the company's supervisory board said in a statement.

Meanwhile a new executive board must be named, along with an interim insolvency trustee who will present a plan to creditors, and the acceptance of this plan is crucial to the business continuing. On Thursday, the board dismissed company founder Frank Thielert and Chief Financial Officer Roswitha Grosser after receiving results of preliminary criminal investigations into their activities. The situation has major implications for aircraft companies like Diamond and Cessna, which manufacture aircraft with Thielert diesels. "We are in touch with the senior leaders there and we continue to assess the situation as it unfolds," Cessna's Doug Oliver told AVweb.

Cessna Puts Diesel Airplanes on Hold


Last Updated (Thursday, 15 May 2008 05:32) Written by Administrator
Monday, 12 May 2008 06:01

Cessna will not deliver its diesel powered C172TD airplanes for now. The decision is a result of the recent bankruptcy of German-based Thilert Aircraft Engines, who builds the airplane's power plant.

“At this point we have decided that we will not deliver 172TD aircraft during 2008, and we have informed our customers accordingly,” the Aircraft Owners and Pilot Association's Web site, AOPA.org, quotes a Cessna spokesman. More

What's the deal calling a diesel powered 172 a 172TD, a 172TD is a 172 taildragger period....

First off the engine has to be a 2 stroke to be at the proper weight. Because it is a 2 stroke and air has to be provided to the engine for start. The supercharger is gear driven so it provides air when the prop turns. Turbochargers are powered from the exhaust. If the engine isn't running the turbo does't work. So to work on a 2 stroke diesel you need both.
The reason fhe germans are in a bad way is because the attorneys want more money. Cessna's diesel would have been built by these folks. I wonder why Cessna said take a hike. The French have a nice diesel though.
For fuel what would be nicer than seperating hydrogen from the oxygen in water on DEMAND and use a form of plant oil for the base fuel. I have dyno run this in a diesel decades ago.
By the way the emissions are nothing but water vapor and a very small amount of CO from the plant oil base fuel. Hydrogen is 119.5 octane so I think it is high enough.
As a by product this engine will not require the replacement of spark plugs or mags.

I might be wrong, but I don't think they are two strokes like a Detroit. I didn't notice any blower, but the turbo is hard to miss.

leeschaumberg wrote: For fuel what would be nicer than seperating hydrogen from the oxygen in water on DEMAND and use a form of plant oil for the base fuel. I have dyno run this in a diesel decades ago.
By the way the emissions are nothing but water vapor and a very small amount of CO from the plant oil base fuel. Hydrogen is 119.5 octane so I think it is high enough.
As a by product this engine will not require the replacement of spark plugs or mags.

Part of the problem is power density. Gasoline is hard to beat in that regard. Hydrogen, on the other hand, is problematic for cars and certainly for aircraft, both in getting enough compressed hydrogen on board for adequate range and then worrying about all that high pressure gas in an accident.

Hello
The following is a response to the two previous posts.

s64pilot
If you use a search engine and look for 2 stroke engine some of the responses will show you what a 2 stroke is and search diesel aircraft engines you will find them all. I use MSN for a search engine.

bumper
What you don't want on an aircraft is a compressed gas that burns. That's why I said (AS REQUIRED). The Isreali's use to have a web site detailing the seperation of hydrogen from oxygen. It requires a temp of 680 deg f, and zinc.

Posted 17:15 on 08-02-08

From wikipedia,
"The first manufacturer to produce a certified design for the general aviation market is 'Thielert GmbH', located at the small town of Lichtenstein, eastern Germany (not to be confused with the principality of Liechtenstein, between Switzerland and Austria). They produce four-stroke, liquid-cooled, geared, turbo-diesel aircraft engines based on Mercedes automotive designs which will run on both Diesel and Jet Aviation fuel (JetA1). Their first engine, A 1.7 litre, 135 hp four-cylinder (based on the 1.7 turbo diesel Mercedes A-class power unit) was first certified in 2002. It is certified for retrofit to Cessna 172s and Piper Cherokees which were originally equipped with the 160-hp Lycoming O-320 Avgas (petrol) engine. Although the weight of the 135 hp Thielert Centurion 1.7 at around 136 kg, is similar to that of the 160 hp Lycoming O-320, its displacement is less than a third of that of the Lycoming. It however achieves maximum power at 2300 prop rpm (3900 crank rpm) as opposed to 2700 for the petrol Lycoming."

There are apparently two stroke aircraft diesels, but I haven't seen one. IF they are like a Detroit diesel, then they have to have a positive displacement supercharger or they won't work. A detroit has an exhaust valve, but intake ports like a normal 2 stroke. Interesting, but as you see they are not ALL two strokes.
Yes, we are a tough crowd but welcome

leeschaumberg wrote:Hello

bumper
What you don't want on an aircraft is a compressed gas that burns. That's why I said (AS REQUIRED). The Isreali's use to have a web site detailing the seperation of hydrogen from oxygen. It requires a temp of 680 deg f, and zinc.

Posted 17:15 on 08-02-08

Lee,

I posted the comment about power density, as I mistakenly thought you were referring to the use of compressed hydrogen.

The most common way to obtain hydrogen is, as you are aware, through electrolysis (passing electricity through water to break the molecules apart). This process uses more energy in supplying the electricity than can be obtained from using the hydrogen, thus obtained, as fuel. That old rule we all learned in chemistry 101 that energy can neither be destroyed nor created. You can convert it from one form to another though.

So, any successful method of obtaining the hydrogen, through a chemical process and heat (as has been done in the lab) or whatever, will still require the use of energy to obtain the hydrogen - - there's no free ride. Not saying it can't be done, I believe it can be. Just maybe not practically just yet or in the near future.

Guten Tag Herr Bumper
Translated that means - Good Day Mr Bumper
Sorry if I am so far into things I assume every has seen what I have seen. But I'm a rotten sales man. The Cessna Skyhawk is the most popular single engine aircraft in the world. 43,000 have been delivered. Before Thielert went bankrupt the 172TD was going to be sold in late 2008. Evey body talks about being turbocharged but not the basics (supercharger). Two stroke gasoline engines (your Chainsaw) use the crankcase to blow air into the cylinder for starting and combustion. The diesel can not do this because the crank case has lubricating oil in it. So some thing else has to compress the air to start the engine. If the engine is in good condition only 1 to 2 revs are required to start. Diesels require a high quality lubricating oil. When the ambient air temp is above 60 deg f there is no problem. Here the low temp was 52 deg f last night. The temp is because of Global Warming! So here it is too cold for a diesel. The french company (SMA) has built a diesel and in the process of certifying and selling a diesel 172. A local company Delta Hawk - Racine Wisconsin builds one too. Diesels have very good fuel economy (a bsfc of about .390). Diesel fuel weighs more than gasoline and has more btus in it. So the fuel tanks now hold more.
So now we'll talk about fuels.
The most common way that hydrogen has been seperated from oxygen has been done for many thousands of years by mother nature. But she uses millions of volts in lightning. That is why we have 20.9% oxygen in our air. But people couldn't sell this so they found a hydrogen bearing material that they could sell. To store hydrogen requires high pressure so no storing. This fuel is a gas so a gaseous fuel carburetor is required. Folks on the west coast have been making and selling these for many decades. What we DON'T want on an airplane is high voltage. So not wanting to to zap things the Isrelis have a method using 680 deg f and pure zinc. Diesels require a fuel to start and idle on. This fuel can be a plant oil. After start up and the increase of temperature the engine can rev to the no load speed of the mid 2000s. When a gaseous fuel is added the engine tries to run faster. A constant speed prop and govenor prevents this. A one lever control makes the airplane take off and go fast. Hydrogen is very light so venting up and away is all that is required for the excess.

Once the diesel is certified for the 172 it should be relatively easy, from a legal standpoint, to do a one-time STC on other certified airplanes.....BUT, can you IMAGINE what that package would cost (if you could even buy one)????????? Holy Moley!!!!!!!! I'd estimate in the $60k range for engine, prop, and controls based on the premium they're charging for the diesel. I'd speculate the cost of repair/replacement parts will be in the realm that causes even the ocassional millionaire to whimper as well. Then you have the disadvantage that almost no AP/IA in the United States is familiar with these TDs, so "Hello Mr. Bigbucks FBO" for every single minor glitch that comes up.

So even though there is a lot to consider and I do think the technology might be moving in the right direction....Unless it affects our avgas supply adversely somehow, the whole thing is a moot point and non-event for many of us who don't stand a chance in our lifetimes of coming up with the buy-in on these hightech oil burners.