But do you believe that the long term replacement for 100LL will be incompatible with today’s engines? I don’t think it will be.
It will have to be, same as with cars. It is technically not possible to replace TEL with something else and retain the characteristics of 100LL. You can get close but not quite there. With such a highly regulated market you cannot just say “oh, it will work fine with all airplanes, no need to test each setup”. TEL is very bad stuff and should disappear altogether, the sooner the better.
Saying that GA is too small to cause any significant lead pollution is like saying that you are going to smoke in the restaurant because you are the only one doing it and it will not significantly pollute the air. I do have a problem with causing 1000x more lead pollution than an average citizen.
If Europe bans it then nothing will happen because the European market is almost irrelevant, and it will just kill much of GA, dumping all the turbocharged aircraft (like yours) onto the scrap heap.
It would finally give a boost to aerodiesel development. Once everybody knows that 100LL engines have no future, it will be an entirely different situation. Manufacturers get the investments, consumers the certainty they’re buying the right technology. There are enough companies in the market (Thielert, Austro, SMA, Conti, …) to make this happen. Nobody doubts that aerodiesels can replace gasoline engines and we need to set the parameters so it will finally happen.
The longer we stay with 100LL, the faster we (as small GA) will die.
It will have to be, same as with cars. It is technically not possible to replace TEL with something else and retain the characteristics of 100LL.
That adage is certainly a bit old school and is not proven.
Quite to the contrary, Swift and GAMI seem to work technically and thus are about to prove the contrary. It might cost double or more per litre than 100LL but that’s another story.
I am convinced that light GA will never be 100% diesels.
What Rutan Pilot said and I repeated was that it will never be the same as 100LL but it can get close. Close enough so there can be a general approval as replacement? I am very sceptical but that is impossible to say today.
I am convinced that light GA will never be 100% diesels.
No but I am convinced our only chance is that we have car fuels for the smaller engines at the typical leisure/sports aviation aerodromes and Jet-A1 at the airports. Airplanes that travel would be diesels and the remainder can run on car fuels. We’re seeing this development today already with gasoline pistons approach resale value zero (the only piston twin selling in quantities is a diesel) and the travelling part of private GA moving to very expensive and rather inefficient small turbines.
There really isn’t any compelling technical reason for running a piston aero engine on gasoline only that most of them do it today.
Well, when we talk about pollution – how about particle filters in Diesel aircraft engines? Lead is only ONE thing and the clean Diesel myth loses credibility rapidly.
There is a reason why lead was outlawed a long time ago, it is a particularly nasty substance. Am I against applying modern exhaust purification technology to aero engines? No, not at all.
PS: Making 100LL disappear would also boost development of other engines, such as fuel cell and battery driven airplanes. Keeping a really bad status quo is what prevents innovation.
There is a reason why lead was outlawed a long time ago, it is a particularly nasty substance
There are loads of nasty substances but that doesn’t mean they should be banned. Why doesn’t the EU ban lead totally. Then we won’t have any car batteries. Will there be replacements, developed immediately, without some massive cost increase? I don’t think so.
Also military and medical got exemptions – as did “internet switching” gear (no kidding) and “control and monitoring equipment” (also not kidding). It’s a farce.
Cadmium plating is still widely used by the military because it is the best.
Action should be based on how much of a problem something is, and piston GA is not a significant environmental problem.
Anyway I am sure cool heads will prevail and nothing will happen until there is a replacement.
I too would like a Jet A1 burning engine but there aren’t any candidates which I would fly behind across any water, the Alps, etc.
because there would be a very small market for incompatible fuel, right?
Yes, unless there is an approved fuel system upgrade path which is easy e.g. replacing o-rings with ones in a different material.
But they have to be accessible. For example there is an o-ring at the top of the TB20 fuel selector. I have had a close look at this (I have a spare fuel selector kicking around, which somebody gave me, from a scrapped TB) and it would take a good number of hours to get to that o-ring. Fortunately it will probably outlast the aircraft… Actually, based on peoples’ experiences with the emergency landing gear valve and its EASA-mandated periodic seal replacement (which is a complete waste of time) I don’t think many maintenance companies can be trusted to replace that seal without damaging something.
There is another big problem which we don’t hear about much: airports don’t want to carry two kinds of piston fuel. Unless the supplier gives you a free bowser (which TOTAL were/are doing) there is simply no point in carrying 91UL. And even then it takes up space, probably needs a risk assessment just to be parked there. One UK airport manager, of a popular GA airport, reported 100LL outselling 91UL by a massive factor; from memory something like 10x to 20×.
Oh boy, I seem to really have stirred the debate. I will stir it a bit more.
Firstly refining. If refining is such a profitable business then why are they shutting down, especially in Europe. We have seven operating refineries in the UK. BP, Shell, Texaco have all sold their assets in the UK to names that you will not know. Total and Murphy would dearly love to dispose of their refinereis bit no-one wants to buy. Petroplus went bust two years ago which shuttered one of the best refining assets in the UK. All over Europe the refiners are clinbging on by their fingernails. Why, because goverments use them as unpaid tax collectors, and the fuels make up only fraction of the cost at the pump. Collecting taxes cost money.
Our refining assets are all dated, designed in the 1960’s to produce gasoline, when the market demands diesel. It is not helped by some seriously flawed EU legislation. Refiners do not want to invest as they do not see a return on their investment. That simple. If you look at all the majors their interest is in finding and extraction oil and gas, not turning it in to fuel. That is where they make their money.
A new world scale refinery will cost in excess of $10 billion to build, and would process 15- 20 million tonnes per year. Who would bother to build such a facility if your GROSS margin was 5%, if you were lucky. $100 bbl oil is about $730 pmt. The gross margin is about $37 pmt if everything goes well. Think of the financing costs and the time value of money. It does not make sense, which is why the Europe in particular has such crappy refining assets.
Continuing with TEL is of course one option. My guess is that if the Avgas market implodes it will start in California. That is where the biggest GA fleet is, and will be the juiciest target for the eco-warriors to attack. I think they are well underway and it would be no surprise if California bans TEL. They did it with MTBE, they could do it to TEL. Then the pressure will really build to find a replacement and fast. If Europe goes first then bad luck.
As someone who has worked in this business for 35 years I have seen quite a few changes. Fuel qualities have improved dramatically and engines have likewise improved. Except of course piston aeroplane engines. I am now going to wind up the Rotax fans, of which I am not one.
I personally do not like engines revving at 5k + rpm and feeding feeding a reduction gearbox to achieve a useable RPM, wankel engines accepted. Aircraft engines cannot be compared with motor engines as the duty is totally different. Cruising is usually done at 65% power whilst is a modern cat it is barely half that amount. One of the biggest problems with high revving piston engines in aircraft is heat rejection, which is why Rotax have water cooled cylinder heads. The heat flux density is much much higher than on say an equivlant Lycoming or Continental.
For me, the ideal aeroplane engine is a diesel running Jet A1. If you consider the duty cycle of a diesel it is very well disposed to operating at high output for long periods. There are some issues with ferocious torsion stresses on the crankshaft but I am sure that with developement they can be managed. Diesels lend themselves to turbocharging and can produce a lot of torque at low RPM. I am not convinced about converting car engines but I am of the opinion that well designed aircraft diesels are a real option. We may not be there yet but each year it gets better. I am not too bothered by exhaust particulates. The reason that these are regulated is due to high concentrations at street level, which is not a problem for aircraft.
Thank you for these insights!
I am of the same opinion, and I can’t wait for a reliable 300 hp Diesel aircraft engine.
I sometimes wonder how well the Diesel from my car would work in an airplane: 3 liter V6, turbocharged, 265 hp and 620 NM at 1600 to 2400 rpm …(mine is actually “only 520 NM”, but this is the newer version).
If 100LL got the axe, we’d see some real adoption of Diesels. Nobody buys diesels because nobody offers them at a competitive price. Nobody offers them at a competitive price, because nobody buys them. Introduce the demise of 100LL and everything will change.
There are good aero diesels up to 230hp today. Nothing really above that just yet but there are no technical reasons for that, just business and it will change eventually. The other issue that we do not have any aero diesels that perform well higher up because turbocharger technology is not good enough. That remains a technical problem to be solved.
620 NM at 1600 to 2400
Well, that is actually part of the problem, it kills the gearbox/prop and at 2400rpm your Mercedes V8 diesel produces less than 50% of its BHP. You wouldn’t force that heavy monster engine into an airframe just to run it at 50% BHP max.
Max. power is at 3800 rpm, (not 4800 as you suggest) but I wonder why it should kill a good gearbox. Shouldn’t that be possible to make?
