eric_marsh

eric_marsh

Well Known Member
I'm very early on in my RV-6 project. I've been thinking about fuel and oiling issues for aerobatic flight and that led me to considerations of fuel injection. That in turn led me back to thinking about using EFI.

I realize that there are fewer benefits to EFI in engines that more or less maintain a constant load than there are in automotive engines. But there are still benefits along with negatives.

From this point forward please think of this as a though experiment.

I'd like an 0-360 but have not yet purchased an engine so that choice is still open.

Taking the EFI question one step further, I got to thinking about how nice a closed loop system with o2 sensors would be. With the fuel air ratio tied into the throttle the system could do most leaning and adjustment for air density automatically. Carb icing would not be an issue and each cylinder would always have the correct fuel/air ratio. Because carb icing isn't a problem there is no need to run the intake through the sump, creating a cooler charge and more power. Easier starting is another benefit.

My Hayabusa's injectors provide enough fuel flow for 250+ horsepower - easily enough for a 180 horsepower engine. I suspect that it would be relatively inexpensive and not too tough to adapt a motorcycle EFI system to an aircraft engine.

The most significant downside I see to EFI is that it REQUIRES 12v. Consequently it's dependent on having an alternator/generator that is working.

I've got a couple ideas on that. One is simply a backup alternator. Another one that I think is interesting would be to also have a carburetor on the engine. EFI still needs throttle bodies so why not use a large carb to do the job. Set up a fuel shutoff to the carb so that it simply acts like a throttle body but in the event that the EFI system fails the carb can be fed fuel and act as a backup system.

Of course 02 sensors require unleaded gas. That brings me to my next thought - mogas - with ethanol.

We will probably be seeing the mandated use of unleaded at some point. It seems to me that since I'm building an airplane now is a good time to look forward to that eventuality.

These are hot subjects - so much so that I've not yet reviewed all the posts. I'm going to continue to do so as time permits.

Having said that, I'd like to focus on four subtopics.

1> Availability of mogas at airports.

I'm not seeing mogas at the small regional airports that I've frequented. Is this an issue?

2> The effects of 10% ethanol on aluminum

Most fuel system components can be upgraded for alcohol without difficulty. The two components that I'm thinking of are the tank and fuel lines.

If necessary the fuel lines can be replaced with steel. It would add a couple pounds to the airplane but it that's the safest solution then so be it.

The tanks are another story. I just don't know if it is likely to be a problem or not. If it is, I have to wonder if the inside of the tanks can be coated with an alcohol tolerant material.

3> The need for lead to lubricate valve faces and seats.

This is a subject I've not seen discussed much. I worked in an automotive machine shop back in the seventies when lead was removed from automotive fuels. As a result of this I saw a lot of hammered out valve seats and valve faces. The manufactures started flame hardening the valve seats to counter this tendency but the best (and most expensive) solution was to put in stellite or hardened seats.

I'm wondering if this would be an issue with aircraft engines. On one hand they are designed for leaded fuel use. On the other, they use seat inserts and one would think that they are using good materials. So this is a big question in my mind.

4> Long term fuel storage

There's not much that can be done about this except draining the tanks or using a fuel stabilizer and testing carefully.

I'm a long way from installing an engine but since I am about to start on the wings this seems like a good time to consider issues relating to the fueling system.

Thoughts? Ideas?
 
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Eric, I can't comment on the effects of ethanol on aluminum, but needless to say the technology to prevent other materials in fuel systems from dissolving in the stuff exists. Witness the bazillion late model cars on the road that are designed to operate with the stuff (not to mention my BMW R1100S, but that's another story).

My Superior IO-360 was delivered to me 3 years ago, rated for unleaded gas, so there again, the parts already exist to deal with that.

As for EFI, are you aware of www.flyefi.com?

Actually, now that I think about it, the fuel tank on my BMW is welded aluminum. Apparently there are issues with ethanol and aluminum, but so far my fuel tank is holding up (2002 model). But that's not 2024 (which isn't a weldable alloy) and there's no proseal in it.
 
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Eric,

EFI has been done as a retrofit to Lycomings. Several years ago someone had adapted an entire GM based EFI to an O-320. I don't remember many of the particulars about it, but I think it ran open loop.

I have also thought this could be beneficial, but as you point out, there are several single point failures in the system. To combat this, how about using a standard carb as the throttle body? Add a TPS to the carb and run it in "EFI mode" with the mixture pulled out - then it is only acting as a throttle valve. If the electrics die, just push the mixture in and you are simply flying a conventional "dumb" carb again.

With an EFI system you still need a throttle body - why not hang a float bowl on it and use that for backup?
 
ethanol and aluminum

I cant speak for aviation, but in automotive use, we havent seen any problems using aluminum with ethanol. BUT, I would recommend that you use a teflon hose, and not a 601/701 hose, We have seen failures with that type of liner. If you have any issues using aluminum, then stainless would work very well, but with a weight penalty,
Tom
 
What about water precipitation in the tanks, which, iirc, was always the achilles heel of alcohol of any sort in aviation fuel?

Warm fuel on the ground absorbs water. You climb to a nice, chilly altitude, and it begins "raining" inside your fuel tank. At least that's the theory, again iirc.
 
Toobuilder said:
Eric,

I have also thought this could be beneficial, but as you point out, there are several single point failures in the system. To combat this, how about using a standard carb as the throttle body? Add a TPS to the carb and run it in "EFI mode" with the mixture pulled out - then it is only acting as a throttle valve. If the electrics die, just push the mixture in and you are simply flying a conventional "dumb" carb again.

With an EFI system you still need a throttle body - why not hang a float bowl on it and use that for backup?
Click to expand...

Michael, what you suggested about the carb is exactly what I was thinking. I guess I didn't articulate it clearly enough. It seems to me to just make sense.
 
delusional said:
What about water precipitation in the tanks, which, iirc, was always the achilles heel of alcohol of any sort in aviation fuel?

Warm fuel on the ground absorbs water. You climb to a nice, chilly altitude, and it begins "raining" inside your fuel tank. At least that's the theory, again iirc.
Click to expand...

I'd wondered why water was an issue since I knew alcohol absorbs it. I did not know that at cold temperatures they separate again. That's something to look in to further.
 
I believe several people have anodized tank parts that are in contact with ethanol fuel. it is supposed to offer higher resistance to corrosion.
 
A desiccant air dryer would go a long ways towards keeping the fuel from absorbing moisture in the first place. I use one to keep moisture out of the isocyanate drum with my spray equipment. I don't know how often it would need to be changed and perhaps more importantly it would be necessary to devise a way to prevent fuel from backing up into the air dryer if it overflows.
 
eric_marsh said:
A desiccant air dryer would go a long ways towards keeping the fuel from absorbing moisture in the first place. I use one to keep moisture out of the isocyanate drum with my spray equipment. I don't know how often it would need to be changed and perhaps more importantly it would be necessary to devise a way to prevent fuel from backing up into the air dryer if it overflows.
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Maybe there could be some sensor which could detect dissolved water in the fuel. If it were integral to the level sensors or flow sensor, that would be convenient. Then it's just a run-up item to check it.

Alternatively, possibly some type of optical sensor could detect the actual onset of preciptitation. Late in the game, I know, but at least then you could seek a warmer level, like on a runway for example...

Wait, I know, how about one of those cheapo cameras _inside_ your fuel tank so you could "see" water. I guess there might be a few complications with that...
 
and then there's...

http://www.rotaryaviation.com/eficont.html
(read carefully; also works on Lycs)
This one has redundant controllers; only the crank angle sensor is common.
and
http://www.sdsefi.com/aircraft.html

There are lots of options for redundant electrical power; that shouldn't be a show stopper. If you're serious about it, it would be worthwhile to start monitoring some auto conversion lists for ideas.

Charlie
 
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The FlyEFI stuff is based on our SDS ECU and automotive type fuel hardware which is well flight proven now with over 70,000 flight hours in the last 16 years and the Super Sport Gold class win at Reno this year.

Robert Paisley has done all the hard work mounting injector bosses to induction tubes etc. and made it more of a bolt on.

We have a number of people running 10% ethanol in their aircraft with no issues. I think the water thing is all theory. Unless you had an awful lot of water get into the fuel somehow, it just stays in suspension with the ethanol. Even then, with EFI, the high return volumes keeps it all mixed up and it just goes through the engine anyway. This is the main reason we don't recommend gascolators.

You'd be running in open loop in an aircraft. Closed loop targets stoichiometric which results in peak EGTs which is not good.
 
The water will stay in suspension in the alchohol to very low temps, much lower than 99.9% will ever see. The number is somewhere in the -40 range, if I remember correctly. Lots of info on the subject if you search some.

The long term storage properties of car gas will give you the most headaches, with or without ethanol. The gas these days just does not have a decent storage life.
 
rv6ejguy said:
You'd be running in open loop in an aircraft. Closed loop targets stoichiometric which results in peak EGTs which is not good.
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Could you run an automotive wideband oxygen sensor in place of a narrowband, for AFR targeting?

I was wondering if you'd tried this already. I've read that the cheaper wideband sensors (Bosch, NTK) have results that vary with air density (altitude). Never flown with EFI myself, but I have done a *lot* of EFI installation and tuning in the racing world,

-Scott
 
We did develop some software to target AFRs at various load ranges when coupled to a WB sensor. Worked very well in flight testing but you rely on the O2 which can suffer the unfriendly effects of lead in 100LL. Then you write more software to detect an O2 failure either partial or total... then. Well you get it. Maybe would not work so well in extended use and guess who gets blamed when the engine melts down due to a bad sensor.

So we operate in open loop.
 
Data from the field

I been running E10 for about 450 hours, both VFR and IFR up to about 15.5k in the dead of Winter (not IMC in the case obviosly).

I have never seen any ill effects of water in the fuel. Now part of that maybe due to the fact the 360 is injected...i.e the surface tension of water in a carb can physically prevent the flow of fuel.

With FI this can't happen as it will always be pumped into the combustion chambers.

I have not seen even a hint of corrosion on anything..My conclusion..E10 works perfectly well. it costs more to run because its basically watered down gas but a heck of a lot cheaper than 100LL.

Now as to wide band O2 sensors all such..well the question is "what exactly IS the correct mixture?

Unless you want to have an automatic way of switching between full power, rich of peak cruise, lean of peak cruise..Well then sorry to be blunt but an airplane engine simply does not need that level of complexity...You only need 3 operating modes and all are easily acheived by the corect use of the mixture control.

Heres my personal flight regime..I take off full rich at sea level...in the climb lean for ROP climb, at altutude haul back on the mixture till the engine almost quits and then just get it to run smooth. because I know I am at least 50F LOP at that point, well thats all I need.

Anything more is layers of unecessary complexity..and each layer of complexity is a potential failure point.

Disclaimer..I don't have a mechanical fuel pump and all the fuel system components are ethanol proof.

Cheers

Frank
 
We have never seen corrosion or water problems either with E10 so I think with fuel injection at least, this is a non-issue.

As far as WB O2 sensors go, we use these to tune the ECU. This is necessary because EFI is not like mechanical FI where the engineering has been done to match the servo characteristics with a particular engine.

Programming is usually done to default full throttle mixture to best power (around 12.5 to 13 to 1 AFR). We don't like to guess at AFRs by judging how rough the engine runs or even EGTs as often no previous EGT data exists. The point of EFI is optimize fuel flow in all areas of engine operation, not too rich or lean. We may automatically lean through the ECU with MAP and rpm or may set it up to manually lean in cruise via AFR or EGT,

For race aircraft running leaded fuel, EGTs are used mainly to tune the ECU as lead adversely affects the sensors over time.
 
frankh said:
I been running E10 for about 450 hours, both VFR and IFR up to about 15.5k in the dead of Winter (not IMC in the case obviosly).

I have never seen any ill effects of water in the fuel. Now part of that maybe due to the fact the 360 is injected...i.e the surface tension of water in a carb can physically prevent the flow of fuel.

With FI this can't happen as it will always be pumped into the combustion chambers.

I have not seen even a hint of corrosion on anything..My conclusion..E10 works perfectly well. it costs more to run because its basically watered down gas but a heck of a lot cheaper than 100LL.

Now as to wide band O2 sensors all such..well the question is "what exactly IS the correct mixture?

Unless you want to have an automatic way of switching between full power, rich of peak cruise, lean of peak cruise..Well then sorry to be blunt but an airplane engine simply does not need that level of complexity...You only need 3 operating modes and all are easily acheived by the corect use of the mixture control.

Heres my personal flight regime..I take off full rich at sea level...in the climb lean for ROP climb, at altutude haul back on the mixture till the engine almost quits and then just get it to run smooth. because I know I am at least 50F LOP at that point, well thats all I need.

Anything more is layers of unecessary complexity..and each layer of complexity is a potential failure point.

Disclaimer..I don't have a mechanical fuel pump and all the fuel system components are ethanol proof.

Cheers

Frank
Click to expand...

And the Lycoming engine pump definitely is not compatible with ethanol.

ACDeltco sure could make the pump impervious to ethanol, they build millions of fuel pumps for autos, but to the best of my knowledge they do not.
 
lancef53 said:
The water will stay in suspension in the alchohol to very low temps, much lower than 99.9% will ever see. The number is somewhere in the -40 range, if I remember correctly. Lots of info on the subject if you search some...
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Tried that, and found some mention for marine applications and this incident report http://www.eaa.org/lightplaneworld/articles/0912_autofuel.asp

Can you point us to something more definitive?

Minus 40 is not out of the realm, at least here in the northeast in winter at 10,000. Indeed, -30f at the surface is not unheard of though I don't plan any flights in such conditions I confess.
 
On the issue of EFI, I have no doubt that there is some potential there. However, the big benefit of involving a computer is allowing the thing to make automatic, predetermined adjustments, or decisions for you. This is in the algorithms and subsequest programming. The requirements for an airplane engine are so different from an automotive engine, that I am convinced that adaptation of an automotive computer is not practical, or has very limited benefit, or both. A Megasquirt could probably be used, but it would be a lot of development work on the programming side that I am not willing to put the time into. What is needed, in my opinion, is a purpose programmed computer of some type, though.

That said, it could be programmed to use no feedback, O2 sensor feedback, wideband O2 sensor feedback, or other inputs, like the CHT's and EGT's that pilots use today. I have not built an airplane yet, and it will be a while before I do, but my plan is to stick with things that have been fully developed, and not to develop a new system on my own. I do plan on FI, but not EFI. Things may change in the future, but right now that looks like the way to go to me.

Tim
 
David-aviator said:
And the Lycoming engine pump definitely is not compatible with ethanol.
Click to expand...

Can you expand on this comment? I contacted Lycoming and asked what material was used in their diaphrams and gaskets. They told me it was a "trade secret". I have been not experienced any problems with the Lycoming pump and I have been using 5% ethanol for several years.
 
Originally Posted by David-aviator
And the Lycoming engine pump definitely is not compatible with ethanol.

ronschreck said:
Can you expand on this comment? I contacted Lycoming and asked what material was used in their diaphrams and gaskets. They told me it was a "trade secret". I have been not experienced any problems with the Lycoming pump and I have been using 5% ethanol for several years.
Click to expand...

It was a logical deduction.

The pump was certified before ethanol was added to U.S. fuels. Like carburetors, the materials could not have been designed by luck to withstand ethanol. Unless Lycoming has changed the original certification, I do not believe the pumps can be assumed compatible with ethanol. I'd like to believe they are, but there is no evidence they are except for a few guys running with ethanol. That's a good data point to start evaluating the matter for experimental use but it is hardly conclusive.

As of right now, Tempest is testing materials that will lead to an approved pump with ethanol. Why are they doing that? Probably because original materials do not meet ethanol standards.

Why is Lycoming keeping the matter secret? Who knows, they do not like mogas in their engines not to consider ethanol. But they are moving SLOWLY in a mogas direction considering how Rotax has captured the LSA market with the 912 (which can burn E10 fuel). Certainly, materials are available to deal with ethanol in this matter, it is mostly a matter of an old corporation moving forward and joining the current world. 100LL is going away with or without Lycoming and they are aware of it.

I'd very much like to run 93 E10 but it does not seem prudent to do so at this time. It is much work and expense to change a Lycoming engine pump.

An interesting question that is presently unanswered - has anyone heard of or witnessed a Lycoming pump failure due to ethanol? I've posed the question to Allen Barrett at BPE, no reports so far is encouraging but it too is inconclusive.
 
delusional said:
Tried that, and found some mention for marine applications and this incident report http://www.eaa.org/lightplaneworld/articles/0912_autofuel.asp

Can you point us to something more definitive?

Minus 40 is not out of the realm, at least here in the northeast in winter at 10,000. Indeed, -30f at the surface is not unheard of though I don't plan any flights in such conditions I confess.
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It really gets me when the water card is played when talking about ethanol. Decades before there ever was such an idea of running our engines on ethanol the industry addressed THE REMOVAL OF WATER from gasoline by the introduction of alcohol in the gasoline. It has always been considered a very good method for removing water. Now, low and behold, we have this notion that alcohol in our gas can cause water to FALL out of suspension and destroy our engines. Once we praised alcohol for providing a method of removal from our gas tanks. Now we think alcohol is going to introduce water into our gas tanks.

There have been many posts on this forum on the subject of water in gasoline and the use of alcohol. Please research and learn. The amount of water it takes in a gallon of gasoline before it will fall out of suspension with alcohol is around 1 pint. That is a tub load of water. Anyone who would have this much water in their fuel tank has a much bigger problem than using alcohol in their fuel. Any less amount than this and the alcohol mixed in with the gasoline will be a positive thing as it will absorb any remaining water and the mixture will pass through the combustion chamber with no ill effects.

I do understand everyone's concern about using alcohol and I also share them. The biggest concern is the fact that the energy level is not the same so you get less mileage for your buck when using ethanol mixtures in gasoline. There are many concerns that can be discussed but please be realistic. Water in the mixture is not one of those concerns.
 
While it is true that there is less energy in the ethanol, the less bang for the buck comment doesnt pencil out.

WHen I run my 8 (IO-360, 180 hp) on strait 100LL, I am burning about 12.5 GPH at 25 squared and 3500-4500'.

When I run 60% ethanol and 40% ethanol, the flows increase to about 13.5 GPH. The performance is the same otherwise.

Considering the fact that 100LL is between $4 and $5, and E98 ethanol is about $2, I am money ahead using the ethanol.

12.5 x $4 = $50 per hour fuel

13.5 x 60% = 8.1 gals @ $2 = $16.20
13.5 x 40% = 5.4 gals @ $4 = $21.60
for a total of $37.80 per hour

These are just my results, please do your own research-your results may vary!!
 
lancef53 said:
While it is true that there is less energy in the ethanol, the less bang for the buck comment doesnt pencil out.

WHen I run my 8 (IO-360, 180 hp) on strait 100LL, I am burning about 12.5 GPH at 25 squared and 3500-4500'.

When I run 60% ethanol and 40% ethanol, the flows increase to about 13.5 GPH. The performance is the same otherwise.

Considering the fact that 100LL is between $4 and $5, and E98 ethanol is about $2, I am money ahead using the ethanol.

12.5 x $4 = $50 per hour fuel

13.5 x 60% = 8.1 gals @ $2 = $16.20
13.5 x 40% = 5.4 gals @ $4 = $21.60
for a total of $37.80 per hour

These are just my results, please do your own research-your results may vary!!
Click to expand...
Yes, I should have not used that phrase. "Bang for Buck" is not correct considering the economic factors associated with the current prices of the various types of fuel.

The price difference is great enough between 100LL and E5, E10, E15 auto gasoline that there is an economic advantage for burning ethanol in our airplanes. There is a range decrease that should be considered when doing so however. A gallon of Ethanol laced alcohol in the tank will not carry you as far as a gallon of 100LL. This was what I was trying to say.

In looking at ethanol in my automobile the price difference between 100% gasoline and E10 that we have in our state is not a great enough difference to make it economically worth using E10. The decrease in fuel mileage between using ethanol mixed gasoline in my car is much greater than the price difference between the two fuels.

If I were trying to push ethanol onto the consumer in hopes everyone would convert, I would be addressing this price issue as it relates to the mileage on a gallon of gasoline vs. a gallon of E10. This is where the true buy in will occur. Until it is economically worth the investment in change, the change will not occur.
 
lancef53 said:
While it is true that there is less energy in the ethanol, the less bang for the buck comment doesnt pencil out.

WHen I run my 8 (IO-360, 180 hp) on strait 100LL, I am burning about 12.5 GPH at 25 squared and 3500-4500'.

When I run 60% ethanol and 40% ethanol, the flows increase to about 13.5 GPH. The performance is the same otherwise.

Considering the fact that 100LL is between $4 and $5, and E98 ethanol is about $2, I am money ahead using the ethanol.

12.5 x $4 = $50 per hour fuel

13.5 x 60% = 8.1 gals @ $2 = $16.20
13.5 x 40% = 5.4 gals @ $4 = $21.60
for a total of $37.80 per hour

These are just my results, please do your own research-your results may vary!!
Click to expand...

This is not the valid comparison that someone that says "ethanol produces less bang for the buck" is using. they are comparing mogas vs eth gas, not eth gas vs 100ll. if you compare my local car gas station ethanol gas apx $3 a gallon right now vs non ethanol at the same station for $3.60, its a bigger difference in $ per hour or $ per mile
of course it looks like car gas is quite a bit more expensive here in oregon than where you are at ( i've heard that we have top 10 most expensive gas in the nation). Btw, 100ll is $4.50 for self serve and $5 for service locally
 
I'm running Tracy's EC3 EFI/electronic ignition system. I have had a few bumps along the way, but the system has never stopped turning the fan. Even on the ground while tuning it has never died, not once since day one. I'm working through some tuning issues, but things seem to be panning out. I'm having some climb performance issues (check earlier posts by me, if interested), but I'm definitely happy with the top end improvement. Appears to be about 9 MPH. My fuel burn seems less, as well, but I'm still in the process of getting my fuel flow meter hooked up correctly, and calibrated. Both Tracy and I are at a loss for why I lost climb performance, but gained top end without any propeller change. I have an O320 H2AD and I know I'm making more HP (at least on the top end) as I have to run 3/4 throttle at 8000 density altitude to keep from passing the 2600 rpm limit. With my carb and mags I almost never bumped up against it unless descending quite a bit. In reference to using the carb as a backup at least one other person is doing that, on a Continental o200 I think. He told me he was going to go to a throttle body soon, however, because he in confident in the system and suspects he might be losing some power with the carb. Additionally, if one is using the carb as a throttle body, carb heat is still required.
Tracy's system is actually two computers in one box. I have my primary computer plumbed sequentially to four injectors (used SDS bungs in the runners) and their own fuel pump. My secondary computer is plumbed to one large injector in the throttle body (TBI) with its own fuel pump. The only thing the two systems share is the tank pickup. Tracy's computer is around $950 I think, but by the time you buy the injectors, coils, bungs, pumps, plumbing, etc you are into it around $2500... Still close to the $$$ of some electronic ignition systems alone. FYI: the throttle body on a 240z is slightly larger diamater than the opening of the sump mainfold, and the bolt pattern will fit the lycoming with only 10 mins of work slightly elongating the bolt holes on the throttle body. If anyone wants more information on the system or some of the issues I've had let me know.

GEM
 
Danny7, the $2 I quoted for ethanol isn't car gas, it is ethanol directly from an ethanol plant. It it what is used to create E10, E85, etc. It is about 98% ethanol, with a little petroleum added to make it different than everclear.

sorry for the confusion!!:eek:
 
lancef53 said:
Danny7, the $2 I quoted for ethanol isn't car gas, it is ethanol directly from an ethanol plant. It it what is used to create E10, E85, etc. It is about 98% ethanol, with a little petroleum added to make it different than everclear.

sorry for the confusion!!:eek:
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i overlooked that part, it shows regionally how fuels are available also. we don't have any ethanol plants close by. There were two in oregon but i believe they have gone out of business when prices dropped from their high 2-3 years ago.
 
says who?

RVbySDI said:
..The amount of water it takes in a gallon of gasoline before it will fall out of suspension with alcohol is around 1 pint. That is a tub load of water. Anyone who would have this much water in their fuel tank has a much bigger problem than using alcohol in their fuel. ...
Click to expand...

How do you know that much water was not introduced into the fuel while it was in the retailers underground leaky tank or while in other storage.

There is very little water in air. Just enough to make a thunderstorm or freezing rain and smash your little airplane like a bug.

I am open to any _evidence_ that this in not a real problem. Which engine/airframe manufacturer/kit manufacturer/standards organizations has documented that it is safe to run with alcohol in our fuel?
 
delusional said:
How do you know that much water was not introduced into the fuel while it was in the retailers underground leaky tank or while in other storage.
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Well, I would know by sumping my fuel. Now one could argue sumping would not find the water if it was in suspension with the alcohol but this is really my point. As long as the water remains in suspension with the alcohol what does that matter. At least as far as the engine's ability to operate. I am not saying anyone would know how much there was. What I am saying is it would not matter a great deal unless one had a large quantity of water (like a pint or more) in the fuel tank. If there was that much water in the fuel I would be tracking down the cause pronto.

delusional said:
There is very little water in air. Just enough to make a thunderstorm or freezing rain and smash your little airplane like a bug.

I am open to any _evidence_ that this in not a real problem. Which engine/airframe manufacturer/kit manufacturer/standards organizations has documented that it is safe to run with alcohol in our fuel?
Click to expand...
I am not talking about whether or not a commercial entity has approved or disapproved of running alcohol in their engines. What I am saying is that for water to FALL out of suspension in an alcohol mixture (regardless of which brand of engine the fuel tank is attached to) takes a great amount of water accumulated in the fuel mixture before it will happen.

I do not have the specific thread at hand but a couple of years ago this discussion was held in another thread. In that thread someone posted a document on a study done that shows the quantity of gasoline, alcohol, water in a fuel mixture and how much of each it takes before water will separate from the alcohol. My memory is fuzzy on the detailed numbers but the study detailed the amount of water in a fuel mixture it took. It was a very large amount of water. If I can find the actual thread I will post the link. Or, do a search on ethanol and I am sure you will find it in here somewhere.

I went back and found the thread and the study referred to above. Here is the link to the previous thread. Click on this link to read the study.
 
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UST's- commercial fuel storage

Originally Posted by delusional
"How do you know that much water was not introduced into the fuel while it was in the retailers underground leaky tank or while in other storage."

Water from a UST is way down low on my list of concerns. The EPA or/or your state's environmental folks ramped up monitoring and enforcement of UST (Underground Storage Tank) regs through the 1990's. Depending on your local, it could have been sooner or later, but as the rules were kicking in, a bunch of old non-compliant tanks got pulled. Some gas stations even closed rather than comply. Not all, but most of the old single wall tanks couldn't comply with the regs, or it was very expensive to comply, so they got pulled and replaced with above ground, or certified UST's.

Single wall UST's require automated monthly leak tests. This is a hardware and software package that runs an integrity test (temperature compensated) looking for product loss (down) or water gain (up). My understanding is double wall tanks have intersitial monitoring, looking for liquid of any kind. Also, the UST owner/operator must have documentation of equipment, materials, installer, and other requirements, that all add up to a very high probability of fuel quality integrity. Any leaks that do occur must be reported and fixed, and if you have one, get ready to enjoy lots of regulatory attention ;)

Bottom line, these days in the US, (I can't speak for other locales) it is VERY unlikely to have a commercial UST that is not tight.

best
Stan
(speaking from UST management experience)
 
still hoping for better diesels...

RVbySDI said:
...I went back and found the thread and the study referred to above. Here is the link to the previous thread. Click on this link to read the study.
Click to expand...


Thanks, Steve, that is very interesting reading, though not really all that comforting as to phase separation. Maybe a refrigerated fuel strainer/tester is in order?

It seem like the only really reliable fuel is JetA, but not many diesel engine options for us little guys...

Every aviation magazine I see lately has some editorial saying how hard folks are all working on a reliable fuel supply, yet not much seems to actually materialize. So we are left here to debate mostly, but not entirely, hypothetical hazards. There must be a better way.
 
delusional said:
. . .There must be a better way.
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The better way is to perform surgery to remove the government regulators from the equation. Open up the environment for true experimentation and then true supply and demand principles without the negative influences of government regulation and restrictions, then perhaps things would begin to move along.

There are truly only two major obstacles associated with practically every problem aviation faces. Those two obstacles are:
  1. COSTS
  2. GOVERNMENT REGULATIONS
In fact, I would go so far as to argue that all you have to do to eliminate the 1st obstacle is to eliminate the 2nd obstacle.
 
Actually, safety is our biggest challenge...

RVbySDI said:
..every problem aviation faces. Those two obstacles are:
  1. COSTS
  2. GOVERNMENT REGULATIONS..
.
Click to expand...

and the problematic accident record has little to do with the government. Though in the case of ethanol-contaminated fuel you're right; regulators certainly are mucking things up there.
 
delusional said:
and the problematic accident record has little to do with the government. Though in the case of ethanol-contaminated fuel you're right; regulators certainly are mucking things up there.
Click to expand...
Well, I am not going to debate against the idea that safety is an important issue. Of course it is. However, it is no more important than automobile safety is, or, coal mine safety, or the safety of our children, or any other issues of safety.

Safety, or the lack of it, is not the PROBLEM that is gradually killing the aviation industry. My statement is motivated by the idea that the growth, expansion, revitalization, whatever you want to label it, of aviation is stifled by the two obstacles I mentioned. And, having said that, I am not too shy to state my belief is that government regulations are the true culprit for that stifling effect. Further concerning safety, I would also state government regulations are not, solely responsible, for providing safety in aviation either.

As my statements relate to safety; if we were to change our ideas concerning government regulations, perhaps there could possibly be a spike in the accident rates in the short term but I believe we would not necessarily see a great spike in aviation accidents or deaths over the long term. I believe safety would be addressed by the market demands in the long term. People are no more interested in spending money to then go kill themselves "willy nilly" in an airplane than they are to do so in an automobile, boat, motorcycle, snowmobile, etc. I do not need government regulations to tell me what is or is not safe. I don't believe any of you reading this need it to tell you that either.

Now, lest someone think I am off my rocker concerning this notion, I am not talking about things such as standards of building such as using AN bolts vs standard hardware bolts in my build. That type of decision is based upon years of experience by others before me who have proven there is a safety benefit by using the correct bolts. That is driven by standards of safety developed that do not require government regulators to drive the decision.

I equate it to parenting skills. A parent does not need a government bureaucrat giving them rules on how they are to go about making sure their toddlers do not stick forks into electrical wall sockets. A conscientious parent is going to heed the advice of those who have traveled the child rearing path before them when it comes to this. So it is with us as builders.

As a conscientious builder I am going to heed the advice of all of those who have traveled the road before me and build accordingly. I have absolutely zero desire to consciously do something that is going to kill me. So, it is my responsibility to make sure I have due diligence when building, and flying. I must do so in a manner that ensures I protect myself and those who put their trust in me when they fly with me. I am responsible for following the appropriate procedures that so many before me have developed, designed, worked out before me. Often times those lessons passed on to me were at the cost of those individual's precious lives. I am going to follow best safety practices based upon those hard learned lessons. I believe you are going to do so also. We are all going to do so regardless of whether some government bureaucrat creates regulations directing us to do so or not. Our desire for self preservation does not need to be externally motivated. It is an inherently internal drive.

Ok, way too much of my .02 that you most likely had little desire to here. Just one last thought.

Live Long and Prosper!
 
RVbySDI said:
I went back and found the thread and the study referred to above. Here is the link to the previous thread. Click on this link to read the study.
Click to expand...

Very interesting thread and study. Thank you for taking the time to find it and repost the links for us.

Based on what I've read here and on other sites, it seems like it would be perfectly reasonable to run E10 in an aircraft as long as you had low compression pistons and had fuel injection. There is apparently still some question as to whether the mechanical fuel pump on a Lycoming would be suitable due to the materials in the diaphragm.

So, hypothetical situation, let's say you had a high wing Glastar (aluminum fuel tanks, no proseal or other sealers are used), and a Lycoming 150hp O320-E2D with a carburetor and the standard Lycoming mechanical fuel pump. What would it take to convert to a fuel injected system with electric fuel pumps that would be suitable for E10 usage, and what specific system would be recommended?

On a side note, why won't a fuel system with a gascolator and carb work with E10?

Thanks,

-Dj
 
deej said:
Very interesting thread and study. Thank you for taking the time to find it and repost the links for us.

Based on what I've read here and on other sites, it seems like it would be perfectly reasonable to run E10 in an aircraft as long as you had low compression pistons and had fuel injection. There is apparently still some question as to whether the mechanical fuel pump on a Lycoming would be suitable due to the materials in the diaphragm.

So, hypothetical situation, let's say you had a high wing Glastar (aluminum fuel tanks, no proseal or other sealers are used), and a Lycoming 150hp O320-E2D with a carburetor and the standard Lycoming mechanical fuel pump. What would it take to convert to a fuel injected system with electric fuel pumps that would be suitable for E10 usage, and what specific system would be recommended?

On a side note, why won't a fuel system with a gascolator and carb work with E10?

Thanks,

-Dj
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The gascolator nor the carb would be an issue what so ever. However, whatever materials the seals in those components are made of would be an issue. So if you wanted to run 100% ethanol in an engine the engine would not care. It is the other component make ups that help feed and support that engine that would have to be examined. As I have stated in past posts, safety is not as a big a factor in using ethanol as is the economics factor of using it.
 
RVbySDI said:
The gascolator nor the carb would be an issue what so ever. However, whatever materials the seals in those components are made of would be an issue. So if you wanted to run 100% ethanol in an engine the engine would not care. It is the other component make ups that help feed and support that engine that would have to be examined. As I have stated in past posts, safety is not as a big a factor in using ethanol as is the economics factor of using it.
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Just for clarity, I'm talking about using E10 (mogas with 10% ethanol), not E85 or pure ethanol. In other words, I want to use regular autofuel at $2 per gallon less than 100LL (in my area). That translates roughly to $1600 saved in a typical year of flying (100 hours at 8gph per hour at $16 saved per hour), or $32,000 over the 2000 hour TBO of the engine, nearly enough to pay for two engine overhauls.

In the thread you mentioned, there was talk about E10 being okay in a fuel injected engine, but there was concern expressed in using E10 in a carb engine. I am curious why the concern using it in a carb. Also, there was concern about the "rubber" diaphragm in the Lycoming mechanical fuel pump.

Firewall back I'm reasonably assured that the fuel system components will handle it just fine. It is the FWF that I am not completely sure of yet, in particular the mechanical engine pump and the carb. The FWF flexible fuel lines can be easily replaced with compatible materials if necessary.

Thanks,

-Dj
 
deej said:
Just for clarity, I'm talking about using E10 (mogas with 10% ethanol), not E85 or pure ethanol. In other words, I want to use regular autofuel at $2 per gallon less than 100LL (in my area). That translates roughly to $1600 saved in a typical year of flying (100 hours at 8gph per hour at $16 saved per hour), or $32,000 over the 2000 hour TBO of the engine, nearly enough to pay for two engine overhauls.

In the thread you mentioned, there was talk about E10 being okay in a fuel injected engine, but there was concern expressed in using E10 in a carb engine. I am curious why the concern using it in a carb. Also, there was concern about the "rubber" diaphragm in the Lycoming mechanical fuel pump. . .
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I will state this before I start lest you think I am an expert. That could not be further from the truth. I am no expert on anything except my own personal life. Of that I can say there is no one on the planet that knows more than I do about that topic. Ok, now that is cleared up.

My thoughts on those voiced concerns about using 10% ethanol in a carb is again going to be because of the type of material the carburetor uses for the seals and various internal components that may possibly be eaten away by the ethanol. I imagine the reason they are not concerned with Fuel Injection is that outside of the fuel pump a fuel injection system pretty much just has a metal line feeding directly into each cylinder. No rubber components or anything else that ethanol could eat up in the line at all. Hope that helps.
 
Fuel Injection Issues with E10

RVbySDI said:
I will state this before I start lest you think I am an expert. That could not be further from the truth. I am no expert on anything except my own personal life. Of that I can say there is no one on the planet that knows more than I do about that topic. Ok, now that is cleared up.

My thoughts on those voiced concerns about using 10% ethanol in a carb is again going to be because of the type of material the carburetor uses for the seals and various internal components that may possibly be eaten away by the ethanol. I imagine the reason they are not concerned with Fuel Injection is that outside of the fuel pump a fuel injection system pretty much just has a metal line feeding directly into each cylinder. No rubber components or anything else that ethanol could eat up in the line at all. Hope that helps.
Click to expand...

I'm running E10 in an IO-360 on my RV-7A. (Actually, a mix if 1/3 100LL and 87 octane E10). The engine is a low compression engine.
Before I started this "experiment", I verified that ALL fuel components were able to tolerate the E10 fuel. While Lycoming will not officially verify that their fuel pump diapham is E10 tolerent, independent testing (other aircraft owners) has not indicated any issues with E10 usage.
As for the rest of the fuel system, the fuel body and fuel distributor have rubber components. My system, the Bendix Silver Hawk Experimental unit, has all E10 tolerant rubber components. Older bendix systems may not.....
All my fuel lines are either aluminum or typhlon. The Sealant in the wing tanks is also E10 Tolerent.
I have not had any vapor lock issues that I didn't have with pure 100LL. So far, I can't tell the difference while flying. I can certainly "smell" the difference!
 
deej said:
Out of curiousity, why the 1/3 mix?

-Dj
Click to expand...

I'm easing my way into a 100% E10 situation. Adding the 100LL increases the octane rating. I have run a 5:1 mix over the summer months in one tank, (50/50 in the other tank) and found that it was hard starting. the 3:1 (E10/100LL) mix seems to start a lot better in hot weather.
I'd like to evaluate engine performance with the lower octane. I'm also thinking it would be better to use 100% 97 octane "High Test" E10 first.....
100LL prices here in the NorthEast are running close to $5.00/gal now, with 87 octane E10 at $3.00/gal. 97 octane E10 is near $3.75/gal, so it's still a better deal than the 100LL.
So far I fly enough hours that I have not seen any E10 storage issues in any of the planes fuel components.
 
Fred.Stucklen said:
100LL prices here in the NorthEast are running close to $5.00/gal now, with 87 octane E10 at $3.00/gal. 97 octane E10 is near $3.75/gal, so it's still a better deal than the 100LL.
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I'm seeing about the same thing here in southern Maine. Locally 87 octane is about $3.09 per gallon, and 100LL at my local airport is $4.95 per gallon (higher at some of the other airports nearby).

-Dj
 
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