The Enya I saw had no provision for varying compression except gaskets. If they added this and mine has it, I'll be happy as the proverbial pig.

Greg

To paraphrase NASA, gentlemen, we have IGNITION.

Latest run on no ether fuel is here.

http://www.youtube.com/profile_videos?user=hopeso

I'm a little pressed for time so this'll be brief. More later.

It appears that the heat sink worked in the fashion I had hoped. It allowed the engine to run cooler, and thus nearer to the start compression than before. That in turn brought the idle adjustment within range and now we have a solid top end, a solid idle and good transition. One out of three times, rapid acceleration produced a flame out. These issues smooth out in the air so I'm hopeful and will fly the plane tonight.

To be posted to YouTube later, is a run with 30 ether and the usual suspects. The difference was that the engine WOULD start on just three or four prime runs. Hot starts were a cinch. The real deal here is that the compression and needle settings were the same as with no ether. I'm having trouble believing that so I'll be double checking during another session. The other difference was that the ether did help the idle sound smoother but only after a small tweak.

So far, it's looking more and more that ether may NOT be necessary. We just need to design the engine to use an all kero fuel. A good ignition improver is essential, along with adequate cooling for the higher temperatures the all kero generates. You don't even need ether in your prime. At least not on THIS engine, this one time.

That LM head suits helis but looks goofy on an airplane. And here I was, turning down the fins. Bad science, I should have known Norvel knew what they were doing.

It also appears that running cooler, as some of my other experiments have implied, is not a bad thing. Too hot is definitely bad, cooler seems to be OK.

And, for those of us that fly in the winter, I've noticed that engines seem to run better in the cold. Higher air density, more mix in the combustion chamber to be sure but there could be another factor.

Next session will be to go back to the stock head on a hot day like today and try again and document any diferences.

With a glow plug equipped diesel you could start it on glow and switch it to diesel after it warms up. Need a fuel filler hooked up so when in the fueling position the carb will draw from an outside glow bottle and when shut it draws from the diesel flight tank. Use a fuel dot to fill the flight tank.

EDIT: oops, just noticed Andy posted a similar response from A1.

Just got a response out of the Aussie Amsoil distributor: http://www.a1oils.com.au

Hi Colin,
Sorry about the slow response, i am in middle of huge move back to
broken hill and am having to check emails from remote pc.
I have plenty of Cetane Boost in stock and it will definetly give your
little ones a boost and keep them clean as well.
It is in storage for next few day but am fairly sure it is $11.00 for
around a half a litre, but it does go a long way.
Please let me know where you are and i will give full quote inc postage.

Thanking you,
Peter Crossing
A1 OILS - Australia


I'm ordering half a litre. Also splashing out on ether so I can compare with 'traditional' fuels - still paranoid about cooking my PAW 19 (given that it was a present from my late grandfather and is of enormous sentimental value. Might have to risk blowing up a cheap-as-chips Russian Marz instead).

cheers,
Colin
Re-learning C/L in Brisbane, Australia

As it turns out, there's no need, really, for any kind of preheat or glow start. Went flying tonight with the dieselized Norvel .074 and the LM heat sink headclamp. Things didn't go as smoothly as at the bench but the evening became quite cool, compared to the afternoon, which involved a blistering sun and temps in the 80s. So the settings were a little off. Just a little. As the last run was with the ether mix, that was tried first. After three prime bursts, the engine caught and kept running. Rough at first but after a bit it smoothed out and I tweaked the needle with the nose up and off I went. The compression screw was left alone.

Touching nothing, I fuelled up with the no ether mix and had a go at it. Six prime bursts and nothing. By this time the engine had warmed up a little so all it took was a tweak in on the compression screw, ( just a tweak) and she lit off. After a bit I backed off the screw to about where it was and we had a run. Solid, LOUD,,, but smooth. The idle got a little ratty. Well, a LOT ratty. Rumble, grumble, brrrr, puff and so on. But the idle, just under 5K, held. I sat for two, three minutes and it did its noisy thing steady and solid. OK, how's transition? At two clicks above idle, it smoothed out and the plane lurched forward so I just punched the throttle and off she went. And I proceeded to put in a normal flight. Well, except that the idle still had character. Lots of it, not like a grrr but more of a gurgle. I wish I could say it never quit but it did, once, on an attempted touch and go. A half dozen touch and goes later and it never did that again. Just all that noise and fuss. You can get a sense of what I mean on the video but trust me, the video is real kind about it. But as the video also illustrates, the throttle response IS instant with no hesitation. The engine did that in the air, in spades. So, as in post 83, we still have an idle that appears undercompressed, or is too rich, or both. As before, I have the airbleed all the way out with no effect. So, apologies to the medical profession, we have a symptom that needs to be looked after.

But now, here's something interesting. A cool engine needs advanced timing to get a start and once running, the timing needs to be backed off as the engine warms. We do that with the compression screw. However, there's another way to advance the timing. Load the combustion chamber with a rich fuel mixture. We do that, after all, when we drown a glow engine with raw prime to get it started. Remember the old days when you used a hand choke to start your car? Ever wonder why you did that, or how it worked? So I backed off the needle valve a full turn, gave it a shot of prime and she lit off, first try. Rough, real rough so I got on the needle right away and bit by bit, as the engine warmed and I dialled it in, I finally arrived at that just right setting for a strong run. No attention whatever, was paid to the compression screw. This mirrors my experience with this fuel on the bench, earlier in the day.

But it gets better. Again, with a cold start, as I applied the starter, I plugged the muffler with a spare finger and lo and behold a burst with no prime. Yes, the needle was backed off a full turn. A second try and she caught and faultered but this time I used the finger to adjust the amount of fuel delivered by muffler pressure, as required, and I milked the engine to life. After it caught and held, I got on the needle to bring it up to RPMs as before. Neat.

There's no question that the ether helped to smooth things out a fair bit. BUT, the engine started and ran and ran strongly at full bore. I have a philosophy that a machine was meant to earn its keep and I know that I'm *****g the needle and compression more than some would like to see. The sharp buzz at full bore is evident, especially in the air. Still, with the pedal to the metal, the engine keeps coming back after a flight, like a puppy, all smiling and goofy like. Well, maybe that's me projecting myself into the machine.

So there we have it. Norvel diesels run on an all kero fuel and this is with 50 weight, non detergent, aviation oil, hardware store kerosene and a quality cetane booster. If not for the Amsoil, maybe none of this would be happening. I owe THAT one, big time, to Kelly. Thanks again, man.

And there's still more to experiment with. Other brands or types of cetane booster. Hey, Amyl Nitrate. What if,,,, Or a magic blend of ignition improvers. Never mind the chemistry, poke and prod and just TRY it. You never know. Sure glad I did.

I would be careful with the words here. We don't need to advance timing at all to start, we need enough heat of compression and fuel vapor to ingite. When the engine is cold the compression temperature is lower. Increasing CR improves that. We also need to vaporize fuel. When airflow through the carb is low vaporization is poor. So excess fuel yields enough vaporized fuel to ignite. Liquid fuel doesn't burn or compress. Once the engine gets hot and fuel vaporizes better due to engine heat and carb velocity, we can run leaner and reduce compression to prevent over advanced timing.

Injected diesels don't richen the mix when cold(no need as vaporization isn't left solely to evaporation). But they do add heat by an intake air heater or glow plugs when things get to freezing. Older non computer diesels, like Dodge Cummins 12 valve, can get some extra starting oomph by just barely touching the throttle in cold weather. Too much and I guess you'll be picking up pieces.

I start my fourstroke conversions wet. Finger over the carb for prime and half turn out on the needle. No extra compression needed, and I was starting by hand. Once it warmed a bit I can lean it out.

I wonder what is causing the extra noise? Do you have any more power than ether fuel?

Greg

Hi Greg,

My experience and assumptions with glow, is likely misleading me in my conclusions. That's my story and I'm sticking to it. But somewhere in all of this, there IS the issue of ignition timing isn't there? On glow, sometimes you can get good throttling by reducing the CR with an extra shim or two, a real easy thing to do on ALL the Norvels. So if you decrease the compression, (on glow) you need to lean out the needle some and this, in turn, leans out the idle. This can help a lot if you don't have a means of adjusting the idle mixture. I regret not having any four stroke experience but any chance that the two, four stroke and two stroke, will respond somewhat differently to the items we're dealing with?

But here's what gets me about four stroke conversions. If someone had proposed the system as used on a four stroke conversion, I would have said, no way. Yes, it would work but the restriction caused by the small hole in the glow sized threaded portion would render the system unusable due to huge losses in efficiency. But not so, apparently. But has anyone just gone ahead and bored out and threaded that portion MUCH larger as in about the same size as the contra-piston that's used?

The noise? The Norvel conversions seem to have quite a broad range on the compression screw. You can back off to a real smooth, quiet run but at the expense of an available 600 RPM or more. Cranking in the compression, you immediately get a sharp tone that doesn't change much till it gets REAL hard and then it gets scary, something is going to break for sure. So I set it at about the middle of this range for the best power. In the air, I can say that the diesel version, on all kero is certainly louder than glow on the next size smaller prop. In fact, it's more like a purr than the normal scream of a glow. I DO have a muffler extension and that may be a factor. Dunno, all my .074s have this extension to clear the fuse.

And I do have the three other Norvel sizes to fool with. Bench running is just the start, they have to fly to prove their worth. Will get busy this winter building big stuff. The SMALL guys are gonna have a fit but hey, it's for science guys. But no,,, I'm just having fun.

my old international tractor don't have glow but a switch on the diesel system that give more fuel when its cold. And my Toyota diesel have some kind of automatic choke.

my sc 108 2stroke convertet to diesel. i use a finger on the muffler output to choke it when its cold. and then i dont have to touch the compression adjustment for every single start. if im using the same fuel mix.

My ford tractor has a button on the injector pump that when pushed increases the fuel injected at idle to help cold start.
in practice I found that not useing it and cranking the motor for 10-15 seconds with the stop pulled out and then pushing the stop in gave instant clean starts, wereas useing the rich start button quite often just made lots of white smoke out the exhaust till the battery was wound flat- flooded diesels wont start!!!!
Stewart

I thought you were talking about starting? I agree that timing is an issue when running. Timing is not an issue when starting. In our engines timing and the extra compression needed to start are related. So is richening the mixture to start, as a good portion of what will be thrown into the cylinder will not be vaporized and incompressible. I'm looking at it from the theoretical side. We know we need heat to start and in the case of the cold engine all of it comes from compression. This means we need to increase CR. Ignition timing is always at lowest advance while starting an engine, that's why it sounds strange when you say you need to advance timing to facilitate starting. We need to make sure ignition occurs.

I did make a lanova with as large a hole as possible to go through the glow plug hole for the FS26 conversion. Actually the whole chamber was that same diameter. It did not run different than a lanova with a hole less than half that size. I don't see it being a problem for the small engine. I could forsee it becoming an issue with larger engines. Fixturing the head to enlarge the plug hole is not an easy task, if there is even enough material to allow it.

Yes, there probably is a difference between fourstroke and twostroke characteristics.

I picked up some Amsoil ACB today. I took out my FS-40 and ran it up on a god knows how old tank of fuel. I was in a hurry and didn't bother pouring fresh Clutton mix. It didn't like the old fuel but it did start and sorta ran. I mixed up a batch of 20% Castor, 78% ace hardware Kerosene, and 2% Amsoil ACB. Drew some fuel to the carb and flipped the prop and it fired right up. It was warm from running the old fuel. The compression settings were similar to the past. Needle I'm not sure as I changed to a Magnum two needle carb from the .30FS. I was extremely happy with the way it ran and tuned. It seemed to make quite a bit more power, but my tach was not within reach. I was able to lean the top end out so much the exhaust felt dry. The carb might have a problem as I couldn't lean out the idle mix so much that it quit. I ran it about 5 minutes before I had to go. I think this is just the ticket for the fourstrokes. More running tomorrow, maybe some video.

I'll probably pick up my Enya Friday. If I have enough time on the weekend I'll be doing some testing with fuels. I'll post pics of the Enya when I get it.

Hi Everybody,

Youre experiments are very interesting. Great work!

Can you please consider and comment on using automotive diesel (pumped into cars) mixed with a little automotive gasoline along with suitable lubricants to run either glow or diesel engines. It would perhaps be easier to experiment on glow engines first because heat can be given to ignite the mixture easier than with pure compression alone. I specifically want to know the results of this automotive mixture of diesel and gasoline because it is the cheapest and most available of all, directly from the pumping station. You have done great work in proving the pure kerosene/lubricant mixture, but I am interested in car fuel as it is the cheapest of all. By varying the proportion of gasoline, the diesel may substitute for the kerosene as the main component, while the gasoline acts like the ether, contributing to ignition. My challenge to you is to come up with a suitable proportion using only these components.

Thanks.
Great modelling.

K&S sells small 1/16, 3/32 and 1/8 diameter copper tubing. If need be I can pop some in the mail for you, the local hobby stores have it in stock.

I thought about the water jacket or marine type cooling head as well, certainly a possibility. Or do like many did many years ago before the manufacturers made the marine heads, wrap a copper tube round the head (I think Octra may have marketed one line that).

However, if you cool the engine too much with one of these heads or jackets, might that not have a detrimental effect on the idle??

cheers, Graham

[/quote]


Many thanks Graham, but I'm headed to Sudbury for the weekend and the shop there just told me they'll be putting some of the 1/8th aside for me.

How cool our engines, (diesel of glow) can be run is a good question. I read the other forums a bit and the car guys use a temperature gauge to tune their needle valves. These are laser devices and their accuracy is suspect in some quarters. So, many just tune by ear and by running the car on a stretch at high speed. For the longest time, we were told that 1/2As throttle poorly because, among other things, they run too cool. The math may be correct but in the real world, I tested the notion and it doesn't seem to hold. You can see what I mean here.

http://www.youtube.com/watch?v=o-uvAb-vQgM

And here.

http://www.youtube.com/watch?v=wwWz9Liv81g

In the second video, we have an engine converted to rear exhaust and idling at 1.5K lower than is typically needed in a plane. It took a while for the ice cube to affect the idle. Later runs showed that a little tweaking of the idle mixture helped prolong the idle. Hotter or cooler running will affect the compression setting and THIS will affect where your main needle will be and this can affect your idle setting unless you have a means to adjust it. Adjusting the idle is not provided for on PAWs and the like. I can't imagine why, I've added the feature and it helps a great deal.


[/quote]


I appologise for coming in late with my additions but what the. . . .

As a kid I recall the instructions that came with all my ED marine engines stated that a diesel is being cooled the right amount if is running so you can place your finger tips on the cylinder head and keep them there for justa few seconds.

I know that's a bit impirical but that's what it said.

As soon as funds allow I'm going to order some Amsoil cetane booster for my OS 160FX. I'll start on glow and switch on the fly to diesel. I'll try to adjust the compression and timing with head shims and prop size. Won't be optimum but it will give something to consider. I have a couple quarts of lamp oil so I'll give that a try first.

Do you think a diesel runs with more or less compression than a typical glow engine?

I need to confirm that a overcompressed engine sounds labored and knocky and an undercompressed engine misses and sputters. Does that sound about right?

I would like to see one of those four stroke conversions.

Which do you think provides better lubrication and a cleaner plane, the 50 weight aviation oil or castor?

I know that if you can't keep you finger on something for more than a second or so it's at 140 deg F. This is typical for most people. 140F for a head temp would be pretty cold for good efficiency.

Andy, how does the motor oil blend smell when running in the engine? The castor mix smells nice.

I don't think that will work well. Whos knows with the glow plug in there. Diesels run about double the CR as glow. So I'm not sure how you can start on glow and switch to diesel. You should still have some on the fly compression adjustment available for tuing to daily conditions.

http://www.edfinfo.com/diesel.html

Greg,

I wonder how well the Enya four strokes run without a compression adjustment other than head gaskets? Does your device protrude into the combustion chamber more than the glow plug?

I ran the FS-40 some more today. It would not start on the no ether mix. I have limited CR range in this engine. If I can determine that it will start well with more compresion I can change that. It doesn't seem to be as sensitive to CR on this fuel. Exhaust gas is hot enough to burn through a towel at WOT. The Magnum carb is junk or simply not adaptable to diesel AFR. I could not lean out the bottom end enough to prevent it from knocking due to rich AFR,. I switched back to the original and this smoothed out the bottom end. It will start and run well when the engine is pretty hot. Power is the same as with regular mix. Actually there isn't reason for power to increase. Power is dependent on how much fuel is burned, not what kind. Little things like CR and timing can slightly change how much power it makes, but not much.

Try this thread for the four stroke conversion info.
http://www.rcuniverse.com/forum/m_900816/tm.htm

I forgot to add this yesterday. I tried mixing some fuel with Sig castor and lamp oil. This stuff didn't mix at all. It separated immediately. I tried saving the mix by doubling it with kerosene instead of lamp oil and this did not help. All of the oil still settled out. I have been using the Maxima Castor 927 I mentioned with kerosene and it blends well at current temperatures.

I'm not sure if it was the castor or the lamp oil but they don't work well together. Even after I added the kerosene all of the oil settled out so it might be the Sig castor oil that doesn't like to blend with this type of fuel. I have used it with ether before with good reults.

Good day all,

Glad to see this thread is still running strong with many good observations and ideas.

Haven't had much opportunity for much test running but I managed to squeeze in a wee bit. With the literally hunderds of possible permuations of fuel component percentages, I thought it might be best to reduce some of the variables and improve my own consistency. With that in mind I took the time to rebuild a 40 year old PAW 2.49cc DS that I had and was going to rebuild anyway. You can see my results and comments here if you wish:

http://www.rcuniverse.com/forum/m_4610628/tm.htm

I was also finding it very frustrating to try and maintain any sense of accuracy using my scratch calbrated re-cycled glass Sig Dope jar that I using to mix fuel with. So I splurged and got a suitable glass graduated cylinder for mixing. It won't help my engines run any better but it will certainly improve my consistency when mixing fuels.

I also picked up a little remote reading thermometer like the car guys use. I realize that their absolute readings will be suspect but their relative measurements are consistent (that is, it may read 200 when the actual temp is 220 but it will read 200 or nearly so each and every time under the same conditions). All this talk of our engines running hotter or colder has all been very general, now I will be able to subjectify "hotter", "warmer", "cooler" etc. And that brings up a good question, just how hot to our little engines run? The car guys claim their engines run about 220 to 250 degrees F. That seems "hot" in relative terms but that is where they run them and on 8 percent oil to boot. I was chatting with a local serious car racer the other day and he mentioned that he used fuel with 8 percent oil and has never had one fail.

I am also going to keep better notes, including ambient temperature, pressure and relative humidity.


So, some of my test results so far. I have managed to run an engine on straight oil and kerosene but didn't take any notes, just trying to see if I could do it. So I will work my way down in ether content and oil content in steps and see if I can add anything to the overall good of this discussion.

Test 1 - my normal diesel mix 35% John Deer Fluid, 35% kerosene, 25 castor oil, 2.5% Amsoil Cetane boost, 2.5% marvel mystery oil

PAW 2.49CC DS Kavan 9x5 prop prior to rebuilding 8600 rpm head temperature 180 to 200 degrees F

Test 2 - 20% John Deer Fluid, 10% castor oil 10% Amsoil INTERCEPTOR sythetic oil, 2.5% Cetain Boost, 2.5% Marvel Mystery Oil, remainder kerosene.

PAW 2.49cc DS Kavan 9x5 after rebulding 9020 rpm head temperature 150 to 160 degrees F
- easier to start by hand or starter than before, steadier runs and cooler. These differences more a result from a good clean and rebuild of the engine. Ambient temperature was nearly the same as the previous test.

I decided to try the Amsoil INTERCEPTOR sythetic oil as I can get it locally at Canadian Tire and is less expensive than the Klotz stuff the local hobby shop sells. Since I am mixing with Kerosene the ability to mix with alcohol is of little consequence at the moment. This test showed notably less oily exhuast which was one goal and that with nearly half the ether I was previously using, starting was still easily accomplished by hand or with starter.

http://www.amsoil.com/storefront/ait.aspx

Further to do is to reduce the ether in half again and continue reduce the oil content. I am hoping that temperature measurements will alert me if I have reduced the oil too much (and sound of the engine too). Also to try some pump car diesel.

I did have another question about Marvel Mystery Oil. There are lots of posts on this product and lots of mis-information too. I am not really sure what it is. I do believe it was also (still maybe) sold under the name Redex overseas or was at least very similar. I have been putting it my fuel mixes because I think it helps the engines run a bit cleaner; in other words helps break up the carbon etc. I have a snowblower that was running rough, I put some MMO in the gas and in the crankcase and it did help it run better. All of this wishful thinking? Perhaps. Simple observations are difficult to quantifiy and good judgement is easily clouded by wishfull thinking.

All that aside, what do you think, does adding Marvel Mystery Oil (or Redex) have any benefit? Andy's post about using the Aviation oil (ashless with low detergents) is interesting in light of the fact that I did read somewhere (mis-information perhaps) that MMO was mostly detergents. This is one of the reasons I chose the Amsoil INTERCEPTOR sythetic oil, it is a 2 cycle low detergent oil. Isn't one of the properties of these 2 cycle TWC or FSO (or whatever designation they have) is to burn cleaner and leave less deposits? Kill two birds with one stone, if these synthetic oils burn/run cleaner with fewer deposits then I can stop putting MMO in the fuel.

Greg, interesting your results. When I tried Sig Castor oil it managed to mix with the kerosene I was using. I have some lamp oil and will try that. I don't know what the difference is between the kerosene and the lamp oil. I have mixed fuel from both and haven't noticed any difference in the way the engine runs.


Back to the workshop for some more tinkerin' and thinkin'

cheers, Graham in Embrun near Ottawa Canada.

Greg,

The castor will not normally mix with either lamp oil or kero, the thing that gets it to mix and stay in solution is the ether. Ether is a very strong solvent, without it we need to use a synthetic oil or mineral based oil. If you still have the mix you made up put in 35% JD and it should mix just fine.

Greg,
Heres a quote from Ron's engine site:- http://modelenginenews.org/faq/index.html#qa5 re castor solubility " Castor oil is not normally soluble in ordinary petroleum oils, but if you polymerize it for several hours at 300 degrees F, the polymerized oil becomes soluble. Hydrogenation achieves somewhat the same effect." So it looks like there is an answer to kero castor only fuel. This also may be why some bottles of castor mix and some dont , depends on how it was processed.
Stewart

Good evening Greg,

Further to my comments earlier about my being able to mix Sig Castor oil with kerosene. Initially it went into solution and seemed to be ok. I looked at it today (4 or 5 days laters) and it too had separated. It was sitting in the basement. I tried some lamp oil and eventually seperated out as well.

So, it seems the old wive tale of Castor not mixing with kerosene is true. However, this still leaves Andy's experience of having it mix reasonably well. I think the difference is he is using Klotz Benol which (according to their literature) is a more highly refined castor oil which they describe as "Blends With Methanol Alcohol, Nitromethane, or Gasoline".

So, if we want to use Castor oil in your no ether diesel we will have to use Klotz Benol but that even has some limitations as Andy has noted with regards to temperature and separation.

cheers, Graham in Embrun near Ottawa Canada.

That could explain it. Klotz Benol or the Maxima Castor 927 I have is a high quality oil. Sig castor is half the price of these. Still, it looks like they will separate at lower temperatures so it might only be suitable for summer. I'm looking at petroleum based oils now. I hate to run regular engine oil as I think it will leave carbon in the engine. I don't think common two stroke oil is going to be suitable. Klotz R50 looks good but it's no cheaper than Benol. I want to blend fuel at less than 10USD per gallon and a special oil kills that when a quart costs $12. Fuel consumption on etherless mix in my four strokes seemed so low that it might still be significantly more cost effective even with expensive oil.

What do we want to call this fuel blend? Etherless? If we can make it work we will need to differenciate fuels in the forum.

I have told the story several times about running a glow plug K&B 4011 on Davis 1/2 A fuel. Started with the glowplug lit, took the battery off after maybe 20 seconds. One engine ran fine, other undercompressed, but would run fine with glowplug lit. Unless the unlit glowplug was contributing some heat (don't think so, but don't know) the glowplug compression was fine for that fuel.

Jim, I'm not sure what you are getting at. Davis 1/2A mix is 52USD per gallon. We are trying to come up with a fuel that is cheap and easy for anyone to get.