When it comes to starting I have been able with the use of an electric starter to start the PAW engines the same way as the conversion engines. I don't move the compression or needle just get a couple of choke primes, pull it through to make sure there's no hyro lock and apply the starter, away it will go burring a bit then smooths. This works with commercial diesel with at least 30% ether.

Since I had not flown continous over the hot summer here in FL my fuel has lost some of the ether and now needs to have the needle opened about 3/4 turn to catch. If I hand start on fresh fuel again no problem but if it loses some ether (my guess is down to about 25% or so) it is easier to start it you increase the compression also by 1/2.

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Let's drop the pretense, Dave. You know perfectly well what I am saying. As does everyone else.

I don't think that Bob is a bad guy. I would have said so directly a long time ago if I believed it to be true.


Ed Cregger

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You missed my point entirely, Dan.

I never write anything on a forum that I am not willing to say directly to someone's face. I am not implying that you said otherwise.

I am fully aware that many people behave differently in person than when on the phone or writing in a forum. Having been a ham radio operator for many years, I have seen this phenomenon demonstrated many, many times.

I've been saying all along that Bob is a very knowledgable person who sells great products at good prices. I am not anti Bob.

Ditto on the forums.

When someone writes a question to the Diesel Forum, it is because they do not know something and they need information.

If I didn't deep down like Bob and have a lot of respect for his intellect, I wouldn't have bothered to write any of this stuff. I have made my point the best that I can, so there is no point in repeating what I have said. As far as my participation on this particular topic is concerned, I am through as of now.


Ed Cregger

The title of this thread is about compression and how that relates or not to exhaust colour.

We have been hearing the old saw for a great many years about how 1/2As run too cool by some very knowledgeable and competent people in the engine business.

Bob Davis is the first I've ever heard of that set that one straight, that in fact, 1/2As tend to run too hot and he did a good job of explaining why. It has to do with mass. This illustrates a high level of knowledge and understanding about physics, engines and fuels. I'm willing to bet that Bob's knowledge is a result of a lot of hard work, research and not the least, an intellect capable of getting to the heart of a problem.

This thread started out well and then fell apart. I was hoping that the feedback from the gang might provide some insight into what NOT to do when dealing with such a diverse bunch as we all are. You have to be unique in mindset and approach to appreciate what diesel combustion can do for you in your love of the hobby. Dare I say that Bob epitomizes this to a degree that even we, in the SAME camp have yet to measure up to and are finding hard to understand. Yet it must be said that if your love of a thing is also your business then business concerns inevitably will taint your reaction to opinions and approaches to issues.

I honestly don't think that any one of us were doing any bashing. I do believe that we were just trying to point out where the thing went wrong. No one, absolutely no one involved in this has any mean spirited motives. We're all seeing the issues from our own unique perspectives. We all have our own personal biases, experiences and points of view along with varying levels of knowledge and understanding.

I've noted differing exhaust oil colours and never thought much of it because I was always dabbling with the chemistry. I assumed that the fuel mix had a lot to do with it and as long as the engine ran, I was happy. Except for rod wear, I've not seen any engine failures related to the colour of the exhaust oil residue on the plane.

But here's something to ponder about colour. After I settled into using the 40/40/20 mix for the Norvel .074 I had occasion to run out and just didn't have any ether left to make some more. Sunday and all and industrial outlets are closed on that day. So I grabbed a can of old fuel just to get in some air time and not let a good evening for flying go to waste.

I wasn't expecting much because this was a quart can in which I had soldered a brass tube in the cap that ran all the way to the bottom of the can. The other brass tube was a short one and this was the fill outlet. The long tube to the bottom was the vent line so that an inverted can could still vent and I could fill the tank by squeezing the can. This was a diesel fuel management system I had made up many years ago based on what I read at the time.

That can of fuel was partly filled with some fuel that was at least 5 years old. That can was also my place to dump excess fuel from the bit left in the bottle left over from a days flying. That can also got a shot, now and again of the remnants of some of my more bizarre mixes. It ended up about 3/4 full and sat like that for at least a year. By then, I was using a transparent poly bottle for fill up and when I did, I noticed that the fuel was a deep, rich, transparent green. Darker even than Cool Power. None of the ingredients that ever went into this can were green.

As it turned out, that fuel was some of the best that the .074 had ever ran on. It started easily and throttled very well but based on verticals that I could now do, it was estimated to be 25% more powerful . Stock fuel will just hover the MiniSport. THIS fuel would allow a gently climb from a hover.

Green fuel. What could have caused that? The only time we see green in a fuel is when those brass tubes and clunks corrode when we leave them soaking in fuel. Copper oxide? Could this, if that's what it is, be a power enhancing additive?

Hi Andy,
I sympathise with your family health problems at this time. I wondered why you had "vanished" for a while.

I came across a reference, online somewhere, about bio-lubrication. It had been found that a very small amount of copper in the lube made a fantasic difference to the lubes performance and lack of engine wear.

Now for a challenge.... being as how it was so good then make another batch of that "unusual" fuel mix. I bet you wish you had details of what went into that can and in what amounts []

Reg

Reg,

Thanks, vagaries of life,,, that's life. There, but for the grace of god go I, etc. so I do what I can, to help.

Yes, it might have been just the copper or who knows what combination. I had castor, 50 wght Avoil, a dash of WD40, mineral spirits, acetone etc. etc Gives credence to Bob's mention of five ingredients instead of two. I'm sure he has something important he's discovered and added to his fuel. In that case, he gets to keep it to himself. More power to that.

But copper in what form? Not sure I can wait five years for brass tubing to do it's magic,,, if that's what it was. And now, as you mention it, we touched on the copper thing a while back. Don't recall what came of that. There should be some chemical supply houses here that might be able to help.

Hi Dan,
I don't really think we need a forum just for diesel fuel. This forum is "Everything Diesel" I guess that means engines,props, fuel, comparisons....... etc, etc.

All anyone needs to do is select the posts they think will be of interest to them. I don't read every post on here. I scan several forums on RC-Universe every night, and I do mean scan.Take for instance the glow engine forum, I look at it every day but there are only a few posts that I read as the rest are of no interest to me. It's just the same as when you go to a library. There is a huge wealth of knowledge and also entertainment in a library. When you go there you don't set off to read every book in the place, instead you browse and select books that look as though the contents will be of interest and worth reading.

I use Linux as my operating system, rather than Windows. I am on a mailing list which gets me 100 to 150 emails a day specifically about Debian Linux. I don't read them all, I just scan through the subject lines and only read the ones that have some interest to me. I KNOW nearly everyone uses Windows in some form, but that's because they haven't explored the alternatives ! So... not everyone wants to use Bill Gates "formula" for the perfect operating system..... there are a significant number who choose otherwise.

As several of us have stated before..... buying commercial fuel, from whoever, is a guaranteed way to easily start and run a diesel. If it is available then it is by far the best way for someone, especially a newcomer, to use diesels.

Those experimenting with "homebrew" fuel mixes are NOT advising anyone to try them. We do NOT criticise commercial fuel or it's suppliers. We are happily experimenting away and discussing the subject with others that are interested. No one HAS to read these posts and no one has to KEEP telling us that commercial fuel is available (from whatever source) we know that !

Commercial fuel is GOOD. Commercial fuel is AVAILABLE (but not everywhere) Commercial fuel ensures GOOD starting and GOOD running.... there is absolutely NOTHING wrong with using commercial fuel. Some however are messing about seeking an alternative both for themselves and others who may want to try a different way of doing it.

There are any number of wonderful commercially produced cars, suv's.etc out there BUT there are still those guys who are going to build their own car from a kit or whatever.

Just one last time.... for those that are criticising the posts on alternative fuel ingredients and mixes..... I am probably wasting my time but.....

If it is not a subject that interests you then DON'T READ the posts, it's not compulsory.

Reg

ugo

Despite all anyone has to say, I still like carmel to clear exhaust!

In my earlier post I mentioned a simple fuel option and it seemed to be taken the wrong way. My intent was not to have everyone switch to home brews but rather for thoses that can't get commercial diesel fuel to look at an option that might allow them to fly and have fun with their diesel. I understand that the simple SF & mineral oil fuel it is not the most powerful diesel mix and that the commercial mixes offer slightly higher output and possibly a little smoother running. The other chemical components that the commercial fuels include serve their purpose but if commercial DF it is not available then something is better than no fuel at all. The idea of using just the starter fluid and oil was to keep it as simple as possible, it has been written on this forum that you could also add Kero (lamp oil) but as I said this adds more complication. As it turns out in a recent artical on Fixed Compression diesels the author said he used a similar mixed because the FC diesel needs much higher ether than those with variable compression, but it should also work in the VC diesels just fine (he did indicate that to get smooth running you need to use mineral oil not castor as the MO controls the tendency of the ether to detonate). Again the commerical mix is easy to use and if you can get it so much the better, if you can't try the SF and mineral oil.

Doh!