Davis Diesel experiences?

Anybody here running Davis Diesel Development heads on engines in the .40 -45 range? What results have you had? What about engines in the
.10-.15 range? How much quieter are they?
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I had a converted OS.32F-H ringed. It was much, much quieter than when ran on glow.
I have also ran a friend's OS .60FSR on Davis's Diesel Conversion head and fuel. It too was very much quieter than on glow. It handled about the same as my .32.
The smell and cantakerous nature of handling the fuel is what made me return the engine to glow use, although it was fun to operate it as a Diesel. If that engine hadn't been such a fantastic glow engine, I would probably have left it a Diesel and just toughed it out through the smell and quickly evaporating fuel of the Diesel.
NI
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Geoff Sanders wrote:

I converted a .75 to diesel and was impressed with the starting, noise, and idle. I didnt keep it as I didnt like the smells.
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Between the noise and the stink, I will settle for the stink. But enough about my sex life!
:-)
Mike Mandaville Austin, Texas
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I have no experience of Davis diesel conversions, but do know of their existence.
On this side of the pond, there are specialist diesel engine makers and, over the years, I have had a wide cross section of these.
Generally speaking, diesels are considerably quieter than their glow equivalents, can comfortably swing larger props at lower revs with therefore less prop noise, and can handle a greater range of prop sizes because of the variable compression. They are also, as a rule, much more economical with fuel.
The fuel isn't as agressive as glow fuels especially those with Nitro, so "high spec" fuel proofer isn't needed.
There is a "down" side - the fuel is more expensive than glow fuel (partly offset by the economy), and the exhaust residue is "dirtier" leaving black streaks on the airframe.
Plastic film coverings suffer - wrinkle up, go slack and peel off. Solartex seems to be unaffected but, unless given a coat of some clear lacquer soon looks very grubby as the exhaust "gunge" sticks in the weave.
HTH
Malcolm

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I had nothing but bad luck with the diesel heads and even worse luck talking to the nitwit that owned the place.
"Sullen" "moody" and "grouchy" all come to mine when I think back on my dealings with Davis.
I'd have to recommend looking elsewhere. Cheers, jc
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jc wrote:

The trick is you dont talk to him, you dont have an opinion, and you just listen. Problem was I didnt know when he was done. He didnt give me a very friendly experience on the phone in the past.
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Judging by what has been said here, and on previous posts re Davis Diesels, I would recommend going directly for a purpose made diesel. There is a considerable choice of makers and capacities.
Just my two pennorth,
Malcolm
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message

Having ran both purpose made model diesel engines and the DDC (Davis Diesel Conversion) heads, I can understand why people buy the latter.
First of all, they probably already have the engine that they might convert to Diesel operation. The price of the conversion head is much less than buying a comparably sized purpose built model Diesel here in the USA.
Second, if they don't like Diesel operation, the DDC user can return their engine to stock and then sell the DDC head very quickly at a small loss, as long as they bought a head for a popularly owned/used engine.
The DDC heads perform close enough to a purpose made Diesel engine to let the owner/operator know if they want to continue this type of operation. If the stink and finicky handling required of model Diesel fuel doesn't turn you off, the Davis setup will serve you quite nicely.
Purpose made model Diesel engines are expensive and unfamiliar here in the US.
The down side of DDC conversions is that a converted engine may not be as easy to set up/handle as a purpose made Diesel. It is also possible that the glow engine that has been converted may not be up to the task of handling the higher cylinder pressure that is developed, IF the engine is ran overcompressed for a lengthy period. Although, I have to admit that the DDC conversion heads do not permit you to run excessive compression ratios on the engines that I have fiddled with. Higher than optimum? Yes. Damaging? Well, it is less prone to damage the engine than were it fitted with a conventional contra-piston setup.
If I lived in England, where there are/were a few manufacturers of model Diesels, I might be tempted to go with those engines instead of a DDC. But here in America, it would be a close call.
NI
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Davis Diesel is now on the web:
http://www.davisdieseldevelopment.com/home.htm
I paid fifty-five dollars for my OS40LA, and I see that it would cost me another fifty-five dollars to convert it into a diesel. To purchase a cylinder head for the price of an engine seems unreasonable to me. Who else makes diesel conversion heads?
Mike Mandaville Austin The United States of Texas
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The reason for the seemingly high price of DDC heads is simply a matter of scale.
OS is a very large organization, relatively speaking, that can amortize its R&D, machine equipment and labor over a lot more engines than Mr. Davis will ever produce. The more you make, the cheaper they get.
NI
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notimprest correct spelling wrote:

Well, thank you for the lesson in economics, Mister Notimprest, but since I have the economic advantage of being already tooled up to produce my own diesel conversion head, should I choose to do so, there is no way in hell that I am going to pay that much. I am still looking for those alternative diesel conversion head suppliers.
Mike Mandaville self-employed in my twenty-first year of business
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Damn, Mike. I didn't mean to step on your toes.
Since you are a businessman, you know that you charge whatever the market will bear. Right? If not, you won't be in business for long. You make the money while you can because it won't be long until what you are selling today won't be in demand tomorrow.
But why am I telling you this? You already know everything.
Still, that doesn't explain the stupid question.
NI
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Hello, Mister Notimprest. That is a very impressive name, by the way. Do you use it at your place of work, or only when you are socializing?

Well, Mister Notimprest, I am happy to inform you that you are quite incapable of stepping on my toes. Whatever gave you the impression that you possessed that ability? Please be specific, for I am finding you to be quite entertaining.

Absolutely not. So far, I have worked in at least three seperate service service fields where my tips _far exceeded_ my official authorized rate.
If not, you won't be

Mister Unimprest, I have been in business for twenty years, and I have yet to set a single price. My customers set their own price, and they compete against one another to do so.
You make the money while you can

Mister Unimprest, "Take the Money and Run" was a wonderful movie, and a wonderful song. They were both meant to be comedies. Neither was meant to be taken seriously. And my present service will be in demand for as long as the grassn grows. How long do you think that wuill be?

No I do not, nor have I made such a claim. You are making an insulting false accusation.

What stupid question? You have not made yourself clear. You obviously percieve yourself to be speaking with authority, but I don't think that anyone here could have any idea what the hell you are talking about

Mister Notimprest, anyone who would try to impress you would be a fool. Should we all be trying to impress you?
Mike Mandaville
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Whatever...
NI
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| I paid fifty-five dollars for my OS40LA,
A pity -- it's not a very good engine. Oh, it works, but it's lacking in power and I've heard they're finicky. A Thunder Tiger 36 or 46 at $75 or $79 would be a lot better. But more money, so ...
| and I see that it would cost me another fifty-five dollars to | convert it into a diesel. To purchase a cylinder head for the price | of an engine seems unreasonable to me.
As suggested, it's very much a niche market. Davis wants to make some money, but doesn't sell too many, so he charges a lot.
| Who else makes diesel conversion heads?
As far as I know, nobody. There's little demand for diesel R/C engines (though our stock engines work on the same principle, except that the glow plug helps the fuel ignite) so there aren't many sold.
Why? I know some people don't like the smell of the fuel. Beyond that, I don't know, but it's true -- they're rare. I've heard that the diesel conversion heads are very finicky to make work, but that the engines that were designed as diesel from the beginning are not.
From what I can tell, you've got a very limited budget. So I'd suggest not messing with diesel for a long time, if ever. You mentioned you wanted to do it to keep the noise down -- well, if you want something really quiet, you go electric or unpowered glider. But you can quiet a glow engine too by using a prop on the larger end of what's suggested, and sometimes you can improve on the muffler.
| Mike Mandaville | Austin | The United States of Texas
Wouldn't we be the `United State of Texas'? Not that Texas is united in anything, but ...
--
Doug McLaren, snipped-for-privacy@frenzy.com
If two wrongs don't make a right, try three.
  Click to see the full signature.
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Doug McLaren wrote:
lacking

Hello, Doug.
Thank you for your offer of pity. However, since I myself am pleased with my purchase, your offer is therefore inappropriate. And now I will return your offer. Doug, I pity you for imagining that I care what you think about my engine. I honestly don't give a damn.
Mike Mandaville
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wrote:

Whatever you paid for your engine, if it does what you want and YOU are satisfied with its power output, whatever anyone else thinks doesn't matter a jot.
Don't waste your pity on those who think you should have gone to a higher spec engine - you're right to "not give a damn".
Malcolm

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message wrote:

What neither you nor Mike seems to understand is that what Doug said was not meant as a put down. Pity.
Mike looks for issues to fight over, as I have recently discovered. I have no time for that behavior or attitude. And I really don't care if you don't like it, Mike, so save your fingers some unnecessary typing.
Ed Cregger
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Mecoa makes one for the OS FP .40, reasonable price too!
http://www.mecoa.com/acc/diesel/index.htm
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