Oil 30% is like ... 5% nitro, how about that ? (Full Version)

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NikolayTT -> Oil 30% is like ... 5% nitro, how about that ? (8/11/2007 12:06:59 PM)

Hi Fellows,

If Methanol is mixed at home with only Castor oil 20% the price for fuel is lot(!!!) lower and the engines last much longer.
Further more, if increase the oil to 30% (and rest only) methanol makes the same rpm (!) as 5% nitro CoolPower fuel.
Surely one has to "wash" the engine&tank at the end of the flying day with one flight with 30% Aerosave(synthetic)oil
and methanol; then spray about 20cc of only aerosave oil inside, rotate with starter and next flight could be even
the ... next year, no corrosion and no black sediments in the engine - it is jist like new inside. I have used this
many years and currently the tachometer readings are on OS.91, standard mufler, rpm 12800 on 13x7 Graupner
g-sonic propeller in either case, CoolPower 5% or my mixture of 30% oil and 70% methanol. Surely there should
be some explanation why higher oil content makes more power; I do not know that; some idea ? Also, what do you
think, do you see any problems in this approach ? Of course glow plug is A3 not OS8, and the shim under the head
is thiner or "lost"; no detoinations and cool running nicely engine with good enough idle and transitions.

Cheers,
Nick



pe reivers -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/11/2007 10:24:01 PM)

Heck, you found out you can do without nitro! Also, that engines run on oil.
Now it's no secret anymore?
enjoy.



XJet -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/11/2007 11:30:44 PM)


quote:

ORIGINAL: pe reivers

Heck, you found out you can do without nitro! Also, that engines run on oil.
Now it's no secret anymore?
enjoy.


Yeah, I flew for about 40 years without using a drop of nitromethane -- just good old 80% methanol, 20% oil (castor or MSSR).

These days however, I'm finding that my (modern, primarily designed for the US-market) engines run perceptably better with as little as 5% nitro so that's what I use.

Oil however, is a whole different story ;-)

Using a (far) smaller amount of the modern hi-tech synthetic oils (which doesn't mean Morgans or Klotz) can produce some significant performance increases without sacrificing protection or longevity. It's still nice to have a few percent of castor to act as a corrosion inhibitor and "last line of defense" against a protracted lean-run though.

Model engine technology has come a long way in the last 40 years, so has lubrication technology. It makes little sense to use 40-year-old oils in a modern engine.



NikolayTT -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/12/2007 5:26:49 AM)

Hi Guys,

Do you suggest to use some Oil-type which one can buy in an ordinary Gasoline Station
and which is used for the 2-strocke bikes/scooters for example ?
In fact that would be very interesting solution and I believe cheaper than Aerosave oil,
which here is about 17 Euro per liter. Sure, price is an issue if one is flying lot more than
couple gallons per year. Castor costs 4 Euro and the Methanol I am buying is 0.8 euro
per liter. I.e. I am flying almost for "free" if we compare the price per galon CoolPower
of any nitro content including 0%, and even cheaper than Gasoline ... almost.

Regards,
Nick



pe reivers -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/12/2007 10:12:26 AM)

These oils do not mix with methanol. The synthetics that do mix are still quite oldfashioned, and the market is too small to do a lot of research for the right additives. That may change if all engines will be required to run on E80 ethanol fuel. Then we would get some decent synthetics that would be as good as castor oil. The Fuchs oils Aerosave and Aerosynth are closing the gap, but are not up to par with castor.



XJet -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/12/2007 10:16:04 AM)

There's not much you can buy from the gas station that will mix with methanol unfortunately.

Virtually all of the modern 2-stroke mixes (for gasoline engines) will not mix with methanol so can't be used.

Here in New Zealand we have the same problem -- oils like CoolPower/Morgans and Klotz are expensive because you must use so much of them (18%-20%). That's why we've been using Coopers Plus C oil. It costs a little more per litre but can safely be used at 12% or less (by volume) so the actual cost (per litre of fuel) is lower than CoolPower/Morgans or Klotz -- and you get better engine performance and protection as well.

I've found that, when mixed at 12% by volume, fuel made with Coopers oils and 5% nitro gives the same RPMs as a fuel that contains 18% of CoolPower oil and 12% nitro -- but at a lower total cost.

In your part of the world you've got AeroSave, AeroSynth and Motul Micro which are also (I believe) very good oils that will work quite happily at ratios as low as 10%-12% by volume.

This means that a litre of AeroSave/Synth/Motul would make almost 11 litres of fuel. A litre of CoolPower/Morgans, Klotz or castor by comparison, will only make 6 litres of fuel. Do the sums and you may find that those expensive oils actually aren't so expensive after all.



NikolayTT -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/12/2007 10:58:35 AM)

Couple fellows arround here run their 20cc and 26cc OSMax on 16% Nitro, 16% Aerosave, and rest Methanol and still ... wander
whey have to change so frequently engine parts, recently one of them had the connecting rod comming ... out of the crankcase.
Aerosave oil seems very good, but it is not a "magic" one. Those around here who use it and do not change engine parts so
frequently are telling that they use it at 20% with 10% Nitro and rest Methanol; those are mostly F3A guys; I was surprised
that most of them do not go beyond 10% even for F3A where they care even too much for power output.

When I asked why not Castor, the only answer was that only the greese and smell is the problem, since Castor is difficult to
wipe out as the Aerosaveoil is; in fact it seems Fuchs has even added some kind of nice smell to it; ohh... those Germans ....
Well, if someone has problems with washing oils, then he better go to Electric as soon as possible, isn't it.

As for the oils in Gasoline station, I just jumped there and the best Fully Synthetic Shell-made Oil is 'Advance Ultra for 2S'.
Its price is 13.6 euro per liter, and even if mixes or not with Methanol, this for sure does NOT "mix with my valet" - it it is
about 3x more expensive than Castor even if I add the price for washing liquids I have to by to clean my models.

At the local Shell station they didn't know about the MVVS's adviced 'Shell-Racing-M'. I wander how much that might cost
and Where to Get that from ??

Still, it remains MYSTERY at which Oil % the delivered power is similar to 5% Nitro CoolPower, and WHY is that ?
Of course if there is such Optimal proportion, that would depend on the Oil type. Maybe there could be something
like 25,67% of Castor oil when the Power is near to the CoolPower of 10% nitro, or I am just dreaming in too
early and in a Daytime for Christmas Presents ???

Let me trow the dices: - I would, in a simple minded approach, suggest that Power increase at higher oil
content is due to a bit Higher Compression in the chamber and a bit less Friction in all moving parts ?!?!
Would you support such Explanation or you have some more, hopefully at least a bit more scientific one ?

Cheers,
Nick



pe reivers -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/12/2007 12:22:10 PM)

Your assumption is scientific enough.



Marcol -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/19/2007 1:06:07 PM)


quote:

ORIGINAL: pe reivers

The Fuchs oils Aerosave and Aerosynth are closing the gap, but are not up to par with castor.


Pe,
Whilst I value your knowledge and experience, I have been using a fuel containing Aerosave for about 5 years now and the performance , cleanliness and corrosion protection offered by Aerosave puts castor oil very much in the 20th century.

I'm curious why you still think that castor oil is better. I certainly would never use it again.

It would be like using an old fashioned mineral oil in your gas engine !

Colin




NikolayTT -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/19/2007 1:23:08 PM)

I hope Pe gives the professional answer, but meanwhile I can share what I am doing: Flying whole day with Castor and the last flight - with Aerosave.
Then spray 20cc of Aerosave oil inside rotate 20 sec with starter and next flight could be after a year, no corrosion at all. Engines are looking extremely
happy. I guess the only bad things about castor are: 1) It is not good to be inside of any metal thing longer than needed. 2) It is not good for lower
temperatures, like winter flying - then only Aerosave oil would work.



pe reivers -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/19/2007 2:50:12 PM)

nikolay,
I think your way of using castor is excellent and shows insight of the needs of an engine.
In my tests on small MVVS engines (8cc and smaller), I also tested Aerosave and Aerosynth, along with other synthetics. The first runs with the synthetic, the engines run like with the devil on their heels, wit a lot more power. Then slowly, power tapered off until the engine would barely run like at half throttle settings, whilst needle adjustments became nearly impossible. Restoring the engine to castor mix, also restored power within a tankful of fuel. I am not alone in these observations.
I now use Tornado fuel with extra castor, which is the only one synthetic that works for my small MVVS engines. Larger engines run well on Aerosave and Aerosynth.
Blending Castor with Aero* did not work well, because the additives in the Fuchs oils causes some strange jelly stuff formation, that plugged the needle jet.
As far as I know, it is only MVVS that responds this way to synthetic oils, but it goes to show that castor oil has no lubrication limits. It becomes thicker at temperatures at which other oils fail. This cannot be said in favor of synthetic oils.
I too abhor the castor mess, but that is no reason to downgrade the lubrication properties of 20th century castor, which still is way ahead of the synthetics that will blend with methanol.
Fuchs succeeded in develloping additives to improve the base stock. These additives are not compatible with castor. Other synthetic oil manufacturers went to castor oil blends (compounded oil) to achieve at least some of the castor benefits.
In standard lubrication history (not for methanol) Compounding mineral oil with castor up to 10% improved the dino oil quality above both the stock oil and the castor. This worked well until the advance of the synthetics, which can be engineered to exactly the purpose they are needed for. Too bad, these syntitics (none of them) will mix with methanol, so they are of no use to us.



XJet -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/20/2007 4:59:43 AM)

quote:

ORIGINAL: pe reivers
In my tests on small MVVS engines (8cc and smaller), I also tested Aerosave and Aerosynth, along with other synthetics. The first runs with the synthetic, the engines run like with the devil on their heels, wit a lot more power. Then slowly, power tapered off until the engine would barely run like at half throttle settings, whilst needle adjustments became nearly impossible. Restoring the engine to castor mix, also restored power within a tankful of fuel. I am not alone in these observations.

This is *very* strange. Perhaps (as you suggest) it's behaviour peculiar to MVVS engines. I've found that after witching to a good synth/cator blend my engines "run like with the devil on their heels" but just keep on going.

quote:

As far as I know, it is only MVVS that responds this way to synthetic oils, but it goes to show that castor oil has no lubrication limits.

Not strictly true. If it were true then you could *never* seize or damage an engine running a fuel with castor for oil. The reality is that you can damage engines even when running castor-based fuels.

quote:

It becomes thicker at temperatures at which other oils fail. This cannot be said in favor of synthetic oils.

That is true. Although castor does reduce in viscosity as it gets warmer, it does polymerize rather than vaporize, thus creating a solid layer that acts to limit metal-to-metal contact -- but this is kind of like saying "you should fly over water or snow because crashing in the ground may damage your motor" because...

The reality is that if you tune your engine properly, modern synthetics will operate well-within the temperature range at which they protect and lubricate well. There are legions of folks who have run nothing but synthetic oil (and some of them even run rather poor PGA-based synthetic oils) but have never had a lubrication-related failure.

The best way to avoid heat-related engine damage is to tune your engines properly and ensure adequate cooling.

quote:

I too abhor the castor mess, but that is no reason to downgrade the lubrication properties of 20th century castor, which still is way ahead of the synthetics that will blend with methanol.

Define "ahead" :-)

It should be remembered that different folks have different priorities in respect to what an oil should do. In the areas of extracting better fuel-economy and performance, the synthetics are *better* than castor. In extremely cold conditions, synthetics outperform castor simply because they don't suffer such a drop in viscosity. In the area of mixing with high amounts of nitromethane the synthetics win again because it becomes very hard to keep castor in solution with high nitro percentages.

True, castor will provide additional "last chance" protection against a lean run -- but if you're the kind of modeller who knows how to tune their engine and who recognizes the symptoms of a lean engine (thus landing immediately), this may be of lesser importance than the benefits you get from a synthetic oil.

quote:

Fuchs succeeded in develloping additives to improve the base stock. These additives are not compatible with castor. Other synthetic oil manufacturers went to castor oil blends (compounded oil) to achieve at least some of the castor benefits.

I've not used Fuch's oil but it might pay to try a different brand of castor just to make sure it's not additives in the castor that are causing the problem. Some companies (such as Klotz and Morgan) claim to add "friction modifiers" and other chemicals to their castor. These may have caused the gelling you speak of.

quote:

In standard lubrication history (not for methanol) Compounding mineral oil with castor up to 10% improved the dino oil quality above both the stock oil and the castor. This worked well until the advance of the synthetics, which can be engineered to exactly the purpose they are needed for. Too bad, these syntitics (none of them) will mix with methanol, so they are of no use to us.

The most common synthetic bases used for automotive engines are PAOs (polyalpha Olifens) and Esters. The first will not mix with alcohol but I gather the second will. Some synthetic motor oils seem to be almost entirely PAO, others Esters. Another group seems to run a blend of both.

The fact that Motul and a few of the other advanced model synthetics are also ester-based indicates that our better model lubes are every bit as good as the automotive ones these days.

In the meantime, I'll keep running a synth/castor blend and get the best of both worlds. Great performance, excellent protection and minumum mess :-)

Note: I'm not a chemist or an oil expert but I'm learning as much as I can as fast as I can ;-)




NikolayTT -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/20/2007 11:37:24 AM)

Well, there would be a point to take more seriously the Synthetic oils, as you suggested, but when you look at
the PRICING the good reasons are downgraded by a factor of at least 4 since the price for one liter Castor from
industry is about 4 Euro, while for reliable synthetic oil you cannot get it for less than 17-20 Euro per liter.
Of course I am talking about frequent flyiers, and after see what is the peromance of my several OS.91FX,
i.e. exactly as Pe wrote, they need to get a tank with castor oil fuel (25% in my case) and then they work
again much better. Can you explain that, and if you do not find explanation, maybe it is good to try and
see by yourself ? - It is not a coincidence that many non-castor oil guys buy a lot of spare parts; that makes
the castor "priceless" and the synthetic oil - much more like an additional "Tax office". Surely I agree about
that castor is more messy and it is not good for lower temperatures, but at freesing temperatures I guess
most RC people build next plane instead of getting their fingers "out of use"; I am happy with castor untill
the temperature goes below +5 Deg C; then also my fingers tell me "go home".



XJet -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/21/2007 4:27:19 AM)

Nikolay, you are lucky to be able to buy castor for such a low price.

Here in New Zealand, castor oil costs exactly the same as synthetic (about NZ$18 per litre).

I would probably use a lot more castor if it were only 1/4 the price of synthetic -- even it that was just to save the money.



NikolayTT -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/21/2007 6:36:27 AM)

XJet,
Have you checked the price in a Drugstore, is it that expensive too ? Also, somewhere in the cosmetic industry
or whatever industry which uses Castor as input material for their products the prices would be very much lower.
That is usually not the case for Synthetic Oil, it is a "fianl" product for sale itself. Nitro is also avaiale at very low
prices but those industries are making "things" which are a bit to off of the general use... Methanol is used in
Washing liquids almost everywhere and thus very cheap. AS it was said already in the discussion, if we take
as normal that RC engine has 100 hours live, that for 15cc engine (average one between 7.5cc and 26cc) will
make like 200 liters of fuel. I.e. What Ever the Price of the Fuel is, the MULTIPLICANT is 200, so that is HELL
off Difference, thus investing time in finding those ingerdients is just very much smart thing to do indeed.
Try harder and post some other ideas about Where the Cheap Fuel is - that might be another good alternative
name for this discussion, isn't it ?



XJet -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/21/2007 9:36:41 AM)

quote:

ORIGINAL: NikolayTT
if we take as normal that RC engine has 100 hours live, that for 15cc engine (average one between 7.5cc and 26cc) will
make like 200 liters of fuel.


You must be using bad oil :-) My oldest engine (a Thunder Tiger 46Pro) now has more than 300 hours running and is only 300 RPMs down on a brand-new one.

I expect my engines to run for at least 250 hours or longer, with only an occasional change of bearings during that time.

But, I also argued the case that sometimes we get too fussy about our oils because it is often much more cost-effective to use cheaper fuel and just replace the engines more often than to waste lots of money on high amounts of expensive oil to protect an engine that is really quite cheap to buy.

Mind you, with modern synthetics and a splash of castor, I can now run low oil ratios *and* get a very long engine life so I'm happy.




NikolayTT -> RE: Oil 30% is like ... 5% nitro, how about that ? (8/21/2007 12:05:10 PM)

Surely you have added in fact two more good points:
1. 250 hours instead of 100 hours ! Great, that makes my statements 2.5 times stronger.
2. Synthetic oil is good but for me in fact I am using it "once-per-day" ...[sm=shades_smile.gif]
Well that "bad" castor oil is used for food, thus it might be quite "healthy" thing too...[sm=tongue_smile.gif]
anyway do not drink that neither at home nor at the airfield...although is less harmful
than Methanol and Synthetic oil which are real poison.

Honestly I break in crashes my engines lot earlier than 250 hours ... [sm=wink_smile.gif]



asmund -> RE: Oil 30% is like ... 5% nitro, how about that ? (9/5/2007 12:26:37 PM)

I keep reading about how engines must have castor to operate well, and especially MVVS. However this season I have fed my MVVS 49 nothing but 5% nitro 15% synth and it runs better than ever. I tached it on APC 12-4 last time I flew and it peaked at 14200 rpm wich is 200 rpm more than last year when it got a healty dose of castor, so go figure..........



NikolayTT -> RE: Oil 30% is like ... 5% nitro, how about that ? (9/5/2007 3:33:05 PM)

Well, surely it is maybe faster onthat mixture, but let see how long it will last ... and also you might still try much higher
oil content and see how more oil "works like" more nitro, yes I am not kidding, just try an look at the RPM metter.
In fact oil is lot cheaper than nitro, isn't it ?



asmund -> RE: Oil 30% is like ... 5% nitro, how about that ? (9/5/2007 4:58:21 PM)

Yes, castor is cheaper than nitro in Norway, but at about 15$ a litre, castor is still expensive enough that nobody cares to buy it and add extra oil to the premixed fuel. I don`t use my MVVS very often and I guess it will last for years and years, besides spareparts are very cheap too. I will rather enjoy a less slimy plane and then MAYBE replace the setup in 5-10 years. It sure runs great without castor, thats for sure



gkamysz -> RE: Oil 30% is like ... 5% nitro, how about that ? (9/24/2007 9:00:40 PM)

Couldn't we attribute the slight increase in performance by adding extra oil to the fact that oil is incompressible. It slightly raises compression ratio because of the volume it takes up in the combustion chamber. It would be easy enough to test?



NikolayTT -> RE: Oil 30% is like ... 5% nitro, how about that ? (9/25/2007 4:46:03 AM)

Similar question I had in my post#6 above. Additional prove for the compression ratio being at least
affected indeed comes from changing the glow plugs - warmer glow plug like OS A3 on 30% castor
fuel gives a bit more rpm than OS8. And also, when the glow plug OS8 was re-connected to the
power supply it gave few hundreds of RMP more at the high-eng, I believe that is a clear indication
that warmer glow plug is needed. Or the other way arround, maybe at given glow plug one should
experiment how much castor from 20 ...till...30 % is the best for max power. And since this also
is sensitive to temperature and humidity (I guess) then obviously a smater approach would be
buy a Glow Plug Driver and forget once for ever the Nitro and also decrease the sensitivity to the
type of the glow plug, i.e. "universal medication". I might be dreaming for that due to the cold
weather here, because I do not see many guys running Glow Plug Drivers; wander why is that ?



downunder -> RE: Oil 30% is like ... 5% nitro, how about that ? (9/25/2007 5:43:00 AM)

Combustion chamber size is on the order of 2000 times larger than the volume of oil that passes through in each cycle with around 20% total oil in the mix so adding a bit more oil will make no appreciable difference.



NikolayTT -> RE: Oil 30% is like ... 5% nitro, how about that ? (9/25/2007 6:02:51 AM)

Because there is visible difference between 20% and 30% castor in the same time&place, i.e.
air temperature etc. so is it then the ignition timing affected somehow ?

Also, I did not try yet changing different shims under the head but I might try that
if A3 is not hot enough (going to real hot plugs for 4S would increase the cost).

Any other ideas how to find the Optimum performance at Min.Cost for Fuel and Spares ?

By the way, Castor I found recently in the paint making factories and also Chocolate fabs
at the cost of about only 2.5 Euro per liter - i.e. almost "free" compared to any other oil.



gkamysz -> RE: Oil 30% is like ... 5% nitro, how about that ? (9/25/2007 1:51:33 PM)

quote:

ORIGINAL: downunder

Combustion chamber size is on the order of 2000 times larger than the volume of oil that passes through in each cycle with around 20% total oil in the mix so adding a bit more oil will make no appreciable difference.


This is true but you must also consider how much is left on the cylinder walls. That portion migrates much more slowly, than what is in suspension in the air fuel mixture. There is an article about how oil content was used to fine tune performance of fixed compression diesel engines on http://www.modelenginenews.org/faq/fc_diesel_ops.html . This is why this came to mind. The actual volume per stroke might not be the only factor.

Castor from paint factories probably wouldn't be the correct type. The stuff from the chocolate factory might work. Have you actually used it?

http://www.groshea.com/caschemprodcats.html

This is a list of castor derived products. I think virtually anything from the "Refined Castor Oil" category would be fine for an engine. Notice the "AA" grade people refer too. This company holds the trademark to Bakers AA castor oil that Americans commonly refer to when talking about engines. The paint factory might be using a one of the dehydrated products, but they might process raw castor themselves, so be sure to ask if you try that.




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