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Glow motors and oil content - why so much?


Nigel R
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Before retiring to Cental France, I bought several gallons of Synthetic Based fuel from Southern Modelcraft. This fuel contains 15% synthetic and 2% castor oil. I still have several gallons left. I am using mainly OS and Laser four strokes and so far they have run well on this fuel. The only two stroke I am running is a Thunder Tiger 46 PRO in the club trainer. This engine seems to run well on this fuel too.

 

Am I storing up trouble for myself?

 

 

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Adding fuel to the fire! I've got a Weston UK 52T2 which I ran for about 6 flights using a fuel mix containing 2% Castor. I had to return the engine due to a fault but Alan got back to me and said that he could tell that I had been running it with Castor and told me, in no uncertain terms, not to continue using that fuel!

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3 hours ago, David Davis said:

Before retiring to Cental France, I bought several gallons of Synthetic Based fuel from Southern Modelcraft. This fuel contains 15% synthetic and 2% castor oil. I still have several gallons left. I am using mainly OS and Laser four strokes and so far they have run well on this fuel. The only two stroke I am running is a Thunder Tiger 46 PRO in the club trainer. This engine seems to run well on this fuel too.

 

Am I storing up trouble for myself?

 

 No only the professionals will scorn you, keep running it or just give it to me. 😍

 

 

Sometimes Ignorance can be a blessing.🥳

3 hours ago, David Davis said:

 

 

 

Edited by Paul De Tourtoulon
Ignorance
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3 hours ago, Paul De Tourtoulon said:

 

 No only the professionals will scorn you, keep running it or just give it to me. 😍

 

 

Sometimes Ignorance can be a blessing.🥳

 

Covid, Ukraine , oil prices, fuel prices, energy WW2 all have one thing in common, Castor oil. Well some would have you believe.😝

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Back in WW1, allied pilots were prescribed Whiskey, to combat the effects on their gastrointestinal channel, ie, breakfast said goodby before lunch, caused by castor oil. Mind, I think I might prefer to be drunk doing that job.

Now, if you prefer, prop off to Spain in a Handley Page 400. Technology same era. 
Use one, not the other? Bring back HMS Dreadnought I say.
 

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4 hours ago, Jason Channing said:

Covid, Ukraine , oil prices, fuel prices, energy WW2 all have one thing in common, Castor oil. Well some would have you believe.😝

In WW2 (& just after) cod liver oil & orange juice concentrate were state provided as health supplements for young children.  

Edited by PatMc
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This article gives the origins of castor oil as a lubricant in ic engines.

 

From the mid 50's until around the 80's I & a couple mates used to mix our own glow fuel. We used Castrol M when we could but it was difficult to find any supplier. As a alternative we sometimes used Castrol R but after mixing it had to be left for several days until the additives that were not miscible with the methanol settled to the bottom then it was decanted into another container.

I also mixed my own diesel fuel which I used mainly with AM 25's & 35's in c/l models. formula for that was 50% paraffin, 25% ether, 25% mineral oil (SAE 40 I think) + 2% amyl nitrate. The reasons for mineral oil were cost & availability but also I mixed the paraffin & oil in gallon or greater quantities then stored it until I was ready to mix a couple of pints or so. The pre ether bulk mix couldn't be done satisfactorily using castor oil as it isn't miscible with paraffin alone.   

 

BTW Charles Wakefield in the article was the donor of the Wakefield Cup which for a long time was the most prestigious model flying trophy that was competed for.

Edited by PatMc
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12 hours ago, PatMc said:

In WW2 (& just after) cod liver oil & orange juice concentrate were state provided as health supplements for young children.  

 

As a child in the 1940s I was fed a desert spoonful of cod liver oil and malt daily.  It was thick and brown and I loved it 🙂  

 

I occasionally used to add a drop Castrol 'R' to the petrol tank of my 1932 Scott TT Replica just for the lovely smell - the shallowness of youth!

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21 hours ago, Paul De Tourtoulon said:

 

 No only the professionals will scorn you, keep running it or just give it to me. 😍

 

 

Sometimes Ignorance can be a blessing.🥳

 

Paul

Been running 2 and 4 strokes on that fuel for twenty years;  from Enya 0.19s to OS 120s; never, repeat never, had a problem.

Maury

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Today I tried some lower oil fuel in my well used Saito 56. One thing I noticed was more power.

 

My old fuel was 15% nitro and 17% oil. My new mix was 12/12. Next time out I will try less nitro. The Saito 56 has way more power than I need in my old 4-star 40.

 

.

 

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1 hour ago, Mike Mc said:

Today I tried some lower oil fuel in my well used Saito 56. One thing I noticed was more power.

 

My old fuel was 15% nitro and 17% oil. My new mix was 12/12. Next time out I will try less nitro. The Saito 56 has way more power than I need in my old 4-star 40.

 

.

 

 

Lower viscosity oil will improve performance too. I have seen an improvement of up to 700rpm going from 15% ML70 to 7% ML70, to 7% Klotz in the laser fuel at the same nitro content with about 250-300 rpm per fuel change on average. 

 

500rpm is more than i would expect from a 5% nitro uplift so with the lower/thinner oil you can also drop nitro and maintain power while reducing mess, fuel consumption and cost. The only thing to be slightly wary of with saito is the lack of big end bush in the rod so i wouldnt go too mad lowering the oil as you run less volume of fuel with the lower nitro so have less oil going through the engine overall. Its why i recommend the 5/15 mix as more or less a guaranteed win in everything. 

 

one of my customers are using the low oil laser fuel in their OS 4 strokes and report excellent performance. That said, its one chap running one engine and that is not exactly a representative sample size so that sort of thing is at your own risk. 

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25 minutes ago, Jon - Laser Engines said:

 

Lower viscosity oil will improve performance too. I have seen an improvement of up to 700rpm going from 15% ML70 to 7% ML70, to 7% Klotz in the laser fuel at the same nitro content with about 250-300 rpm per fuel change on average. 

 

500rpm is more than i would expect from a 5% nitro uplift so with the lower/thinner oil you can also drop nitro and maintain power while reducing mess, fuel consumption and cost. The only thing to be slightly wary of with saito is the lack of big end bush in the rod so i wouldnt go too mad lowering the oil as you run less volume of fuel with the lower nitro so have less oil going through the engine overall. Its why i recommend the 5/15 mix as more or less a guaranteed win in everything. 

 

one of my customers are using the low oil laser fuel in their OS 4 strokes and report excellent performance. That said, its one chap running one engine and that is not exactly a representative sample size so that sort of thing is at your own risk. 

Thanks, That's the information I was looking for. I will add a add oil and reduce nitro before I go flying.

 

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1 hour ago, Paul De Tourtoulon said:

Getting technical now the lubrication properties of thin and thick oils,,,

One for you Jon, looking at the different viscosity's is 15% micro motul equivalent to 7% klotz ?.

 

 

( I won't mention Castor 🤣)

 

Its not just viscosity but its the film strength which is important. As my expertise is in the engines themselves i am not a chemist or an oilologist so i left the specific oil choice in the laser fuels to those who have that technical training. 

 

 

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I've been running an old Laser 62 on some 10+yr old Southernmodel crafts synthetic (which I think has 2% castor) 0% Nitro but add around 25% Methanol to reduce the oil content, engine runs lovely on it. But it's in my Majestic Major so doesn't have a hard life.

 

Just about used up all the old Southern Model Craft straight fuel i was given, so will have to think of what to use next, but it will probably be 0% Nitro and the engine runs really great without nitro.

 

I've also been using the same fuel in an OS 55 AX and it too runs great on it.

 

My Saito 40 and a Magnum 25 do like a bit of nitro though, the Saito 40 seems happiest on Westons Prosynth 10% Nitro.

Edited by Frank Skilbeck
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The laser 62 has a soft EN24 crankshaft so its not as tolerant of low oil as the modern range with EN36 hardened cranks. There are also differences in the conrods so i would keep the 62 on 15% oil. 10% would likely be fine, and i have run them on the 7% for short periods but i wouldnt recommend the low oil for long term use. 

 

As for the prosynth, ugh. im done, i simpy cant be bothered. Nothing personal frank, im just too tired. 

 

 

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11 hours ago, Jon - Laser Engines said:

 

Lower viscosity oil will improve performance too. I have seen an improvement of up to 700rpm going from 15% ML70 to 7% ML70, to 7% Klotz in the laser fuel at the same nitro content with about 250-300 rpm per fuel change on average. 

 

500rpm is more than i would expect from a 5% nitro uplift so with the lower/thinner oil you can also drop nitro and maintain power while reducing mess, fuel consumption and cost. The only thing to be slightly wary of with saito is the lack of big end bush in the rod so i wouldnt go too mad lowering the oil as you run less volume of fuel with the lower nitro so have less oil going through the engine overall. Its why i recommend the 5/15 mix as more or less a guaranteed win in everything. 

 

one of my customers are using the low oil laser fuel in their OS 4 strokes and report excellent performance. That said, its one chap running one engine and that is not exactly a representative sample size so that sort of thing is at your own risk. 

Interesting that lower oil content increases performance. I have read the Saito manual and they recommend a minimum 20% oil content I was a bit taken aback by them mentioning Castor. I am thinking the high oil content is because some will use poor quality Castor and if using synthetic the oil content can be reduced and performance increased. What really puzzles me is that some on here add Castor to commercial glow fuel which then makes a 20% oil mix which, by the above, is detrimental to the engine's performance and adds to the cost then to reduce cost they buy 'any old rubbish'.

 

My conclusion is that I can't trust everyone on here as some are self-professed experts drawing subjective conclusions from one off events.

 

Jon it's a good Job you are here with your wealth of knowledge. Keep up the good work.

 

Steve

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49 minutes ago, Masher said:

"My conclusion is that I can't trust everyone on here as some are self-professed experts drawing subjective conclusions from one off events."

 

You got it kid  😉

 

 

Yes everyone to their own kind, i have over 40 models and they fly regularly, hot at the moment so only around 3 mornings a week I have 2 strokes 3 ( HP .21vt )and 4 strokes, OS fp to  Rossi .90 rear .50 hyper helicopter,  2 pylon racers a Novarossi .61 screaming around the sky, saito 120  also a twin and  4 x 45s,  OS 4 strokes from 1985 to 2005 a couple of Enya ( modified ) and one Laser, they all run on the same mix, it saves fiddling about on the model field tuning when you could be flying, if you find a mix that suits you and runs well don't listen to every ' Expert' just use it.

 

Enough said, not even the 'C' word 🤣

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6 hours ago, Paul De Tourtoulon said:

Yes everyone to their own kind, i have over 40 models and they fly regularly, hot at the moment so only around 3 mornings a week I have 2 strokes 3 ( HP .21vt )and 4 strokes, OS fp to  Rossi .90 rear .50 hyper helicopter,  2 pylon racers a Novarossi .61 screaming around the sky, saito 120  also a twin and  4 x 45s,  OS 4 strokes from 1985 to 2005 a couple of Enya ( modified ) and one Laser, they all run on the same mix, it saves fiddling about on the model field tuning when you could be flying, if you find a mix that suits you and runs well don't listen to every ' Expert' just use it.

 

Enough said, not even the 'C' word 🤣

Hm you have a few then, unfortunately I don't have any so I can't try a mix to suit me. What can I do, along with everyone else in the same position, but listen to an expert and follow their advice. 

 

Steve

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Today I did more fuel testing with my Saito 56. Because of Jon's recommendation I increased the Oil and decreased the nitro. Old mix was 12/12, new mix is 9% nitro and 15% oil. I could feel the difference in flight (less power). Engine runs well and power is plenty for my 4-star 40 so that will be my standard mix for that engine, and probably all my Saito engines.

 

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