Castor Oil with 30% Nitro 23% Synthetic

Iceberg Fri Oct 18, 2019 7:06 pm

Hello Gentleman
I have relocated to Bangkok now and was able to locate and purchase some Rapicon fuel. It is a 30% nitro with 22-23% synthetic.

I'm sorry for rehashing this question again.... It has been answered before but with the 30% and higher synthetic I don't think exactly the same parameters. Balogh has kindly already helped but was curious about the higher volume of synthetic.

So I have a 4 liter bottle of 30% fuel or 4.22 quarts. I currently have 250 ml or 8.5 ounces of castor oil. I would like to mix up and get going. How many ounces or ML would be the best for the 4 L of nitro fuel. I have always in the past added 10% castor per volume but usually the synthetic was only about 12% this time more synthetic volume at 23% +-.

Here in Bangkok the average daily high temperature is about 33 degrees celcius (95 Fahrenheit) and low 26 (78 F) so never cool. Elevation is 1.5 meters about 5 feet...….. that's right almost smack on sea level.

What does the collective gurus think would be a good mix of castor. I am running same fuel in everything. Everything from .010 up to .15 all types of heads and motors.

Thanks!!

Iceberg RC Plane

**Cribbs74** Fri Oct 18, 2019 7:16 pm

So you are saying you have 23% synthetic in it already? If so you are already over the recommended total amount of oil. Adding Castor at this point while necessary will pretty much turn your fuel into syrup making it unusable.

Ken Cook Fri Oct 18, 2019 7:18 pm

I personally feel your oil content is fine regardless of being synthetic. I run synthetic all the time and never experienced what others say is going to happen to a Cox engine. If you feel the need to add castor, raising the oil to 25% would require 5.1 ounces. This also reduces your nitro percentage 28.9%. if you add the 5.1 ounces. However, I have found castor oil to float on top when adding to fuel which is all synthetic with a higher nitro content. It mixes and then separates. I have since switched to Klotz synthetic and castor and use that to mix with existing fuels. I have not experienced separation issues in doing so and I use this for old iron piston technology.

Iceberg Fri Oct 18, 2019 7:24 pm

Interesting Ken
I have always scrupulously been following the 10% castor mix for years. It is sure messy as oil is all over the planes. However to only add the castor to increase total volume to 25% might be good. Just don't want to risk any wear issues due to only 2-3% castor and the rest synthetic. However if you are confident with that approach might be good?

Thanks
Ice

Ken Cook Fri Oct 18, 2019 8:23 pm

I have the same mess on my plane regardless of oil type. Your higher nitro fuel is going to require you to run richer which just hoses out the exhaust residue. I would just be cautious and try the fuel first on a engine which could be used for experimental purposes. I did this prior to my use running almost a entire gallon of full synthetic through it. This was 30% nitro 24% synthetic oil heli fuel. The engine showed no appreciable issues therefore I used it on others. I can't speak for others that have made claims of engines seizing or breaking. So in no way am I telling all to go out and run synthetic oils, I'm just offering my experience in doing so. Again, I will say that when I have used Sig castor added to these fuels, it didn't stay mixed and floats to the top. Klotz Super Techniplate has 20% castor mixed with it and it mixes fine with existing synthetic based fuels which I have used.

Iceberg Fri Oct 18, 2019 8:26 pm

Got it Ken.

Many thanks
Ice

aspeed Fri Oct 18, 2019 8:37 pm

Nothing to add to the castor debate other than cleaning the varnish off the piston cyl. once in a while. Here is a handy chart for mixing fuels if you haven't seen it already. http://www.nitrorc.com/fuelws/allmix.asp

**944_Jim** Fri Oct 18, 2019 9:13 pm

Iceberg, any chance you can get straight methanol? Then you can cut the synthetic lube down (and the nitro too-side effect) , and then bring the oil content back up with castor.

Iceberg Fri Oct 18, 2019 9:18 pm

Hi Jim
I doubt it. It was a bit tricky to track down just the heli 30% fuel I got. Your idea would be really good if you could though. I will continue to look.

Thanks
Ice

Iceberg Fri Oct 18, 2019 9:28 pm

So Ken is suggesting that the 23% synthetic mixed fuel is ok WITHOUT any castor or at most a few % 2-3 of Castor.

Any additional technical comments to that?

Thanks
Iceberg

Oldenginerod Fri Oct 18, 2019 10:17 pm

I'd follow Ken's line. 25% oil is what I generally use. Just a splash of castor is probably enough to do the job for the ball-joint. All that synth should clean up easier, plus stop varnish forming. Take a look at that mixture link from aspeed. It works well. Just type in your ml rather than ounces and it still works.

I'm fortunate to have methanol and caster to add. I just buy buggy fuel and modify it to suit my needs. Could do the same with heli fuel.

Levent Suberk Sat Oct 19, 2019 4:20 am

Here is useful information about oils:

"Castor is a natural oil obtained from the castor bean and it has many valuable properties from the perspective of a model engine lubricant.

Firstly, it is very slippery -- which is to say it has great lubricity.

Secondly it has a very high film strength.

Why is film strength important?

Well oils protect our engines by ensuring that there's no actual contact between the metal parts. As soon as metal touches metal, you get wear so it's the oils job to keep the moving parts from actually touching and it does this by forming a thin film between them.

In the case of castor oil, this film is very tough and it requires a lot of pressure to force metal surfaces together when they're separated by a microscopic layer."

https://www.rcmodelreviews.com/goodoil2.shtml

fredvon4 Sat Oct 19, 2019 9:09 am

mix you fuel in small batches....use metric and use base ten math so much easier to see and figure

one Liter of your blend has

1000 mL liquid
30% is nitro or 300mL
23% oil or 230mL
47% metonal or 470mL

adding 2% castor is only 20mL for a adequat 25% oil
as Ken said you will now dilute the others by a fractional percent because the math is into a new total volume of 1020mL

I would divide all above and only mix 500ml at a time
Thus each of these:
30% is nitro or 300mL is now 150ml
23% oil or 230mL 115mL
47% metonal or 470mL 235ml

you add 10mL castor....a half liter is a lot of run time on a cox engine
Label your fuel......PS the small batch is good for another reason if the Castor you have is not dioluting in the Synth high Nitro mix you will have not wasted the entire Gallon

I know for a fact Methanol is available world wide and Bangkok is no different...get creative searching...find a local who might know where in Thailand is drag racing, cart racing, motocross racing

germanbuddy Sat Oct 19, 2019 10:07 am

Mix my own "brew" for decades with best results.
I stay away from Synth. oils for older steel cylinders engines like COX
because overheating, run aways and such.
For me ?......Castor "ONLY" !!.
PLEASE READ YOUR ENGINE MANUAL.

O.T.
https://www.youtube.com/watch?v=RMWgSNdfXZM

cheers
Peter
GER-1223

fredvon4 Sat Oct 19, 2019 11:29 am

There is NO perfect or Mandatory fuel spec for any commercially made engine...Just MFG recommendations and many of those were published way back when the engine was first designed and few fuel formulas existed.

Many modern PAG (google it please and learn something) oils meet or exceed our needs.
Castor is a very good Lube BUT even it is not perfect and comes with down sides. Many have found blending oils is an acceptable practice that yields good results and long engine life

I followed Ken's advice back nearly a decade ago here and I was a PURE Castor ONLY in Cox engine believer....
Well I do not run nearly as many hours of .049/.051 time as some, but I detect no extra wear in my 25%~35% N ....23% oil 70S /30C blend

Here is a link to a long dissertation from a guy who manufactures his own award winning engines, Randy Smith and his Precision Aero engines

https://stunthanger.com/smf/engine-set-up-tips/fuel-glo-plug-and-running-tips/

germanbuddy Sat Oct 19, 2019 12:07 pm

but many new COX users dont know
that pure Synth.Oil + 30% Nitro RC CAR Racing Fuel is NOT
the RIGHT brew for our COX.
Do you agree ?.

Peter
GER-1223

fredvon4 Sat Oct 19, 2019 12:35 pm

I do and yet do not agree

We do not know the Cox engine use intended and we do not know the 23% synth type...If it is UCON LB625, Any KLOTZ variant I would not hesitate at all to use 100% synth in a infrequently run sport application for a typical good condition C0X engine

As a kid I never smoked a Cox engine or popped a con rod through the top of the piston and we ran a LOT of questionable fuels and also knew nothing of con rod seating or the tools to do it

Point is Cox engines actually took a hard beating in the hands of KIDS who knew nothing...to this day 60 year old engines are resurected every day and run just fine with that abuse

second point is the almighty MUST USE 100% Castor only is not Gospel for me and aperantly a lot of other Cox users...

That is NOT to say 100% Castor is WRONG...it most certainly is NOT....

All out TeeDee or Mouse Motor tweaked to MAX RPM (thus some extra heat) I would definitely run some percent castor as a hedge against a over lean run

germanbuddy Sat Oct 19, 2019 1:05 pm

This might be an engine/fuel- wise Off Topic thing.....but....

I once blow up , ruined,(many moons ago) because overheating
1 "LIT" F2D Engine (Lithuanian, ex Russia) Combat Engine at 30K rpms,
running only Synth. oil.
The AAC P/L set was GONE in seconds because overheating.

These engines are ONLY MADE ,Metallurigie wise,
for 10%Nitro , 20% Castor, 70% Methanol ,
FAI Rules.
Nothing else will work.
If you try some else….you are in BIG TROUBLE...
belive me or not.....its your money .

aspeed Sat Oct 19, 2019 2:48 pm

944_Jim wrote:Iceberg, any chance you can get straight methanol? Then you can cut the synthetic lube down (and the nitro too-side effect) , and then bring the oil content back up with castor.

Iceberg, You may try a hardware or paint store. That is where I get mine. (ya I know, different countries) Methyl Hydrate is the name on ours, but there are different names in other countries. A bit more money than bulk, but likely a bit fresher than other options. I get a gallon for about $11. I don't want to get much at a time because my smaller motors don't use much.

ticomareado Sun Oct 20, 2019 6:15 am

German buddy-- Any and everything can and does happen at 30K RPM regardless of fuel/lube mix. it just goes with the territory.

Iceberg Sun Oct 20, 2019 9:09 am

Fred love the real comments!! Really good to hear from you Fred!! Kids should have destroyed these Cox motors 40 years ago and YET they live on.

As from the rest of the gang. Thank you!

I like the balanced well rounded thoughts. Yes as in big V-8 racing motors synthetic is beautiful if all clearances are very close. If the motor is bad for clearance then expect noise and knocks and bangs and failures. I guess as Fred & Ken have said. If the motors are in good running shape likely the synthetic will be fine. I will take your thought Ken and add 5.1 oz of castor oil to make sure the lube and micron filling space is used up. This will give about 25% total oil and reduce my nitro to 28%+ I would be happy with that. I will use your suggestion to use one of my less "favorite" motors for a few runs just to be positive.

Once again many thanks to all. Every one has some good points.

Talk Soon
Ice

Ken Cook Sun Oct 20, 2019 11:05 am

I would like to know how the new added oil mixed. I have heard over the years that you can't keep castor oil in suspension with 40% and over nitro. I just think there's more to it than just the nitro issue. Twice now I have tried to add castor oil to pre made fuel with not so good results. When I add Klotz Super Techniplate with 20% castor , it just flows well into the mix.

Levent Suberk Sun Oct 20, 2019 1:57 pm

Using an after run oil is a good idea to prevent rust, because castor oil content is low.

**Cribbs74** Sun Oct 20, 2019 3:13 pm

Ken Cook wrote: I would like to know how the new added oil mixed. I have heard over the years that you can't keep castor oil in suspension with 40% and over nitro. I just think there's more to it than just the nitro issue. Twice now I have tried to add castor oil to pre made fuel with not so good results. When I add Klotz Super Techniplate with 20% castor , it just flows well into the mix.

There is a also a temp variable too. When cold Benol separates from fuel as well. On my motorcycle I use Benol in the summer and Super Techniplate in the winter. To be honest though I am about to use Techniplate year round as it contains synth and castor and saves me some hassle.

roddie Mon Oct 21, 2019 6:26 pm

Hey there Iceman! I wish you the best in mixing a glow-fuel that suits your needs. Not sure if this was mentioned yet.. but synthetic oils are less tolerant of a lean engine-run. This does happen.. and it's more concerning when you find yourself committed to running-out a full tank of fuel in a control-line airplane model. Castor-oil thickens with increasing heat; where synthetic oils begin to break-down/vaporize.

If you play the odds; you won't ever encounter a potentially damaging lean engine-run.. Hot

..

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got it Fred !

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absolutly right Fred , Dacor

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