Fuels Paradise

[William Morrison]

If it is glow fuel, then the basic fuel is Methanol Alcohol.  The remainder in the fuel is the lubricant.  Our little alcohol engines use the "lost method" of lubrication, that is the lube is either consumed by combustion or expelled from the engine after combustion, nothing is retained other than the film coatings found on the internal parts.

 

Brian Winch is a bit screwed up vis-a-vis using Castor as a lubricant.  It has superior temperature qualities; that is, it is not completely consumed by combustion and thus hangs around longer in your engine.  Castor will coat your bearings and prevent rust from forming inside the engine on the bearings.  It is a mess to clean up but it does the job.  Winch is really a journalist and makes a living writing in magazines.

 

Today we find that a smaller per centage of lubricantion can be Castor and still be very effective.  So "blended" fuels are common.  The ration is something on the order of being 75% synthetic and 25% Castor.  That minimizes the mess and provides the best protection to the bearings and potential lean runs where insufficient lube gets run through the engine.  All synthetic fuels can be dangerous if you have a particular lean run as they break down at a lower temperature inside the engine.  Adding a couple of ounces of Castor to all synthetic fuels will provide excellent protection.

 

Good luck.

 

Chip

[Former Member]

[This posting has been removed]

[William Morrison]

I'll jump in.  The use of oils has been and will be a continuing argument amongst us small engine users.  Our little engines use the "lost lubrication" techique where the lubrication is mixed in with the fuel and is either consumed or expelled (usually both).

Castor oil has several redeeming characteristics.  It has a higher burn temperature thus holds up under more harsh operating conditions.  When it gets hot it "morfs" into an even longer molecue and thus gets slicker.  It sticks to our bearings better than synthetic lubes.

But since it has higher temperature characteristics, more of it is expelled via the silencer and tends to coat our aircraft liberally.  Thus it becomes a clean up job after a days flying activity.  It forms varnish - coats our engine's heads and silencers with a brown coating.  It does this internally too.  With time it turns to gunk and glues everything together (not altogether a bad thing as it ends up protecting things inside and outside of the engine).

Synthetics burn at lower temperatures and much of it is consumed (less mess but still get some mess).  Mixes well with methanol (alcohol).  Tends to go away with hot lean runs.  Some synthetics are decidely better than others but cost more too.

We in the colonies tend to use a blend of synthetic and Castor with 25 to 20% of the mixture being Castor.  That way we get the benefits of both lubricants.

I use whatever fuel is available.  I "doctor up" the fuel, if all synthetic, I add three or four ounces of Castor oil to the mix.  If already a blend, I add Klotz synthetic to bring it up to 20% total oil content of the fuel.

Some engines, more specifically, sleeve bearing engines need Castor oil, perhaps a higher ratio.  Those are usually low end engines, cost less etc.  Wankels require a lot of Castor.  Old engines that use ironmehat pistons absolutely require Castor.

I find that owners manuals vary between nations.  We here in the colonies have access to lots of Nitro, poor access to high grade synthetics and Castor is commonly avialable.  Our manuals all generally say blended fuels with 17% to 20% total oil content are acceptable.  Both YS and Saito manuals say use at least 20% total lubricant.  No manufacturer manual says not to use Castor.  All tend to say do not use 100% Castor as a lubricant.

 

 

 

 

Edited By William Morrison on 03/12/2010 19:24:55

Edited By Tim Mackey - Administrator on 03/12/2010 19:48:06

[Myron Beaumont]

William

Well spoken ! Couldn't have put it better myself -That's the reason I didn't intervene earlier

Myron

[Myron Beaumont]

PS just read your details  My dad was a major (test pilot )in the USAAF --Long story but nice to meet you  His surname was Wusza (& mine)changed to Sudymont for various reasons He is in Arlington cemetry

Myron

Edited By Myron Beaumont on 03/12/2010 20:07:30

[Ernie]

Did I get a wee sniff at a criticism of WOO? before it vanished under the censors pen? STEADY lads, he is one of our highest of high  priests

 

ernie

[Dave Towell]

Need some advice guys.

Just been given 3 gallons of heli fuel, Wildcat 18% nitro, and want to know if its any good for use in my aircraft as I dont fly helis. and no before people ask I'm not going to give it away either. I dont know what the oil is or its precentage but can find out if it makes a differance.

Please help.

[Ian Jones]

A couple of links that might fuel your deliberations:

 

Model Technics Fuel Details

 

Just Engines Fuel Info

 

The "5" in GX-5 (most fuels have a similar designation) is 5% nitromethane.

 

Apologies if I've repeated something but I didn't see this info when I scanned through the thread.

Edited By Ian Jones on 18/09/2011 21:27:32

[John Privett]

Dave, I don't see why not. 18% nitro is probably more than you normally run so you'll get a bit more power. Also, the heli fuels I've used (Magnum, Rapicon and most recently Optifuel) all use a lower viscosity oil so you'll probably need to wind the needle in a bit compared to your normal fuel.

 

I once absent-mindedly fuelled my Irvine 36-powered Limbo Dancer from the heli fuel bottle. Once I'd filled the tank I realised what I'd done but flew it anyway rather than draining and refilling. On starting up, the engine was very rich and needed around 3/4 turn leaner on the main needle before flying.

 

[Dave Towell]

Thanks guys will look into this further, but looks good so far.

[Mike Wabe]

Hi all,

I have read all the above posts, but I think I still need enlightenment. I am a newbie, learning with my instructor ona trainer. However, swmbo has bought me a lovely Chipmunk ARTF for when I can do it all on my own! The destructions say 61 2 stroke or 91 4 stroke engine and, having heard other club members 4 stroke engines, they just sound so nice. So I have just bought a Thunder Tiger F-91S. I don't know, but I suspect that 4 stroke fuel is different to 2 stroke. So I've arrived at the question at last - what fuel do you recommend?

[Codename-John]

Most people at my club use model techincs "Bekra", I use 5% for 2 stroke and 16% for 4 strokes, the 4 strokes will run on 5% but I get a better idle with the 16%, its meant for heli`s if you read the bottle but its got an additive in to stop it frothing with vibration etc and fully synthetic so the engines dont get the castor burnt on varnish effect

[GrahamC]

I use Model Technics 10% for an almost identical engine, a SC 91. I also fly ASP 61 four strokes, and two strokes on the same fuel. And..... I'm not the only one! So not it's not different at all, which makes life easier.

As for the type, I thought it was 'contest' but that is not listed on their web page. It's just the standard 10% mix. You don't want too much castor in the mix. 

Edited By GrahamC on 15/07/2012 21:15:33

Edited By GrahamC on 15/07/2012 21:15:49

[Ernie]

Ask 10 flyers this one, and you'll get 11 answers....It's like the downwind turn.

For simplicity, I use the same mix for all engines. 10% nitro, and synthetic oil

ernie

[Bob Cotsford]

I'm tight, I run all my engines - 2 and 4 stroke - on Southern Modelcraft 5%. I did buy higher nitro fuel once for some small Cox engines but decided it was cheaper to give the engines away and go electric for the tiddlers! Even the RCV91CD seems happy on 5%.

[Steve Hargreaves - Moderator]

Exactly as per Bobs post above.....all my engines (2 & 4 stroke) run very nicely on Southern Modelcraft 5% Mo-Glow fuel....this has 15% synthectic oil, 2% castor 5% nitro (higher percentages are available but don't waste your money..) & 78% methanol....this is fine for all "sports" engines & flying

The only problem is you can only get it at the shows...unless you live local to Tonbridge & can collect.....

[Paul Marsh]

Model Technics Sport 5. Maybe Contest 10 if you want more nitro. Use them for both engines and you can get them from the shows and most model shops. Found that after lay-up, the bearings and moving bits still move. Avoid totally caster-based fuels at all cost - they make a mess!

[Mike Wabe]

Thank you all for your comments, they are very helpful. It seems that the recommendations boil down to a choice of 2; 10% and 5%, with 5% edging it at the post. It was also good to learn that I can use the same fule for both 2 and 4 stroke engines.

Thank you everyone.

[Josip Vrandecic -Mes]

I use only syntetic fuel for all my engines, (2 and 4 st) ,last 10 years with no problems.Personally prefer

Morgan high power 5 or 10 % nitro (1 gallone 17 euros...yes is expensive..but good quality).

Only my opinion and remarks : In the last ten years a technology and materials for models engines are so qality and does not need castor oil anymore.

[GrahamC]

You think that's expensive do you Josip? Try £21.50 for model technics 10% in my local model shop. What's that? 25 /26 euros? That's I'm thinking about switching to petrol expensive!

[Josip Vrandecic -Mes]

Dear GrahamC,You told me about local shop....haha...My local shop is in Austria,650 km from my home,and another 650 km back.... ...You know that a fuel is not alowed to send by mail.Calculation

told me that 1 gallone cost me 76 euros..... Du not be strict and prompt JUDGE.please...and thanks for Your time

Cheers

Jo

note: I think of You and hold my fingers crossed for Your "B"

Edited By Josip Vrandecic -Mes on 16/07/2012 11:21:06

[GrahamC]

HaHa Josip - point taken. I hope you buy a few gallons when you make that trip.....

Odly enough.... I just happened to be sat on the local bahn between Neu Guntramsdorf and Shopping City Sud in Wein about the time you wrote your reply! I was wondering about the extent of the hobby in Austria!

We might have the odd grumble about the prices at our local model shop, but then we sould be grateful that we have a local model shop!

[Josip Vrandecic -Mes]

Hello GrahamC,thanks for You replay and by the way, one of the best hobby store in Central Europe is located in Austria : www.der-schweighofer.com

Happy time and drive carefully.....To all apologies for off topic....

Jo

 

Edited By Josip Vrandecic -Mes on 16/07/2012 16:53:37

[cymaz]

To set the cat among the pidgeons, I use Prosynth 2000. Weston won't tell you the oil content. You can phone up and try but you won't get nowhere.

However, I use it because it's the fuel that I buy through the club and therefore get a discount..£12.75 / gallon for 5%.

I use Prosynth 2000 10% for my Evolution/UMS 7-77 radial. Goes well but spits out quite a bit of oil residue. Do I worry...no not much, oil coming out means there is plenty going around the engine. And oil coming out means there is heat coming out with it.

[Greybeard]

Posted by cymaz on 01/10/2012 19:27:42:

To set the cat among the pidgeons, I use Prosynth 2000. Weston won't tell you the oil content. You can phone up and try but you won't get nowhere.

However, I use it because it's the fuel that I buy through the club and therefore get a discount..£12.75 / gallon for 5%.

I use Prosynth 2000 10% for my Evolution/UMS 7-77 radial. Goes well but spits out quite a bit of oil residue. Do I worry...no not much, oil coming out means there is plenty going around the engine. And oil coming out means there is heat coming out with it.

Surely if they won’t tell you what is in it then that is an excellent reason for not using it!