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Model Forum / Radio Controlled / Air Models / February 2007Why castor oil?
Here is a good question - why is castor oil preferred in some engines? Cox, for example, their fuel was 25% castor oil. Granted that 30 years ago they didn't have the synthetic oil that they have today, but I understand that even today for the little Cox engines you still want to use Castor oil. Why? What is special about Castor oil, what will it do that other oils won't? I understand we can't use automotive engine oil - it's way too thick for the tight clearences the small engines have. What about regular 2 stroke oil? Or lightweight machine oil? Marvel mystery oil? Etc.? What is special about castor? On Thu, 15 Feb 2007 23:34:48 -0800, "Ook" <Ook Don't send me any freakin' spam at zootal dot com delete the Don't send me any freakin' spam> wrote: >I understand we can't use automotive engine oil - it's way too thick for the >tight clearences the small engines have. Have you seen pure castor oil? It is very thick. The reason you can't use petroleum based oil is that it does not dissolve properly in methanol.  SignatureRoRo Castor oil has some interesting properties It sticks to metal well even at high temperature so it provides goo lubrication at temperatures that most of the synthetic lubricants (use in model fuels) quit working. Its relatively cheap. The main negative property of Castor is that it turns into a gumm varnish just before it burns. This causes problems with stickin valves in 4-stroke model engines. There are petroleum based oils that mix with alcohol... I've mixe motor oil in alcohol fuel by adding a little gasoline. (don't do thi at home... strange chemical mixes can be dangerous -- fhhuber50677 "fhhuber506771" <fhhuber506771.2m3k8b@rcgroups.com> wrote in message > There are petroleum based oils that mix with alcohol... I've mixed > motor oil in alcohol fuel by adding a little gasoline. (don't do this > at home... strange chemical mixes can be dangerous) Gasoline doesn't have any alcohol in it before you mix it?? | Here is a good question - why is castor oil preferred in some engines? Cox, | for example, their fuel was 25% castor oil. Granted that 30 years ago they [quoted text clipped - 6 lines] | lightweight machine oil? Marvel mystery oil? Etc.? What is special about | castor? It withstands high temperatures better than other oils. I still have some Fox breakin fuel that lists 27% castor oil. Fox recommended 20% to 22% castor with all of their lapped piston engines. I still use a castor blend in my ABC engines. A good after run oil is a 50% mix of Marvel mystery oil and transmission fluid. SignatureJarhead Castor will protect your engine from a *lean* run. That hated varnish that castor generates at high temps is actually a lubricant. The castor has a higher flash point than the synthetics we use so when the synthetic oil breaks down because of high temps the castor is still doing it's job.. A lean run (extremely high temp) will destroy an engine running synthetics only. Also using castor eliminates the need for an after run oil. BTW, using a castor blend will not gum up a 4c unless you lean it out to the point that it overheats. If you do that the engine using castor will still survive. > Here is a good question - why is castor oil preferred in some engines? > Cox, for example, their fuel was 25% castor oil. Granted that 30 years ago [quoted text clipped - 7 lines] > oil? Or lightweight machine oil? Marvel mystery oil? Etc.? What is special > about castor? I definitely recommend a fuel that has some castor oil in it. All synthetic may run ok and keep from getting stuff all over the plane..but if you ever run the motor too hot or get a lean neede valve settiing, especially on a 2 cycle engine, the synthetic crap is long gone and you have no protection. The very high flash point of castor is your protection. I have engines that are over thirty years old...still running strong on a castor or castor blend fuel. Can't imagine why any thinking modeler would want to use a total synthetic fuel anyway. Frank Schwartz Because it smell good. I was at the field Sunday before last flying glow for the first time this year and was having a good time when I caught a whiff of that castor burning.......mmmm almost like my wife's cologne(ok not really) mk > Here is a good question - why is castor oil preferred in some engines? > Cox, for example, their fuel was 25% castor oil. Granted that 30 years ago [quoted text clipped - 7 lines] > oil? Or lightweight machine oil? Marvel mystery oil? Etc.? What is special > about castor? You got it mk! The smell and the sound of a hot 2c unloading in the air! All heads turn to look - beautiful > Because it smell good. I was at the field Sunday before last flying glow > for the first time this year and was having a good time when I caught a [quoted text clipped - 13 lines] >> oil? Or lightweight machine oil? Marvel mystery oil? Etc.? What is >> special about castor? Hi, guys, excellent answers, thanks! So, Castor can withstand the high temps that synthetics can't, and castor will mix with methanol while most petroleum based oils won't. Hmm...so why don't we use kerosene or some other fuel oil in our engines? I understand that alcohol is safer to store and use - you want to spill a couple of ounces of gasoline and watch it ignite - POOOFFFF. Spill a couple ounces of alcohol and ignite. It just slowly burns with a low blue flame. OK, so maybe I answered my own question :-P When I was a kid I used to put a match to a bottle of alcohol and watch it gently poof out the top. If I did that with gasoline, it would BLOOOEEYYY out the top and probably blow my head half off. I don't know how I survived my childhood. > Here is a good question - why is castor oil preferred in some engines? > Cox, for example, their fuel was 25% castor oil. Granted that 30 years ago [quoted text clipped - 7 lines] > oil? Or lightweight machine oil? Marvel mystery oil? Etc.? What is special > about castor? > Hi, guys, excellent answers, thanks! So, Castor can withstand the high temps > that synthetics can't, and castor will mix with methanol while most [quoted text clipped - 5 lines] > ounces of alcohol and ignite. It just slowly burns with a low blue flame. > OK, so maybe I answered my own question :-P No the reason that we use methanol is that there is a catalytic reaction between it and the platinum in the plug that maintains the heat in the element until the next compression stroke. If you change the methanol or plug metal then the engine won't run without the glow plug heater attached. That's why an old plug which glows when the heater is attached won't run an engine as the platinum is a very thin coating on the wire and has probably been burnt off at some point. Chris >> Hi, guys, excellent answers, thanks! So, Castor can withstand the high > temps [quoted text clipped - 19 lines] > > Chris Huh. No kidding. Learn something new every day. I've flown these things for over 30 years, and I didn't know that....but then, I didn't know why we use castor, either. Methanol also runs cooler and has higher horsepower potential, because although it has lower BTU per pound than gasoline, it burns at about 6:1 air:fuel, versus gasoline up around 12-13:1 - therefore per intake stroke you get a much larger MASS of fuel air mixture per stroke since so much more of that mixture is dense liquid versus gas. This more than makes up for the small deficiency in energy/unit mass. Castor oil is an interesting molecule - it is actually a prepolymer, with functional hydroxyl groups on it, and is often used as a modifer in urethane chemistry. When heated beyond a certain temperature, it cross-links with itself (homopolymerization) and forms higher molecular weight molecules with correspondingly higher vaporization temperatures. While they are not as desireable as lubricants as the unaltered material they provide some semblance of lubrication beyond the temps that synthetics tend to break down. There are many lubricants in the chemical world, and while many of them look and feel similar (hey, it's oil, right?) there are differences in their properties that make them good for one application and not another, hence the reason there is no universal oil for internal combustion engines. The area of highest concern in Cox engines is the ball and socket joint between the connecting rod and the piston - it is under a lot of duress, and survives the best with a notable percentage of castor in the fuel mix. You really don't need all castor, but I strongly suggest 50% castor (i.e. 50% of the oil is castor..) and 20-22% total oil for Coxes. Sig Champion 25% is actually a really good 1/2a fuel, with a 50/50 syn/cas blend and 20% total oil content, and 25% nitromethane which is baby formula to .049's. Really, the major negatives about castor are that it is more prone to varnish buildup, which BTW is preferred to flashing off and metal-metal wear, and the tenacious nature of the goop that comes out of the exhaust. But wipe down soon after flight with some Fantastik or mindshield washer fluid (not the anti-streaking kind) whic is water, detergent and methanol, and you'll live through the experience. MJD > >> Hi, guys, excellent answers, thanks! So, Castor can withstand the high > > temps [quoted text clipped - 23 lines] > over 30 years, and I didn't know that....but then, I didn't know why we use > castor, either. On Fri, 16 Feb 2007 10:27:18 -0800, "Ook" <Ook Don't send me any freakin' spam at zootal dot com delete the Don't send me any freakin' spam> wrote: Model 'diesels' do run on kero, the ether is there to aid ignition and allow solution with the castor, the castor for lubrication. A property of castor not directly mentioned in the foregoing is that it has exceptionally good anti-seizure properties. Probably second only to lanolin. >Hi, guys, excellent answers, thanks! So, Castor can withstand the high temps >that synthetics can't, and castor will mix with methanol while most [quoted text clipped - 5 lines] >ounces of alcohol and ignite. It just slowly burns with a low blue flame. >OK, so maybe I answered my own question :-P Methanol has a lower BTU content per oz than gasoline, but you burn muc more alcohol per cubic ft of air. The end result is you get more powe per combustion stroke with alcohol. The glow plug feature is an added bonus... that eliminated the need t carry the hevy battery, coil and points ignition system which needed lot of tinkering on early model engines. Much simpler more power an weight savings.. that wins. Gasoline is more economical because its cheaper and you use less pe "horsepower hour". Thats why the 40% scale IMAC planes are almost al gasoline powered. The added weight of the ignition system and th heavier engine is not as big a factor because the big planes usuall need the nose weight anyway. Early gasoline ignition systems were an RF nightmare, especially wit the early home-made AM radio systems. Modern gasoline engine ignitio systems put out far less RF interference and the FM radios are bette at resisting the interference. Also a modern electronic ignition i lighter, more powerful and more reliable -- fhhuber50677 Furthermore, you probably already know that any modeler who uses castor in his fuel is never constipated. The body absorbs enough of it through the skin....and you know the rest. Subject closed.... Frank Schwartz That was a real problem for the WW l pilots. > Furthermore, you probably already know that any modeler who uses > castor in his fuel is never constipated. The body absorbs enough of it > through the skin....and you know the rest. > Subject closed.... > Frank Schwartz That's a crappy thing to say :) mk > That was a real problem for the WW l pilots. > [quoted text clipped - 3 lines] >> Subject closed.... >> Frank Schwartz Woo...too much information :-P > Furthermore, you probably already know that any modeler who uses > castor in his fuel is never constipated. The body absorbs enough of it > through the skin....and you know the rest. > Subject closed.... > Frank Schwartz >Woo...too much information :-P That's OK - just take a dose of castor oil and go to bed. ;-) There's a bloke in Australia, Brian Winch, who writes a column on engines in several magazines, who swears that castor is no longer the best. In the USA he appears in R/C Report. I suppose if one is extremely careful never to run lean, and never runs a lapped iron engine (some Foxes and all Coxes) castor isn't worth the mess, but I'll just keep on wiping off after spooging oil all over the right side of my glow engine-powered toys. >>Woo...too much information :-P >> [quoted text clipped - 6 lines] > Coxes) castor isn't worth the mess, but I'll just keep on wiping off after > spooging oil all over the right side of my glow engine-powered toys. Well, it isn't as though this issue isn't quantifiable. Of course, drawing a conclusion requires that we make subjective decisions about cost, clean-up, residue, etc. So it is possible that someone may favor synthetic oils over castor oils. It really depends upon their priorities. There was a time when I had had it with the tedious clean ups and the varnish that castor oil produced. I burned nothing but synthetic oil type fuels for several years of very active flying. As long as I stayed with using high quality engines I had no problems. If I ventured away from OS, Enya, Webra, YS or Rossi I paid the price. At the time I didn't have much time for venturing, so Morgan's Cool Power served me well. Ed Cregger >>>Woo...too much information :-P >>> [quoted text clipped - 23 lines] > > Ed Cregger So What are you using now, Ed? I'm a beginner and using Cool Power. In the one engine (Tower .61) which I still have and have used, that's what I've used. I sold a couple of trainers with LA engines that used the same juice. Never had any problems, but I used them for less than a year before I sold them. Engines on the shelf and soon to get mounted are Evolutions, Enyas, Tower, OS 4 Strokes, OS 2 strokes, Thunder Tiger and Super Tigre. All are in the .40 to .91 range, and as I said most are new in the box except for a few older OS FP .40 models, some of which are slightly used. Since I've been running the Tower .61 on Cool Power, is there any problem with switching to something with castor? Should I, in fact, switch to something else? Harlan >>>>Woo...too much information :-P >>>> [quoted text clipped - 38 lines] > > Harlan -------------- Hi, Harlan. I'm glad that you are still here too. <G> You can buy Cool Power fuel with a dash of castor oil added by the same folks. It is called Omega. I tend to use fuels that either are Omega, or are very similar, such as Wildcat, Tower (Wildcat again), etc. When I flew pattern years ago, there were still a few engines being made that did not utilize bushings in the upper end of the connecting rod. These were the engines that had problems with Cool Power if there was an accidental lean run. As long as the mixture remained in a rich two-cycle, these engines did just fine on Cool Power, but one little problem and the connecting rod's upper end egged out. Some of the bushing Fox engines and ball bearing K&B engines (.40) did not utilize a bushed wrist pin in their connecting rods. K&B did finally bush the connecting rod's upper end. What a difference. Buy Morgan's Omega instead of Cool Power and you'll never have to worry about it again. I run Omega in my four-strokes too. Ed Cregger ">>> There was a time when I had had it with the tedious clean ups and the >>> varnish that castor oil produced. I burned nothing but synthetic oil >>> type fuels for several years of very active flying. [quoted text clipped - 55 lines] > but they seem to lack something. Some call it noise, but that's not it. > What they are lacking, in my opinion, is soul. Looks like I'll be taking this case of Cool Power back and exchanging it for Omega. Thanks for the education ........... again. Harlan > Looks like I'll be taking this case of Cool Power back and exchanging it > for Omega. Thanks for the education ........... again. You can also get castor oil for engines, in pure form. I get that, and add it to synthetic fuel. Castor oil has well documented advantages, and anything said contrary to that is not to be considered as truthful. Use castor, and add life to your engines. Protection against lean runs and long term inactivity are two of the best reasons that exist. SignatureJim in NC I am, and always have en an advocate of using castor oil in my fuel. Many years ago, most of us ran Dukes Fuel, which had the entire oil 100% castor oil. It was good, but one does not neet that percentage of castor. If I am given or acquire a gallon of fuel, such as cool power, (I prefer Omega or other castor blend fuel) I add at least two ounces of castor oil to it and the results are excellent. One can buy pure castor industrial grade from Sig. There is another point for using castor oil in your fuel. If you are running a four stroke engine on pure synthetic, you are going to find the bearings do not last very long. The reason is simple, the ONLY lubrication in the engine below the piston, bearings etc., is from blow by..that is, only combustion products and a small amount of fuel blow past the piston down into the crankcase to the bearings. There is no other lubrication that makes its way down there. This combustion product usually leads to the early demise of the bearings in the four stroke. It ruins the bearings and literally eats them up. But.. using a castor blend fuel assures that there will be some castor oil that makes its way into the lower crankcase, coats the bearings and other moving parts and ensures long life. I have had four strokes that ran for years with no ill effects and no bearing failure using a castor blend fuel. Case closed. Frank Schwartz > Heck, Ed, I'm not leaving this news group. I fit in better here with guys > who like to build planes at times, run liquid through their engines and > have experience which I lack. I'm trying out a couple of electric planes, > but they seem to lack something. Some call it noise, but that's not it. > What they are lacking, in my opinion, is soul. It's like using gas to BBQ versus charcoal. There are plenty of reasons to use gas - even heating, instant on, instant off, burn as long as you want. Charcoal takes time to start, might burn out before you are done cooking, might flare up and burn your food, etc. But cooking with gas just lacks something. It's like kissing your sister, there is a pizaaz that is just not there. I'd never cook with gas - its charcoal or nothing.. And if the engine doesn't make noise and spit fire and smoke, spray castor oil all over everything, it just isn't the same. >It's like using gas to BBQ versus charcoal. There are plenty of reasons to >use gas - even heating, instant on, instant off, burn as long as you want. [quoted text clipped - 4 lines] >doesn't make noise and spit fire and smoke, spray castor oil all over >everything, it just isn't the same. Now that is a fellow I admire. I, too, love the noise, fire and smoke and oil all over....and electric planes just don't do much for me... nothing there to get excited about. Heck, you turn them on and you turn them off...very antiseptic...no challenge...no excitement.... I've tried electrics...and he is right...no pizazz there at all... but spin the prop, finger or starter..it bangs, fires, smoke comes out and it is off and running...oh, joy! It's alive!! Fun, fun, fun..... Frank Schwartz >>It's like using gas to BBQ versus charcoal. There are plenty of reasons to >>use gas - even heating, instant on, instant off, burn as long as you want. [quoted text clipped - 15 lines] > and it is off and running...oh, joy! It's alive!! Fun, fun, fun..... > Frank Schwartz Hard to get all excited about an electric. I have some, I build some, I fly some, but I love my noisy liquid fueled birds. Like you said "It's alive!" Fire, smoke, and screaming people notwithstanding. >Some of the bushing Fox engines and ball bearing K&B engines (.40) did not >utilize a bushed wrist pin in their connecting rods. K&B did finally bush >the connecting rod's upper end. What a difference. Both Fox and K&B enlarged their wrist pin diameters as well. I learned this when I tried to replace the rod and pin in an early K&B .40 and ended up having to buy a piston too. Same thing when I replaced an early large frame "tall back door" Fox .40 rod. Geoff And to think I thought all my "accidents" at the flying field were caused by flying too low.. > Furthermore, you probably already know that any modeler who uses > castor in his fuel is never constipated. The body absorbs enough of it > through the skin....and you know the rest. > Subject closed.... > Frank Schwartz Here's an interesting excerpt on the subject... http://www.flitelinesolutions.com/castor_vs_synthetic.html Personally I switched away from Castor when I started running primarily 4 strokes a couple seasons ago. Just don't need all that gummy crap inside my valve train. Now I run full synthetic only (even in my 2 strokes) but I'm just a sport flyer and I have a pretty good handle on how to tune my engines so I just don't run my engines lean. I have had it happen once or twice on a couple of the 4 strokes whilst still getting them tuned properly but I quickly corrected the issue and never let it get to the point of any sort of damage. Of course I'm dealing with OS and Saito, which I've found to be hard to hurt if you take just a bit of care with them. I've seen some lesser engines destroyed by very minor "mistakes" that I used to make frequently when I had little experience with these engines. So maybe that's why I haven't had a problem. Also, I note that every gas engine I've seen run at our field (and a couple of these guys are high placed regional competitors) runs on pure synthetic and gas engines get hotter than our Glow engines right??? Jack > Here is a good question - why is castor oil preferred in some engines? > Cox, for example, their fuel was 25% castor oil. Granted that 30 years ago [quoted text clipped - 7 lines] > oil? Or lightweight machine oil? Marvel mystery oil? Etc.? What is special > about castor? |
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