Why I'm going back to glow
 

About 4 years ago, I got hot for a gasser and bought a DLE 20 for my Four Star 120. It was for the usual reasons like being cheaper to run, less slop on the plane and you can put the fuel tank on the CG. Plus, it ran better than most of my glow engines.

Then, about 2 years ago I started researching mixing my own glow fuel and discovered a few interesting things. First and foremost, there is no need to be paying $20+/gallon for glow fuel at the hobby shop. I found a place near me where I can buy Methanol for $4/gallon. There were other places not near me selling it for considerably less. Then, I found a place where I can get (real) castor for $27/gallon delivered. Finally, I read where glow engines don't really need any nitro and that if you're using real castor oil, 12% oil is plenty and that larger engines can even go as low as 10% oil content if real castor oil is used

I mixed up a gallon of my own and I was shocked at how much better my engines ran. First, they started easier and didn't load up when idling. Transition was much better and, despite the lack of nitro, the engines made the same or even a little more power. Also, there was less slop on the plane. Icing on the cake is that the mix is under $7/gallon:)

I think the reason for the better performance was the fact that I was using less oil. The thinner fuel seemed to eliminate issues of loading up, transition, or fuel starvation with the nose pointed up. The difference was even more pronounced in cooler weather. I had always thought that glow engines needed 18-20% oil to be protected, but the reason the manufacturers specify this is because they have no idea what type of oil you're going to be using and real castor has far higher film strength than synthetics. The weak link in a glow engine, lubrication-wise, is the bottom of the connecting rod and 12% real castor is plenty to protect the bottom of the connecting rod. One of my engines, an ASP .46 has a lot of time now on this thinner, 0%-nitro blend and has never run better. There have also been no issues with the engine gumming up or getting coated with brown varnish.

When switching to this 0% fuel the only thing I changed was to a hotter plug. I also found that fuel consumption went down by about 15% since I'm not just sucking down a bunch of nitro plus a huge amount of oil that isn't adding any power...just making a mess of my plane.

I'd be curious to hear from other flyers from around the world who mix their own fuel and listen to their two cents worth.

PS: I almost forgot, no gasser has that wonderful smell of burning castor! (plus my basement no longer stinks)

I use nitro, all castor oil, and my engines run fine too. If the needle is set properly, I rarely encounter any tractability issues unless a glow plug is crapping out or the fuel tank insulation is falling apart.

Agree with both of you. I run fuel I modify from a store bought base. My basic mix is 7% nitro and 20% all castor fuel. I run old Enya engines with lapped pistons and sleeves. They run very well on this mix.

$27 a gallon for castor is a very good price, can you share the vendor with us? I need a gallon right now!

I paid $25/gal plus shipping for castor oil from SPLUBE.com (S&W fuels) for anyone interested. They were good guys to work with.

In the early RC helicopter years when Ernie Huber represented Kavan Helicopters he did a lot of Hollywood movie work (notably The Towering Inferno), he ran Super Tigre .61 ABC engines. Since the movie shots could not show exhaust smoke Super Tigre said he should run 100% methanol and 6% castor. I watched, and talked, with Ernie at a heli demonstration flying one of the movie helis on a hot Central California day. It was flown hard yet never missed a beat and absolutely no exhaust smoke.

I used ST engines in at the time (still do). A local fellow mixed fuel on a custom basis so he blended methanol/10% castor for me. Worked beautifully in both helis and airplanes. Very little residue to clean up.

Some commercial model fuel suppliers still make a Super "T" blend which is primarily for the large Tigres. I believe the blend is 100% Methanol/12% Castor/synthetic.

Your success with the glow fuel is based on proven blends. And is about as cheap as mixing gas/oil.

1qwk:

Thanks for the info. I checked the sight, looks like castor went up to $30 per gallon, still a bit cheaper than most other sources. I'll give them a try.

I called them to get the price I listed - they didn't have a gallon price listed on the site. Try calling them and mention the $25 price and see if they'll give it to you?

On the main subject about oil type/quantity.. My $.02 worth here is this... Castor oil is not going to save you in a lean run necessarily, and when running 12% oil content, your buffer zone for lean/safe is about as narrow as you can be especially using no nitro. If you use nitro, the needle setting automatically is/needs to be richer so there is more fuel volume going through the engine thus more oil going through. If you used 10% nitro and 10% oil, that would flow as much oil as roughly 0% nitro 12% oil which would run clean and not make much mess plus allow the engine to run a little cooler. My values are appoximate; YMMV.

I run 11% castor oil in my RC car fuel - I've run as low as 8% and as high as 18%. I settled on 11% as it runs clean and with using 25-30% nitro, there's a LOT of oil going through the engine at high RPM. The crankcase was left dry as a bone on 8% oil whereas 11% or more left some oil in the crankcase to protect he internals. I like using more oil to give a bigger safety margin. 20% in aero, 11-12% in cars.

A gallon of caster oil now that's one heck of a lot of laxitive:confused:

The website price list for S&W / SP Lube is not dependable. Call them for prices and ask for Stan. He is a nice guy. He came to one of our club meetings several years ago an gave a really interesting presentation on glow fuel.

The thought of a gallon of castor as a laxative is terrifying. Although not as bad as a 2 lb bag of diet gummy bears. http://www.amazon.com/Haribo-Sugar-F...ews/B008JELLCA

pspugrad : what is a gallon of glow fuel made of, in other words whats your recipe?

Sounds great, I for sure will be looking into mixing my own!

Couldn't be simpler: 88% Methanol and 12% real castor oil. I don't add any nitro, just a hotter plug, My favorite is the McCoy #59 (hot). Remember that nitro is virtually impossible to get in (most) countries outside the USA so it's not necessary...we're practically the only ones using it. It makes the engine a little easier to tune as the engine becomes a little less sensitive to needle settings. PS: I'm talking about engines .25 and bigger. When you get into the smaller engines like .15 and smaller then they can become a bit more difficult to tune with 0% nitro fuel. On the other hand, bigger engines (.60+) don't seem to notice the lack of nitro at all.

psgugrad- are you buying your methanol locally? I'm north of the city.

Great discussion. Can you guys answer a few questions?

I know there's a difference between percentages by weight and percentages by volume. How do you guys do your mixing? Can you explain if you measure by weight or by volume and how you make those measurements?

Also, is there a difference in "quality" of the ingredients, depending on the manufacturer/source?

Tom

I mix by volume using weight. Most manufacturers mix by volume though.

I take whatever volume I want of part A, convert to a weight measurement and use a scale. Add part A until scale measures desired weight and zero scale. Add part B, and repeat. I feel this is a lot easier than measuring in a graduated container and transferring to a third container.

As far as chemical quality goes, I use what I know works and has worked in the past. Same goes for diesel.

Hi TJK,

Quick Sport's method is the best if you've got the equipment and the math skills.

Historically most home brewers mix by volume though. In the days before cheap accurate electronic scales there was no choice really.

I'd have to disagree with Quick on the large manufacturers though. Mixing by weight is a better industrial process, you don't have to worry about the temperature of your components or of the final product. You get a consistent product from one day to the next.

Quick is right though, you have to adjust the percentages of each component according to its specific gravity to end up with the equivalent of the by volume mix.

psgugrad,

Good on you for trying the DIY fuel.

I've used home brew fuel for the last 30 years on both glow and more recently Diesel.

I would have thought your 12% oil would be fine for .46 and up engines as long as you're a bit careful with the tuning, smaller engines might be happier on a bit more oil though.

My brew is 18% synthetic which I use on 2 and 4 stroke engines. I've got engines with over 300 hours with no undue wear or corrosion.

Cheers,

Dave H

Daver, woops, that's what I call my son, he's Dave also. I am a recovering "castorholic" I have gone through 3 gallons of WildCat 10% fuel they call 2/4 with 18% full synthetic. I have been monitoring my engines, (mostly Saitos), regularly by pulling the backplates now and then. Some of the rear bearings were stained from castor use, they are now shiny and clean. My Fox .25 with a meehanite piston quite literally howls on it with a Taipan 10x6.

I have checked 3 RC car blends commercially available off the shelf and evaporated them off so all that was left was the oil. I was verifying what the oil content really was. If mixed by weight, the volume I ended up with would have been wrong. Now I understand this was only 3 brands out of how many, but it makes the most sense to mix by volume. You end up with just a touch more nitro because it's so much heavier than the other components (about 13% heavier than castor oil).

If I used commercially made fuels still, I'd consider emailing some of the fuel companies to find out what method they really use. If one does mix by weight, you could be getting shorted on oil or nitro.

If I'm wrong, please provide information showing such. I prefer to be properly informed.

Blended by volume. Their nitro content is probably a touch higher than advertised which is great. That's the most expensive component in the fuel.

Great thread guys, do love my glow engines, they have just got so expensive to run, but the power is awesome, the mess has always been a downer but sounds like it does not have to be that messy.

One way to really cut down on clean up is to wax your monokote type of covering. I don't think people take me seriously when I say that, but it makes a big difference in clean up as when you wipe the oil comes right off. Also, the wax keeps the covering shiny and protected from scuffing and the minor surface scratches that cause it to look dull after a year or so. But clean up from glow fuel and bugs is a major plus.

Running 12% oil presents the risk of having a much narrower "safe zone" with fuel mixture - if it goes lean, you're in deep doo-doo. Engine wear/longevity can be a problem too. If you guys have luck with it, great! I personally wouldn't risk it, but that's me. I don't mind wiping oil off.

Will try the wax thing, thank you!

I actually enjoy cleaning my models. It gives me a chance to look them over carefully, examine the control linkages and hinges and look for problems. I think I spend less than 5 minutes on cleanup. I keep a few old bath towels in the car to wipe down a model before I drive home. Then at home I give it the Windex / paper towel treatment.

you missed the point, other than the cheap fuel, not needing a bunch of extra crap to make them run (ignitors, starters, glow plugs, etc)

http://www.bulkapothecary.com/raw-in...ls/castor-oil/

16.67/Gallon plus $10 shipping from OH to IL. If you're in TX you'll likely pay a tad more for shipping, but it's still a great price

I would want to know if that's from the first pressing or from subsequent pressings. First pressing doesn't have the gum substances in it the subsequent pressing have. "De-gummed" castor oil is from the first pressing and is the oil you want to be using in model engines.

Auto wax works good. But, I use a product call "Gel-Gloss," available in the shower/tub cleaning section at most hardware stores. It is a crème formulated for fiberglass, plexi, plastic cleaner and polish. Makes the shine on Monokote look inches deep. The polished finish is so slick most everything wipes off easily with a moistened towel.

Good stuff for polishing canopies and painted parts too.

G'day 1QwkSport2.5r,

I'm not quite following your post #18. Are you saying that a manufacturer who sells say '10% nitro' fuel but mixes by weight uses 10% of the weight being nitro? I don't know why a manufacturer would do that. If that is what you are saying, do you have any examples?

We all understand and expect that a fuel advertised as say 10% nitro should have 10% of the volume of the fuel being nitro.

If a manufacturer chooses to mix by the weight method then he isn't going to make 10% of the weight of the fuel nitro, he's going to work out how much that 10% volume weighs and use that figure. Isn't that exactly what you said you do in post #15?

To repeat myself, if the manufacturer is mixing say 20% oil, 10% nitro, 70% methanol fuel by the weight method he won't be using the figures 20, 10, and 70. He'll be using the specific gravity of each component to determine whatever weights are required. If he wants to short change the modeller on oil or nitro he'll just do that by reducing the weight of those components in the mix, but as you point out, it's easy enough for the modeller to check so why would they try and rip us off?

If you mix by volume on a hot day your product will be different than if you mix on a cold day, that's the advantage of mixing by weight. The product is consistent from day to day.

You can describe your fuel either by weight or by volume, and you can mix it either by weight or by volume. It's the exact same fuel (if you do it right).

There are good reasons to mix by the weight method. And good reasons to describe it by the volume (that's what we modellers understand).

I have no proof that this the case but it is logical.

Please accept my apology if I've misunderstood your posts.

How're you getting on with your Diesels?

Dave H

It is assumed that businesses are out to make money. Not saying they all do or will do it, but I know some RC car fuel makers mixed their fuel by weight and that isn't volume converted to weight. 30% nitro 8% oil racing fuel was 30% nitro by weight and 8% oil by weight. Which means they essentially shorted the user on oil and nitro. I just assume since they're in the business to make money that some companies are cutting corners and using a straight weight figure and not doing the volume to weight conversions. If you mix by volume only, it's by far the easiest because it's X ounces of part A, X ounces of part B, and so on. With today's technology, there are machines that can accurately measure volume as easily as by weight. For the modeler, there's extra math involved to work by weight but I suppose a computerized blending system could do the trick if every modeler had one. I'd love to take a tour of a fuel blending factory and see how they really do it. Some of that stuff is hush hush. It's good to know Wildcat states they mix by volume and what goes into the fuel they make. Not many companies do that.

The only reason I mix my own fuel is because it saves me a lot of money. $10-12/gal average versus $28-34/gal at the store. Volume converted to weight works well for me, but I don't have a hydrometer so I don't bother doing the air temp/density conversions.

In short - some fuel is what they say it is, others not so much. It's easy to verify oil content, but not easy to confirm methanol and nitro content.

Been busy getting ready for a family vacation. Got the ether, need some kerosene & ignition improver, and some time to set the engine back up, convert a fuel tank, and let her make some noise. Before fall it should run again. (The Fox .50 diesel)

Historically, meaning from the late '40's, modellers always mixed by volume because it's simple and trial and error determined what a safe blend was even if that "safe" blend varied a little over time so it's accepted that any % markings on bulk manufacturer's fuel labels mean by volume. Yep, some have been known to cheat. However there's nothing wrong if a reputable company mixes by weight so long as the final result gives a commonly accepted volume at a standard temperature which I believe in America is 59F.

Once you know the SG (density) of the 2 or 3 ingredients in our fuels it's quite simple to make up a spreadsheet to convert whatever volume you want to a weight and do the mixing on digital scales by zeroing the scale before adding the next ingredient. Essentially this means that, regardless of temperature when mixing (winter or summer), you'll end up with an exact same fuel blend all year round. This actually suits the engine because we don't tune the needle for a volume of fuel flow but a mass of fuel flow. But that's being pedantic :).

Hope you have a great vacation Quick.

Jet A fuel is really good for the kerosine component if you can get it. Amsoil is a great ignition improver.

Mixing your own Diesel fuel is almost back on topic isn't it?

Cheers,

Dave H

Great information on blending your own glow fuel. I've enjoyed reading the thread. Maybe I missed it, but I did not see anything regarding the use of an anti-foaming agent. Do any of you use or need an anti-foaming additive? And if you do, what do you use and how much?

I'd be very interested in mixing my own fuel, just can not find any local sources and shipping makes it too expensive.
I am very happy with my castor/synthetic blend with 15% nitro - I'd want the same mixture, great universal fuel for my two and four stroke and helicopter engines.
A gallon is about $24 / gallon plus a 100 mile round trip, plus more parts and more planes I always wind up buying....

Gasoline works great on large models, but for the small and fast stuff they are too heavy.
Electric motors do not make the right noise, maybe some edf jets, but most planes sound more like a hair dryer (and I have some of those too)

I have a fuel station that sells kerosene for about $4 a gallon. Jet A will be harder to get I think.

Vacation on should be fun. Taking my 2yr old fishing for the first time. Should be a good time.

If your fuel tank is padded/isolated well enough, you shouldn't need any defoaming additives. The engines that vibrate more (high performance engines like Jett and Nelson) should use a bubble/free tanks like BubbleJett and Tettra. Otherwise a few drops of Armorall original work well but may cause your glow plugs to crap out on you a little faster. I used to use Armorall in my RC car fuel but I quit doing it because I isolated the tanks better.

Remember that nitro is virtually impossible to get in (most) countries outside the USA so it's not necessary...we're practically the only ones using it.

Do you live in bottle?
Where did that was invented?
In europe we can buy nitrofuel from every country or order it online.
Sorry my bad english and google translater.

särpet - I agree. You can get nitro pretty much anywhere, it is just more expensive.
I remember in Germany we had normally no more then 5% nitro in the fuel. Except some racers or rc cars, they got up to 40%.
Some ran without nitro or add just 1%.
It was always available, just pricey.

And people here live under a rock, not in a bottle :cool:.
I hear assumptions and opinions on a daily basis. Somebody told me Germany didn't have paved roads. So the Autobahn would be some sort of dirt road in their mind :confused: Just don't take everything you see here too serious.

Huh? The only difference being - Gas guys have to fly with their ignition source and batteries, Nitro guys can leave that stuff on the ground.

Nitro guys always tout the weight savings with Nitro engines but we usually forget to mention we have to carry around twice the fuel weight.

Starters = Wash. I can start both with a flip. Or lots of flips, or just use a starter.
Eric