Lou Crane

aspeed,

Yes, traditionally, Fox iron/steel engines thrived on castor-only fuels, for a long time. Why?

Meehanite (a cast iron material) was - is- porous. As wear developed, castor varnish filled much of the surface porousness and maintained piston-sleeve seal. Castor did this best because it was the only oil available that (mostly) withstood the operating temperatures it was subjected to. It still works! We had no "better" lubricants.

Synthetic lubricants came into being. They were 'created' like a stew, if you will. You could cook a thin, clear broth, or load it into a thick, creamy consistency, by what went into it, how and how much. Early synthetics favored thinning at working temps, and had a lower allowable max temperature than castor ( see Gierke's books and 1970's series in Flying Models.) Synths were excellent lubes, within those limits...Newer synthetics, apparently, can have more "body." When things like this became of interest, I checked with a few fuel producers about how and what they used in their blends. I think it was Wildcat that said their fuel was blended by weight percentages. For our general purposes, that could skimp on both nitro and castor (or synthetics, which have specific gravity similar to castor.)

Methanol has a specific gravity of about 0.7 - the same volume of methanol weighs 7/10ths of what the same volume of water weighs. The same weight of methanol occupies 1.43 times the volume of Castor (and the synthetics, then) have SG very near 1.0 (very nearly the same weight per unit volume as water.) Nitromethane has an SG about 1.3 - a cubic inch weighs 1.3 times as much as a cubic inch of water. That's about 3/4 of the volume its percentage suggests - a 12% nitro fuel (by weight) has 9% nitro (by volume.)

Most commercial - and home brew - fuel is blended by volume. Play with the numbers above to see how that makes weight-based fuels differ from volume-based fuels. Anyhow, I'm glad to hear Wildcat uses a denser - or thicker if not denser - synthetic, now.

Back to castor v. synthetic - A friend, recently lost to eternity, asserted that his iron/steel Fox engines, broken in on a "stunt" blend (10% castor/ 10% synthetic) fuel lasted and performed as well as any castor-only Fox he'd ever used. And they did not crud up with excess 'varnish' over time.

Jim (and I) mostly flew/fly stunt CL, where engine runs are longer than on racing, lower stressed than speed or combat, and more consistent. We have the opportunity of moderate load (with temporary exceptions) flight. So long as the max temperatures are not exceeded brutally, such fuels seem good. UNLESS, that is, initial break-in started a "varnish plating" that became essential to later running,

Just a few thoughts to thicken (or thin) the brew... ( I haven't had the guts to try Jim's recommended Fox break-in... yet, anyway)

Hobbsy

My Feedback: (102)

Wildcat is blended by volume, it was Byron's Original the was blended by weight. It's scary that Byron Original recently bought Wildcat Fuels, but to their credit are still blending by volume. I'll be running Power Master or Red Max if that changes. I've been running the Wildcat since about 1992.

http://www.wildcatfuels.com/index

Excerpt:
2&4 Cycle is available in 10%, 15%, and 20% nitro blends. This fuel was developed with 4-stroke engine performance and protection in mind. Wildcat 2&4 Cycle fuels contain18% oil volume (except YS/20 which contains 20% total oil) and is totally synthetic. Due to the 18% oil content, Wildcat 2&4 Cycle fuels can be run in any 2-stroke engine (except ducted fans) where a fuel with total synthetic oil is desired.

Bill Adair

My Feedback: (1)

Actually, it is Morgan fuel that was/is blended by weight, and the oil content was significantly lower than their claimed percentages (claimed in a phone call, as they included no mention on the labels). The tests I ran showed Morgan fuels had less than 13% oil, when samples from new containers were tested, and all other fuels I tested were exactly as indicated on the labels!

Samples were evaporated over a period of days, and the 3 samples of each fuel tested all agreed, having the exact same figures.

Every other fuel tested was exactly as marked on their respective containers, and these included Byron, Red Max, Fox, Sig, and several other popular fuels available at the time (early 90's). The results were published in our club news letter, but have long since disappeared during multiple computer crashes.

Bill

hsukaria

Rich's Brew is also blended by volume. I run 20% all synthetic on my 4-strokes, 20% blend on all 2 strokes except the Fox engines, and 20% castor on the old Fox engines. Maybe more oil than needed, but better safe than sorry!

Hobbsy

My Feedback: (102)

Sorry, Bill, I broke my own rule and used an "I heard" to state the Byron's name. So, you're saying that Crewel Power really is.

Bill Adair

My Feedback: (1)

Hi Dave,

Yes, and as far as I know they still mix fuel by volume?

I might add that there is absolutely nothing wrong with mixing fuel by volume, as long they blend a truthful 18% lube (that they claimed over the phone back then).

I still have part of the gallon I bought for that test (won't use it in my engines), but found it's good for cleaning baked on Castor oil from old engines. Another club member had the other Morgan fuel in an unopened jug, and donated a sample for my test, as did several other club members with other brands of fuel.

I just remembered another brand of fuel I tested. It was Powermaster, and the lube content was exactly as labeled.

Bill

1QwkSport2.5r

I think the more accurate way to measure fuel components is by weight of a given volume. That's how I mix my fuel. If it's been awhile since I'd mixed a batch, I will take a graduated cylinder and weigh (1) fluid ounce of each component. Then do some math and mix away. Ive evaporated my fuel blends to ensure proper accuracy and I'm usually within a 1-2% error if even that. I don't run my engines competitively, so I'm not one to measure to .10g/mL.

I did verify the oil content of a commonly used RC car fuel that was said to be 12% oil and it was exactly that. That was Blue Thunder Sport fuel. Sold/distributed by Horizon Hobby. I'm not sure who makes it though. It was good fuel while I used it... It tended to turn the innards of the engine blue from all the dye they added.

Bill Adair

My Feedback: (1)

I'm sure it makes no difference how you measure the components, as long as the measurement equipment is of nearly equal accuracy.

I've never owned a precision scale, so I mix all my diesel fuel by volume, and purchase all glow fuel.

Bill

1QwkSport2.5r

As long as the result is repeatable, it's good enough for me and for science... I'll weigh for glow fuel, but I mix diesel by volume too - the ether evaporates so fast, it's hard to get a super accurate weight measurement of it.

Ever compared how Jet A runs compared to regular Kerosene?

Bill Adair

My Feedback: (1)

No, but I've heard that Jet A runs better than pump diesel? Have you tried them both?

Not sure anyone has actually done a lab test to compare the two, but it would be interesting.

Bill

1QwkSport2.5r

I have run Jet A in only a couple of my diesel conversions and found no difference in power. The Jet A smells different and is clear as water; my kerosene is an off clear light tan color and smells more like #1 diesel. It's for home heating systems, so it's probably a little cleaner than the junk you can buy off the shelf at a farm supply store or big box store. Jet A is basically a cleaner kerosene. Some guys have found more power with Jet A, but I didn't. And Jet A is a $1 more a gallon.

I haven't tried pump diesel (#2) yet. Our gas stations just recently went from the winter blends to summer blends (mix of #1 & #2 to straight #2). Now if only they still left some of the sulphur in the fuel, there's a chance it would run pretty good. A project to try this summer. I wonder if there's a sulphur additive that could be had - I've heard the sulphur helps with combustion. (sorry Dave, I know you hate "I heard's"... )

I'll find out how Midwest pump diesel and John Deere ether work in a Few engines this summer...

fujiman

My Feedback: (133)

back when i worked for skywest airlines in ground support we used jet a in our diesel powered tow tractors and boy did they love it!!!!!!!!!! ran better and cleaner of course and no stinky diesel exhaust. a bit off subject but i thot i'd throw that in anyway.

fly in the middle of the air..........danger lurks at the edges

hsukaria

....and quit sniffing those diesel fumes.

I used to love helping my father-in-law driving tractors and his bulldozer on the farm. But with time I developed a sensitivity to the diesel exhaust and I get nauseous real bad. Bummer.

1QwkSport2.5r

You probably shouldn't run model diesels then. The odor is quite pungent whether using kerosene or jet A.

Kinda makes me wonder if a lighter distillate would work in place of kerosene and not smell as much... Maybe naphtha or mineral spirits.. Might have to try it for the heck of it.

aspeed

I got nauseous on diesel fumes until I bought a Mercedes diesel. Then I was OK. Propane tow motors still bug me. We seem to be typing at the same time. Vegetable oil can work, and smells like french fries. Andrew did some tests. https://www.youtube.com/watch?v=3g0ri5kiRkM

Bill Adair

My Feedback: (1)

Sport,

Interesting observations. I'm looking forward to your next comparison tests.

I'm also going to mix some more diesel fuel. This time I'm going to treat the liquid extracted from JD spray cans as 80% Ether instead of 100%. I've been told that the liquid is closer to 80% Ether, and the other 20% should be treated as Kerosene.

All the diesels I've run in the past have been .09, and smaller, but I recently picked up a new Map-3 2.5cc from Ed Carlson, as well as another new MK-17.

Bill

Bill Adair

My Feedback: (1)

Well, thanks for adding to the thread!

I've worked around jet engines for many years, and never got tired of the smell.

Bill

Bill Adair

My Feedback: (1)

Hsukaris,

I grew up on a farm.

We used Kerosene in lamps for lighting before we got electric service, also used it for cooking for years. Even ran our Model A Ford tractor on diesel, after a proper warm up on gas. Only did that when I did not have money for gas, as we had a drum of Kerosene in the basement! <G>

I've always liked the smell of Kerosene, and fortunately diesel fumes have never bothered me.

Was also a crew member on a C-130 for a few years, and it smelled just like the inside of a Kerosene drum!

Bill

1QwkSport2.5r

I've read the MSDS for the JD ether and even though the sheet says the fluid is 80% ether, the other 20% is basically propellant which I believe is propane. There isn't any oil or lubricant in it AFAIK. I was advised to treat the liquid portion as basically straight ether. I mix my fuel at about 31% ether and most of my conversions will hand start. I haven't quite mastered getting the perfect prime, so I probably tend to either under-prime or over-prime. So far not enough to hydraulic lock, but wet enough that they don't start easily. I kinda went backwards somewhat and started using a starter and leaving the compression at the "run" setting until the engine fires and adjust compression and needle valve when the engine warms up. I usually find I have to increase compression a half turn to get the burping to stop and actually build up enough heat to be able to properly adjust the compression and needle valves. I'm still new to diesels, so I'm still working to find my comfort zone with them.

Bill Adair

My Feedback: (1)

Sport,

Let's move this to the "Everything Diesel" section, as this thread has transformed to chatting about something nicer than glow engines. <G>

I'll quote your last message in full, so readers there won't get lost.

Bill

1QwkSport2.5r

Fair enough. FWIW, I have a couple Fox engines converted to diesel. A beat up .50 and a compact .40.

Sport_Pilot

Lighter fluid = naptha
Mineral spirits = wide naptha
Aviation fuel = narrow naptha

Basically wide and narrow means that they include more or less of the heavier and lighter hydrocarbons on either side of the naptha band of distillates.

spaceworm

Hi. My G23 runs and smells great using naptha (Coleman's camp fuel). It would also run great on AVGAS. Does that mean it would run on mineral spirits also? Thanks, this is a real question.

Sincerely, Richard

Sport_Pilot

Maybe, but the heavier oils in that might dirty up the plugs and combustion chamber. Actually although the distillation overlaps naptha, the average is a little oiler a bit closer to kerosene.

1QwkSport2.5r

So maybe there is possible creedance to using a lighter distillate in place of kerosene... Probably wouldn't make as much power, but I'm sure it would cost more. But if someone wanted to run diesels with less smell, it might be a possibility to make it work.

FWIW - some companies' mineral spirits is really naphtha, but others has a completely different smell. Oddly enough, Ronson lighter fluid reformulated their lighter fluid to be "less flammable" and instead of being more naphtha based, they use more mineral spirits/paint thinner in it. I have a bottle of the old stuff (blue cap) and a bottle of the new stuff (red cap) - they smell different and burn different. Enough of a difference that I won't use the new red capped stuff in my Zippo lighters.