Byron mixes by weight (Full Version)

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PlaneKrazee -> Byron mixes by weight (11/17/2005 8:49:07 PM)

People had been saying that because Byron mixes by weight there is less oil and nitro.

A friend was running Cool power 15% in his Saito 72 the other day and we switched to 10% byron fuel 18% oil. We had to richen the engine to prevent it running lean. I thought that if Byron had less oil and nitro it would have had to be leaned. It funny how things work.



MJD -> RE: Byron mixes by weight (11/17/2005 9:37:28 PM)

Do these people mean that they mix by weight in production, or label the cans by weight? Because assuming there is a problem simply because they mix by weight may be a flawed assumption. All you have to do is adjust the standard volume percentages for specific gravity and away you go, you can mix by weight which is a convenient way to batch process products depepnding what equipment you have. If however, the can says 10% nitro and 18% oil and those are weight percentages, then yes that certainly conflicts with industry standards which are percentage by volume - if that is what they mean by "mix by weight".

MJD



hauckf -> RE: Byron mixes by weight (11/18/2005 12:22:41 AM)

MJD: A couple of years ago I sent the following e-mail to Byron Fuels: "A Byron fuel user stated in a post on RCUniverse that an experienced flyer told him that the nitro % in Byron fuels is calculated by weight, not volume. Is that true? Thanks."

I received a lengthy reply from Marc A. Jensen at Byron that started "Yes Fred, it is true and never been denied." The rest of the e-mail explained that they mix by weight because it results in "... a consistent blend year round ..." because of the differences in the coefficients of expansion of the individual ingredients. He went on to say that Byron fuel has high quality ingredients, etc., and that if a fuel works for you, just use it and enjoy the hobby.

I did the math. Differences in the temperatures of the individual components when mixed to make glow fuel have very little affect on the final percentages. I have an Excel spreadsheet that will do the calculations that I will e-mail to you if you are interested.




MJD -> RE: Byron mixes by weight (11/18/2005 3:10:01 PM)

So their published NM percentage is indeed by weight - interesting. I certainly agree that the concept of charging your fuel mixer by weight is a more consistent, repeatable practice than by volume. As a formulator by day, that is the only way I do things for that and other reasons.

But - I see no logic from a marketing standpoint to label the products in a manner inconsistent with industry standards. How then is the consumer who tries to compare apples to apples able to make intelligent comparison/decisions? At a spec grav of 1.127 the differences are not huge, I realize this. For example "10%" NM by weight (at standard ambient temp) would be 8.87% by volume. Yet I do not understand why the company would choose to do so. Why not make 10% fuel with 11.27% nitromethane by weight? They could still brag about their manufacturing methodology in marketing literature, yet, their fuels would be consistent with known standards in the marketplace.

I certainly hope the bottom line plays no part here - if you offer 10% fuel at the same price as other companies, but by comparison it contains 1.127 times less of the most expensive ingredient, well.. you see where that thought goes. It, again, is a small difference but it is certainly in their favor, isn't it? I doubt they would design a manufacturing process to exploit that factor.

Thanks for the spreadsheet offer, but I enjoy developing tools like that myself, it's part of the fun. Although, did you source out thermal expansion coefficients for fuel constituents? If so I might be lazy and try to pry those from you! [:)]

MJD



PlaneKrazee -> RE: Byron mixes by weight (11/18/2005 7:33:31 PM)

All I know is their fuel runs great and I have not noticed any performance problems.



hauckf -> RE: Byron mixes by weight (11/19/2005 12:58:47 AM)

MDJ: I agree with you 100% - almost; perhaps I'm a little more cynical than you. I do agree 100% that developing the tools is part of the fun, as that's why I pursued the question in the first place. As for the coefficients of thermal expansion, or more correctly, the coefficients of cubical expansion, finding them was VERY challenging. I visited a local library and a university library, contacted a couple of fuel manufacturers, and finally spent tens of hours searching on-line. Here's what I found for the beta values: (all are per degree Celcius).

Methanol: .001178
Nitromethane: .001195
Synthetic Oil: .000783 (Ucon LB-625)
Castor Oil: .000831

Have fun!



downunder -> RE: Byron mixes by weight (11/19/2005 2:38:49 AM)

Mixing by weight is the most accurate way to do it because we tune the mixture to match the weight of fuel to the weight of air. Air/fuel ratios are by weight, not volume. However the standards that modellers are used to is by volume and long experience with this slightly less accurate way has given knowledge of what's needed. I'm somewhat cynical too so what Byron should be doing is advetising that they mix by weight to give an equivalent volume at 60F (59F actually because that's 15C or a standard temperature).

A few people have done evaporation tests on Byron fuels which seem to indicate that the 17% oil (by weight) is actually closer to 14% by volume.



PlaneKrazee -> RE: Byron mixes by weight (11/19/2005 4:12:49 AM)

Byron doesn't sell 17% oil fuel.



vlizard -> RE: Byron mixes by weight (11/19/2005 5:14:41 AM)

I think the 17% was an example. I ran Byron for quite a few years and never had a problem however after actually reading and getting an education of sorts I felt a little more than cheated. I repeat I never had a problem while I used Byron's but I am one of those who reads the instructions that come with my engines and follows them. Still I have to wonder about oil percentages and so on. I feel personally that both the Wildcat and the Powermaster run better and stronger than the Byron's I used to run. Byron obviously makes a "steady" mix of fuel but I feel that I have been robbed in the past. All this being said, in flight I think Byrons still smokes brands like coolpower and so on. Just my opinion though.



downunder -> RE: Byron mixes by weight (11/19/2005 11:45:57 PM)

quote:

ORIGINAL: Skypilot_one
Byron doesn't sell 17% oil fuel.

Woops, correct. I was going by memory and probably thinking Cruel Power :)
When I checked the Byron site I found one of my pet peeves (and they're not the only one who does this). FAI fuel with 18% oil....that's not FAI fuel!



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