Welcome to Home Brew Buddy
the "modeller's assistant"
Home Brew Buddy is a free calculation utility designed for all Win9x / ME / XP / NT40 / W2000 / Vista / W7-10 platforms.
It allows you to compute the amounts of ingredients required to mix methanol based model fuel at a specified temperature.
If you are new to mixing your own fuel, we suggest you refer to the many excellent discussions on the subject which can be found on the World Wide Web and in various discussion groups, in addition to checking the Introduction page in this document.
Feel free to send us an email if you have further questions not covered in this manual : Eagle Air Technical Support
What is Home Brew Buddy
Home Brew vs. Factory Blend
Many modellers prefer to blend their own fuel, often referred to as Home Brew. Mostly this is for reasons of economy but can also be because an appropriate factory blend is not available or just for the pure fun of doing it themselves.
It is undisputed that the very best fuels are supplied already blended from quality fuel manufacturers, but this quality comes at a price. Some modellers activities require a special fuel blend which cannot be obtained as a standard product from the fuel manufacturers. Others may find that the demands of practice for competitive events is such that they require large quantities of fuel and cannot afford to pay for factory blended fuel. There are even modellers whose enjoyment of their modelling activities is obtained from doing as much as possible themselves without reliance on commercially produced products.
For any or all of these reasons a modeller may wish to blend his own fuel. The traditional method of home blending is simple and straightforward. Determine the ingredient quantities by calculation using the desired ingredient ratios, then mix the ingredients together in a large container.
There are a number of drawbacks to this method, chief amongst them being the requirement for a large, clean container. The other drawback is that, in the case of mixing smaller quantities, errors in measuring volumes of ingredients have a significant influence on the quality of the end product. The effect of ambient temperature should not be underestimated and this is difficult to account for using simple computational methods.
Home Brew Buddy
Home Brew Buddy provides a solution to the problems of blending fuel in the following ways;
•It automates the computations providing error free results which can be sent to a printer for hard copy that can be used at the mixing table.
•It compensates the ingredient quantities for ambient temperature relieving the modeller of the tedium and potential errors associated with manually performing these calculations.
•It allows the ingredient quantities to be specified as weights and therefore enables the use of inexpensive, highly accurate measuring equipment. This feature thus makes it possible for the modeller to mix small quantities of fuel, or batches of small quantities, with minimal equipment and very little cleanup.
Weighing Ingredients
The advantages of weighing ingredients are many compared to the alternative of measuring volumes. To measure a liquid volume accurately is a laboratory skill requiring practice and the use of expensive calibrated volumetric measuring equipment. Measuring cylinders must be used, set up on a level surface, and the liquid meniscus read in the correct manner. Furthermore, time consuming drainage procedures are necessary when measuring viscous ingredients such as lubricating oil to ensure that all of the measured ingredient is added to the final mixture. When mixing large quantities of fuel, lack of precision in measuring the ingredients can have only a small effect on the quality of the mixture. When mixing small quantities however, the mixing must be performed with precision.
Most inexpensive digital kitchen scales have a range of 2kg and an accuracy specified by two parameters. The first parameter is the span error and is expressed as a percentage of full scale. Typically this is ¼% which, in the case of the 2kg scale, is 5g at full scale. The other parameter is a resolution or digitizing error, whichever is the larger. In the case of kitchen scales this is equal to the minimum resolvable display value which is usually 1g. Measuring a weight of 500g would therefore incurr a maximum expected measurement error of 1+5/4=2.25g. This accuracy is a great deal better than could be expected by measuring by volume and is obtained with ease using inexpensive equipment. All of these inexpensive scales have a Tare facility that enables the ingredients to be added directly to the mixture and thus eliminate the problems of residual material, such as oil, remaining in the measuring equipment.
Home Brew Buddy allows the modeller to leverage the accuracy advantages and ease of mixing afforded by weighing ingredients into a method of mixing ideally suited to individual or batches of small quantities.
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