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accessories
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Mk95 Mod 1 mount, on Mk16 tripod. Holds two .50 cal machine guns (one will need to be altered for right-hand feed), two 200 round boxes, two feedways, and an armor shield 6mm thick. As used by the Navy since the 1950s.
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Mk16 tripod. A 107 cm tall gusseted tripod with traversing socket for various gun cradles; can handle .30 or .50 cal machine guns and grenade launchers. 23 kg.
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jeep pedestal mount. Designed to support a cradle and .30 cal machine gun, but a .50 cal machine gun can be fitted. A wide variety of these were made to be used on trucks, half-tracks, tanks, landing craft, etc.
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Mk19 Mod 2 mount.Would be attached to the Mk16 tripod. Can hold one .30 or .50 cal machine gun, includes an ammo can tray, and a 6mm thick armor shield. 53 kg.
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M-548 gun mount for mounting .50 cal machine guns on truck cabs. Includes four legs, a back rest, cartridge catcher, canvas cover, M23 gun cradle assembly with ammo can tray. 265 kg.
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.50 cal deck mount. A heavy, sturdy 1930s mounting for air-cooled or water-cooled .50 cal machine guns. Includes a 250 round "tombstone" magazine, a canvas "swing" seat and a 6mm armor shield (covers the gunner from head to roughly knees). 220 kg.
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pintle swing arm. Extends the gun cradle or pintle away from the actual mounting point. About a half-meter long collapsed, a meter long when fully extended. 18 kg.
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gun cradle, .30 cal. Holds a machine gun and a box of ammunition. Fairly basic, not a "softmount". 4 kg.
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gun cradle, .50 cal. Holds a machine gun and a box of ammunition. Some will work with .30 cal weapons also. 23 kg.
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armor plate upgrade: this is 9.5 mm thick, for any single .30 or .50 cal machine gun cradle.33 kg, plus 7 kg bracket if your cradle didn't already have armor plate..
Gas Generator Notes
gas generator powering an engine, seen at Maker Faire
Charcoal is preferred - wood chunks and chips can be used, but are less efficient, make much more tar, smoke and steam, and must be less than 20% moisture content (which means no green wood can be used). Twigs, sticks and bark aren't good, they tend to jam up the hearth; and in fact the charcoal is preferably chopped to specific size pellets. A few places (such as the Foundation) have produced biomass briquettes, mostly for non-military uses. Starting time is usually at least 10 minutes, and the first 5 minutes of startup are sort of involved; and the gasifier continues to operate for another 20 minutes after stopping. You can restart pretty fast if you've only stopped for less than 2 hours. There's a real danger from the large amounts of carbon monoxide produced. The Imbert-style generator is usually a galvanized steel garbage can, mounted atop a 55 gallon drum (the gasifier unit); the can and drum have to be kept sealed, but opened to refuel (releasing hot, toxic smoke). The gas generator needs its own precipitating tank and a cooling radiator.
Diesel engines can be converted, but either need to input a small amount of diesel fuel with each stroke, or (more commonly) replace their glow plugs with spark plugs, and adjust timing, spark etc. like a gasoline engine. Cylinder heads can be reshaped for greater efficiency.
energy content: 1 liter of gasoline (0.75 kg) =1.25 kg of charcoal = 2 kg of oven-dried wood or biomass briquets = 2.5 kg 20% moisture wood
charcoal is 208 kilograms per cubic meter
200 liter (55 gallon) drum can hold about 42 kg of charcoal ... energy equivalent of 21 liters of gasoline
120 liter (32 gallon) trash can holds about 25 kg of charcoal ... energy equivalent to 12.5 liters of gasoline
empty 32 gallon trash can with lid, 7 kg
Using low-energy fuels, such as coconut husks, corn cobs, etc. may require about 10% of the fuel mass to be in the form of alcohol, diesel or gasoline ... something to get the temperature up.
An example of a gasogen-driven electrical generator for a small town: 190 kilowatt output requires 75 kg of charcoal per hour.
Ethanol and Methanol Notes
Consumption of alcohol, compared to gasoline is 2.2:1, so the distance you can travel with the same gas tank is less than half. Methanol is very corrosive, unlike ethanol.
Modifying Engines
Older radial aicraft engines run on avgas: 100 octane gasoline. They might run on gas as low as 80 octane. Water contamination in avgas can destroy an engine in one flight!
Alcohol does not lubricate valves and moving parts, and destroys a lot of gaskets, hoses, etc.. Modifying an engine to run on alcohol can be done, but you'd need to take the engine completely apart, fabricate non-rubber substitutes for various synthetic materials (fuel hoses, seals, gaskets), adjust fuel systems, ignition systems, etc. Valve systems especially rely on lead in fuel to keep lubricated. Modern (21st Century) American cars operate on up to 10% alcohol, normally, but of course they're designed for that.
Alcohol burns most efficiently at a 9:1 ratio with air (whereas gasoline is 14:1 to 16:1, depending on the engine and fuel); hence the alteration to the engine's fuel injection system. Alcohol has about 34% less energy per gallon than gasoline, but can produce a bit more power; range will be reduced about 10% if the engine runs well otherwise. More improvement in fuel efficiency would require changing the compression ratio of the cylinders -- unlikely in the field with minimal tools!
Alcohol will loosen dirt; good fuel filters are even more important in an alcohol-fuel engine. Charcoal can be used to pre-filter the alcohol before it's put into the vehicle. Alcohol-fuel engines don't start well in cold weather -- ethanol doesn't vaporize sufficiently below about 60 degrees fahrenheit. Using a bit of gasoline, propane or ether for starting is common in older, simpler alcohol-fuel engines.
The engine will still need regular lubricants -- oil, basically. Probably some very nice animal oils could be handwaved as good enough to substitute for motor oil.
Alcohol Production
Ethanol is the best fuel, but uses raw materials that might be better used as food. It's produced in bulk by the fermentation of sugars -- wheat, corn, rice, sugar beets and cane are examples of vegetation with high sugar content; they give a high yield when fermented and distilled. A basic fermenter takes 50 gallons of water, 130 pounds of sugar, and some yeast to produce basic alcohol in about 24 to 48 hours (varies by temperature). Then you'd need to run it through a reflux still ... the basic pot still only makes about 70% alcohol. The output from that water-sugar fermenter + a reflux still is about a gallon of reasonably-pure ethanol in a day or so. Of course, more or bigger fermenters, and bigger stills, gives more output.
In a general way, using sorta-woody, sorta-sugary "feed" in a fermentation-distillation process, 1 ton of "dried plant matter" will produce 20 to 40 gallons of ethanol -- at best.
The construction of fermenter tanks and reflux stills calls for some effort. The body of the still and the tubing needed for the actual distillation coils will be the hardest part to build.
"We hauled in wagon loads of sugar beets, chopped them up in a chipper and fed them to the big fermenter tanks (made like large enclosed wooden vats). Drawing off the raw alcohol after a day, we ran it though the reflux still; a fire fed with plant debris and stalks kept the still hot and bubbling along. Out the other end of the still dribbled hot, pure alcohol, to be filtered through charcoal and poured into the drums.
Other Gasoline Substitutes
Grease or vegetable oils need to have their wax components removed before being useful in a converted motor. However, some sort of super-peanut could be imagined, that, when pressed and filtered, produced something that could be used in the engine -- again, at least some adjustment of the fuel pumps and fuel injectors would be needed, but (with some handwaving) perhaps less than for ethanol conversion. A biological-derived oil would probably need more cleaning and de-gunking of the engines -- they're not a happy in the high temperatures of an internal combustion engine, and produce a lot of gunky deposits (compared to gasoline or ethanol). Peanut oil, butter, animal fat, deep-fryer oil (used in "frybrid" engines), algae oils, etc. have been used to operate internal combustion engines -- especially diesel engines (in fact Rudolf Diesel's first engines ran on peanut oil). You need to add a pre-heater to the fuel feed system -- natural oils of this sort need to be heated to reduce their viscosity.
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