Ken's pressure regulator suggestion would be a good idea with a CO2 extinguisher tank. I don't believe CO2 would be corrosive and damage the brass. However, I'm not metallurgist or chemist knowledgeable with such matters. So I leave that to others with more experience.
compressed air works well its how I work my small collection of them I several from railroad locos , shop buildings, the steam crane I ran till it derailed and got destroyed. I also have seveal off steam traction engines and one ship whistle a large will be a must they use lots of air if blown a lot you might need a compresser that can recharge the tank rapidly. good luck and have fun I do I take mine to threshing reunions to operate them on steam
Thank you--a large air compressor will be a must? some words dropped out I think but I think you are stressing it will take a lot of compressed air, and we need the biggest air compressor we can get, probably. And it will empty out fast and need to be recharged fast, right? Which will mean we will have to have electricity on the float and then will have the noise of the compressor when we have to turn it back on. If we run an inverter from the tow vehicle back to the float that will take care of the electrical need?
Compressors large enough for what you need probably will draw more current than what a 12 Volt inverter and truck alternator can supply. An inverter will be demanding significant wattage from your truck's alternator. For instance, a 15 Amp compressor will be demanding 1800 Watts which equates to 150 Amps on the 12 Volt input. Add to that the power lost due to inverter inefficiency, at least 10%, usually more. So the alternator should be rated for at least 180 Amps, and that would be at maximum RPM. Therefore the truck engine would have to be running at close to its maximum RPM all the time, even when sitting still or creeping in a parade. Consider one or more CO2 fire extinguishers. Even buying them probably will be less expensive than buying, or renting a large air compressor and a heavy duty inverter. Though you may be able to borrow fire extinguishers just for the cost of recharging them when you're through. This is what we were able to do for our Mardi Gras float.
Another alternative would be a 2KW, or larger, generator in the truck bed next to your compressor. I suspect the noise from your various horns, whistles, float riders, and surrounding spectators would override any noise from the truck bed which would have become merely a steady drone in the background. Many Mardi Gras floats have generators running and nobody notices after the adult beverages start being consumed. Whatever else, Laissez Les Bon Temps Rouler! (Let The Good Times Roll! The Mardi Gras motto.)
Thank you, everyone, for these thoughtful suggestions and helpful advice. Please weigh in on the suggestion someone made today, which would be to use one of those large tow-behind compressors like used on construction sites. Now this also brings up the question of the historical (in)accuracy of how we depict the locomotive in the float design. We thought to make the float more compact, and to reflect the mid-1800s when the Irish first came to our area, we would base the "locomotive" appearance on the American 4-4-0 type. In that case, we could hitch a tow-behind compressor (decorated as a tender car with firewood on top) to the back of the float. Of course, the whistle we are using probably came from the more elongated-looking Pacific type locomotive. So historical purists will probably find fault with us using the older design for the locomotive with the later-era whistle. But back to the question of the tow-behind compressor, what would be your thoughts on that, please? I am not familiar with the noise level involved with them. Relative merits of using one of those versus using a generator next to regular compressor?
This could be the answer to your quest. Those construction type tow behind compressors make a lot of air and have a reasonably sized storage tank and recharge very quickly. They also idle down when the pressure in the tank meets the press reg valve setting usually 110-120 psi. They are usually reletivly quiet, at least as quiet as a generator. It should run your whistle for a few seconds at a time at least. No need for reg valve, just a feed valve to the whistle, which could be a simple ball valve. May be your best option yet. Believe me when you blow that whistle more than a few seconds at a time, folks will be asking you to slow down.
