MAKING A SIMULATED SPRAYER
Since the all the sprayer components have hollow entry and exit points, I decided to see if I could arrange some sort of simulated chemical spraying effect. This would involve adding a smoke system and diverting the engine exhaust through the “sprayer” components.
There is plenty of room in the fuselage for an extra smoke fluid tank and associated smoke pump. The key would be constructing exhaust components as it would need to be heat-resistant and somewhat practical to assemble and dis-assemble.
Fortunately I found an easy solution. Hightemperature silicone tubing and copper pipe L-bends, courtesy of the local hardware store. Exhaust gases are diverted down and rearward via the copper piping bend and then directed to the spray bars with a length of high-temperature silicone tubing. Quick-release spring clamps allow the tubing to be easily installed and removed for transportation.
I should mention that the twin exhaust ports of the Stinger 35 RE’s muffler simplifies things by splitting the exhaust in two. To maintain as much as the engine performance I could, the spray nozzle tubes had to be drilled out as large as I dared, and I ultimately left the outer ends of the spray bar open.
This setup will steal a few hundred rpm off the engine’s top speed, but it’s a small price to pay for some pizzazz. As it turned out, the remaining power in flight was more than adequate.
When it’s assembled, the setup looks the part for a crop-duster model and garnered lots of attention at the flying field. To my delight, the smoke sprayer system is pretty convincing in the air, despite a minor exhaust leak or two in the plumbing. Making several passes, I could see the white smoke emanating from the various outlets in a chemical sprayer effect.