Smoke System

4/28/2013

I originally acquired the kit form smokingairplanes.com. This is a full, comprehensive kit with everything you can imagine already thought of and in the kit. There is one element I felt was missing, and that is a solenoid for instant oil shut off, more on that later...

There was one item in the kit that I felt was way too heavy - the pump. This weighed almost 5 pounds. After some research, I learned that the pump is a Sur-Flow brand, marketed in the RV world as a water/sewerage pump (not RV aircraft - rec' vehicles) and is very robust. It can even run dry for quiet a while without breaking. That last point is I think why such a battle tank of a pump is used in the kit; less failed pump returns.

So, I went on the prowl for an alternative, lighter pump, that would do the same job of pushing around .8 gal/min, which seems to be the golden number for oil flow.

My first pump was a disaster. The second was a Carter Universal Rotary Vane Electric Fuel Pumps GP4601HP at 18psi. This pump was used in a long-eze plane that showed great smoke in a youtube video. However, in my flow test, it worked great with the very low viscosity smoke oils, like, super-dri (viscosity is almost the same as water), but if you tried the slightly thicker oils (still 'runny' compared to say, 10W engine oil), it crapped the bed. So, I could lock myself in and 'always use super-dri', or I could leave my options open and get a more powerful pump to cover all options. I decided on the latter. I bumped into a local guy who performs in airshows, and I noted the pump he used; I bought one. The pump is a Mallory Comp Pump Fuel Pump 4060FI. This is a 45 psi pump. This pump is right on the money, and is half the weight of the kit pump.

BTW The pumps were from Summitracing.com, and their customer service is awesome. My early test pump was bad, I called, they shipped another one without charging me any shipping, they shipped it without waiting for the return pump at no charge, and they said 'put the bad pump on the porch and the UPS guy will stick a label on it'. And wait for it...I did the same thing all over again when I wanted to send back the inadequate pump for the Mallory'!

To Solenoid or not to Solenoid...

I suppose for show pilots, a crisp smoke cut off is a good thing, fitting a solenoid into the mix will do this. It is also a good idea to have one if you have no manual shut off valve, upstream, and you tank oil level is higher than the injector nozzles. In the kit, there is a solid brass shut off valve, but since by tank is lower than the nozzles, I don't think I will have siphoning issues while parked, so I left it out to save a few ounces. Later down the road, I could always retro fit a solenoid to the firewall.

The kit comes with only one injector nozzle, my reseach implies that you really need two. An extra one is $118 from the vendor, but I did stumble across this guy: http://www.smoke-system-helper.com/. According to two other sources, his injectors are really well made, and he charges $105 for two. His site is new, and it looks like there is a lot of experience on there regarding homemade smoke systems which wasn't available till recently.

Inertia Switch

This is an automotive (Ford, I think) inertia sensor used, for fuel tanks. I am utilising it to cut the power to the smoke and fuel boost pump during a hard impact (think, Amanda Franklin Incident).

Sources

Mallory Pump - http://www.summitracing.com/parts/maa-4060fi

Nozzles - http://www.smoke-system-helper.com/

Smokingairplanes.com

Inertia switch - http://www.summitracing.com/parts/sum-890145