Pump Programming

   Setting up on the ground is an easy way to do this with your airplane securely restrained. Ideally we want to get 4 ATV set points to begin the tuning of your smoke pump to throttle program mix. The ATV points that we want to achieve and note are described as percentages of travel:  1-WOT, 2-Minimum throttle setting with smoke ON, 3- Pump speed at WOT, 4- Pump speed at minimum throttle setting with smoke ON.  For this setup test if you can set your pump ATV function on a rotary dial it will be simpler than switching between menus. (Depending on the make of your radio.) For the sake of discussion, the values in parentheses are ATV examples.

• First we’ll start with high rates. Set your throttle at WOT and note the ATV value. ATV (+125%) throttle WOT

• Flick on your smoke switch and start your smoke pump at a very low setting and increase your pump speed until no more noticeable smoke output is visually noticed. Too high of a pump setting at this point means that you are just wasting oil and making a mess on your airplane. ATV (+72%) smoke pump high rate

• Next, find the low rate setting. Set your throttle on the lowest setting you wish to smoke.  ¼ to 1/3 throttle is typical. ATV (-70%) throttle low setting.

• For the low end smoke setting start with the smoke switch OFF and throttle at your low throttle level for smoke as noted above. Reset your pump speed rate to zero when you flick on the smoke switch and very slowly increase the pump speed to a point in which you see smoke.  Pay closer attention to what your hearing with the throttle and RPM’s. You are not looking for big smoke here, just some smoke. More importantly is to not get a bog or sag from the engine when the smoke is switched on with your TX switch. An RPM loss of more than a couple hundred can mean that the pump speed is still too great or the oil is being blown up and into the cylinder. ATV (-40%) smoke pump low rate setting

   Once these points are known, these will be the limit points of your pump curve setup. Setup a PMIX program where the smoke pump input is slaved from the throttle and activated by a TX switch. Also note that the pump curve may not be linear and may need some tweaking based on your mechanical differential or throttle curve that you may have already set up for the throttle.