Airflow and components

Don Belfort


Hi park pilots. If the recommended fl ight batteries in

your new ARF airplane are performing fi ne but tend to run hot, check for fl ow- through ventilation. Having an air intake at the front of your model is only part of what is needed for air to fl ow well over your power system components. An exit for the air to leave the interior of the model, and a pathway for the air to travel through the model, are required.

Some of my fellow pilots noted that the recommended LiPo battery packs in their aircraft were becoming hot. A review of the models found intakes at the front and exhaust outlets under the rear of the fuselage, but a closer examination revealed that the foam bulkheads behind the battery packs were solid and did not let air fl ow through the fuselage. After this problem was identifi ed, it was easy to cut airfl ow passages in the foam bulkhead, allowing the battery to stay cool. ESC manufacturers, including Castle Creations (, note that ESC amp ratings are based on having a 5 mph fl ow of air that is 77° F or cooler. A quick check for fl ow-through ventilation can be done by

holding a hairdryer on a cool setting up to your model’s air intake and feeling for the airfl ow at the air exhaust. Having good airfl ow over your power system will help ensure that the components have a long life.

We should all take great care when we review a new model’s setup and functions before a maiden fl ight, but what about following up on potential issues as you log more fl ights on a new aircraft?

I spent more than two weeks testing and taxiing last year’s project, my Convair 240, before its maiden fl ight,

which went smoothly. On the day of the fl ight, as I moved the wing into position to attach the three sets of servo connectors, my friend, Luther Vanover, commented that the wires needed to be harnessed. Letting them fl op around was looking for trouble. I heeded Luther’s advice and wrapped Velcro strips around the wires and two Velcro strips on the wing. The modifi cation took only minutes and likely prevented a disaster. If you see a potential problem, it is good to address it. Often, it’s an easy fi x. A tight power plug might only need a dab of lubricant to become easier to use.

Model storage is a never- ending problem, and a product from Sullivan Products (sullivanproducts. com) might be just right for park pilots. The Marcy’s Mini Wheel Chocks are perfect for safely storing small electric airplanes on walls or transporting model aircraft to the fl ying fi eld. They are made of aluminum, can handle wheels of up to 2.5 inches, and should last a lifetime.

My winter project was a designed and kitted 1965 VK Cherokee that I obtained at a swap meet. It has been a fun build.

Having an air intake is only one piece of a flow-through ventilation system. A passage through the fuselage and an air exit are required and help cool the power components. A hairdryer on a cool setting can be used to test the airflow.

36 PARK PILOT [Summer 2018]

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