The Sail-Cam Project

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Page 4

       EPP foam has insulating properties that can work to your disadvantage. In this case the speed control is mostly covered up by the EPP foam and this can overheat it easily. Because of this I will need to dissipate the speed controllers heat with a heat sink. I made a heat sink out of a piece of scrap aluminum in the shape of a fin (mostly for aesthetic reasons).
       I wedged the finished heat sink against the flat side of the speed control and dabbed a spot of glue to the side touching the foam. This tight contact with the heat sink on the speed controller should “wick” the heat out of the model and dissipate it into the cool outside air. Besides it will make a great conversation piece :0)

       The next step was to install the Supercircuits AVX900T4 ATV transmitter into the canopy. I selected a spot on the canopy that was thick enough to hold the T4 transmitter vertically. I then cut out a slot slightly smaller than the T4 with my Stanley razor knife.

       The T4 can generate a lot of heat when transmitting so a heat sink system was also fabricated for it as well. I installed the T4 in it’s slot and the wedged the heat sinks along either side of it. The shape of the heat sinks are purely aesthetic.

       I temporarily mounted the bullet camera in place to fit check the 1320 mAh battery. A scrap piece of foam was used to secure the battery in place. The canopy was then fit checked to make sure all of the components cleared

       I have had some previous experience with the Supercircuits PC75WR bullet camera and find it one of the best for use as an onboard camera. It has number of advanced automatic controls that produce an incredible picture for such a small device. It has a good tolerance to voltage fluctuations and works perfectly on an 11.1 volt Li-Po battery.

       The heart of the PC75 is a Sony Ex-View 1/3” CCD imager capable of a 510 horizontal X 492 vertical effective pixels. This produces a 380 TV line interlaced image that is very clear for a microvideo camera. The PC75 will capture images as low as 0.5 Lux and has a automatic shutter capable of 1/60 to 1/100,000 of a second.
       The camera is housed by a “watertight” anodized aluminum housing that is incredibly light (total camera weight is 1.6 oz). It is sealed with a number of O-rings and features a scratch resistant dust lens on the front side. The lens is a 3.6 mm compound lens with a 55 degree viewing angle.
Supercircuits has other focal length lenses available for this camera as well. And just so you know, disassembling the camera will probably void the warranty ;0)
       When I get a new PC75 I like to refocus the lens for a focal length of about 100 feet. This seems to work best for aerial video applications in my experience. I set the camera up on a stable surface and focus it on an object 100 feet away. There is a set screw on the front of the camera that releases the lens and allows you to change the focal length.
       I use a large TV to view the image while I turn the lens until it is as sharp as it will get. I then tighten the screw and install the cap, good to go !    

       The next step was to wire up all of the video equipment in the plane. I installed a Deans 3 pin quick disconnect to the hook up leads of the PC75 so it can easily be disconnected from the canopy wiring harness. Notice the shrink-wrap and soldered connections, these will ensure a good connection.

       To capture the sounds of flying I incorporated an amplified microphone to the system. The Supercircuits PA3 amplified microphone works extremely well with the T4 transmitter and runs on 12 volts to boot. The microphone can be too sensitive for some environments but this can be fixed with some masking tape over the microphones end.

       I hardwired all of the connections (except the battery connector and camera connector) to save space and weight. The PA3 was then installed in a hole made in the canopy (Note that the hole does not go all the way through). It is important to use a battery connector that will not allow reverse polarity or damage may occur to the system. I used a male JST type connector that mates with the female plug already installed on the Thunder Power battery.
       Most of these camera systems use the same wire color coding. Red is usually positive 12 volts, black or bare wire is usually ground or common, white is usually audio signal (mono) and yellow is most always the video signal. The PC75WR camera has a three conductor configuration: black is ground or common, red is 12 volts in and yellow is video signal out.
       The PA3 microphone has a four conductor cable  but both of the shields (bare wires) on each side of the adjoined cables are the same, a common ground. The white wire is the audio out and the red one is 12 volts in. The T4 transmitter usually has three individually shielded cables coming from it, one red one (12 volts in), one white one (audio signal in) and one yellow one (video signal in). All three have their own bare shielding conductor but they are all connected to the same point, a common ground.
       Hooking up the system is basically going color to color but it would be a good idea to have a basic understanding of electronics before attempting to hardwire the harness. If this is not your cup of tea you can always use the supplied cables and just deal with the added weight and loss of space. Although I would highly recommend hooking up the individual parts initially to make sure they work properly as cutting or modifying the cables will probably void the warranty :0(
       The PA3 microphone has an nearly identical hook up connector as the T4 transmitter so one may use a “spare” PA3 wiring harness to fabricate a new T4 wiring harness if they did not want to cannibalize the factory one and thus saving the warranty. The PC75 camera uses a BNC connector for the video out so you would need to pick up a male BNC connector to use the factory camera cables.
       Note that almost all of the Supercircuits 12 volt products use a type “M” power connector with the “pin” being positive.

       A plywood support was used to zip-tie the connector leads to the canopy relieving stress on the wires at the transmitter.

       A final fit check as well as a video transmission test was in order. At this point I oriented the camera with the horizon and marked it with a label so it could be easily be straightened “upright”. Notice (below) the receiver foam installed around the camera to help support it as well as the “V” mark on the camera marking the “up” position.
       An important note to remember when using this system with a 11.1 v Li-Po battery is that there is no voltage cut off circuit in the system. This means that if you were to leave the system plugged in it will drain the battery dead which is almost always death for a Li-Po battery. Fortunately the system will run on a 1320 mAh pack for 3 plus hours before reaching 9 volts.
       There are external voltage cut off circuits available for the purpose but I choose to trust my memory :0)

       The wings were next on the list of things to do. I layed out the wings and proceeded to install the HS-55 servos and 24” servo extensions. I used the hot glue gun to fasten the servos in place as well as tack the servo extensions to the spar cover piece in preparation of glueing them to the wing.

       I used thick CA to glue the spar covers into the wings and taped them in place. I then sprayed a generous amount of CA accelerator down the hole of the spar tunnel. A vacuum was used to suck fresh air into the spar tunnel for 5 minutes to make sure the glue was cured before the spar was inserted in the tunnel. Once cured I inserted the spar in the spar tunnel turning it as I inserted it as to not let any uncured CA to bond to the spar (this would ruin your day!!!). Luckily the spar fit nice and snug without any “sticky” spots :0)
       Before I installed the wings into the fuselage I cut servo wire pockets in the bottom side of the wings to allow for the aileron servo wires. Notice the wider pocket on the right wing (#1) as it sets deeper into the fuselage

       I could now install the wings into the fuselage. I inserted the left wing into the fuselage and attached the left aileron servo wire.

       The right wing was then installed making sure that the servo wires fit into the pockets made for them. The wings kind of snap in place using the “dovetail” shaped piece below as an anchor.

       I was now ready for checking the models center of gravity or CG. The CG on this model is about 2-3/4” behind the leading edge of the wing at the root. I used my Great Planes CG Machine to balance the Easy Glider, only having to add 3/4 oz to the nose of the plane.

       I set all of my control throws and programmed some mixing into the radio to set up the remote gain for the FS8 Co Pilot system. I tested out the functions of the FS8 as well as testing the brushless motor system. Everything seemed to be working perfectly.

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