Edge 540
The layout of electronics on the underside of the model (at left). Keep wires neat and tidy to avoid snagging on launch. Rather than use the traditional hook and loop, Daniel made a simple cradle (above).
72 MHz band with four KPS12 servos. One had a raised dot on the mounting tab that indicated that it was the one servo that “Turned the other way” (no servo reversing on the transmitter in those days). So the en- tire system was treated as a recoverable ex- pense and was very often moved in its en- tirety from one aircraft to another in an attempt to save money. Fast forward thirty-five years and wel-
come to the age of disposable electronics. For models of this type, the street price of one of the Hitec HS55 servos that’s used is about $12–$15 (there are others out there that are even cheaper). Considering the relative price of the kit and the additional materials that are used to put it together and the method of mounting the servos, the servos have moved from the world of recoverable expense that they occupied 35 years ago to that of “consumable material” that they oc- cupy in this market today. This becomes even more apparent when comparing the price of a servo like this with a sheet of EPP foam, a graphite 4mm tube, a sheet of balsa wood or aircraft plywood at the local hobby store. It changes the way you think about the servos entirely. Because most of these models are very
similar in nature and many are made from kits, the primary way that the builders dif- ferentiate their own models from their peers is very much like that of the R/C helicopter and R/C car communities. That is with a very distinctive and unusual paint schemes. As the model itself can be fairly quickly as- sembled and rigged, a good deal of the time spent in the construction here is spent in elaborate paint schemes and fancy air brush technique. If this is your first one of this type of aircraft and you intend to try learning how to fly in this particular style, it is high- ly recommended that you not construct a “golden calf” for yourself and end up with something that you are not prepared to put at risk. Keep the design of the paint scheme as
simple as possible and yet still easily visible and pleasing. You will also want to make the top and the bottom look very different so that you can tell them apart easily. I used a simple triangle pennant motif on top and a circular motif on the bottom to make them easily identifiable and easy to mask for the airbrush operations. Later, if you want something fancier you can build another plane in a day or two and spend as much time as you dare in decorating it after pick-
60
ing up the necessary flying techniques. These things are surprisingly durable and can last a long time if you are half way careful. I painted mine using a product called “Faskolor” paint for Lexan plastic by Parma International Inc. There is a large selection of bright pleasing colors and, when properly thinned with water, it airbrushes on to the EPP foam very nicely and is easy to work with and also easy to clean up with no messy thinners and no bad vapors. The use of the airbrush also keeps the added weight down on the model. It had been years since I last used my airbrush so I was really out of prac- tice and yet the model came out looking great with this product. I also bordered the colors with black trim lines using a “Sharpie” permanent marker. In fact I have heard about some of the flyers decorating their models using only the colored “Sharpie” type markers for application of trim and color. So decoration of these type models is real-
ly open to a lot of different styles. Just re- member that if you want your plane to hov- er and fly well that you do need to keep the weight well down to or under the prescribed limits. You could say that in decorating these models weight and your imagination are your only limits. Also remember that the darker colors do
color more completely and provide stronger contrast for less weight. Lighter colors take more paint to get the proper effect. The shade of yellow I used gave good coverage, but did require more for proper coverage than either the red or the black. Still, I don’t regret the choice as the effect I was going for gave very gratifying results. Keep it light and keep it bright. You’ll be surprised at the number of complements that your paint scheme will garner. One other reason that these models are
quite durable is that they are fairly light weight. I’ve included a listing of the compo- nent weights found in the kit as well as some of the additional equipment. Mine weighed in at 206 grams (71
⁄4 ounces) without the
flight battery installed in the aircraft. The 315 mAh 3-cell flight battery weighed in at 1.5 ounces with the connector installed to connect with the 10-amp ESC. This would give a total flying weight of about 8.8 ounces ready to fly. The E-flite Park 300 motor used on the model would just barely support its own weight at full throttle with a 2-cell pack. With the ESC reprogramed for a 3-cell
pack and using the 315 mAh pack shown, the result was quite different. The model would literally climb straight up vertically, accelerating as it went. Although the bat- tery warns againt a burst current above 7.87 amps it is capable of continuous output at 6.3 amps. On my watt meter the completed model showed a peak reading of 6.5 amps with the 3-cell pack which provides about five minutes of flying on a fresh charge with the various throttle settings required for this type of flying. The final result when the model was com-
pleted and painted was a total weight with- out flight battery of 7.25 ounces. With the equipment and hardware located on the model as shown the required battery loca- tion to balance the model was very close to the c.g. location required by the model’s rather brief instructions. This was a fortu- nate coincidence as it would make the use of different sizes and types of battery possible without changing the battery location very easy with this model. The general instructions indicated that
the battery pack should be mounted using hook and loop fastener which is perfectly fine. I tend to build a small mounting plat- form that the batteries can be mounted to using some rubber bands to secure the bat- tery. I find the hook and loop tends to wear out after a time (how many times have you seen one of these flying around with the bat- tery pack hanging underneath them be- cause the hook and loop was worn?) and needs to be replaced. Removing this stuff with its double-sided
sticky backing can put a hole in your model if you are not careful. I find that the rubber bands are a more flexible for various battery configurations and easy to replace or repair if necessary. My cradle was made from a piece of 1 craft plywood and two 1
⁄16 ⁄8 ×1 spruce strips for ⁄4
the rubber band retainers. The total weight for this simple little assembly was 9 grams and it also provides a generous amount of gluing area to insure that it won’t come off in hard maneuvers or during a stiff impact. A quick word about the prop on these planes. Your model will be hanging from this thing like a helicopter hangs from its main rotor. I usually spend a good deal of time balancing a helicopter rotor assembly and I also check balance on all my props with a Robart blade balancer. These molded plastic props all seem to need a small amount of balancing and at the speeds they
DECEMBER 2011 air-
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