Mustang Page 1 http://www.electricflyermagazine.com/mustang-page-1.html Electrifying The Midget Mustang 60 Converting this high performance thriller to electric was surprisingly simple. Distributor s Supplied Specificatins (See Bench Test at End of Article) By David Blensky Wing Span: 59.5 in / 1510 mm Wing Area: 6657 sq in / 43.0 sq dm Flying Weight: 7.5 / 3400 g Fuselage Length: 51.0 in / 1290 mm Engine: 2-stroke 0.61 or 4-stroke 0.91 Radio: 4-channel radio with 5 standard servos Available from The Wings Maker.com
Mustang Page 2 http://www.electricflyermagazine.com/mustang-page-2.html e re not really big on what s in the box reviews. In fact, most of them bore us. So we re not gong to do that here. However, when we did open the box and after carefully examining the parts, and studying the overall construction, it became apparent that this is one hell of a high quality product that The Wings Maker people have made available. So how did we arrive at that conclusion before even building the kit? By checking the manufacturer s attention to details, the little things, like the way holes have already been drilled to accept the control horns, how the predrilled hole for the canopy screws fit the holes in the canopy for the fibreglass cowling and wheel pants. Note how considered were the designers in supplying grommets for the screw heads to protect the canopy and fuselage surfaces. The included control horns and connectors are all first class EZ Links that connect the push rods to the servos. No need for a Z Bender here just, a 90-degree bend and snap on the links. Surely we should be able to find some glaring fault in this kit? After all, it IS just an ARF. So we had a look at the hinge lines. No gaps to be seen in the elevators; the same can be said for the ailerons. The instructions manual that comes with the Midget Mustang 60 consists of 11 pages of some of the clearest instructions we have ever seen with just one exception: Nowhere does it indicate the amount of dihedral in the wings, nor if any is even necessary. However, the wing joiners are canted, so if you glue em right I guess it will be ok. We hope! Any how, with such great instructions other than how we did the electric conversion we are not going to bore you with a step-by-step build. But some of the design and construction features are particularly interesting.
Mustang Page 3 http://www.electricflyermagazine.com/mustange-page-3.html in the photo bottom left. Then simply push them through the holes in the control surface, elevator or aileron, and then screw to the mount on the opposite side. If you have never used this type of connector before, note that you screw the rod connection down for more throw, screw it up for less. the slots, placed there to protect those areas in shipping. Just another indicator of the care that went into this kit. More in photo photo below: This is a bottom view of the tail wheel assembly and control connector to the rudder. Screw the connection down for more throw, up for less. Note the highquality metal pin in the white clevis providing a more secure connection. Installing the wing servos: Wing servo openings are already prepared with a cover for each. The cover is slotted for the servo arm to stick through. Note the strings in the photo below: Their purpose is to assist you in pulling the servo wires through the wing to the receiver located in the fuselage. The high-quality control horn mounts are pre-drilled as are the holes in the control surfaces to receive them. The trick here is to run the screws about half way through the mount as shown Covering is already stripped from the horizontal stap to provide a gluing surface. But before you glue on either of the tail stabs you must, of course, remove the fitted balsa blocks that fill Below is how after opening the round holes in the wing covering we pulled the strings through. Careful: If you lose control of those strings you are in for a fishing trip. Our servo wires turned out to be a bit short, so we had to lengthen them.
Mustang Page 4 http://www.electricflyermagazine.com/mustang-page4.html Below is one of the wing servos mounted on it side and attached to the cover and two wood blocks provided in the kit. The connector that joins the two push rods leading to the split elevators (right photo) comes in two parts, top and bottom and three screws. The push rods are over-long to accommodate various servo positions. Once you have determined the correct length, cut to fit. But be sure to account for the L bends that you must make for them to fit into the three pre-drilled holes in the bottom part. Fit the top and tighten the screws. See the above right photo. Now Let s Make It Electric There really isn t much more to say about the basic construction, so lets now move on to converting this glowpowered Midget Mustang 60 to electric. With any electric conversion, the builder must first decide on what kind of power system he will use and why. On this Midget Mustang 60 we will deal with the specifics of those decisions on a separate page. Meanwhile consider the primary construction problems that must be solved. They are: Where and how to install the battery for easy removal for charging. Mounting the motor with its connectors to the ESC, and mounting the ESC where it will receive as much cooling air as possible. Let s start with installing the battery: Cutting the Battery Hatch On most low wing electric ARFs the canopy and cockpit are often removable for inserting batteries. We considered that, but it would have meant chopping out a nine-inch hatch in the top of this beautiful fuselage, and the original construction did not make that option easy. Also, the batteries would have wound up behind the CG, never a good idea. And anyhow, we were afraid it would have been sin ugly, so that was out. This meant not only cutting through the bottom of the cowling but the flat plywood fuselage section ABOVE it. Note: As you look at the following photographs keep in mind that you are looking at the bottom, not the top.
Mustang Page 5 http://www.electricflyermagazine.com/mustang-page5.html We cut the hatch between the first former and the firewall and installed the battery tray. Once the cowling is on, it would have been a deep reach to get a hold of the batteries and our fingers are not that long, so we raised the front end of the tray. Of course this meant that the batteries are going to slide down the sloping tray. See next photo. On the firewall in this photo you can see a section of PVC pipe that we first attempted to use as the motor standoff. As you shall see, we later changed this. Looking into the back of the cowling you can see how we mounted the ESC directly in the airflow through the cooling vent in the front of the cowling. Note: Unlike most of these photos, this one is right side up as is the one below it. Below, wall installed to prevent tray from sliding backward. Note in this photo and the one below it that the cowling is fully in place. Futur-E speed controller from Dymond Model Sports. It is 100 amp, opto coupled no BEC. Here the plugs have not yet been soldered on. Below you see the 100 amp Futur-E speed controller mounted directly in front of the bottom cooling air inlet. and the ESC plug that goes to the battery. Also the 4130/6 Gunther motor. Both from from Dymond Model Sport Another Battery Tray Problem In level flight the rear end of the battery would fall. (Remember, this is a bottom view.) So we put a block over it to prevent that. Also note the small blocks on each side to prevent the battery from shifting side to side.
Mustang Page 6 http://www.electricflyermagazine.com/mustang-page6.html Note that in this photo the cowling is only partially installed. In the photo below the cowling is fully installed. Below are the two Dymond 5000 mah, 11.1 volt batteries with the series harness in place. Wiring in series in this way turns the two 11.1 volt batteries into one 22.2 volt. The 5000 mah remains the same. This series harness is available from Atlanta Hobby.com. They also have available a parallel harness. For installation in the Midget Mustang 60 the batteries are bound together with tape and stacked one on top of the other.
Mustang Page 7 http://www.electricflyermagazine.com/mustang-page7.html Installing the Motor Below is the original firewall for mounting a glow engine. We would very much like to make use of the blind nuts already installed in this firewall After mounting the cowling and taking a measurement (see next photo below) we found a 2 ¼ inch standoff would be necessary for the spinner and propeller to clear the front of the cowling. Of course, the cross mount provided with the Dymond Gunther 4130/6 motor from Dymond Model Sport would not fit those blind nuts. We used nylon standoffs available from Hobby Lobby. They come in various lengths, so we were able to get a perfect fit as you can see in the spinner photo at right. Switch harness. Plug on right is inserted to power-up system. Harness available from Atlanta Hobby.com Remove plug to disconnect power.
Mustang Page 8 http://www.electricflyermagazine.com/mustang-page-8.html So How Does the Midget Mustang 60 Fly Scott Brown, Electric Flyer Mgazine s chief test pilot, makes some last minute checks in preparation for the Mustang 60 s maiden flight at the Field of Dreams in San Pedro, California. Scott is president of SULA. Watch the video of the maiden flight with Scott Brown on the sticks, and Mike Baltes flying in fog. With 1lb, 14.2 ounces of Dymond Li- Polymer batteries in the fuse, the 10 oz Dymond Gunther motor mounted in the nose, our Midget Mustang 60 came in at 8.5 pounds. Even though our bench tests predicted it would be flying on 125 watts per pound we were still a bit concerned about the weight and cautioned our test pilot, Scott Brown. Scott said no, that that was just bout right. And off he went. Since there is now a video of the maiden flight that pretty much tells it all, we won t give a maneuver by maneuver flight description here except to say that it was a beautiful thing to behold. Smooth take offs with not even a wing quiver, landing approaches were long smooth flairs a foot above the grass, ending in slick wheeled landings. Mike Baltes, another of our favourite test pilots, flew it on a foggy day. He commented on the excellent slow flight characteristics. His landing approach was with power full off. A Few Specs on the Power System The Dymond Gunther 4130 with a KV of 430 is good for 16 to 25 volts, so two Dymond 11.I V 5000mAh batteries wired In series for a total of