| Power Planes |
Trick RC Zagi 400/400X |
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This is my first, and so far only electric. It's a fun little plane....fairly fast, aerobatic, and nearly indestructible. I started off with the original Zagi 400 full kit, which includes the plane, motor, prop, speed control, and 600mAh 8 cell battery, and a roll of colored packing tape.
Construction: The plane is pretty simple, of course. It consists of two white styrofoam wing halves which have EPP foam leading edges glued to them. First you glue the wing halves together. I also choose to add a span-wise carbon fiber strip top and bottom for reinforcement, as the 400 has no spar. Next, you dig out the holes for the radio gear (I think the instructions say to do this after taping the wing, but I prefer to do it before). I used Futaba 133 micro servos, and mounted them as far forward as I could. The receiver got buried near the center of the wing, under where the motor tray goes, just forward of the motor itself. When that's done, you can apply the reinforcing strapping tape, and then cover with packing tape. I used the colored stuff on top and clear on the bottom (so it appears white). After covering you add the coroplast wing tiplets. Finally, you cut and trim the motor tray and canopy, tape it in place, and install the motor (it gets strapped to the tray with a zip tie) and battery. That's pretty much it.
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| Bottom view: You can see one of the carbon fiber reinforcement strips. There's another on the top. |
Motor break-in: Following advice from an article on www.ezonemag.com, I broke in the electric motor. The idea is to wear in the brushes in the motor to the shape of rotating part that they rub up against. If you don't do this before running the engine at full power, you get electrical arcing on the brushes, which pits their surfaces and reduces power and efficiency. Supposedly, break-in can give you an additional 10-15% more rpm. Basically, what you do is hook the motor to 2 D-size dry cell batteries in series, and let it run (without the prop) for several hours, or until the batteries are dead. There are several other ways to do this, but this seemed to work pretty good.
Flying: As I said, it's fun to fly. Top speed is about 30-40mph, which can seem pretty fast if you're flying in a small field or schoolyard. Turning performance is good, especially at speed. I love doing tight pylon turns one foot off the ground! The roll rate is also good, although loops are so-so. The prop the Zagi comes with seems more optimized for speed rather then climbing. Perhaps a lower pitch, larger diameter prop would increase the climbing and aerobatic performance. Low speed performance is okay, but if you are looking for a model to putt around a really small field at low speed, this isn't the ideal plane. The Zagi is much more fun at mid to high speed.
I'm not sure if all Zagis do this, but one thing that annoyed me was the there was a big pitch trim change depending on speed. The plane would really want to climb when going fast, which required lots of down elevator. I somewhat solved this by placing a shim under the front of the motor, giving some down-thrust. The other annoying part is that the 600 mAH battery would only give about 3 minutes of run time at full throttle.
My new favorite trick is to do touch-and-goes in the grass. At first I tried doing this by just lightly skimming the grass, but more often then not, the prop would drag and the plane would just skid to a stop. The secret, I found is to literally bounce the plane off the ground. I cut the power, drop to a few feet above the ground, then enter a shallow dive and hit the grass just hard enough so that the nose gently bounces back into the air. Then I hit full power and off I go!
Zagi 400X Conversion: A few months after I got my 400 Trick RC brought out the Zagi 400X. This is the same airframe as the Zagi 400, but with carbon fiber spar and a deeper motor tray and taller canopy to accommodate a large 1700mAH battery pack. The motor and speed control are the same. The bigger battery pack gives much longer run times then the 600 pack....10 minutes or more at full throttle. Shortly after, Trick released a conversion kit to turn a 400 into a 400X. This includes the new tray, the new battery, carbon spar, and some extra props and zip ties.
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| The motor tray area after conversion to the "X". |
Although the conversion kit seemed a bit pricey ($50...half the cost of a new Zagi), I thought the extra run time would be worth it. I bought the kit, and opted for the clear plastic motor tray and canopy, which allows you to paint the parts from the inside, like an R/C car body. The modifications were pretty quick to make. I had already reinforced the wing with CF, so I decided not to install the carbon fiber spar. Therefore, the only job was to install the new motor tray. After removing the stock tray, I had to carve out some foam from the center of the wing, since the new tray goes deeper then the original one. Because the battery sits further back in the tray, I also had to remove the receiver from the middle of the wing and dig out a place for it near the leading edge. After filling the old receiver hole with a block of foam, I installed the new tray. That's it!
With the new battery, the run time is dramatically increased, as advertised. The larger battery spins the prop a bit faster, although this is offset by the increased weight, so performance is about the same. Obviously, really low speed performance suffers, but as I said, I usually fly fast anyway. The old battery can still be used, and does not change the CG.
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If you don't have a Zagi yet and are thinking of getting one, I would highly recommend the 400X.
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