FMA Direct: Park Razor: User-friendly flying wing

User-friendly flying wing

Well-known for its aftermarket RC receivers, FMA Direct recently introduced the Razor series of flying wings. Made of a durable, resilient molded foam, these ARF models range from non-powered gliders to a Speed 600powered model. The subject of this review, the Park Razor, has 3-channel control and comes with a small Speed 280 motor geared approximately 3.5:1, an FMA Mini-20 ESC, a 7x5.7inch prop and a 7-cell, 600mAh Sanyo Ni-Cd battery pack. You can also buy it as a package with an FMA Fortress micro receiver and two FMA S-80 or S-100 microservos.

The Park Razor has vertically mounted winglet plates at each wingtip that act as vertical fins. An equipment bay molded into the center of the wing holds the RC equipment, motor and battery. Control is exercised through a set of elevons that are controlled by two channel functions: aileron for roll control (one surface goes up, the other goes down) and elevator or pitch control (both surfaces go up and down). By using your transmitter's mixing function, you can control roll and pitch simultaneously, e.g., you can get a right-turning bank (using the transmitter aileron stick) and, at the same time, haul back on the elevator stick to pull the wing around in the turn. If your transmitter doesn't have a mixing function, you can buy FMA's subminiature onboard mixer, MX80.

SOME ASSEMBLY REQUIRED

Total assembly time is only about two hours. The wing comes in halves that you cement together; be sure to sand the joint first with the supplied sandpaper so the recommended 5-minute epoxy will stick better.

When the wing halves have been joined, a long slot in the center section accepts the battery pack. I had to position the pack 1 inch back from the front of the battery compartment to achieve the correct center of gravity. The battery is press-fit into place and will stay where you put it.

The kit comes with an ABS plastic motor mount/equipment tray; the lip of this tray is epoxied to the edge around the battery compartment, and the center of the tray can be lifted to allow access to the battery. I attached the receiver and ESC to the top of this flap with hook-and-loop fastener. An ABS plastic canopy covers the receiver and speed control and is attached with hook-and-loop fastener. I press-fit the S-80 servos into cavities in the wing panels and covered them with clear Lexan tape. The servo cables are pressed into small channels cut into the foam leading up toward the receiver.

Final assembly involves hinging the elevons using the supplied thin (0.005-inchthick) clear Lexan tape. My kit came with only the thicker (0.010-inch) clear Lexan tape that's used to structurally enhance the wing; this is far too stiff to use as a controlsurface hinge and would likely over-stress the servos. Be sure to use tape of the proper thickness for the specific application. I suggest that you also cover the elevons with an iron-on material, such as Super MonoKote. I didn't do that initially, and the surfaces eventually got wet and became warped. Both wire control rods come bent to shape and include the necessary hardware.

The receiver antenna exits the side of the canopy and runs along the top of one wing panel. It is held in place with strips of the dear Lexan tape.

The motor is mounted on the ABS tray with double-sided tape and a single nylon tie. It is very secure. Be sure to provide a path for the battery cable from the ESC so that it can be plugged into the battery.

As a guideline, when the airplane is finished and ready to fly, the aileron function (of my elevons) allows the control surfaces to move up and down ' inch (on either side of neutral). Using the elevator function, the surfaces go up and down approximately 4 inch.

FINAL THOUGHTS

At the start, I measured the motor current at 8.3 amps and 6,300rpm with the supplied 7x5.3 prop. Using the 600mAh supplied battery, the flight time is about 5 minutes. At 8 amps, the Speed 280 motor and battery pack will get quite warm during a flight. To help this, an addendum to the instructions suggests that you drill a vent hole in the front of the plastic canopy. This will allow air to enter, pass over the motor and exit at the rear. I also suggest that you allow the battery to cool down after each flight before you recharge it; it helps to have several battery packs.

The FMA Direct Park Razor is an excellent example of how an electric-powered model can be ready to fly in a few hours. It also provides sensational flight performance. If you've never flown a flying wing, here is your chance to try something very maneuverable yet still easy to fly. This model has absolutely no bad tendencies. FMA Direct, 9607 Dr. Perry Rd., Unit 109, Ijamsville, MD 21754; (800) 343-2934, fax (301) 831-8987; www.fmadirect.com.

MonoKote; distributed by Great Planes Model Distributors Co., P.O. Box 9021, Champaign, IL 61826-9021; (800) 682-8948; fax (217) 398-0008; www.greatplanes.com.

Sanyo, 2055 Sanyo Ave., San Diego, CA 92173; (619) 661-6620; fax (619) 661-6743.

Copyright Air Age Publishing Apr 2001
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