Spectra (oz13538)

About this Plan

Spectra. Radio control powered glider model, for Goldfire 550 brushed electric motor. Wingspan 2m.

Discontinued kit from Great Planes.

Note the Spectra is an electric-powered version of the earlier Spirit (oz13188) design. See https://web.archive.org/web/199904... for original listing and spec.

Note this plan file is derived from the raw scan posted by MileHiHerbaFly on the AF site (see datafile). This version here has been aligned, had the edges cleaned up, then exported as a 400 dpi 2 colour bitmap, reducing the filesize by 80%.

Quote: "Introduction: You are about to enter one of the most exciting realms of radio control flying - Electric Powered Sailplanes.

Electric powered soaring is one of the most enjoyable types of R/C flying because it combines the convenience of being able to fly from almost any small field with the challenge of staying aloft for long periods of time. There is something very gratifying about defying gravity and being able to gain altitude using only nature's own air currents. The Spectra's powerful Goldfire motor quickly pulls it up to thermaling altitude where the motor is shut off and the Spectra becomes a 'Thermaling Machine'. With a little practice, you will be able to soar for hours in a single flight!

We would like to take this chance to thank you for purchasing the Great Planes SPECTRA Electric Sailplane. It has been designed to give you many hours of enjoyable flight, and we spent many months engineering it to be a very enjoyable kit to build.

Note: We, as the kit manufacturer, can provide you with a top quality kit and great instructions, but ultimately the quality and 'fly-ability' of your finished model depends on how you build it; therefore, we cannot in any way guarantee the performance of your completed model, and no representations are expressed or implied as to the performance or safety of your completed model. Remember: Take your time and follow directions to end up with a well-built model that is straight and true.

RAdio: A radio having at least 2 channels is required to control the SPECTRA (a third channel is required for throttle control). Standard size servos can be used without any problem but a 250 mAh receiver battery is recommended but not required. Make sure that the radio is on an 'Aircraft
Only'' frequency.

Flight Battery: A 6 or 7 cell battery with a 'Kyosho' type connector is required to power the electric motor. We recommend you use a 7 cell battery as it offers much higher performance than a 6 cell battery. The capacity (mAh) of the battery can be anywhere from 800 mAh to 1700 mAh. For general flying a 1200 -1700 mAh 7 cell battery will provide good power, good motor duration, and good flight performance. For contest flying an 800 - 900 mAh 7 cell battery will provide a shorter motor duration but its lighter weight will enable the SPECTRA to climb quicker and soar better. A 1200 -1700 mAh 6 cell battery should be used if you just want to fly around with the motor on continuously. If your batteries have 'Tamiya' style connectors, you'll have to change the connector on the wiring harness, or purchase a Kyosho #6195 adaptor.

Optional Folding Prop: A folding prop can be used instead of the 8 x 4 nylon prop supplied. It will fold back against the fuselage when the motor is not running and enhance the soaring performance of the plane. Sonictronics makes several nice folding props and we have found the model #174 8 x 4 folding prop to work well on the Spectra with the Goldfire motor. The spinner may have to be carved out slightly to clear a folding prop. Because the prop may have a tendency to keep spinning after the motor is shut off, the switch/motor should probably be re-wired to provide dynamic braking to the motor. This is easy to do and will make the motor stop turning so the prop will fold back. There is a sketch on page 35 showing this wiring modification.

Motor: A Goldfire motor is included in this kit. It is a 550 size motor designed especially for airplanes. It is an inexpensive motor that is as powerful as many motors costing 3 times as much. We do not recommend that you use any of the 540 size 'Car'' motors. Their smaller size and higher RPM requirements do not work well when trying to turn a propeller at 12,000 rpm. If you want a higher performance motor, we recommend you use an Astro Fight .05 Cobalt Motor (Model 6605 or 6605 S). These motors are very powerful and will make your SPECTRA climb like crazy with some sacrifice in run time. We recommend that you use either Sermos Power Pole Connectors or Deans Connectors on the battery and motor when using high performance motors. These connectors have a very low resistance and will carry the larger currents better than the more popular connectors provided..."

Supplementary file notes

Instructions.

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