After about a 12-month hiatus from flying any kind of model airplane, and having sold all of my RC gear prior to moving to Erie, PA, I looked around for something that would get me back into the air quickly.


My first inclination was to build yet another Spirit 2-meter sailplane and put a brushless motor in it like before, but I really didn't want to have to take the time to build it first. I also did not particularly care for most of the ARF gliders that were available, but seeing the ParkZone Radian on the Horizon Hobby website and watching the video of its flight convinced me to spring the $250 for the RTF version. There certainly is no better value out there - a nice-looking sailplane with brushless motor and controller, servos, a 3-cell Li-Po battery, and a charger, along with a 2.4 GHz spread spectrum radio system. You cannot buy the parts individually for that much.

Note: I have discovered that the stenosis (nerve pinching in C4-C5 area) in my neck vertebra is too painful to spend a long time staring upward to fly the Radian. Therefore, I am going to have to offer it for sale. It is in absolutely perfect, like-new condition. I'll sell it for only $150 ($250 new) + shipping... the Spektrum 5-channel radio is worth more than that. For $175 I'll throw in the the HowHigh™ altimeter.

If you would like to buy just the airplane w/motor, 2 props, 2 servos I'll sell them for $70 ($130 new) + shipping.


Here are examples of Parcel Post shipping costs to a few different areas for the entire setup; it will be less for just the airplane, motor, & props. I'll get you an exact price if you provide your zip code.
Insurance (required) is $2.75.  Please send an e-mail if you are interested.

Atlanta, GA (31301): $16.94	Baltimore, MD (21201): $14.48	Boston, MA (02116): $15.30
Cheyenne, WY (82001): $20.16	Chicago, IL (60601): $15.30	Dallas, TX (75201): $20.16
Denver, CO (80201): $20.16	Louisville, KY (40201): $15.30	Miami, FL (33101): $20.16
San Diego, CA (92101): $25.51	San Francisco, CA (94101): $25.51	Seattle, WA (98101): $25.51
Syracuse, NY (13210): $ 14.48

See September 7, 2009 update:

Assembly was a piece of cake - just slide the horizontal stabilizer / elevator into place and secure it with the supplied clear tape, then connect the pushrod wire to the control horn. I didn't like the way the straight wire put a twist on the control horn, so I bent an offset into it to relieve the strain. The pushrod is plenty stiff to function with the bends. The four AA alkaline batteries were installed into the transmitter, the Li-Po was charged (only took about 15 minutes), and off I went to the flying field.

The recommended range check was performed on the radio, and controls were verified to be moving in the right direction. I slowly revved the motor up to about half throttle and launched the Radian into about a 5 mph wind and away she went. At about 3/4 throttle, the Radian will climb nearly vertically. It has a strong nose up tendency at more than about half throttle, so a significant amount of down elevator is needed to keep it from literally climbing into a straight up attitude. This can be a bit of a pain at altitude. A computer transmitter would be of great benefit because you could program in down elevator as the throttle is advanced. But, for a $100 savings, I'll feed in the down elevator myself (at least for now).

I have to say that this Radian is the best 2-meter sailplane I have ever flown. It is amazingly stable even in gusty conditions, and floats like a butterfly in calm air. Each flight has lasted well over 30 minutes, and that is without coming anywhere near depleting the Li-Po battery; it typically has 11.5 V of charge left after flying around for 45  minutes to an hour. One time when I was flying over a school building and parking lot, I got over 30 minutes just on thermal lift alone - a record for me. The Radian was so high and in such a strong thermal that I put it into a spin to lose altitude. then, she went right back up again. That was at around 2:00 on a Saturday afternoon. I sure wished I had installed my HowHigh™ altimeter. It was so high that I could barely tell which way it was going.

September 7, 2009 Update:

Well, the new propeller was installed and the Radian is flying again. With the Winged Shadow Systems' HowHigh electronics altimeter installed, I launched the Radian at my Erie Tech Center flying site. After a powered climb to a couple hundred feet, I began searching for a thermal. It did not take long to find a boomer. In no time, the Radian was a small dot in the sky. My no-so-great eyesight caused me to to abandon the thermal and land to see how high it got. 1,122 feet, per the HowHigh. The altimeter was reset and up she went again. This time the Radian made 964 feet. Nice. I spent about 10 minutes just launching to about 50 feet and practicing landings. There is one spot at the south end of the approach that would be ideal for a hand-launched glider (HLG), because is seems every time I pass over it at low altitude I can circle a few times before landing.

Here is a little exercise to figure out just how big a 2-meter wingspan looks at 1,122 feet. The first step is to figure out how far away the Radian is. I estimate the Radian was about 20° off my vertical, so by the trigonometric relationship shown to the right, that makes the Radian 1,194' away (only about a 6.4% increase over vertical). So, the next thing to do is calculate how big the wing looks at that distance. Again, trig is used to calculate a subtended angle of around 0.33°. How big is that? Well, the sun and moon subtend angles of about 0.5°, so the Radian appeared roughly 2/3 the size of the sun.

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Webmaster: Kirt Blattenberger, BSEE, UVM 1989