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Which Multiplex powered glider makes the best UAV platform?

Posted by Chris Anderson on January 6, 2008 at 11:00am
Like everyone else, we're huge fans of the Multiplex EasyStar, a cheap, sturdy and good-flying powered glider. It's a great aerial imaging platform (see our how-to here), but a bit small for a full suite of autopilot electronics. Fortunately, Mutiplex makes some bigger birds, too: the $195 Cularis and the $70 EasyGlider (shown).

People (such as our own Paul Gregory--see his build tips here) have tended to go straight for the larger Cularis in seach of room and lifting power for bigger cameras and more electronics, but Stewart Long from Pict'Earth, who tried that, has just written in with some cautionary advice and a surprising recommendation.

He says:

"The increased size of the Cularis has not allowed us to use larger cameras that we could with the Easy Glider. the wings are larger, and with more lift, but the Cularis that we set up was too nose heavy , even without a camera. We tried counterbalancing the setup by placing the servos in the rear of the plane, but the plane remains overly nose heavy. We have also had a difficult time with the wing spar, servo connection and latch mechanism. Because of this the plane flutters a little bit like the Easy Star.

So, the Cularis provides some interesting features, but I see a lot more bang for the buck with the Easy Glider. The materials cost is half with the Easy Glider, the flight of the wing is great, and the center of gravity in the Easy Glider allows for more tinkering. From an RC operations standpoint it was not very difficult for me to start using the Easy Glider after starting with the Easy Star.

Here is the setup for the Cularis:

  • Motor Dymond Gunther
  • ESC Hacker 70
  • Prop Cam 14X9.5
  • Lipo generic 2s3p (2 cell x3)
  • (Approx 450 watts, with 75 degree climb.)

Easy Glider (photo setup shown):


 Easy Star:

  • Motor: "Multiplex Permax 480-4D , and Multiplex Permax 480-6D. The 4D is more powerful, and will fly a heavier plane. With the 4-D full throttle is too high, I take off with about 60% throttle. The disadvantage to the 4-D is that it wears down the lipo battery over time. This has not proven to be a big problem though, because we have lost batteries at a higher rate"
  • Speed Controller: "Castle Creations Thunderbird" 36 Amp
  • Propeller: 6/4 plastic. "The first number is for thrust, the second number is for speed. The higher the number, the higher the value. For our platforms we want to have more thrust than speed."
  • Lipo: 3 Cell 2100 mAh


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Comments

  • Javier Garcia Lomas February 26, 2009 at 5:46pm
    Thank you for your fast reply Chris, I didnt know if it was oright to ask this in here... I have to choose a platform to carry about 18 ounces (plus battery (3 S I guess) , plus nice brushless motor, plus nice ESC)...
    I was thinking also about to use the Multiplex Twin-Start II, but people dont like how it flies...

    I am just worried about easy reconstruction (to do a lot of testing...)
    Easy landing (We want to program an autolanding) using differential GPS and three or 4 ultrasound sensors... So its nice & sweet if its able to land on its belly on the smooth grass :)

    The only point I dont like of the Easy Star is the no-ailerons...and for control I like inputs... that's all...

    So Maximum payload using a nice Brushless Motor and a high thrust Propeller?
    Any experience with Twin Start II ???

    Thank you for everything!
  • 3D Robotics
    Chris Anderson February 26, 2009 at 5:39pm
    EasyStar and EasyGliderPro are best. EasyStar has more room and is easier to set up, but EasyGliderPro flies better.
  • Javier Garcia Lomas February 26, 2009 at 5:13pm
    I really like this site, good stuff :)

    I would like to know about your experience reaching the payload limit and fitting complications using the different Multiplex versions or other nice foamie models:
    -Easy Star
    -Easy Glider
    -Easy Glider Pro
    -Cularis
    -Any other foamie model that you consider nice to carry a lot of electronic stuff?????

    Thank you!!
  • T-Rex January 9, 2008 at 6:32am
    Jani: Thank you for the information. I look forward to seeing your project develop. I almost started with a Telemaster Electro, but since I am new to RC planes and need to learn how to fly first, Chris Anderson convinced me to start with a smaller foamie. Now that I've built an EasyStar I can see that these planes have a lot of merit in and of themselves. Go Multiplex!
  • Jani Holopainen January 9, 2008 at 1:04am
    T-Rex: I started TwinStar AP building project this week. I was quite surprised how big this model is compared to Easy Star and Easy Glider. Fuselage has plenty of room for equipment (at least three times more than Easy Glider) and airframe structure is very convincing for this job. I'll post more when this project goes on.
  • T-Rex January 8, 2008 at 5:59pm
    Has anyone tried a TwinStar? I'd like to hear about the interior space, center of gravity, and payload lifting abilities. Seems like this airframe would work well too. Multiplex makes good planes.
  • Paul Gregory January 8, 2008 at 10:32am
    Well I am still plodding away with my Cularis, athough these posts worried me enougth to try balancing the nearly finished airframe. If you look at my latest post, you will see that it works fine with the Pentax A30 and PicoPilot set up, though I think I would have a problem if I tried adding data loggers, radio modems etc.

    I originally chose the Cularis (not on the basis of any real experience) because I assumed that a larger airframe would be more stable in flight for my photmapping. Only time will tell.

    Paul
  • paul hubner January 7, 2008 at 8:27am
    I love my EasyGlider. I dropped in a brushless and modded the holds to accommodate my electronics/cam/cargo.

    I started on an EasyStar, which is a delight. The EG increases the payload size and still has great flying characteristics for me.

    Paul
  • 3D Robotics
    Chris Anderson January 6, 2008 at 5:05pm
    Mike,

    Thanks for the tip. For those who don't know it, the Multiplex Cargo is a four-motor transport that Multiplex made a few years ago. Now discontinued:
    http://www.multiplexusa.com/models/Discontinued/Cargo.htm
  • Mike Mc Smith January 6, 2008 at 4:58pm
    I just finished off a multiplex cargo this weekend-

    Nice and smooth to fly- Plenty of space for equipment.
    With a different power set you would have a real nice
    platform for DIY UAV.

    I just have this one to play and learn for now-

    There is a FPV with down-link- and a stills camera in the cargo bay (kind of pushing the limits for the motor set thats on it) and still plenty of room.

    Only a few modifications are needed from the factory build instructions- two most important being the battery positioning and the second being how you attach the wings to the main fuselage.

    My two cents are that most multiplec models, given a little modification take a lot of hassle out of creating something that already exists- mainly a nice smooth flying plane/glider.

    cheers
    mike
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