We all love the Multiplex EasyStar, but for autopilots that separate stabilization and navigation, its lack of ailerons is a limitation. (Stabalization--FMA Co-Pilot in our case--uses ailerons and elevator; navigation uses rudder and throttle). The next plane up in the Multiplex family is the EasyGlider, recently upgraded for brushless power with the EasyGlider Pro. It's bigger (71" wingspan vs the EasyStar's 54"), has ailerons and can lift more weight. But it's also a lot more expensive ($256 with power package, as opposed to just $66 for the EasyStar), and the front-mounted motor takes up a lot of interior room. How suitable is it for a UAV? I got one and tested it out last weekend. Here's my report:

As with all Multiplex kits, the build quality is excellent and the Elastopor foam goes together nicely with CA glue. If you get the optional power kit, all you need is four servos (2x HS55 and 2x HS81), a Deans connector, and a LiPo battery, along with your RC kit. You can put it together in one evening.

I of course added a FMA Co-Pilot, and mounted the sensor above the wing. The plane is slightly nose-heavy in this configuration, but nothing a bolt or two in the tail can't cure. But when you put in all the equipment, you'll spot the first big disadvantage of the EasyGlider Pro: it's got less room inside than the smaller EasyStar!

That's not just because the motor and the ESC are in the cockpit. It's also because the servo and pushrods are, too. In the EasyStar, they're all on the outside, leaving the cockpit entirely open for radio and camera equipment, but in the EasyGlider you have to share a narrower (albeit longer) space with everything else.

You can see the two side-by-side in this picture:

The EasyStar is closest to us (it's the beat-up one!) and the EasyGlider is behind it. Even though I've added a camera-trigger servo on the EasyStar it still has more unused space than the EasyGlider. The only way to add more space to the EasyGlider would be to create a second "floor" layer above the servos and put autopilot equipment on that, under the foam canopy. Otherwise, anything you stuff in there risks tangling up with the servos, pushrods and other wires.

Obviously, the other problem with the EasyGlider is that it's hard to put a forward-looking camera in it, since the prop is in the way, something which isn't a problem for the EasyStar with its pusher prop. There are people who have modded the Easy Glider to put the prop in a pusher configuration with a pylon, but that's too much work for me ;-)

As for flight, the EasyGlider flies really well and the ailerons give more precise control than the EasyStar's rudder. But it's also a bit harder to fly for beginners, and if you crash nose-in, you're going to damage the prop and maybe the motor, which isn't a problem with the indestructable EasyStar. I found that the FMA Co-pilot had a hard time maintaining level flight at high gain settings, but that may be due to calibration problems. I'll have to test a bit more to see what the problem is.

Bottom line: I prefer the EasyStar, but since I need the ailerons I'm going to continue working with the EasyGlider and create an autopilot layer for the cockpit as mentioned above. What I love about these foam powered gliders is that you can fly them anywhere and they can land on any surface without damage. So as an autopilot test platform, they're great for quick trials and experiments. But I wouldn't recommend the EasyGlider as the optimal UAV platform for serious use. For that, you'll want the usual high-wing trainer, even if that means having to take off and land from a proper runway.

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Comment by automatik on December 5, 2008 at 11:21am
Truth be told I haven't made an RC plane in little over a decade (but I am planning to :) ) so take this with grain of salt - it shouldn't be too hard to add ailerons to EasyStar's wings with little cutting, sanding and gluing. There are pre-cut balsa pieces in the shape of trailing edge that can be used (which can simplify build process)....I actually remember doing this on a basic glider way back when. Also, if memory serves me right I once added "flaperons" (spl? flaps + ailerons combo)....
As for motor location on EasyStar Pro - if more nose space is needed it might be possible to build "pod" over the wings (attaches to the where base of the wings and fuselage meet) and put a motor there - it can still be puller motor. I remember having that kind of a set up on my first RC plane - Amigo II 4ch RC glider. looked like this:
http://www.rcgroups.com/forums/attachment.php?attachmentid=570706


I built the thing from scratch - just using a plan and a lot of balsa cutting. At first my grandpa, and his Big Lift would bring me up to altitude (Amigo attached to Big Lift via pod over the BL's wings), we would separate and I would learn how to fly for a while. Afterwords I added little engine to Amigo (via custom pod) and I could take off by myself). Speaking of Big Lift, it could be good platform for drone.... Here is picture of it I found o the net:
http://www.emerge.net.au/~daznsuz/biggy.jpg

Comment by Jhon on December 5, 2008 at 11:55am
i think elektro junior S is the best for UAV and long range. it can glide for 1,5km just losting 100m of height and can cimb to 3000 meters, this would result in 45 km of distance with a 3200 mAh lipo without thermals.

the new version of electro junior S has servos in the tail so much more space is free in the cockpit.

also tail can be detached for easy carry, and removing a little bit of foam you get all that space!!!:


enought for 2 batteries of 3200 mAh and another one of 1000 mAh for video.

3D Robotics
Comment by Chris Anderson on December 5, 2008 at 12:11pm
Unfortunately, the Elektro Junior S is not available in the US, as far as I can tell.
Comment by Jhon on December 5, 2008 at 12:47pm
ohps im sorry, mmmm but im sure you can buy it thru internet at UK or germany webs,
Comment by Wim De Wilde on December 5, 2008 at 3:51pm
Nice plane, this Elektro Junior S! The glide number you mention is almost twice what I measure at my EZ.

A remarkable EasyGliderStar that should also be overlooked in this thread is here:
http://www.rcgroups.com/forums/showthread.php?t=822678

Another option in the picture below: wings with ailerons, made out of some isolation material I found in the DIY shop. It won't break endurance records, I just made this to play with thermopiles.


Up to now my autopilot EZ had stock wings and rudder. It's stabilized via a yaw gyro, calibrated by GPS. This works fine, even in moderate winds (10 mph), but there is room for improvement.

3D Robotics
Comment by Chris Anderson on December 5, 2008 at 4:05pm
@Wim: Thanks for the link to that terrific EasyGliderStar mod thread. For those of you who didn't click through, here's what it looks like:

Comment by Jhon on December 5, 2008 at 5:58pm
http://www.aeromodelismovirtual.com/showthread.php?t=1467
for people that like so much the pusher option of the easystar, there is aso a mod of easystar+elektro junior wings:

Comment by corey on December 5, 2008 at 8:14pm
while there's no denying the amateur uav market is growing fast, it seems the talent so far has been focused on the autopilots. i see a market lurking for model uav airframes and i wish i had the resources to capitalize on it!

Moderator
Comment by Gary Mortimer on December 6, 2008 at 5:13am
The Twinstar is a fantastic airframe as well, you can use the copilot on rudder, its less elegant but works.

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