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To allow the EasyStar to have better turning authority, Dave installed a plastic tab (above left) on the rudder. The bare EasyStar wings with lightening holes


A photo will show a close-up of my modi- fied tail, where I have extended the hinge line vertically, by carefully cutting a verti- cal groove upwards along the hinge-line of the rudder on both sides, but leaving enough Elapor foam to form a hinge. I joined the two with a small piece of 1⁄64-inch ply slotted into the old and new parts. When that also proved insufficient, I added a Plexiglas extension also slotted into the rudder and glued in with canopy glue. The Plexiglas has the advantage of retain- ing the elegant tail outline in flight. The lack of power can be solved quite eas-


ily by installing a substitute brushless mo- tor with more oomph. In fact, there is a com- mercially available upgrade kit featuring the Himax 2815-2000 (275W) brushless in- runner, which turns the normally docile machine into what I call an “AngryStar” ca- pable of nearly vertical climbs. I believe this follows a published article in one of the magazines on “hotting up” the EasyStar. Or you can buy an EasyStar II.


Watching these so-called “AngryStars” perform made me think that there must be a lot of reserve in the EasyStar wing to take this increased performance (although the EasyStar II has an even thicker wing, per- haps to more easily allow for aileron servos). Since soaring is my thing rather than verti- cal climbs, I thought I would try for an EasyStar Lite. Along the way, I learned a few things that may be of interest to others. I started with the wings. I weighed the un- touched wings and got my first surprise. The


FLYING MODELS


cut (above right) before covering. Note the extra hole in the right wing panel, out near the tip, to help lateral balance.


initial wing weights were nearly 10% differ- ent. The slight asymmetry in the wing roots is not enough to explain this. That foam is not as homogeneous as it looks! I have since checked with other EasyStar owners and they have found the same thing. And my ParkZone Radian shows similar differences. I cured the latter by differential painting of the wing undersides which also improved the high-altitude visibility. So even if you don’t end up cutting lightening holes in them, foam wings are worth weighing and balancing.


Best/easiest is to install the weight differ- ence wherever needed to balance the model laterally on the centerline. Less weight on the tip may balance it statically, but doesn’t do as good a job dynamically. The suggested method is still not perfect dynamically, but it will be closer than the tip weight method. But for small differences, and sport flying, it doesn’t matter that much anyway. My main line of attack to lighten the mod- el was to cut large holes in those strong wings and cover them with UltraCote Lite or equivalent. Note that I have assumed that the wing joiner takes most of the load on the inner part of the wing, and hence one can re- move as much of that material as you feel comfortable with, leaving enough to keep the shape and overall structural integrity. Outboard of the wing joiner, I left the ini- tial part untouched as it will be highly loaded as the load transfers out from the wing joiner to the bare wing, and then ta- pered the cutouts towards the tip. I did all


this by hand with a No. 11 blade, so I also put a little thin CA in the sharp corners of the cutouts to help avoid later cracks start- ing. I also sanded off all the residual mold- ing marks to provide a smooth surface to cover.


This is not an easy way to save weight. The untouched left and right wings weighed 69.3 and 63.8 grams respectively, then 55.0 and 52.5 grams with the holes (I deliberate- ly cut bigger and more holes out of the heavy side) and 62.7 and 59.0 grams covered, for a total savings after quite a bit of work of 11.4 grams, or about 9%. But I did end up with a unique look to the model as seen in the pho- tos, which was also part of the motivation; it lets the “lite” through.


When I began, I approached the covering very cautiously, since I didn’t want to melt the foam, but there was absolutely no prob- lem, at least for temperatures up to about 250°F needed for the UltraCote Lite. If I were doing it again, I would just make cutouts for aesthetics in the inner part of the wing and then avoid covering the curved tips.


The real weight savings were much easier: I replaced the heavy plastic wing joiner with a carbon fiber tube for a savings of 16 grams, and replaced the brushed motor that comes with the kit with a small brushless Turnigy C2230–1780 (about US $11.50 from Hobby King). I had used this motor in a previous EasyStar and it provides just over 100W stat- ically using a 3S Li-Po and a 6–4 prop, which just clears the aft fuselage. The combination


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