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October 19, 2021, 05:53:12 AM *
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Author Topic: Ellipse 16in.  (Read 4148 times)
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Tapio Linkosalo
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« Reply #100 on: July 10, 2021, 01:19:07 AM »

Have not come across such balsa hot wire. But CNC airfoil shaping is proven and this company does very well. Like this video here:

I have not heard anyone using a diamond saw with a "hot wire" jig to cut balsa. I would guess it would have similar issues as with hot wire, if the cutting wire is lagging it would disturb the airfoil in the center.

But alas, CNC is a proven method to produce balsa wings. If you browse to the start of this thread (first page) you will find that actually the glider discussed - the Ellipse - was produced by CNC (like in this message: https://www.hippocketaeronautics.com/hpa_forum/index.php?topic=24385.msg259683#msg259683 ). I do not know how the GTS company has managed to position and keep in place their parts to be CNC'd, as in the video it seems that they cut the outline first. I make it the other way round, start with a rectangle of sheet wood, first cut the surfaces using the sheet outline as a reference, and only as last part cut the dihedral breaks to desired angle, and the wing outline to release the part from the sheet block.

One nice feature is that you can easily modify the wings. I have two versions of the Ellipse, 16" and 18". First designed the 18" and the smaller version was simply made by stretching the wing to smaller span, wider wing (thus the same area) and thicker airfoil (to maintain similar airfoil).
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Tapio Linkosalo
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« Reply #101 on: September 30, 2021, 04:27:27 AM »


The competition next weekend looks to be windy, and on a field with longish grass. So I added a tracker to my CLG to ease retrieving. the tracker (by VanWallene) weight 0.4 grams, and it moved the CG so that I needed to move he wing 3.5mm forward to retain the same CoG location relative to wing. I hope such small change will not impact the trims!

(The tracker can be seen in front of the timer, with the antenna facing rearwards over the wing. The tracker taps the same battery as used by the timer for motive power.)
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Re: Ellipse 16in.
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esmerejon
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« Reply #102 on: October 04, 2021, 04:25:06 PM »

Incredible electronics!

Please, do you have the web of the maker? I canĀ“t find it.

Thanks.
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The man who loves art for art's sake usually finds the most intense pleasures in the most humble and less important things.

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Tapio Linkosalo
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« Reply #103 on: October 05, 2021, 12:52:02 AM »

The tracker is made by Allard VanWallene, you can find him in Facebook. I do not know if he has a web page. The timer is made by myself, no web page for that.

I flew the 16"er on Saturday. Had to move the wing a little bit back (as in msg #59, the wing saddle has slots so that you can slide the wing forward or back to fine-tune CoG) to dampen some stalls, after that the model flew perfectly with the tracker onboard.

« Last Edit: October 05, 2021, 01:34:25 AM by Tapio Linkosalo » Logged
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