Le Micro Slope Fish? - RC Groups
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Dec 22, 2015, 06:44 PM
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Build Log

Le Micro Slope Fish?


Creds to Surfimp for the two ideas I'm about to hack, his Micro Slope Stick and the Le Fish.

Wanted to make an all corflute Le Fish for a while. I believe a couple others have done this already but wanted something smaller to experiment on first and a pocket style fuse to hide the gear.

As a first attempt and to keep the weight down, going with a Le fish body scaled to 60% (600mm long - like the micro slope stick) and a single plate wing scaled to 66% (1000mm wide). Originally tried a 50% scale overall but the wing loading was too high.

With these proportions, by my calcs I'm looking at a CWL of around 4.2-4.5

Anyway, here's my plan so far. Should be a fun Xmas break project.
2 x 5g servos
4 Chanel rx - 3g
ZIPPY Flightmax 700mAh 6.6V 5C LiFePo4 - 41g

Wing
- Plan to use 5 foam ribs, one in fuse, mid span and tip, with either a 6mm wide cf ribbon spar or 4mm hollow cf tube.
- 2.5mm cf rod in LE flute

Fuse
- 2.5mm corflute
-Possibly 1 or 2 2.5mm cf rods in flute for stiffness
-Some cut down pp tube (leftover from the Fastjet) to close the gap in fuse and to give a rounded outer edge. I've hot wired a much smaller diameter (20mm) and cut in half length ways to create a u profile. Just need to cut straight edge on both sides so it can be glued to inside edges of fuse with rounded edge protruding.

Horizontal Stab
Plan to go with mad stab. Base plate for h stab pivot possibly from 3mm Corflute and control surfaces from 2.5mm corflute as I have cf rod that will sleeve perfectly in hollow cf. Hope to slide a long servo horn onto the h stab cf rod as control horn.

No rudder in this version but easy enough to add.

Thoughts welcome.
Last edited by pzanni; Dec 23, 2015 at 06:06 PM.
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Dec 26, 2015, 01:09 AM
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Progress so far.

Fuse and stabilizers 39g
Dec 27, 2015, 05:40 AM
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Tip rib, 2mm mdf and foam.
Same style for mid span rib.
Jan 12, 2016, 07:41 PM
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Le Micro Slope Fish?


Here's the idea I had for mad stab. Simple and light I'm hoping.

3.5mm cf tube inside the centre 3.5mm corflute with 2.5mm cf rod inserted thru tube and 2.5mm corflute horizontal stab.

Old servo control arms drilled out to 2.5mm and additional arms cut off. Slid onto and glued to 2.5mm rod and h stab along chord to strengthen a little.

Images probably easier to understand. Everything is just dry fit at the moment.
Jan 16, 2016, 12:07 AM
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The plan for the inside of fuse.

Centre foam strip bends up to follow contour of tail for a bit. Helps keep fuse at correct width for length of wing root chord.

Might put a foam support in nose too.
Jan 16, 2016, 04:41 AM
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Tail complete sans decoration = 18gms
Fuse with servo X 2 and foam support = 42gms
Wing, ribs, 2.5mm cf rod and 3.5mm cf tube = 75gms
Battery: 39gms
Rx: 3gms
Total: 177gms
On track for AUW of 186gms
Jan 17, 2016, 08:14 PM
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Went with a 3mm squarish cf hollow tube for wing spar.
Ailerons cut out and hinged.
Jan 18, 2016, 04:38 AM
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Ribs on one side of wing done, ready to slide thru fuse.
Jan 19, 2016, 01:40 AM
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Another custom hot wire foam cutter jig thing… cutting the pp foam tube down to 15mm thick to close fuse.
Jan 20, 2016, 03:54 AM
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Wing thru and ready for 2 rhs ribs.

Starting to look like a glider.
Jan 21, 2016, 12:29 AM
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Pushrods and Aileron control horns in.

RHS ribs in.

Should've cable tied servos at same time as glueing the fuse. Managed to thread the elevator servo cable tie from the inside but not the Aileron servo.
Jan 21, 2016, 02:38 AM
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Extreme Sports's Avatar
Been following this with interest as I thought about building a correx LeFish for sloping, but never got much further than that (not helped by not having reliable winds or any decent slope nearby).

How are you doing the wing? It looks like an under-cambered, single skin type wing. If so it will be interesting to see it performs - has very high drag, so not an obvious choice for a glider. But then again, the LeFish is not quite a normal glider

Looking fwd to flight tests!
Jan 21, 2016, 03:44 AM
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Thanks ES.

Plenty of hills here but not all suitable. There's a quality slope about 30 min away tho, hang gliders etc.

Re the wing, tbh I'm aware of the importance of aerofoil choice when it comes to gliders but I don't have any experience with them, let alone creating an accurate airfoil!

I've used the standard airfoil for a le fish (SB96V?) and made as accurately as possible considering scale/materials/skill and tried to ensure the le flute with cf rod reaches just round the le to bottom of rib a little.

Given the Micro Slope Stick slopes with a single skin kinked wing, I'm hoping this thing will work just as well if not better. Not very scientific I know.

Off to the coast camping tomorrow. Hoping to finish tonight and take with (and find a suitable sand dune etc)!
Jan 21, 2016, 04:20 AM
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Tail on. Think it's even straight…


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