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Old Jan 01, 2013, 02:20 PM
Crashing? Hunting the mole!
Honza C's Avatar
Česká republika, Jihomoravský, Brno
Joined Jan 2011
112 Posts
After the old big (80cm) Index has served almost 10 months, I had to dump it before Xmas and build a new one. This time with the following changes:
* basis from 6mm EPP to be crash resistatnt (I wanted 5mm, but no hobbyshop had it here...), rest as usually 3mm Depron.
* SFG
* pull-pull for elevator and rudder.
* a separate servo for each aileron (I wanted them to be separately tuneable, differentiation, etc.).

See the photos for the result. The electronics is just slightly changed from what I had before:
* R610 OrangeRx R610 Spektrum DSM2 6Ch 2.4Ghz Recei ... stripped of the box to save weight.
* TR_P10A TURNIGY Plush 10amp 9gram Speed Controller
* 3 x TGY-1440A Turnigy 1440A Servo 4.4g/0.8kg/.10sec - ailerons, elevator
* Dymond D47 for the rudder.
* TR2204-14T TURNIGY 2204-14T 19g Outrunner
* 8x4 GWS prop.
* 300mAh 2S Turnigy Nanotech batteries.

The weight w/o battery is 126g, so with a Nanotech (~20g), I am at 146 which is just 9g more than my previous version - very good result !

I tested is in the hall (so far with one pair of SFGs) and outside and it flies great - the SFGs help to hold it in KE. I will see if I install the breaks, but probably not - it would be nice for the hall but I want to have a universal Index also for outside, and I guess it would behave very bad even in the slightest wind.
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Old Jan 06, 2013, 04:36 AM
Crashing? Hunting the mole!
Honza C's Avatar
Česká republika, Jihomoravský, Brno
Joined Jan 2011
112 Posts
Looks like I could open an Index factory ... my small (55cm) one was also in a pretty bad shape, so I decided to build a new one. This time ultra-light, looking at every gram. The goal is to have something not only for the hall but also for smaller spaces (such as lecture room at work . The key points are:
- milling the 3mm Depron to cca 1mm using my home-made tool - look at http://rcmania.cz/viewtopic.php?f=6&t=51638&start=15 (Czech, but the images are self-explanatory). I did not have any CAD for placing the ribs, just did it by hand.
- pull-pull system for elevator and rudder. The servo shafts are drilled .8 mm and a CF rod is run through. The levers are also .8mm CF supported with Depron triangles. Kevlar thread is simply atached by a drop of CA + activator. See image for the elevator servo.
- the wing is strenghtened with .5x3mm that is however no more .5mm thick, as I cut it approximately to half - it goes very well with a sharp knife!
- the motor (AP05) has a new glass-textite back - this was not really driven by the quest for lower weight but because I screwed it up when changing the bearings. It is fixed on 1.5mm CF rods that are run to rubber blocks (6 x 6 x 1mm). This allows for re-ajustment of the axis and is quite good in crashes as the rubber takes most of the impact.
- there is a Kevlar thread fixing the angles between fuse and wing not only in the lower part (as suggested in the plans) but also in the upper one.
- I cut the balancing connectors on the batteries (Zippy 180mAh 2s), and removed the plastic cover.
- I removed the plastic cover of TGY 6A ESC.
The electronics is what I had before: HK AP05 motor, 3x HK 282 servos, TGY 6A regulator and 4ch Orange receiver with these small connectors. Prop as usual: GWS 5x3. Batteries Zippy 180mAh 2s, but I'll probabl also try with TGY Nanotech 300mAh (that perform very well in our big Indexes) and GensAce 250mAh that I just received.

I did not have occasion to weight it yet, I will post the weight when it's done. Subjectivelly, it feels lighter than my son's one that had (when new) 54g without battery. So far, I was hanging in our living room, flight test to come, stay tuned

EDIT: I have the weights:
- w/o battery, the new Index has 43g - this is 11g saving, not bad. I looked forward to even less weight, but I would need to add some helium...
- batteries (all with a piece of velcro, all 2s):
-- zippy 180mAh 14.5g
-- zippy 180mAh with cut balancing connector and stripped of the blue covering film 13.5g
-- GensAce 250mAh - 18g
-- Nanotech 300mAh - 17g
This means that with the Zippies, I will be at around 56g, not bad. Looking fwd to maiden flight !
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Last edited by Honza C; Jan 06, 2013 at 11:34 AM.
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Old Apr 13, 2013, 07:36 AM
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stegla's Avatar
Guernsey
Joined Jan 2002
1,297 Posts
Here's a pic of my 580mm span index. Milled freehand like Honza C.

Milled 2mm depron plus loads of carbon weighs 52g with a 2s 160mAh battery

Steve
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Old Apr 13, 2013, 01:02 PM
Crashing? Hunting the mole!
Honza C's Avatar
Česká republika, Jihomoravský, Brno
Joined Jan 2011
112 Posts
very nice, I'm looking fwd to hear how does it perform ! I had quite some flights with my milled 55cm Index, but I'm not totally happy with it:
* it would need more carbon - the wing bends, the ropes are for nothing. If I built it now, I would place one 3x0.25 CF all the width of the wing and another 3x0.08 (they have it now in our LHS) on the leading edge.
* the motor mount with rubber blocks is also pretty stupid, I'd do the classical way now (plywood cross and little screws).
For the moment, it's crashed and would need repair, but this project is frozen as I'm working on 1.8m Katana for the coming season I'm flying with the regular 80cm Index in the hall.
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Old Apr 18, 2013, 10:48 AM
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stegla's Avatar
Guernsey
Joined Jan 2002
1,297 Posts
Hi Honza,

My 580mm Index has quite a lot of carbon to keep it stiff. This Index is very easy to fly and even I was hovering and knife-edging and looping and rolling. However clubmate Dave Wilkinson is on the sticks in this vid.

Steve

R/C micro Index flown in a small hall (4 min 0 sec)
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Old Apr 29, 2013, 12:47 PM
Registered User
Rem 1973's Avatar
Holland
Joined May 2006
100 Posts
Here is my build of the Index.
Thanks for your plans.
This is my 4th build of a flatout, and i realy like the way these things fly.
Last picture is my previous build, it lasted 2 seisons

The Index has pull-pull on elev and rudd.
Used E-flight EFLRDS60 all around.
HET-RC Typhoon 6/3D I had laying around, with Plush 6Amp HK Esc.
Together with a 610mAh 2S Rhino gives Actualy more than enough power.
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