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Old Nov 17, 2012, 02:27 PM
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Micro Eros for indoor flying..

With the onset of winter and windy weather I enjoy dabbling in the indoor meets around the country.
After building the full size Eros, and restoring a mini Eros, both of which fly beautifully, I thought I would try to bring the 'Vintage' theme to indoor flying. After thinking for a while about what size to go for, I thought 25" span is a good trade off, I can use light thin balsa at this size and it should still be light enough to fly in a realistic manner for the type of model it is. I have seen other similar size models fly with the Parkzone brick and an upgraded motor..
So I hope to build with very close to the original type structure, minus the sheet covering, and rib spacing more suited to the wing size. Fuselage stringers are 3/32"sq and I will use 1/16 sheet formers and make a real effort to keep the weight down..
If this model is a success, I will probably build more micro oldtimers once I have experimented with motors etc..
For lightness, I want to go with an iron on film, the only one I have used is Model Span which I like and gives pleasing results, but I was thinking of trying So-Lite or something similar.. If anyone has any recommendations I would be grateful to hear them
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Old Nov 17, 2012, 05:47 PM
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Probably not much i can say that you don't already know.I've done a little indoor RC in the past and these are the 4 important things i found when building
1 Keep it light
2 Keep it light
3 Keep it light
4 Use an under cambered wing section. The slower the model can fly the better, those walls close in real quick indoors . i,ve normally used jap tissue for indoors but any light covering should be ok. Watching with interest.

Colin.
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Old Nov 18, 2012, 03:23 AM
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Thanks Colin,
I like your idea of the undercambered wing!
Will definitely include this..
Mark
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Old Nov 18, 2012, 03:49 AM
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Hi Mark if you look at my blog you will see some of my indoor models.(click in ColinNZ top left corner)

Colin.
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Old Nov 22, 2012, 05:06 PM
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Colin - very nice indoor model collection, nice to see you fly a 27" span model indoors without probs. I like your idea of undercambered wings. As for the micro Eros, the fuselage is now finished, apart from the detachable cowl top. This is a faithful scale down. Should get the wings done this weekend. I think the rc gear of choice will be the AR6400 with single cell lipo and I will select the motor when I know what the final weight will be..
Mark
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Old Nov 23, 2012, 12:19 AM
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Canada, AB, Edmonton
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Quote:
Originally Posted by marksherlock View Post
...I was thinking of trying So-Lite or something similar.. If anyone has any recommendations I would be grateful to hear them
Mark, I used Solite on my last two models and can highly recommend it. It's the easiest-to-apply covering I've ever used (and that includes most of them), it's very light, shrinks beautifully, sticks like crazy, and won't distort delicate structures. Try it, you'll like it.

I recently completed building a Keil Kraft Dandy (http://www.rcgroups.com/forums/showthread.php?t=1731640) and am very pleased with how that turned out. It's similar to your Eros in many ways, and just a little smaller (21"span). You may care to take a look at the power train and radio gear I used for that - it worked out very well, was under 1 oz total weight, very low cost, and so far has functioned perfectly. I've used the AR6400 system but much prefer the kind of equipment I used there - in particular, the "real" servos.

My Dandy ended up at a hair under 2 oz ready to fly, and your Eros shouldn't be much more than that. The Dandy flies just fine in the fairly confined indoor space I have access to.

All the best with your Eros. Watching with interest.
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Old Nov 23, 2012, 12:20 PM
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Harry,
Your Dandy build thread and model are just great Do you find the motor suitable and powerful enough? I know the Eros is a little larger span at 25" but I might copy your set up. The trouble with the AR6400 is it is designed for single cell operation of brushed motors, which limits experimentation!
Thanks for your advice on Solite as well, I will try it on my Eros.. when I have decided on a colour scheme!
Mark
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Old Nov 24, 2012, 02:02 PM
Since 1952
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Mark, that power setup I used for the Dandy is more than adequate. I never need full throttle (especially indoors) and I think it would be fine for models up to about 3 oz and possibly more.

These little guys donít need much power. Iím using a 2S100 lipo with the Dandy, and I can get 12 minutes easily even outside with some wind. That works out to about 3.5 watts average over the flight (about 30 watts/lb).

With brushless motors, thereís plenty of choice. Popular ones are the AP03 (http://www.hobbyking.com/hobbyking/s...tor_3_1g_.html) and AP05 (http://www.hobbyking.com/hobbyking/s...tor_5_4g_.html) outrunners from HK. Theyíre very well made, and are available in various Kv depending on what you want to do with them. Iíve used both of those and they work just fine.

For the Dandy, I used the A05 (http://www.hobbyking.com/hobbyking/s...er_2900kv.html)
which is similar to the AP05 but is a bit lighter.

BTW, you can run brushless motors with the AR6400 if you use the little 0.7 gram XP3A ESC from HK (http://www.hobbyking.com/hobbyking/s...ntroller_.html). It plugs into the AR6400 motor output port and can handle up to 3 amps. Iíve used that setup where the weight savings of about 4 grams or so (over my Dandy setup) is important.

Speaking of AR6400s, you can get clones for less than $20 from Target Hobby (http://www.targethobby.com/ar6400-ds...p-4162189.html). I bought a few to try out and they seem to work exactly the same as the $60 originals.

Iíve done a fair bit of investigation into these small power setups for indoor and small outdoor models. If you have any questions, ask away and Iíd be happy to help if I can.

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Last edited by Harry D; Nov 24, 2012 at 02:44 PM. Reason: Fixed wrong font.
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Old Nov 24, 2012, 02:17 PM
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A good thread, Mark, following it with interest as I have started going to indoors on occasion and hope to do more. Good info coming out of the thread as well - keep it up

john
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Old Nov 27, 2012, 06:09 PM
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Well, the wing is finished now, apart from a final sanding. As you can see I was quite generous with the undercamber, which is the only mod which deviates from the original aerodynamic design. I just need to fit the wing to fuselage fairing to blend the leading edge with the top of the windscreen.
The fin and tailplane should get done this week. I will keep the undercarriage as per the original, the spats will probably be blue foam, or if i can, do very carefully hollowed out balsa ones.
As for the colourscheme - I am very tempted to do all-over yellow, with mid blue trim as per my full size Eros, which copied the 1948 painting on the cover of the Aeromodeller that featured the model. I dont want it to look like a cheapy foam ARTF J3 Cub though!!!!
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Old Nov 27, 2012, 07:21 PM
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ARTF shouldn't be mentioned in the same breath this is a work of art.

Colin.
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Old Dec 02, 2012, 01:51 PM
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Bit more progress, Got the tailplane and the fin sections built, which just about concludes the main structure.
Next is the undercarriage and spats. main structure is still nice and light..
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Old Dec 02, 2012, 03:07 PM
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Wow - she's a little gem Mark
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Old Dec 04, 2012, 12:39 PM
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The undercarriage and wheel spats are now done. The legs are detachable at the moment and locate into alloy tubes as per the big version, but once its covered, I think i might just secure them. Just loosely assembled the model for a few pics, The cowl and tail feathers need a final sand and tidy up. Will stick it on the scales soon!!!
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Old Dec 05, 2012, 03:05 AM
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gets nicer each time you post

john
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