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Old Mar 02, 2014, 01:57 PM
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Build Log
Mountain Models/Laser Arts Round2It

I have not seen a specific build log on the Mountain Models Round2It so I decided one should be accomplished. I have normally been doing build videos, but those take much longer and I'd like to knock out this build in short order.

I normally don't have two builds going at once but since I am still waiting on my servos to get here for my SA Soarstik, I figure now is a good as time as any.

Here is the details on the Round2It:

Quote:
The Mountain Models Round2it! is a small electric sailplane model designed to bring back that relaxing feeling of catching small thermals in the local ball field. The 36 inch Round2it! is super easy to build and easy enough for a beginner to learn how to fly with some friendly help.

The Round2it! was designed using a state of the art 3D CAD package, to allow for exceptional interlocking parts design and fit. 3D design also allows us to provide clearer assembly images, without having to use photos.

The Round2it! is built from self-jigging interlocking laser cut balsa and plywood parts. It's like a 3D jigsaw puzzle with instructions. Although not needed for building, full size plans are included for reference. If the instructions are read before hand and followed during the build, the Round2it can be built up and ready to fly in only 2 to 4 evenings.
Without further ado, let's begin.

Frank
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Old Mar 02, 2014, 01:57 PM
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Component Choices and Steps For The Fuselage Build

Pictures are worth more than words so here is a photos build with descriptions. We'll see how this works out with RCG's new format. If it's too confusing I'll do it the old fashioned way.

Frank
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Old Mar 02, 2014, 01:57 PM
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Empennage and Wing Build

The pics show the empennage and wing build.

Found an unusual problem building the emepenage sections. Some of the little tabs broke off. They are usually a tight fit, but I have never had the tabs break off like this. I wonder if it's the balsa tree issue that people have been talking about?

Step 16 and 17 will come later. I only like to clean up balsa dust once during a build. I do have a great method to sand exact 45 degree bevels in my flight controls now. Will post pics later in the build.

Frank
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Old Mar 02, 2014, 01:58 PM
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The Final Touches

Here are the last few steps in the build process.

Step 37 note: I never have used this method before so I experimented with it. The heat shrink and CA works very well to hold the pushrods together. I had to cut them apart with my scalpel to separate them.

Frank
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Old Mar 02, 2014, 06:02 PM
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I'm watching! Looking great. Does the motor you chose have the same power as the recommended set-up?
Did anyone find a folding prop/spinner that will work on the R2I?.
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Old Mar 02, 2014, 06:25 PM
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Quote:
Originally Posted by TScott1118 View Post
I'm watching! Looking great. Does the motor you chose have the same power as the recommended set-up?
Did anyone find a folding prop/spinner that will work on the R2I?.
That's a good question. I could not find the specs on the D1811-2000 anywhere so I just used the AUW of the plane to find the motor I chose. The T1804 weighs in at 14 grams but I am guessing can provide a lot more power than the 1811 (even though it doesn't need it but it will be fun nonetheless.

WRT folding prop, if your motor has a 3mm shaft then you can find the folding spinners here: http://www.headsuphobby.com/Folding-Props_c86.htm

I was going to use one as well, but decided against it due to the additional weight. I am hoping an ESC break will work well enough.

Frank
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Old Mar 02, 2014, 09:25 PM
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I love the Round2It! It is probably my most frequently flown plane recently. I set the ESC brake to activate and that seems to be plenty. I can glide with motor off for quite a while, so the excess drag doesn't seem to be an issue. One problem I have had, is the wings can warp, and just a little bit will effect the flight characteristics quite a bit more than I thought it would.
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Old Mar 03, 2014, 10:23 AM
Veni Vidi Volavi
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Frank

Looks like it is going together well as one would expect from a MM kit.

Need to get started on mine.

Brian Allen

Veni Vidi Volavi

I came I saw I flew
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Old Mar 03, 2014, 01:03 PM
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D1811-2000

I found the specs for the motor right on MM's website. Link follows:

http://www.mountainmodels.com/produc...roducts_id=636

Just going by weight, it looks like yours should be more powerful. 15G vs 10 for the 1811.
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Old Mar 03, 2014, 06:59 PM
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Thanks Brian, too bad that's about it for the week though. Hard to believe you can glue a plane together in just one day. I never expected to get that much done.

I'll be sure to watch for wing warp as mentioned above.

Mike,

FYI

The weight of a motor is not considered "specs". Specs look like this:

Stator Diameter ................................... 22.0 mm (0.866 in)
Stator Thickness .................................... 8.0 mm (0.315 in)
No. of Stator Arms .................................................. ..... 12
No. of Magnet Poles .................................................. .... 14
Motor Wind .................................................. 26 Turn Delta
Motor Kv .................................................. 1550 RPM / Volt
No-Load Current (Io) .......................... 0.53 Amps @ 8 Volts
Motor Resistance (Rm) Per Phase ..................... 0.150 Ohms
Motor Resistance (Rm) Phase to Phase ............. 0.100 Ohms
Max Continuous Current ...................................... 15 Amps
Max Continuous Power on 3S Li-Po ...................... 165 Watts
Weight .............................................. 46.5 Grams (1.64 oz)
Outside Diameter .................................. 27.7 mm (1.091 in)
Shaft Diameter ..................................... 3.17 mm (0.125 in)
Body Length ......................................... 24.0 mm (0.945 in)
Overall Shaft Length .............................. 38.0 mm (1.496 in)

and this:

http://innov8tivedesigns.com/Cobra/C...8-26_Specs.htm

Frank
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Old Mar 03, 2014, 07:05 PM
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Yes, I know what motor specs are. I was using the 15g and 10g to differentiate which motor I was speaking of. The post I made included a link to the motor that is specified by Mountain Models for this plane. The link is to their web page where many of the specs for that motor are included. I do not know, nor do I care to look up, the specs of the motor the OP has purchased to use on this model. All I was saying is that since the motor is larger than the specified motor that it would likely work for this airplane.
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Old Mar 03, 2014, 07:13 PM
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No worries Mike, just trying to help you out when you said this:

Quote:
Originally Posted by Mike Dubovsky View Post
I found the specs for the motor right on MM's website. Link follows:

http://www.mountainmodels.com/produc...roducts_id=636

Just going by weight, it looks like yours should be more powerful. 15G vs 10 for the 1811.
I Just wanted to make sure that you knew that motor specs are more than just the weight of a motor. There are a lot of newcomers that read these threads and they could misunderstand that like I did because a heavier motor does not always equal more power. That is where the specs really need to be researched.

Frank
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Old Mar 03, 2014, 10:25 PM
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Quote:
Originally Posted by Murocflyer View Post
Thanks Brian, too bad that's about it for the week though. Hard to believe you can glue a plane together in just one day. I never expected to get that much done.

I'll be sure to watch for wing warp as mentioned above.

Mike,

FYI

The weight of a motor is not considered "specs". Specs look like this:

Stator Diameter ................................... 22.0 mm (0.866 in)
Stator Thickness .................................... 8.0 mm (0.315 in)
No. of Stator Arms .................................................. ..... 12
No. of Magnet Poles .................................................. .... 14
Motor Wind .................................................. 26 Turn Delta
Motor Kv .................................................. 1550 RPM / Volt
No-Load Current (Io) .......................... 0.53 Amps @ 8 Volts
Motor Resistance (Rm) Per Phase ..................... 0.150 Ohms
Motor Resistance (Rm) Phase to Phase ............. 0.100 Ohms
Max Continuous Current ...................................... 15 Amps
Max Continuous Power on 3S Li-Po ...................... 165 Watts
Weight .............................................. 46.5 Grams (1.64 oz)
Outside Diameter .................................. 27.7 mm (1.091 in)
Shaft Diameter ..................................... 3.17 mm (0.125 in)
Body Length ......................................... 24.0 mm (0.945 in)
Overall Shaft Length .............................. 38.0 mm (1.496 in)

and this:

http://innov8tivedesigns.com/Cobra/C...8-26_Specs.htm

Frank
I wish I know what all of that meant. I only worry about watts, amps and kv and weight.
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Old Mar 03, 2014, 10:40 PM
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Well some of the specs are physical dimensions, so that you will know if it will fit in your airplane. Some of the specs like phase resistance are electrical parameters of the motor. You would want to know some of these if you were putting the motor information into a motor simulator, so that the program would be able to more accurately predict motor performance. Some of the specs just tell us how the motor is built, like number of poles and number of magnets. I guess some of the motor simulators use this and tell you how many steps the motor takes in one revolution, but you really don't need to know that to predict amp load or power consumed. My feeling on it is you can never have too much information, just too little.
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Old Mar 03, 2014, 10:41 PM
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Quote:
Originally Posted by TScott1118 View Post
I wish I know what all of that meant. I only worry about watts, amps and kv and weight.
Yea, me too.

But, if you ever do decide that you want to learn more, download these podcasts.

http://www.allthingsthatfly.com/

I download a bunch at a time and then listen to them only way back and forth from work. You would be surprised how much you can learn just from listening to them. Best thing is, if you hear something you didn't quire understand, you can "rewind" it and play that part again.

Frank
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