Opus … 100g (3.5 oz) 20-inch quick build delta ... Video & Plans post 2 - RC Groups
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Dec 13, 2007, 10:22 AM
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chaosMurphy's Avatar
Build Log

Opus … 100g (3.5 oz) 20-inch quick build delta ... Video & Plans post 2

I would like to revisit joyous moments and share
an easy quick build fun fly model with a huge flight envelope.
Set reflex at zero and WOT she is super fast with quick crisp response
5-10 degrees and quarter throttle a docile floater
10-15 degrees and dead stick she will land thumbs off.

The fuselage is neither profile nor built up
rather a two section compound twist.
Bamboo, carbon, glass tape is not required on
wing or fuse with Lowes fan-fold.

servo 5g (2)
esc 7g 10A
motor 16g 2211-17-70W (WOW sweet little low $ motor)
prop EP6030 develops apx 50 Watts on three cells WOT

Opus is a Latin word used in many fields, notably architecture and music.
In architecture, specifically describes a technique or method or a style of connecting building elements, i.e. this fuselage. I’ve bounced this design several times with no damage other that tossing lipo from masking tape binding.
Last edited by Gramps:>); Jan 01, 2008 at 09:07 AM.
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Dec 13, 2007, 10:28 AM
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chaosMurphy's Avatar
This is my third Opus
no hardware other than motor mount
lightest yet 57g.

The “22 inch” fuse pattern is cautiously too long. Bevel top inside edge, optional.
I suggest, first, cut in motor mount slot, then trim ‘fuse’ to 20 inches then cut fin slot and last, glue fuse panels

Not as easy to build as a profile but much, much stronger and
no carbon or bamboo required on blue single side fanfold.

…edit 23dec…
The fuselage sides are twisted … no angle cut required.
This twist occurs naturally during build process.

Cut two fuselage panels.
Glue nose section flat together (like in a vice) an inch or so.
After glue sets, remove from vise, twist tail section open 90 degrees (I use a 2inch steel cube covered wax paper) and glue two inch length in front of fin cutout. At this point every thing is cock eyed, not to worry (yet). After glue sets, place fuselage on flat surface and glue length from nose to tail. Top fuse-panel line must be straight, bottom fuse-panel line (on table surface) will be curved (like drawing an >arc< on paper), not to worry (yet), the fuse-sides will twist (monocock) here sets part of its strength the OPUS.

Now the worry part, glue wing to fuse…
Maintain desired dihedral
push that >arc< to a straight line.
No effort or force required just patience waiting for glue to set.
I start at tail with hot melt and apply about 2 inches at a time.

Glue second wing panel, then flip model and glue underside wing to fuse, keep it sparse a little dab of hot melt goes a long way.

At first, I found it easier to cut motor mount slot before gluing wings.

BOXHEAD found a much better technique, a twist off bottle cap motor mount.
See detail in post 44 and 53.

TNX Box!

Ducks Guts
Maiden …19 dec 07

dihedral one inch each tip
zero degree reflex, vertical roll unlimited
fantastic s l o w dead stick glide

and post 65

150g (5.25oz) no batt
24g 1500kv UH pink-wonder motor
APC 7X5 apx 80W on 3-cell
She is quick and wild!

Opus (2.25 inch each tip) is more a new pilot entertainer than Ducks Guts

Opus 2.25 each tip AND elevator/rudder (verses elevon) post # 55 is a docile trainer
Last edited by Gramps:>); Jan 01, 2008 at 09:04 AM.
Dec 13, 2007, 12:34 PM
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dekan's Avatar
Gramps, I like deltas I have 4 now.. the Opus look interesting. I like the built in plan, that is novell.
Where did the motor come from....
Dec 13, 2007, 01:20 PM
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chaosMurphy's Avatar
Thank you.

and not tested yet 50W baby sister weighed in at 9g, ain’t she sweet?
I will probably buy a second 9g and try a twin tractor Opus-71
Dec 13, 2007, 02:21 PM
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dekan's Avatar
Just finished a mini Arrow with a 9grm motor weighs 3.1oz
Dec 13, 2007, 03:53 PM
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chaosMurphy's Avatar

I am very interested in motor and model
you are welcome to post comments pro or con here.

p.s. Invitation extended to all
Dec 13, 2007, 05:00 PM
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dekan's Avatar
I haven't maidened mine yet, Gramps.
Its a bit soft on 2s Dan at lazertoyz reckons 19W. however 3s..... very impressive.
Dec 13, 2007, 05:19 PM
feel no remorse
youth must fly's Avatar
neat design reminds me of the original paper plane model.
Dec 13, 2007, 09:20 PM
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chaosMurphy's Avatar
Astute observation youth_must_fly …
My Opus lineage dates back to the late 1980s flown from a European hotel window.
Dec 13, 2007, 09:28 PM
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Dickeroo's Avatar

Gramps, you put a smile on my face.

What a kick to realize that my paper airplane traveled so far from home. It's a great feeling to know that I have made a connection with so many wonderful people in the RC Groups. I feel honored to walk among you. You are all so creative and full of ideas. It really is the high point of my life.

Dick Kline
Dec 13, 2007, 10:20 PM
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chaosMurphy's Avatar
Thank you Dick, the admiration is ours.
Don’t know who had the most fun this day, neighbors, grandkids or me.
Dec 14, 2007, 08:35 AM
You deserve my opinion
FirstShirt's Avatar

Can I come to your house and play?

Gramps, looks like a blast! Thanks for putting the Opus out there!

Dick, you are a very gracious man. Thanks for your wonderful contributions.
Dec 14, 2007, 01:18 PM
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dekan's Avatar
Is the dihedral required? The gliders don't seem to have any.
Dec 15, 2007, 12:04 AM
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chaosMurphy's Avatar
Is dihedral required?

I don’t know. In this case, gliders were identical except for CG. KF step was added later to evaluate any change in distance. The catapult is for consistent launch speed. Grandkids caught me in the act so we created more fun that day than empirical data.
Dec 16, 2007, 06:05 AM
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dekan's Avatar
Gramps I have flown my Mini Arrow.

I have only flown it 2s at the moment, too chicken to to try it 3s as most of the time unless it vey low I have problem telling which way up it is.

Very tight loops even on 50% rates, very hi rate of roll.
It needs a much better pilot.

My FB who flys very hi speed ducted fan planes....refused to fly it. He said "it hurt his eyes trying to fly someting that small"!

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