Unicorn Wing Building Process - RC Groups
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Dec 09, 2003, 08:50 AM
sargentw's Avatar

Unicorn Wing Building Process Underway!

Updates: 10/13/06

1. Keep in mind this build thread uses the older lighter motor tube. Be extra careful to perform trial COG balancing early in the build with the battery packs you intend to use.

2. Here is a link to an EZ Star build thread. The EZ is a great plane for new flyers as well as old timers and can be tossed in the back seat with your Unicorn.

I recently received my Unicorn and examined all the parts. I have opened this thread to post various stages of Unicorn construction, including some pictures. I welcome any comments, ideas, encouragement, and insight along the way.

I have a completed Combat Wings XE2 Aveox Brushless that was fun to build and even more fun to fly. Since I have both, comparisons will be made from time to time and kept in a positive nature.

The Unicorn appears to be a good deal. For $50 bucks you get EPP precision precut wings, 3 graphite spars, horns, rods, connectors, motor mount tube/ motor retainer, motor tube covering, good instruction book, and a roll of single strand strapping tape.

I’ve noticed the Unicorn leading and trailing edges are sharper than the XE2. The Unicorn wing is narrower than the XE2, especially, as you move towards the wing tips. The Unicorn's extra spars should help keep the wings stiff and prevent “Zagi” flap.

After listening to all the battery bay hype, I see the battery compartment on the Unicorn is just as far forward as the XE2. Strapping tape reinforcement on the nose seems to be a good idea for the Unicorn too.

Initial Unicorn building plan:

1. Use crisscrossed fiber strapping tape rather than single strand tape provided.
2. Coat motor tube with 3m77 spray and reinforce with strapping tape.
3. Reinforce Motor tube spar hole with plastic tube glued with marine goop.
4. Cover the motor tube with florescent yellow oracover (same as top of wing).
5. Use hs-81mg servos, Hitec 555 rec, and Electrifly C20 esc.
6. Use 6 volt pretuned Zagi pusher motor.
7. Use cam type prop adaptor with APC prop.
8. Use flexible Kavan control rods buried in foam to connect servos to ailerons.
9. Cover with oracover top and bottom with sharp top/bottom contrasting “beach party” colors

Time to get building!

Last edited by sargentw; Oct 13, 2006 at 08:24 AM.
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Dec 09, 2003, 08:55 AM
Just fly the darn wing!!!
ScYcS's Avatar
Huzzzahhh.....thanks sargentw. The thread i was waiting for.....btw, where the heck do you guys buy the crisscrossed fiber tape? I looked everywhere and no go.
Dec 09, 2003, 08:58 AM
Motocross Nut
TwinSpar's Avatar
I found the crisscrossed tape (Scotch brand) at Office Depot in the packing materials section.
Dec 09, 2003, 09:00 AM
Just fly the darn wing!!!
ScYcS's Avatar
Dangit! Didn't even think about OfficeDepot. Thanks for the tip!

Dec 11, 2003, 07:05 PM
sargentw's Avatar

Building Continues

The build is underway. I'm going to stick to the Unincorn building instructions as much as possible because they are clear and make sense.

The first picture is the motor tube. After glueing the motor retainer with goop I sprayed outside with 3m77 and wrapped it with crisscrossed strapping tape with overlaps. I glued a short plactic tube reinforcement/protector for the carbon spar with goop. The motor tube is now very strong yet light and flexible.

I lightly sprayed the tube again with 3m77 and applied the yellow Oracover.

The wings were sprayed with two coats of 3m77 and the motor tube was gooped. The assembly was joined together and taped with blue painters trim masking tape and left to dry over night.

The spars were installed and glued in place and left to dry. The rec will be installed next. Note: the wings are extremely well cut and everything alligns perfectly.

Details Motor Tube Construction added 2/23/04:

Some folks are having trouble with their motor tubes. I'll supply more detail about what was done to the motor tube.

A piece of flexible fish tank air supply tubing was used to reinforce the spar hole. The tube was a perfect fit and fits snug on the spar, but the spar can still slide through it. The air supply tubing also protects the spar from being chopped off during a hard impact. If you look carefully you can see the ends protruding out the sides of the motor tube. The air supply tube is gooped and wrapped with smaller pieces crisscrossed packing tape. Also note that the packing tape is doubled up in areas of higher stress, the end by the motor and around the spar junction.

Also note the inner motor tube retainer ring is gooped in the exact measured place. The goop is very strong. It will not move. The stock motor is glued in with a tiny amount of goop only on the prop end. I want to be able to remove the motor easily when the time comes. Remember to rough up the tube/ring inside and out with 100 grit sandpaper and clean every thing with alcohol before gluing. There is always a good chance that oily fingers were placed on the parts (including your own) prior to the gluing step.

I had a chance to use some 3M90 heavy duty adhesives spray. It comes out a little thicker than 3m77 but it's extremely tuff and flexible. I used the 3m90 on our kitchen chairs to glue new plastic glider/noscratch feet. They are on for good! I think this is the same stuff spider man uses in his webs. The 3m90 would work with the strapping tape around the motor tube. It might be too thick for a pre-covering spray, but maybe not.

It is very important to put the strapping tape on tight and smooth around the motor tube. If there are wrinkles and clumps of dried glue it will show and be amplified by the covering. Remember the final coat will only be as good as the prep work underneath.
Last edited by sargentw; Feb 23, 2004 at 08:40 AM.
Dec 11, 2003, 07:06 PM
sargentw's Avatar
Unicorn motor tube oracovered.
Dec 11, 2003, 07:07 PM
sargentw's Avatar
Unicorn Wing with installed motor tube.
Dec 11, 2003, 07:08 PM
sargentw's Avatar
Unicorn Wing Motor tube installed battery bay side.
Dec 13, 2003, 04:05 PM
sargentw's Avatar
The next step break in the new motors and test the electronics.

I bought two Zagi "tuned" pusher motors. One I'm using for my Unicorn and the other for my SKY Scooter Pro II.

The water breakin method is really easier than it seems. The picture shows what the setup looks like. I hook em up and let em run until the batteries wear out. Next I unhook the batteries and flush the motor out with clean tap water. Next I dry em with the Boss's hair dryer (better put the hair dryer back if you know what's good for you ). Next put a drop of teflon oil on each bearing. Then hook them up for an electronics test.

BTW: The water flushes away dirt and debris as the brushes seat. The brushes will get a very smooth "polished" surface without pits. Kinda the same reason you use water or oil when sharpening a knife on a whetstone.

Note: the water in the 2 cup measuring cup will be grey to black when the batteries run down. Slap on a couple of rubber bands to keep everything snug.
Last edited by sargentw; Mar 29, 2006 at 09:45 AM.
Dec 13, 2003, 04:12 PM
sargentw's Avatar
The electronics test. Hook up the motor, rec, esc, servos. See the picture for what the setup looks like.

I put a prop adaptor and prop on when testing/breaking in the motor. I ran the motor at different "low" speeds. There is no need to crank up the motor for sustained full power while in the vise.

I'll tell you what, I did crank em up for a second or two. These special speed 400 balanced Zagi pusher motors are "hot". After breaking them in properly they run smooth as a baby's butt.

BTW: in the picture you can see the "deans" connectors being used. You can also see a Cheapbatterypacks.com 1400 mah, 8AA cell, NIMH battery pack. The prop is an APC 5x5 mounted on a M5-2.3mm collet prop adaptor.
Last edited by sargentw; May 30, 2006 at 02:14 PM.
Dec 13, 2003, 04:44 PM
Playing R/C lawn darts...
Great stuff sargentw! I just ordered my 'Corn core kit Thursday. I hope you do keep up with all the great pictures and info....as I will be about two steps behind you.
BTW, where did you pick up the 'tuned pushers'? And have you used them in anything else? If so, !?WELL?!


Dec 13, 2003, 05:21 PM
sargentw's Avatar
Thanks! I hope this helps others out.

Motors=Zagi website. Not tested in a plane yet. Have something similar in the Scooter. I have heard good things about the Zagi pushers. My bench test shows lots of smooth power.

Last edited by sargentw; Dec 15, 2003 at 08:59 AM.
Dec 13, 2003, 05:46 PM
Registered User
Originally posted by TwinSpar
I found the crisscrossed tape (Scotch brand) at Office Depot in the packing materials section.
Also at Staples.
Dec 14, 2003, 02:29 PM
Playing R/C lawn darts...

Just a few more Quaries

So sargentw,
What Tx do you intend on using? And also, I hear a lot of talk about the 'new' and 'old' versions of 3m77. Are you using the 'old'? And if so could you post a picture of the can....or can you tell me the difference on what I should look for. I want to start getting of of me materials together before the kit arrives so I can just start right away!

I tell you, I think the UPS guy is never going to get here!!!! BUT!, when he does, rest ashurd that I'm probly going to FREAK him out.....(You know... jumping up and down like a three year old for an ice cream cone! )

Dec 14, 2003, 02:36 PM
Playing R/C lawn darts...
Oh yeah,
One more thing, is the Zagi pusher the same sive as a standard sp400? Does it just slide right in or do you have to do some triming?


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