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Old Feb 24, 2015, 07:10 PM
andrewbrockman's Avatar
United States, FL, Jacksonville
Joined Jan 2015
71 Posts
Build Log
Sig piper j-3 cub kit

I used to build control line planes back when I was a teen. Got into RC in the late 90's and built an ARF trainer, but never got to solo, thanks to life changes. It's all good though, cause now life has turned another corner and I am getting back in. Jumping in with both feet, so to speak.

I bought a DX6 Spektrum TX and RX and the new RealFlight 7.5 sim. Have a little Yak 12 foamie electric park flier for training. A buddy that is experienced and going to train me and a bunch of stuff bought at the LHS that I don't even need yet.

This build log is starting a little prematurely, as I don't even have the kit yet. I have ordered it through my LHS, and am expecting it in the next week or two. In the meantime, I am getting tools, build boards and various items together to start the build.

Super exited to do this and will keep y'all posted!

So far I have the kit and a Saito FA-40A 4-Stroke Engine on the way. Updates coming soon

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Old Feb 24, 2015, 07:19 PM
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piperjoe's Avatar
Joined Dec 2009
2,302 Posts
Welcome back to aircraft modeling, Andrew! I look forward to following along with you on this build and wish you the best of success with your J-3 Cub.

Soft landings,

Joe
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Old Feb 24, 2015, 07:29 PM
andrewbrockman's Avatar
United States, FL, Jacksonville
Joined Jan 2015
71 Posts
Plans for this build:

Individual aileron servos
Push pull for rudder and elevator
Detailed cockpit
Working top and bottom door
Scale details as I can do in a reasonable manner
Yellow finish (just have to do it on my first build and first Cub)
Probably going to cover in silk

Any other ideas are most welcome
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Old Feb 25, 2015, 07:46 AM
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United States, KY, Taylorsville
Joined Mar 2010
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All right... another Cub! Silk, too! I love covering in silk. Here's an idea: make your stab in a right and left halves to be joined after covering the fuselage. You can get that perfect fin to fuse covering fillet done a lot easier that way. I have done this using dowels on one stab half and aluminum tubing on the other.
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Old Feb 25, 2015, 10:58 AM
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Isn't it funny, how a scale method addresses a scale model issue?
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Old Feb 25, 2015, 03:13 PM
andrewbrockman's Avatar
United States, FL, Jacksonville
Joined Jan 2015
71 Posts
Great idea, Arup. I'll definitely be doing that. Thanks for the tip!
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Old Feb 25, 2015, 09:09 PM
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United States, KY, Taylorsville
Joined Mar 2010
2,124 Posts
Here is a pic of my 1/6 SIG Cub converted to a PA-12 Super Cruiser's stab. The aluminum tubes are in the fuse. The fore one doesn't show because the covering wasn't cut to reveal it in this pic. The stab halves are glued with slow cure epoxy then the (previously constructed) support rods/ bracing added to create the classic cruciform tail. Next, slow cure epoxy used to add elevators to stab and elevator connector/ crank. To get around the fin post being a problem with the elevator joiner/crank just take the SIG item and clamp in a vise. Heat, using a torch, one leg then twist. Let cool then do same for other side. This puts the elevator horn at an angle to clear the fin post and is plenty of elevator travel for this airplane. Hope this is helpful and not too wordy!
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Old Feb 26, 2015, 12:27 PM
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E-Challenged's Avatar
United States, CA, Garden Grove
Joined Oct 2000
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Some Tips and Recommendations:

Silk and dope are great old school coverings, but can lead to wing and tail surface warps. Modern iron-on coverings may weigh less and are a lot easier to patch. IC power is nice if engine does not flame out during a take off or landing or in the middle of a field requiring a long hike. ( I have bad knees and use a mobility scooter at the field). I am using a Cobra 3515/14 brushless motor and two 2200 mah lipo packs in parallel for my current Sig 1/6 Cub. Covering is Cub-yellow iron on film. Model is light and flies like the real thing. Duration is 9-10 minutes with some loops and rolls and maybe a touch and go or two.

My 6-foot wing is one-piece and is removed for storage or transport in my Subaru Forester. It takes me about 5 minutes to connect aileron servo extension, Install wing and wing wing strut connections, install and connect battery packs. At times, I wish I had made removable right and left wing panels and center cabin section for storage and transport, but the amount of assembly and disassembly time is about the same.

It was fun making my own dummy engine shrouds and cylinders of balsa, manila folder, brass tubing, etc.

Getting the fillet between fuselage and vertical stab is a bit tricky as is understanding how to finally assemble the covered horizontal stab and elevator parts. The Sig instructions and plans are not very detailed on this.
You might find my overly long build thread helpful:

http://www.rcgroups.com/forums/showthread.php?t=1754853

Lastly, you should try to build in equal wing-tip washout during wing assembly, completed and covered wing is not easy to twist in washout with heat gun.
If no washout is built in you can angle both ailerons upward an eight of an inch or so (instead) . I have aileron-rudder mix set up on a switch so I can turn it on or off . Cub will turn on rudder alone, but turns best with coordinated rudder and ailerons. Cub needs a lot of rudder throw throw to offset "adverse yaw" tendency. Use moderate amount of elevator and aileron throw.

You may be surprised how much like real Cub this one flies. Do not fly tail heavy, best to maiden it with a little nose-heaviness and remove nose weight if needed. Model should lift off when ready at less than full throttle. Good luck and don't stop for building and finishing the model. You will really enjoy flying it. It's not just another Cub, it's your Cub.
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Old Feb 26, 2015, 05:13 PM
andrewbrockman's Avatar
United States, FL, Jacksonville
Joined Jan 2015
71 Posts
E-Challenged,

Thanks for those great tips! I will keep each in mind as I build. I'm sure I'll reach out for more help and tips and opinions and options as the build progresses

I built a lot of line control models when I was a teen. Started with tissue and then silk. I remember the power of the warp I may change my mind later on the covering, but right now I'm leaning towards silk.

As far as power options, I really went back and forth between glow and electric. I understand the pros and cons of each, but ultimately I like engines, the smell of glow and the sound of a little 4 stroke.

Andrew
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Old Feb 26, 2015, 07:06 PM
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United States, KY, Taylorsville
Joined Mar 2010
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I'm still a CL flier! I love it! I fly scale RC for my own pleasure (no competion stuff).
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Old Feb 26, 2015, 07:17 PM
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The PIPE's Avatar
USA, MA, Weymouth
Joined Mar 2004
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You MIGHT want to check out The CUB DEN...

Dear Andrew:

The PIPE Here...welcome to RCGroups!

I've built the exact same kit you did, waay back in the late 1970s, only a year or so into the RC hobby...I've still got mine, done up as an L-4 Grasshopper, with civil registration NC51992. When I can get back to RC flyin' again someday myself, an Enya 46-4C (the ONLY four-stroker in its day that would fit the Sig RC-3 Piper J-3 Cub's cowl WITHOUT protruding in an inverted orientation!) that I've got as "well-used", that desperately needs an overhaul will be its power, but for now...

...may I recommend a vist to "The Cub Den" site, with a click on the linked text in this sentence?

There's a WHOLE LOT of Piper J-3 scale info at that site, and I provided the "Den" with the RC Sportsman magazine article from the mid-1970s (at the Den's "J3/L4 Related" menu item, named "RC Sportsman L4 Conversion Article") item and PDF file, that guided me in changing over my Sig J-3 kit into NC51992 quite nicely way back when.

I've also been gathering more scale info for my L-4's restoration, and to prepare for an eventual scratchbuilt Giant Scale version of NC51992 in full-blown 3 inch = 1 foot scale size, for OS FT-160 opposed twin power someday.

Please let me know if you can use anything, and even though The Cub Den SEEMS to be mostly "giant-scale" Cub related, even our smaller, just about 1/6th scaled Sig J-3 or L-4 Cubs can use some of the "scale-info stuff" from that site if desired!

Thanks and Yours Sincerely,

The PIPE....!!

P.S. I've got a brand-new, never-run Saito FA-40a as well, but my example is for a brand-new version of the aircraft of mine that you can see here...that I've drawn up CAD plans for the all-new version!
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Old Feb 26, 2015, 07:53 PM
andrewbrockman's Avatar
United States, FL, Jacksonville
Joined Jan 2015
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Pipe,

Thanks for that link. I already have it in my reading list on my iPad. It is a great site.

I would really like to put a Saito 30 on the cub, but it seams like they are not being made any more. My LHS can't get them, and I am dead set on supporting my LHS and not buying anything online. I'd rather wait a few weeks and support the small local business, even if it costs a little more.
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Old Mar 01, 2015, 07:41 PM
andrewbrockman's Avatar
United States, FL, Jacksonville
Joined Jan 2015
71 Posts
So, looking at this again, is it just me or has OS and Saito stopped producing 30 size four strokes? That's what I would really like to put on this build ...
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Old Mar 01, 2015, 07:50 PM
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United States, KY, Taylorsville
Joined Mar 2010
2,124 Posts
They are no longer produced. You will have to source one in 'the wants adds'. I've had good luck on RCG Classifieds. MECOA has some neat four strokes.
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Old Mar 01, 2015, 08:59 PM
andrewbrockman's Avatar
United States, FL, Jacksonville
Joined Jan 2015
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Thanks Arup, that's what I have figured
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