im new here and new to rc flying. would appreciate some guidance with building my first kit. im building a greatplanes electricub kit. when finishing the sub assemblies, should i sand the leading edges of the various parts with a radius?

A radius is more aerodynamic than a square edge so, if they aren't rounded, I would.
Are you a total beginner, meaning no experience flying or building? If so, I wouldn't try to fly that Cub as a first plane. I would finish it and hang it from the ceiling or put it on a shelf as Cubs are not a good plane to learn on. I would find a trainer or a trainer kit and learn to fly using that instead.

Definitely. That's what the instructions mean when they say "Sand the rudder and fin to shape using the fuse planas a guide." You should be able to find a top view of the fuse that shows the proper shape of the leading and trailing edges of the vertical fin and rudder, and a side view of the fuselage that shows the proper shape of the leading and trailing edges of the horizontal stabilizer and the elevator.

Oh, and Kudos for building your plane rather than buying an ARF.

Yeah, I would. You got too much work invested in the project not too.

thank u. i say im a beginner. i built a dumas hotshot 45 hydro years ago and had a blast. loved building and still do, but that was long ago and havent built any models since, well till now. i was pretty sure i needed to sand radiuses, but green i am and away from the hobbies many years. a wise man will say i dont but a fool will just well. thanks again to you all for the help.

I race scale hydroplanes and can tell you that running a boat in two dimensions is a whole lot different than flying a plane in three. Blow over the boat and you just go get it. Crash a plane and you break out the broom, dustpan and garbage bag. As I said, if you want to fly, get a legitimate trainer and learn on it before you try to fly that Cub.

To the OP/Dale
+1 on getting a trainer before you fly the Cub, That said weather you build the trainer or go with ARF,
I would on any butt joints push the point of a round tooth pick through the joint and glue with an alfic thinned wood glue it will give you a much stronger joint, Ca's are great for tacking things together and then go over all joints with a small art brush and thinned alfic glue

Just my 2 pennies worth

Cheers Bob T

I agree with Hydro Junkie that it is smarter to learn to fly RC models with a real trainer type plane rather than a semi scale Cub. I am a Cub lover so it's not that I don't like Cubs, I do. It's just that your chances of success learning to fly on that semi scale J-3 are very slim at best. Are you going to power that G P electric Cub with an electric motor or a small glo engine? The older versions of this model gave instructions for both electric or glo power. Those older versions were also intended as 3 channel with no ailerons, and the newer current version as 4 channel with ailerons. What version are you building? A helpful experienced mentor would also be of great assistance to you both in building the Cub kit and learning to fly these things without destroying them on your first flight. Hooking up with someone at a local RC club as a mentor would be very valuable to you. I too applaud you for building a kit in this age of ARFs. so lest save the Cub and all your work, money and effort from a bad fate and learn to fly these things with a good trainer. There are lots of good electric trainers in ARF form these days but as a glo flyer I am not sure what is available today as an electric trainer in kit form. Perhaps someone who is an avid electric flyer can give some recommendations for a good kit built electric trainer. You could also learn to fly on an ARF, then move to your kit built Cub when you're ready. For general information, the common electric foamy ARF Cubs that people do start with and learn to fly on are no where near scale proportions and that is why they are easy to fly and can be used as trainers (they are trainers that look a little like a Cub). While your G P electric Cub is not dead accurate scale, it is not "cheated up" enough to be a good learning tool. Get some local help, a mentor.

Please practice on a flight simulator on your computer while you're building. Good Luck. Also, having 2 airplanes instead of just one is a good thing.

I agree with putting the cub on a shelf.
Go to your local flying field and get with an instructor. Let him teach you all the things you need to know from field rules to tuning an engine to flying. Not mention safety. If you don't know where a field is go to the AMA website.
A sim is a great tool and you will progress quicker with a sim. But a sim can enforce bad habits.
Good luck and welcome to the addiction.

Dale, we probably should explain why we are recommending a trainer.
A Cub has a very short nose and a very long back as compared to a trainer. This makes a Cub much more difficult to balance and fly than a standard trainer due to the very short distance between the CG and the front of the engine. A Cub can also be very "twitchy" due to the long back end as a little input can be almost non-effective while just a touch more can cause and out of control condition

I too am a Cub lover and agree that the Cub is not the best plane to try and learn to fly first . They arent really hard to fly as much as they can get olut of control quickly on take off . You would be far better off with a high wing trainer plus you mreally should get your self an instructor. That said ,some kits come with a pre shaped leading edge and some don't . You are going to need to do some sanding regardless . Good luck and good for you for chosing to build a kit rather than going with an ARF . You will learn a lot. For many of us building is as much fun as flying .