GP J-3 ARF Ca vs hinge points
 

Hey guys....I like the Robart hings points and am considering using them on my J-3 ARF instead of the Ca hinges. Any opinions on just drilling holes where the slots are and epoxying them in? I would think the epoxy would simply wick into the slots further strengthing the slot. Any ideas would be appreciated! Time is not of the essence as it's so cold here in Pa. I won't be finishing this bird until mid spring anyway! Thank you. Bill

RE: GP J-3 ARF Ca vs hinge points
 

Greetings,

Sorry I cannot comment on your question...yet, but I have just received this plane as a birthday present from my wife and I have a couple of questions. I am awaiting a new cowl from GP as the one that came with the ARF was quite deformed - how is yours? It looks like a nice kit (ARF) but I am already thinking about some changes like putting more scale like (and tougher) gear on it. My landings leave alot to be desired and I never cared for the strength of wire gear. I was looking at the Robart gear but it is a bit pricey for this plane, I may go with the Hangar 9 gear and make whatever mods are needed to fit them on this bird. I am also replacing the foam tires with more scale like tires from Dubro. You have me thinking about the hinges now also. I cannot foresee a problem with using the Robart hinges, but I need to look at the plane in more detail to answer your question. What powerplant are you using?

Note that we are in the same neck of the woods, where do you fly?

Steve

RE: GP J-3 ARF Ca vs hinge points
 

There is a small problem with using hinge points on an ARF that is designed for CA hinges. The Surfaces that the hinges go into may not be wide enough to accommodate the hinge points correctly.

RE: GP J-3 ARF Ca vs hinge points
 

Good Point... That is what I was worried about. I also just though about the fact that the ailerons are buit up barn door type and not solid strip type. That means that there is definitely no material in the ailerons to work with, however, if you really wanted to use these hinges, I suppose you could open things up and add some material - but this is probably not worth the effort in my opinion. I plan on nice and easy scale flying for mine so I am not too worried about the hinges.

RE: GP J-3 ARF Ca vs hinge points
 

Why complicate an easy installation?? MinnFlyer has also demonstrated why you should stick with what the plane was designed for.

On a scale plane such as the J-3, there is no reason at all to go to hinge points. The surface loads are low, and so are the speeds. I use CA hinges on every one of my planes up to 1/4 scale and never have problems. Even on my large CAP and Giles with 40CC engines and speeds approaching 100MPH.

If you want a bullet proof, good looking install, try using the CA hinges and then using thin V-shaped strips of clear ultracote to seal the hinge gaps from underneath. You will never have a problem with CA hinge failure or surface flutter again.

DP

RE: GP J-3 ARF Ca vs hinge points
 

J3 Get back to me tonight if you can, I'm at work now, and we'll talk J-3s. Bill

RE: GP J-3 ARF Ca vs hinge points
 

On an aerobatic plane with a lot of stress on the ailerons, I would suggest to change them to hinge point. I did that on my Christen Eagle, and glued the hinge points in with Gorilla glue, which expands and creates a plug behind the wood. Works great and is plenty strong. Did a test on a 3/4" balsa and could not pull hinge point with pliers.
OK, as for the GP CA hinges : They are crap quality and break after some use(sometimes after only one or two flights). They simply look like they have been cut in the middle with an exacto. I would suggest you use the 1/4 scale hinges (blue colored) from Radio South. These are the best CA hinges out there IMHO. You could also mark the center line with a crayon to keep it always flexible (to much CA will harden the hinge, and that is why they break).

Enjoy your Cub !