I've been having problems with those weak CA hinges on the GP Cub J-3 ARF. While I'll repair them again, I was wondering if those struts are just for show, or are a really necessary part of the structure. It doesn't seem like it to me, but I wanted to check with you all just in case.

Could I get by with not using them? I don't want to have to worry about babying the plane without them, but sometimes the strut fails and ends my day early.

Has only flown the plane without the struts?

Thanks much.

Yes the struts are critical. mine did the same thing as yours broke after just a few flights. the fix I did was to take some coke bottle plastic and cut it to fit all the way into the wood of the strut and the wood that the bolts go thought to hold them to the plane. used some epoxy and drilled some holes for some wood pins and redrilled the holes for the bolts and have not looked back since. if I have a pic I will post it but if I do not I will post one in a few days. I am going out town later today

OK here is one pic that I have look at the strut on the left at the time that I took the pic I had not fixed the others I wanted to see how the fix worked first before I did all of them. they all are done this way now and work great

Well I can't get that pic to upload will try to get one later.

for a never have to fix them again use small robart hingpoints and gorilla glue . it will be there its even easlyer than replacing the ca crap . [8D]

Here is one pic that I have

Interesting. The struts on my H9 cub are purely cosmetic. It has never flown with struts. I guy at my field has the GP cub and he flies without struts also. The planes look exactly alike sitting side by side, except for the landing gear...

Hay Dude, The instructions say that the struts are functional. I also did the coke bottle fix and it works great. However my Cub is usually used for introductory flights so I also glassed the wing center section. I cut the covering off two inches from the center of each wing. Then put six layers of ¾ oz. glass 3in wide over the center section and recovered with replacement fabric purchased from Tower.

Being used as a introductory flight plane I can say unequivocally that the glass eliminates the need for the struts. But it requires more time and money (just like any ARF).

Good Luck

Joe Felice

I never fly with them either and have no problems.. What do they give you in flight?

Well, I went the epoxy/Coke bottle (actually Dr. Pepper) route and replaced two hinge points on the left wing. I pinned them too, just like RamDuster did. Seems to be pretty solid.

Flew it once, then noticed the right bottom hinge popped. I'll just replace them all with the plastic from the soda bottle.

Even if the plane didn't need the struts, it just wouldn't look right without them. I dream of the day when I can take this plane out for four or five flights and bring it home not needing any repairs on it.

Thank you again for your suggestions!

SkyDude watch out for the covering mine keeps coming off on the wing tips and yesterday I was flying so much that it came off the bottom of the fuselage but sure did have a lot of fun yesterday.

Hey Duuude, While the instructions say they are functional I have had to land with the strut hanging below the wheels on a number of occasions. I’m averaging 50% on yhose types of landings with no damage. But on those landings were I damage the plane it usually breaks free the back wing strut mount. That gave me the opportunity to see how it was constructed and as a mechanical engineer I can say it was not built to withstand much load. The wing hard point is a peace of cheep hard wood cantilever glued to the balsa rib. No hardening of the rib in that area or bracing for the cantilevered hard point either. The loading that hard point is going to see will put the glue bond in tension and no provision was made to dissipate that load in a reliable and repeatable fashion.

Having said that and now that you know how it is constructed I do a maneuver I call the Crazy Ivan with the cub, its basically an our of plane barrel role with the plane stalling at the top and falling through the rest of the maneuver. The plane actually stops and momentum carries it through. On several very windy days when I get hit with a gust just as I’m doing the stalled portion of that maneuver it pulls out the sheet metal screw holding the strut to the fuse. So that tells me that the wing hard point design is adequate for its function.

Before your seams start to pull!!!!!! Buy some of the Century 21 fabric and some pinking shears (at the local fabric store). Cut some pinking strips and cover all the seams with pinking tape that you make. It makes the cub look much nicer and you don’t have to rip off the factory covering because you have exposed wood after two or three years.

Good Luck

Joe Felice