I'm gonna replace the CA hinges on the GP Extra for Robart hinges. I don't know if I should go for 1/8" or 3/16". The Leading edge of the elevator and rudder control surfaces which are the ones who mate with the main surface are 5/16" thick. The leading edge of each aileron is 3/8". I'm concerned both with the thickness of the hinges as with the length.

These hinges come in another format which is 1/2A which seem to be shorter and could be a better fit for the ailerons.

Of you people out there who have used Robart hinges, are there any suggestions?

3/16"



1/8"



1/2A

the 1/8 " should be fine.

I've used'em, and the 1/8" will do just fine. Space then about 3" apart.

Dr.1

In theory shouldn't I put them where the CA ones where originally intended to be?

http://www.robart.com/how_to/hinge_points.aspx

Use the size that fits best but remember that as stated in step 5 of the instructions above "you can trim the length down" if needed.

DON"T use CA, Hinge glue would be best or polyuerethane (sp).

Is the robart drill jig for these hinges useful? I think I can handle the drilling but as I don't have a drill press, I don't know how to get straight perpendicular penetration to obtain perfectly aligned hinges.

IMHO the drill jig makes a huge difference in getting the job done right. While it's possible to do it without the jig, it's much easier to do with it. In fact, I think it's next to impossible to do it wrong with the jig. Without the jig it's very very hard to get it right.

Ken

Ken, using the Jig properly will always result in perpendicular aligned hinges? If so, then its a must get.

You can buy your initial hinges in a combo pack that will include the proper tool
http://www2.towerhobbies.com/cgi-bin...&I=LXADE6&P=SM

the robart jig I have will just center the hinge on the piece being hinged up to you to drill the hole perpindicular.I took a 3 ft long piece of mdf. 4"wide added a 1"high fench on one edge then used a square to draw some perpindicular lines from the fence.for strip type surfaces I place the te up tight against the fench put the jig on where I want the hinge and using the drawn lines as a reference drill the hole.

my jig is over 20 years old and after looking at the new one it has bushings to keep the drill perpindicular,looks like I may have to buy a new jig.

Yeah, my original had plastic guides and they did tend to wear fast. On the other hand, they were cheap to replace too.