How often do you space them on a control surface? The application is on a trainer. What do you all use? 1 every foot? Every 8 inches? Or what ever seems good?

Generally, on a trainer sized plane,At least four hinges on each aileron, six on the elevators (three on each side) and three on the rudder. More,but not less ! Just simlpy evenly space them. On the ailerons, come in 1/2" form either end and space the other two evenly between. the same with the elevator. On the rudder. just center the odd one.

Ugo

Also depends on WHICH Robart Hinge points... there are at least 3 (I think 4 or 5) sizes.

With the ones that are appx 1.8 inch dia, and on a .40 size trainer I agree with the above numbers of hinges.

You NEED 2 on each moving surface no matter what size hinge point. In the case of the elevator halves, the 3rd each side is for safety, not because you need it to hold the elevator on. (if its a full span strip elevator like on a Kadet Sr... 4 total is plenty) On the ailerons you need the 4 because the ailerons would otherwise potentially flex between hinges.

Go to a .60 size plane... you need 4 on the rudder, and 5 on the ailerons (if full span strip ailerons)

I agree except on one piece elevators (.40 size) I use 5 on the elevator.

Thanks for all the help! I'm going to use the 1/8" hinges so this advice is perfect! Drilling holes is another matter...

This probably won't be of much help to you because you've already built the tail, but this is how I do it and works very well.

For you, I would suggest the Robart Jig. It works nicely.

http://www.airfieldmodels.com/inform...ints/index.htm

To get perfect holes... you can make a jig. You can even make a jig set for each model because they are easy to make and cheap (and disposable)

Take a scrap of 1/2 inch X (Y)thickness of surface to be drilled, drill it (in a drill press preferably) centered in the (Y) edge. If its a balsa scrap harden the hole wth CA and redrill.

Glue the scrap to a 2 inch square of 1/8 inch lite ply. ( the punch-out scraps from a 4*60 fuselage make good pieces for this)

you now have a drill jig for use with a "Pin Vise" A Pin vise is the ideal way to drill balsa for Robart hinge points. (power drills tend to rip the balsa) All holes driled with the jig will be exactly the same angle and exactly the same distance fom the edge. (remember to always keep the thing on the same side of the wing or stab...)

**** note... if yuo WANT the hinges offset or angled... you can make the jig appropriatelyand all holes will be lined up.

Not sure I understand the building the jig directions and I don't have a drill press.. but I do have a dremel tool I"m planing on using. I can drill fairly straight holes. Caffeen man I have read your website top to bottom! It rocks! You are the main reason I'm going with the Robarts over the CA hinges. I want my plane to last! Thanks all!

Spokman - I seriously do not recommend using a dremel - it's fraught with potential for disaster. When using a Robart jig, I either hold the bit in my fingers or use a pin vise. You have to go slow because it's easy for the bit to start cutting at an angle and go through the surface - even if it started out straight.

Thanks for the compliments too.