I am building the 4*40 and was wanting to know how much gap should there be between the rudder,elevator,aileron's and the T.E.'s. The instructions say to deflect the elevators to the maximum amount needed then wick in thin ca to set hinge gap. That sounds simple enough but I was wondering how much gap is too much?

anything over 1/16" is too much. If you build carefully you should be able to consistently get a 1/64" gap. But with CA hinges apparently you have to deliberately give them a larger gap so they don't break. I don't use them because they are fundamentally wrong in how they work, but a lot of guys swear by them.

Anyway, if you seal the hinge line with iron-on film or clear packing tape, the gap doesn't matter much. However, a large gap also means control slop which sealing the hinge line won't eliminate.

Point being that a smaller gap is better, but planes with larger gaps still manage to fly.

Mike's guide to hinge gluing 101...... if you encounter problems go right to step 9

1) First take the hinge and draw a line down the center. (The Sonictronic ones come in strips so mark them all before you break them
off.) You will use this mark to ensure the correct depth on the hinge. I re-open the slot with a sharp scalpel or knife and trial fit the
hinge so that it only goes in up to the mark. If you've used proper heat the covering will not lift.

2) Once you've done this to all the hinges I then go to the control surface and make sure the hinges go in slightly past the mark. This will ensure that no problems occur during installation of the surface. Take your time as nothing gets glued until everything fits perfectly.

3) Once the hinge fitting is complete, insert all the hinges into the wing (e.g.). If you've done your job, they should all line up nicely
with the mark.

4) Install the control surface onto the hinges being careful not to bend any of them. Start at one end and slowly work towards the
other end. Turn the wing over and make sure the hinges are all "in" as they can fold up or worse, miss the slot altogether! I've seen it!

5) Make sure your aileron tip is lined up and your satisfied with the centering. Slide the whole surface gently one way or the other
being careful not to move the hinges to much.

6) Place a pin (medium size T pin) between the wing trailing edge and the leading edge of the aileron in several locations along the length of the surface. Don't push to hard against it! It's just a spacer.

7) With everything double check for accuracy (Last Chance!) it's time to wick in the CA. Use "thin" and apply the CA tip to the slot. It will gulp up the CA like crazy. Three or four drops (slowly) on both sides then move to the other end and repeat. Flip the wing over and repeat the process by first wicking in CA into the original starting slot (couple/three drops each side) then go and do the other end. Make sure your not letting the glue run under the wing! It should wick nicely into the slot on each side. (If you see the glue stop wicking at any time... your done.) Try not to go crazy with the glue.

8) Rest... whew! Exercise the surface back and forth a couple times and then repeat the process working towards the center of the control surface, exercising as you go. Keep track and do not re-glue any joint. Repeat for other surface.

9) Have a cold beer. After the beer is done (very official timing here!) The CA will harden a little so just keep exercising the
surface until it's free.

10) For a final step, I cut a thin strip of clear monocote and apply it to the trailing edge of the wing and the leading edge of the aileron (the V if you will) on the bottom of the wing. This will "gap seal" the control surface very nicely and is practically invisible. Avoid touching the ca hinges with the trim seal iron, you don't want to weaken the hinge material with high temperature. I do all surfaces this way.

Hope this helps,

Mike

The other Mike's hinge gluing 101:

http://www.rcuniverse.com/magazine/a...3-5709ca96ad27

Thanks for the help guys!

Mike,

You are so RiGHT about the critical timing thing. I make sure to incorporate that exact same procedure for:

1. Admiring engine mount and wondering how to drill four perpendicular holes, each catching good material on beams. [sm=confused.gif]
2. Needing to read instructions more than 3 times. (this is sometimes hampered by the number of official timers consumed)
3. Watching newly built tanks for leaks
4. Double-checking incidences and 90 deg tail-feathers. (reference #2 note applies here too)
5. Figuring out how you built two left wing halves. (easily blamed on the official timing procedure) [X(]
6. Relaxing after slicing open your thumb cutting that unruly Monokote. [sm=crying.gif]
7. Rationalizing why you should laterally balance your plane. (can get very creative here)
8. Wondering if the CA will hold your sliced thumb together better than the band-aid that fell off 5 min after you put it on.
9. Convincing yourself that no one will ever notice the pilot you glued in back wards.
10. The most important !QUOT!official time out!QUOT! occurs prior to calling it quits for the night as you look at the mess you made and wonder, !QUOT!Why didn't I clean up as I was building. Oh well I'll get it tomorrow.!QUOT!

Thought I'd pass these on. I'm sure there must be others out there.

ROFLMAO ! Well I am taking some time off now figuring where to put the lightening holes in my new 1.5-inch-longer rudder for my 4*60. I had a longer "time off" thinking why I didn't modify the original rudder the first time around, having to rehinge the whole ?!@# thing all over again . Hoping for a better knife edge performance

If using the CA type hinges that came with the kit. The correct gap will easilly slide a piece of typing (computer printer) paper through, but not 2 sheets.

The lines you draw ont he hinges... do them with grease pencil or crayon on both sides. Helps keep the CA from depositing in the hinge line. (this makes the hinges more flexible and they last longer)

Use the thinnest CA you can get. Medium and thick do not wick in properly and are the cause of a lot of CA hinge failures. I use "Superglue" brand because its thinner than any of the hobby CA's. It takes longer to set up too.. and that means it wicks in further. I use 6 drops per side on a precut CA hinge. Drip in 2 drops each hinge... then go back and do it again, then again. This gives time for the CA to wick in rather than run off.

When I have had a crash that pulled a rudder off... it took large hardened chunks out of the fin.

ARFs are the easyest. j/k. Yeah, I finished my scratch project. I used GP CA hinges, and the slot machine. The Slot Machine is very nice.

And here's my new rudder ready for covering and installation. This time I am using Robart hinges

And the final installation of the new enlarged rudder. Hinge gap 1/32" and max throw. It was easy to cut through the old ca hinges, drill through them with a 1/8" sharpened brass tube, and install the robarts with epoxy. Flight test this weekend.

rajul - You do good work! Looks real nice.

Larger lightening holes!

Seriously... those (what? 1/2 inch?) holes really didn't do you any good.

FH, know what you mean, but I didn't want to make them too large as I found the wood more flexible (than my liking) in the cross-grain direction, and I actually need a little more weight at the back. Hope it holds up well in flight.

I am glad I did this mod ! The 4*60 knife edges effortlessly at 1/2 throttle (61fx). It pulls a little towards the belly, but a little up elevator fixes it. I also noticed more crabbing in crosswinds, but that is expected with the larger rudder area. Very pleased with the results