OK, we've talked about spars, now how about rudder construction? What are the building techniques used and what are their advantages and disadvantages? I can think of the following:

1. Traditional thick balsa outline with balsa cross pieces (which is what I ended up using on my EIII)
2. Curved multi-layer ply with epoxy
3. Wire (with soldered cross pieces)
4. ?

In the case of my Nieuport none of the internal structures will be visible because I'll be painting it black but I'd like it to be as strong as possible to handle those inevitable nose-overs and yet light. It really is a massive rudder hanging off the end of the airframe!

And I suppose we can add "solid sheet with lightening holes" to the list. I guess we could also be talking about stab cnstruction.

And let's not forget the Asian option: Steamed bamboo + bamboo chopstick! (Experimental but VERY resistent and VERY light!)

There is also my favourite way for "rounded" tailsurfaces Don. Build the ribs and spars as a conventional wing. Then "tack" 1/16" balsa sheet between ribs where the edges are curved. The 1/16" sheet follows the edge curves of the tailsurfaces. Once done I then soak 1/16" x the thickness of the tail, strips of balsa and glue 3 laminates to the ribs and 1/16"sheet using thick cyano(one laminate at a time). The CA dries very fast as the wood is wet so you only hold in place for a few seconds as you work your way round the outline. Once dry..the 1/16" sheet is cut out so only the spars ribs and edges are left...sand to shape. Very strong as the cyano hardens the edge laminate. Thats how I did the curvy profile of the Jenny and Batboat. Proctor use cane/bamboo for the edges but I didnt have access to any ..and even if I did ..would probably do it the way I did..

Donnie, I'm having trouble visualizing this. You wouldn't have a photo would you? The Nieuport rudder doesn't have much in the way of "ribs" or "spars" In fact very little structure for such a big surface.

SkyShark uses the following system for their ailerons, rudder and elevators.

1/4" thick leading edge.

1/16" balsa sheet CA to the center of the LE.

1/2 ribs of 1/16" balsa CA toboth sides of the balsa sheet and LE.

Quite strong and very light. Check the online manuals at their web site.

SkyShark http://www.skysharkrc.com/

Don..I knew I was toiling trying to explain it..Picture tells a better story ?

And since we're on the subject of rudders, what are the preferred methods of attachment. I'm assuming that since we're talking about scale models CA hinges on a rudder are out.

Very neat work Donny! Wish I could think of such solutions myself. (btw, what do you use to stain the wood such a nice antique hue?)

Don, you've probably seen this before, but for the sake of the thread:

On my EIII rudder I used laminated ply strips.

The approach is probably more laborious than Donnys.
As with the nieuport rudder this doesnt' have many ribs to support the structure so lamination is best to get the frame very stable.
I first cut a template and wrapped the strips around keeping them in place with tacks/ at one end they're held by a notch (arrow). As it was already rather late in the evening when I started I decided to use white glue and let dry over night, didn't regret that, it is extremely rigid.
the ribs are capped with very thin ply that overlaps onto the frame, this improves integrity even more.

Anyway, pictures are better than words:

i have also found out that a edge of laminated balsa is very strong and very light. it also holds its shape much better then the reed that proctor uses. i usally use 3 sometimes 4 layers of 1/16th balsa to make them. i use a series of nails to wrap the layers around and to hold until the glue dries. you wouldnt beleave the shapes possible doing this. if its a very tight corner i will soak with some ammonia for a bit then put in place, let it dry then add the glue. thin ca wicks in quite well.

Ah yea, and wetting the wood works wonders around such curves

I plan to try strap hinges on the elevator (and ailerons). On the original Nieuport the rudder appears to be supported in a set of tail brackets. This is always a sticky part of WWI modeling. On my EIII I used a funky semi-scale sort of arrangement with a modified tail wheel bracket formed the top bracket for a wire that passed through a tube in the rudder and then into a gap in the tail skid support tubing (which was ultimately connected to the wooden tail skid). Maybe it's time to try some silver sodering on some nice brass brackets!

Well my first effort at Donnie's technique was a total cock up. All I ended up doing was wasting half a bottle of CA and several hours of time. At the moment I'm sortly tempted to go back to the old fashion Guillow's arrangement of curved pieces. In short the balsa would NOT bend even when soaked and cracked all over the place. In pure frustration I tried a bit of "gorrilla" construction whereby you just CA the h**l out of it, zap with fixer, and sand the crud out of it. I ended up putting the mangled result out of its misery by tearing it to pieces. At least that part was fun!

Time to go do something else for a while.

Hehe, everyone's probably had to endure such minor building disasters.
Sometimes (and more frustratingly) it's also the result of an overzealous attempt to 'put the last shine' on an already decent part which then gets messed up beyond recognition.

If you have problems with the wood cracking, here's a trick I've found works. Soak it for a few min and then with an iron on low heat carefully iron it around a gentle bend (glass bottle or similar) gradually progressing to smaller bends as required. Once dry balsa will tend to retain the curve...at least long enough for you to glue it.

I'd still try the template method as even dry wood is less likely to splinter when wrapped around a 'solid' core.

Another option that just came to mind is this: considering that the finish is completely opaque and you don't want to build museum scale, you could simply make the entire rudder out of sheet balsa and glue ribs and frame pieces on either side....once covered and painted it would be virtually indistiguishable from the 'real' thing.

Don..are you sure its balsa you are using ? Ensure the sheet you cut the balsa strips for the laminate has straight grain running the full length .. for a tight bend .. slowly pour a kettle of boiling water over the strips ..then leave soaking wet for half hour or so. You should be able to tie a knot in it then without it breaking. If its really tough old balsa .. throw it in the bath over night ..then the kettle trick. Because the balsa strip is only about a 1/4" wide x 1/16" thick .. ive never had to use amonia in the past..but it works wonders too .. just slow down and let the balsa get waterlogged get waterlogged

Trev, Donnie, that's for the words of encouragement. A good night's sleep and I'm ready to go again. Much as I liked to just make a solid core rudder (with fake ribs) I suppose for the sake of future models I'll give the balsa strip technique another try. I don't think I soaked the wood long enough -- and this particular balsa might have been more on the hard side. Unfortunately, I don't get to go through piles here in Japan but just buy the balsa in plastic packages (like buying a KILO of eggs in Mexico).

Anyway, I'll try again and post my finished product on my "build" thread.