To attach cabane struts to their scale locations requires that they be attached at the spars. But drilling a hole in the spars is not a very good idea. How do people deal with this problem? Also, just generally, how have you dealt with wing attachment on your biplanes?

A related area of personal ingorance is how exactly "hinge and pin" type lower wing attachments actually work. I can see how this holds the wing against the fuse but I don't see how lower wing dihedral can be set using this technique. Is it the case the the lower wing is literally hanging below the upper wing -- supported by it? Is the answer all in proper set-up of functional rigging?

Don, I've tried to circumvent the problem of drilling the spars with a sort of bracket attachment, this was (as usual) inspired by the method Donny uses except it doesn't need soldering.
As always I can only include a pic of my EIII's installation (it's getting a bit old, I know..) but you might be able to adapt a similar setup for your top wing.

The spars are left intact/ instead the webbing (ply, reinforced with hardwood on inside) is drilled to hold both brackets (top, bottom wires) with a single bolt. Make any sense?

You might not even need any drilling or bolting if you 'wrap' the attachment around the spar entirely. Not sure if sheet aluminium would do the job, the stuff oughta be strong to prevent deformation or 'tearing' at the bend..probably brass or better yet steel/

Fraid I share your 'related area of personal ignorance' with respect to lower wing attachment...

Trev, I did think about your bracket but the problem I'm having is the the connecting bit has to run perpendicular to the spar not parallel to it as on your bracket. I'm afraid the solution is going to be some bit that requires soldering. [:@]

I wish Donnie would get on with his wing so I can see how he'll do it since I'm using the same wood laminated aluminum method as he is on the cabane struts. I'm really tempted to just permanently install a bolt (downward) through the spar to that it would attach to the cabane with a simpel (lock?) nut.

Bob, how about you? How are you holding the wings on your SE5a on?

Hmm..I see your point there
Be darned if I knew how do it without hurting the spar...unless you happen to find a suitably modifiable 'bit' in the hardware store I reckon soldering would probably be the best course.

You could always make a 'bracket in a bracket' (perpendicular to each other i.e. one around the spar to hold down the other thats in line with the ribs) but that would probably be rather clumsy and too much fiddling about...

If this were a semi-scale project, then I'd suggest you install some aluminium ribs with the attachments built in.
Maybe we should just wait for donny's wing and all will become clear

If you have a hole in the spar and you fill the hole with a pin of sorts you won't weaken the spar at all. You would only weaken the spar if you left a void in it .

Trev, I got all excited when I read the aluminum rib idea. But then I remembered that there isn't a rib at the point where the cabanes connect. Oh well... maybe I can use that idea on the interplane strut connection.

Bob, the spar (which is of the box spar type) is only about 10mm wide and I'd have to drill a hole at least 4mm. Maybe I could wrap it with glass first...

What I have done in the past is to glue 1/8" light ply to 2 ribs and the spar. In the "plate" I have a blind nut and I use a ring terminal from the cabane to attach it. If you are using streamline (teardrop ) aluminum tubing, JB Weld (original formula ) works exceptionaly well. I normally use a 4-40 cap head screw about 3/8" - 1/2" long to secure everything in place.

Hi Bob ..noticed your SE5a build slow down again..get them golf clubs back in the boot A simple test of the strength of a drilled spar is take a bit of scrap spar wood ..drill a hole and put a bolt through it .. now test to destruction .. bet you a golf ball where it will break Yup ..hole in one

Don not sure of your setup for the cabane to spar but an easy way to secure the top wing centre section is a right angle piece of metal..epoxy and bind with strong thread to both cabane and spar .. normally the thread can be covered with wood .. sometimes the real deal has rope binding at the top of the cabane to prevent the wood splintering..dont know about the nieuport though. Alternatively ..as I did with the Jenny ..reinforce the spar with the aluminium strip that holds the wing spars in position then you can drill to your hearts content (within reason) as the aluminium takes the stress. (see pic)The wing spar will be similar but in reverse. The functional landing and flying wires will hold the dihedral on the bottom wing and top wings. It will surprise you how rigid even a flimsy wing becomes solid when properly rigged.

PS though not scale .. I always like to sheet the under side of the top centre section .. why ? ..Because I always carry my bipes by hooking my hand under the top section ..saves sticking my digits through the "canvas"

Donnie, I actually did this bit of destructive testing last night (before reading your post) and yes indeedy the "spar" breaks at the positon of the bolt. Thanks for the photo of your Jenny's center section. Unfortunately, the Nieuport doesn't have a fixed center section so the whole wings needs to be removable. ((Actually from what I can tell, the orignal wing may have been composed of two separate wing panels covered separately and joined in the middle))

Campy, I like your idea but since I'm using bar aluminum stock sheeted with hardwoods for the cabanes I'm not sure how I could connect the electrical socket at the top. Looks like I'll probably end up needing to fabricate some sort of bracket. Lucky I've got all stuff for silver soldering now! If only I had easy access to some brass square tubing!

How I attach the ring terminals is:

I solder the terminal to a piece of 3/32" or 1/8" music wire.

I leave about 3/4" - 1" of music wire after the ring terminal (or more depending on the size of the plane and the load that will be placed on it).

I bend the ring on the terminal 90 degrees (or what is needed to mate up with the wing surface)

The part that sticks down I attach to cabane. In your case, you would need to drill a vertical hole in the end of the bar stock to take the piano wire. Make the hole slightly oversize and put some JB Weld in the hole with a toothpick. Rough up the music wire a little and put some JB Weld on the music wire and insert in the hole. Align the ring terminal up with the blind nut and let dry.

I do this all the time for struts and cabanes and I use K&S aluminum streamline (teardrop) shape aluminum. Depending on the size of the plane you may want to JB Weld a longer piece of wire into the bar stock.

I have had some "unscheduled landings" with a few of the planes, and while the tubing bent (and in one case the plate ripped out of the wing), the JB Weld held the wire and ring terminal as if it were actually welded in there (the struts were "functional" struts). If you do try it, use the original formula, not the 10 minute stuff.

Don, maybe the full scale uses metal plates to reinforce the spar. Many WWI planes have through the spar holes with plates and bolts.. At least that's what I have seen in my searches. And yes of course the hole is the weakest spot but that doesn't mean that it will necessarily fail. That would depend on the loads on the spar...
Donny, yep I have slowed down a bit. and I need the excersise I get from golf!!!! but I have been making some detail bits so all is not wasted time lol.

Bob, that's an interesting possibility: through the spar bolts with metal retaiing plates on both sides. Hmm...let me think about that.

You could make a strip that looked like a T. The top of the T would be long enough to wrap the spar. Then bend the stem of the T 90 degress and maybe you have what you need.

Carl