Hi folks
Looking at my next project which is a ZN line Synergy which has a one piece wing.
Because of space and transporting constraints I am thinking about making the wing into a three piece unit.
Ie a centre panel attached to the plane in the normal way with two outer panel plugged into it.
The principal problem I can see is boring the hole for the wing tube.
If it was a two piece wing plugged into a fuselage i can be out by a millimter or so with no big problem.
However making it three piece means it has to be exact.

Has anyone ever attempted this, I know Probuild Uk have done it for a client however they wont tell me the secret. Yes I had the brass neck to ask when i was putting in an order.

So Has anyone done this themselves, how successfull was it and how about telling this poor boy from the country the secret.

Mike

Why three piece? Why not two piece and save a lot of time, work and weight?

But, there is no secret. You just need to build a drill jig to hold whatever you decide to drill with steady. The drill can be fashioned from a sharpened tube, a forstner bit or anything else that will cut foam instead of simply tearing it up. Do a search in the archives and you'll find several threads which cover this topic including diagrams of the drill jig.

John

Not to be butting in here, but a consideration to be made is ---- Aren't the Synergy wings pre-sheeted? If that's a YES, then you have some real challenges to overcome....like...

1. Carving into the sheeting, trying to remove some and making a place for the tube socket supports and
2. Deciding how you're going to reinforce around the tube socket within the wing....

You'd be most fortunate if it was un-sheeted, and if so, please ignore my comments.

Aerobob
You are correct that the wings come presheeted. However i dont see it as a problem as a bit of composite reinforcing in the right places should restore the strenght for minimum weight gain. However I am open to debate and advice on the subject as I am really out of my experience envelope on this one.

Mike

I'll be very interested to follow this thread.... There is so much load transferred span-wise to the sheeting from the center outward. Any weakening, or separation and re-gluing of the sheeting concentrates forces (again, at least in my experience). If the sheeting is well-adhered, and solidly glued to the foam, I'd be really concerned about tearing into that.

Some believe that a wing tube socket must be mechanically "tied" to the top and bottom sheeting, and at a minimum, overlayed with fiberglass or CF cloth "spars" running spanwise to distribute loads from the tube socket area along more of the length of the wing.

Recently having a tube socket separation in the wing, I know whereof I speak concerning load concentration....and distribution.[]

I've done something similar in the past and put a half rib near the end of the wing tube. I just cut into the sheeted wing after drilling the wing tube, slipped the wing tube through the half rib. After the glue dried, i sanded the half rib smooth to the wing surface and put 1/2" wide fiber glass over the seam to tie the rib to the sheeting. On the other subject of turning a one piece into a three piece. I'm considering the same thing on my Jupiter. I haven't quite figured things out, as there is no other way into the fuse on this plane.

Again, I have to ask. Why not just make the wing a two piece with the joint at the wing center section? I've done this on previous models and there is nothing to it. You don't even need to run bolts through the tube to hold the wing halves together as the bolts holding the wing to the fuse keep everything tight. I just cannot see where doubling the amount of weight in added hardware, not to mention the extra work, will have any benefit at all.

As a side note, if the wing in one piece is a problem, what do you plan to do with the fuse? Even if the fuse is a couple of inches shorter, you still have the added storage/transport space demands of the tail feathers.

just my .02,
John

JWN
To be honest my brain hadnt ticked onto the idea or a two piece wing until you mentioned it.
I guess I got a tad hung up on trying to make the plane a more traditional plug in type configuration.

Regarding the reduction in size issue. As far as I am concerned any reduction in size will make the bird easier to store and transport.
It is a damn site easier to transport and store one big bit and 4 smaller bits ( tailplane and wing halfs) than two large bits.

I fly mostly on my own so anything that makes it easier is a bonus as far as I am concerned.

Mike

Mike,
That's a valid reason for wanting to break the model down. I was concerned you drove a commuter sized shoe box and were trying to do the equivalent of a clown stuff with a pattern plane. I've seen a few models where the wing would break down, the tail plane was removable and the fuse would break down into two pieces as well. The owners of these models spent more time assembling and disassembling than they did flying. On top of that, they were always talking about how one of the assemblies needed some sort of work as they were getting loose. My personal preference is to keep things as simple as possible so there's less chance of something going wrong. But, you are right, the model must be manageable when you are by yourself at the field.

John

JWM
Err not a problem on that front I drive a SAAB estate ( station wagon to our colonial cousins) which would happily swallow 2 Synergies maybe 3 at a push.
My driver as I said is storeability and managability.

Mike

To attach the socket to the sheeting at the ends, you could router out a slot once the socket hole is cut and fill w/ balsa of the correct size. My EMC had the sockets attached to the sheeting this way, 1/4" balsa short spar about 6" long centered at the end of the tube socket. No added glass re enforcement, but the sheeting was 7-8# wood.

Hi
Byoungs idea was along the lines I was thinking about except I would still reinforce the are that was routed with GF or CF to spread the stress round the slot and the mechanically tie to the sheeting.

Ask Phil to do it for you.
Sure it's going to cost some, but so will a botched job.

Bla Bla
Right idea wrong direction.
I was thinking of more along the lines of an Irish direction rather than a Southern English direction. I will get just as good a job and I wont have to wait the thick end of half a decade.

Mike

Mike,

Check out Probuild's site. Their newest Synergy has that done to it. Sorry this is so late. It looks like the center section was molded from CF or something like that.

I know for a fact that the Probuild three piece wing Synergy was overweight (i.e. >11lb) with the three piece wing. The owner has now purchased a Carbon pipe to get just under the weight limit but really this model should be able to be built at around 10lb and the characteristics will suffer even with the increased power of the DZ's.

A few years ago I tried the same thing with a two part wing for my Caprise again via Probuild, and this came out at 10 3/4lb despite all the best efforts to keep the weight down. The wing itself weighed 3lb 2 oz; I replaced this with a one piece wing from ZNline and lost 3/4 lb immediately!

Sure the transport facility of two and three part wings is great but a heavy model will always hold you back and may ultimately not be worth it.

Regards

Keith

Hi folks
I am the person who started this thread and it certainly has given me food for thought.
I am surprised at the weight gain this mod would have.
My initial thought was " bloody hell is the centre section made of reinforced cement"
I am going to think long and hard whether I am sacrificing too much for a little bit of convience.

Mike