swampyankee

I'm just curious as to how many here have to sometimes open a notch to get the stringer to run straight? No matter how exact you try to be when cutting the part you have one or two that just doesn't come out perfect.
I submit one curious case I've run into. Both sides of the bulkhead seem to share the same amount of offset to the second notch from the top. In the pictures you can see the jog the stringers take on each side of the fuse. I know that the plans may shrink, but I would think the sheet would've shrunk uniformly across it's entire surface. And I don't cut up my plans while working on them, so I would expect other notches to be misplaced from the same sheet. But it didn't happen.

So how many others here find that they have to open notches now and again, or more often? Or is this a common newbie problem that can only be solved through practise?

Check6

My Feedback: (427)

I have had this happen many times. I usually put the stringer in the first bulkhead notch and the last one. Then mark and open the notch in between if it needs it. fill the space with some scrap and you are good to go. Make sure you install the stringers opposite of each other so you don't build in a twist,
Thanks,
Fred

swampyankee

Thanks Fred, it makes me feel better to know I'm in good company.

butlern

My Feedback: (15)

Fred is correct, this is very common. Best solution that I have found is to use a razor saw (to cut the depth) and hobby knife (to whittle the material out) to widen the notch in the ply former so that the stringer runs straight. Then use the material that you remove to fill the notch on the other side of the stringer. CA the stringer/former and the filler all at once. Plenty strong and makes for a perfect fit.

I had to do this repeatedly on the plane that I'm currently building, but it only takes about 10 seconds to make the fit perfect using the method that I suggest above.

Good luck with the Zero! (Isn't that what I see in the photos?)

Noah

swampyankee

Aye Noah, Meister's own.

These responses have really made my day. I don't feel so bad since it seems to be a malady that strikes the best of builders. Really turns down the frustration factor too.[sm=48_48.gif]

Chad Veich

My Feedback: (60)

It very well may be a design issue an not a problem with you (the builder) or with whomever cut the parts. It is VERY difficult to design a fuselage with multiple stringers and not have at least one of them be slightly out of whack somewhere. Probably the only way to get them all perfect the first time is if you are designing in a 3D program that allows you to lay down the stringers and then remove the proper material from each former. This is why I love building in balsa, easy to fix these kinds of minor issues as you go.

allanflowers

Chad is correct. These things are usually design problems stemming from inaccurate lofting. There may occasionally be an airplane where the longerons are funny looking and don't flow nicely - for some mechanical reason with the original full scale aircraft. I am doing a Siemens Schuckert D-III and the panel lines clearly shown on numerous photos and 3-views demand funny looking longerons. The engineers who designed this plane originally are long past so we can only guess why.
The pix is of my CAD workout - the light green lines are from the 3-views.

DaddySam

My Feedback: (9)

I had this happen with a Hurricane - and you can imagine how many little stringer notches had to line up?

Sam

swampyankee

Man, this gets better and better. Nobody has posted on here that they've never had this problem. Now some wiseguy...