kenv56

For a kit im building i need to make a wing spar shim that is tapered from 1/16" to 1/8" and is 39 inches long.
How would you go about making something like that, and is it even worth the effort? Could i just make it 1/16" or 1/8" the
whole way?

scale only 4 me

My Feedback: (158)

You'd use a straight edge,, the ones for cutting drywall are 48".
I saw your other post,, I'd probably just use 3 pieces 1/16", 1/8" and 3/32" in the middle to shim the spar
That minute of a taper will be hard to cut accurately over 39"

good luck

big max 1935

My Feedback: (9)

I would like to see the plans to see what a strange part like that is used for .Built a lot of models but never needed a tapered part like that. I would go with the 1/8" added on & re-notch the ribs to fit . Max H. AMA14958

MinnFlyer

My Feedback: (4)

Ditto

scale only 4 me

My Feedback: (158)

My understanding is,, it was to shim the spar up off the table during construction,,

http://www.rcuniverse.com/forum/m_10...m.htm#10980552

kenv56

That's what I'm thinking too, I just wonder how important it is? Would they be trying to setup some washout doing this?

invertmast

My Feedback: (23)

If its for shimming the actual spar, I would add a 1/16" shim at the (root or tip) and the 1/8" shim at the (root or tip) then place the spare on the shims, then a straight-edge on edge to make sure it is straight. Then fill in the gaps with varying thickness' of balsa to keep the spar straight along the length of the spar.

scale only 4 me

My Feedback: (158)

probably,, I'd have to study the plans to know for sure

kenv56

Well I finally got some progress on the plane. I ended up doing the three shim idea.
Im thinking that when i install the shear webs onto the main spar I will get a level on
the top spar to hold it straight. Thinking that should hold everything where it should be
if there is any sag in between the shims.

KitBuilder

1/16" inch difference over 39 inches?? not worth it. it would be extremely difficult to build that accurately due to variations in the wood alone.

LesUyeda

"1/16" inch difference over 39 inches?? not worth it. it would be extremely difficult to build that accurately due to variations in the wood alone. "

I don't think so. But then I use a machinist scale for my building:-)))))))))))))))))))

Les

rica1

My Feedback: (32)

Any luck on using the spar shim? What is the date of your plans? I have a kit that I haven't built and reviewed the manual some time ago and believe the shim is a different size on my kit. I could look at it again if needed.

KitBuilder

Just saying it's not noticeable to the eye if its off.. I built a early 80's pattern plane which required the same and just shimmed each end and middle and laid the spar on that. Came out fine. I preferred to put my enerigies into other areas of the build.