Wash out or not once more...

[Dave Stroud]

While getting the spars done, I'm looking ahead at the wing washout question. I did a search on this site and found various posts on the subject, mostly older and the overall consensus seems to be that washout isn't really needed or you can do it and it will be just fine. Any further findings or opinions on the subject would be appreciated.  My plans say 2 degrees. 

The reason I ask at this early stage is that I remember trying to twist my Christavia wings to get some washout and with the leading edge  D cell in place, it was only possible to get a very little twist into the wing. So, I'm thinking of building the washout into the wing while it gets assembled on the table in the first place. Thoughts appreciated. While we're at it, I'm curious about my plan set number. It is F80 and I see many other letters and numbers of other peoples plans which don't seem to follow any sequence. Any clarification again appreciated. Thanks.

[stevejahr]

When building R/C model wings... I like to save the shear webs for last for just that reason.  Closing the D on the front locks everything in and twist just really is not possible after that.  One bay of shear web was enough to lock the washout right in.

Of course we don't build full size planes using CA glue... and it would probably be difficult to install the shear webbing on the spar after the nose sheeting.  Otherwise this would work well ;-)

[Dan_]

While getting the spars done, I'm looking ahead at the wing washout question. I did a search on this site and found various posts on the subject, mostly older and the overall consensus seems to be that washout isn't really needed or you can do it and it will be just fine. Any further findings or opinions on the subject would be appreciated.  My plans say 2 degrees.

The reason I ask at this early stage is that I remember trying to twist my Christavia wings to get some washout and with the leading edge  D cell in place, it was only possible to get a very little twist into the wing. So, I'm thinking of building the washout into the wing while it gets assembled on the table in the first place. Thoughts appreciated. While we're at it, I'm curious about my plan set number. It is F80 and I see many other letters and numbers of other peoples plans which don't seem to follow any sequence. Any clarification again appreciated. Thanks.

Read this on wing design pg. 48 on...

[Dave Stroud]

Excellent reference, thanks Dan. Good all round info. We met Barnaby down at SNF many years ago. Cool guy. 

2 degrees it will be....so here goes the question. For those who have put washout in their wing, at what point in the assembly process do you build in the twist ? It appears that 2 degrees requires the outer end of a rear spar to be about 1" above the front spar. With the spars fixed in that position and the ribs in position on the spar but still loose, could we fasten each rib to the spars with a slight adjustment to accommodate  the angle ? Or, is it better to build the wing flat, then force in the necessary twist and then attach various braces and the leading edge ply ? Thanks for any ideas.

[leshoman]

Build it flat and adjust with strut length on assembly. Actual degree is not as important as making sure both wings have same wash. If off will want to roll. Not a big issue but uncomfortable to fly

[rfeenstra]

I too built flat and put a little twist in with the rear lift strut.  Not the full recommended amount, maybe 1.5 to 2 degrees.  Later reduced the washout on the left wing slightly to compensate for my heavy butt sitting on the left side.