Wingtips (Building Questions and Suggestions)

[wirejock]

Starting the wingtips.
I am planning the hinge method with wider P4 hinge on one side.
They are pretty floppy.
A rib seems appropriate somewhere inside the tip to stiffen it. Maybe a foam/fiberglass rib or two?
Did anyone install a false rib to close the open area aft of the rear spar?

[Carl Froehlich]

Originally Posted by wirejock

Starting the wingtips.
I am planning the hinge method with wider P4 hinge on one side.
They are pretty floppy.
A rib seems appropriate somewhere inside the tip to stiffen it. Maybe a foam/fiberglass rib or two?
Did anyone install a false rib to close the open area aft of the rear spar?

The wingtip rib that goes in on the aft end comes with the kit.

Carl

[wirejock]

Originally Posted by Carl Froehlich

The wingtip rib that goes in on the aft end comes with the kit.

Carl

Doh! Guess I should have studied the plans more. Thanks.

[jibby212]

A few balloons in the wingtip will help keep the wingtip tight to the wing while fitting, also a V cut into a 2x4 approximately 2' long and place over the aileron and tip trailing edges helps keep everything aligned, after I figured these two things out, the fitting was easy.

[wirejock]

Originally Posted by jibby212

A few balloons in the wingtip will help keep the wingtip tight to the wing while fitting, also a V cut into a 2x4 approximately 2' long and place over the aileron and tip trailing edges helps keep everything aligned, after I figured these two things out, the fitting was easy.

Excellent Tips tips. Thx

How wide should the gap be between the aileron and wing tip?
I don't see anything on the plans. Scale drawing seems about 1/4".

[wjb]

Hi Larry,

My tip to aileron gap is the same as the aileron to flap gap .. about 1/4" works well.

I did the hinge option as well .. and found that once I cut off the fiberglass flanges and put the hinges on, the tip was pretty floppy in aft half (straight section), possibly do to lack of stiffness across the tip to wing gap. I glassed in 3-4 plies about 1.5' x 2.5' on the top and bottom inside the tip to stiffen it.

Take care to get the aft edge aligned with the aileron and flap TE; I had pull my tips and reset the hinge because the tip was a bit droopy (sighting down the TE of the wing) once the control surfaces were rigged.

[Desert Rat]

^^^

The dimensional callout is in the bottom left corner of drawing 9. 1/4"

[Ralph Inkster]

Actually probably a bit less ounces than your hinge attachment...

Consider installing a foam rib inside the wing tip to prevent cracking damage caused by the people leaning on the wing tip thinking it is stronger than it actually is.
Do all your wing tip fitting/aligning/nut plate/or hinge installments first before doing the foam rib.
I use 1/2" blue or pink foam to make a 36" airfoil shaped rib to support the aft 2/3 wingtip area where it is wide and flat, end the rib about 6" forward of the trailing edge. Wing tip forward concave areas tend to be more rigid & don't need extra support.
Rib attachment- position the rib inside the wingtip snug to the bottom skin, but spaced about 1/4" from the top skin. Use aerosol expanding foam to lock the bottom rib edge to the wingtip. After that is hardened up, remove the spacers and apply the expanding foam to the rib top edge and immediately install the wing tip to the wing while the foam is soft to let it harden in place, this establishes the final wing tip shape without distortions, and preserves your prior wing tip fitting/alignments.

[Carl Froehlich]

Originally Posted by wjb

SNIP
Take care to get the aft edge aligned with the aileron and flap TE; I had pull my tips and reset the hinge because the tip was a bit droopy (sighting down the TE of the wing) once the control surfaces were rigged.

The exact reason to defer wingtip fit up until after the wings are on and rigging done (and checked by as many builder as you can find).

Carl

[Ralph Inkster]

Originally Posted by Carl Froehlich

The exact reason to defer wingtip fit up until after the wings are on and rigging done (and checked by as many builder as you can find).

Carl

I agree with Carl on this