Rib Spacer Design

Task Description

The ribs in our wings need to be appropriately spaced out to ensure they retain their shape and position. Currently, we have 3D prints that cover the Leading Edge (LE) and Trailing Edge (TE) to prevent the wrap from caving between the ribs. We would like to accomplish 2 tasks by redesigning this print to also act as a rib spacer. The current design can be found in PDM at Fixed Wing → Fixed Wing Design → Wings. Refer to Wings for additional info. You may need to make adjustments to the ribs as well.

There are multiple ideas for this (see below). Make sure to think about how it’ll attach to the ribs:

• Modifying the current print to be glued at each rib

• End cap + print that bolts to spar to keep wood on aluminum spar (shoutout Sohee)

Constraints

Relevant Contacts

Assignees

Task Progression/Updates

Author: @Sam Wong updating Date: Sep 25, 2024

Progress

Decided to add to the existing leading edge cover to allow it to function as the spacer and the leading edge cover.

On the leading edge 3D print I added slats that the ribs would be glued into as seen in the following figure.

Open

Full assembly of the leading edge cover.

Sizing Problem + Solution

A small problem encountered while creating the CAD was some errors in the lengths and spacing of the ribs. the wing is made of 3 * 200mm long leading edge covers for 600mm. There are 8 * 1.59mm ribs that need to be spaced 83.9mm apart (face-to-face) for a total of ( 8 * 1.59mm ) + ( 7 * 83.9mm ) = 600.02mm. This means that there is an extra 0.02mm of the rib protruding from the side.

My solution to this was to have two of the ribs be a distance of 83.89mm apart. this slightly shorter distance is in gaps 3 and 5.

Author: @Nathaniel Li Updating Date: Sep 26, 2024

CAD Review 1

• Looks good!

• I would like it to be split where the ribs are connected instead of where they are now

  • The original for each piece was arbitrary

  • Up to you where you’d want them split but because of that small gap variation it may be best to have both those gaps included in one piece to make it easier to identify

• Would also like a tolerance of 0.1mm added to each gap for gluing

Author: @Sam Wong Updating Date: Sep 30, 2024

CAD Review 1 Update

• The rib spacer has been split where the ribs are connected

  • the small gap variation is in the end pieces as these parts have to be unique from the middle pieces as the rib only gets glued on one side for the end pieces

• a tolerance of 0.1mm has also been added to the middle slots to allow for gluing

• a tolerance of 0.1mm/2 = 0.05mm has been added to the ends as they are only glued by one side

Open

Updated Assembly of Rib Spacer

Author: @Sam Wong Updating Date: Oct 29, 2024

Spar design progress

• created a simple design to space the ribs along the spar

• design implements a hollow tube to encase the spar

• hollow tube is 3mm thick which allows for enough surface area to glue while not protruding outside the wing profile

• 0.1mm tolerance to allow the case to easily slide onto the spar

• triangle cutouts in the sides to reduce weight

• the 5 middle ones are the same size and the outer 2 are the same size due to the slight variance in the distance needed between the ribs

Side thoughts

• I don't know if it even needs the triangle geometry if it isn't needed structurally I could also fully remove these and make it one big rectangular cutout

• between the spacer and the rib should there be a tolerance to allow for glue

  • didn't know if I should add this as a 0.1mm tolerance as this would allow more space for glue but also might skew the regular spacing between the ribs

Author: @Nathaniel Li Updating Date: Nov 4, 2024

CAD Review 2 - Spacer

• The design looks great and would work great

• However, upon further inspection it would be better to have a design thats simpler and requires less material

• This would also require quite a lot of supports when printing and I’m not entirely sure it would come out great

• My thoughts were to take what you have and chop it down to only have the square outline on each side that connect end-to-end:

  • The cross supports aren’t really needed here as this won’t be load bearing

  • If you have other ideas I’m open to them!

• Here’s what i mean by “chopping it down”

• The ribs are also bigger now so you have some more space to play with

  • The size you have right now is already pretty good tbh, if you want to use a bit more space for design changes feel free to go for it

Author: @Nathaniel Li Updating Date: Nov 11, 2024

CAD Update 2 - Spacer

• Simplified by taking out more weight

• Less supports needed for printing