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Constraints | Written By | Append Date | |
|---|---|---|---|
Design integrates an 0.5”x075”x0.5” 75” aluminum box tube | Aug 26Nathaniel Li | Sep 8, 2024 | |
Airfoil is based on a selected NACA airfoil | Aug 26, 2024 |
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Designed a cut-out for the ribs. Based on this research article, elliptical cut-out shapes result in lower stresses in the aircraft ribs (studied using ANSYS) since sharp corners was what leads to higher stresses. Hence, I used elliptical cut-out shapes for our ribs. I also used a similar design in their studies (e.g., 3 ellipses) and chose the size in respect to their ratio between ellipses.
But…I did read on reddit that this doesn’t matter if your wingspan is greater than 6 inches…but that’s also from a random redditor 🤣
The placement of the ellipses solely depended on the spar cut-out and the thickness of the outline. There is at least 2-3 mm distance of clearance and 12.5 mm distance from the outer edge of an ellipse to another ellipse.
The ellipses and spar cut-our follow (or on) the camber line.
I wasn’t sure if the main spar and rear spar will be the same so I just made a cut-out with the one Evan Janakievski added in the Wings file. This is welcome to change
I’m curious if we should fillet the corners to reduce stress but idk if the spar will fit
Thickness is 5 mm but we can def slim it down to 2-3 mm like Nathaniel Li suggested
Wings Update
8 ribs are spaced 80 mm apart and the wing skin is 600 mm (all are estimates rn)
LE and TE Concave Issue
3D prints that cover them is one solution but I was also considering a long wooden rod like in the images below and we can cut-out a circle in the front to insert it. But this will only for the the LE issues.
Control Surface Idea
I thought this idea was pretty cool, where the servo to control the flaps are inside the wing (attached to the ribs): Aileron Servos on my Guillows Sopwith Camel. I’ll prob look into it more tho
Author: Nathaniel Li Updating Date:
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These are looking great!
Disagree on 12g being a small weight savings! 16th ribs > 1/8th ribs imo → this is 24g overall for the drone!
Don’t design around prusa dims, we should have bambu labs printer back
Unless you have a reason not to, I would make the cutouts larger but keep more vertical supports (more material in the vertical direction will help reduce bend more than more material in the horizonal direction, think like beam bending)
How are we thinking of adding ailerons to these?
How are we spacing out the ribs?
maybe LW PLA spacers?
TE print could probably be bigger, LE slightly thicker
How are the LE and TE prints attached? → glue
End cap + print that bolts to spar to keep wood on aluminum (shoutout Sohee)
You may want to make a test rib to check tolerance of the square cut-out after laser-cutting, talk to the person who does the laser cutting to find out what tolerances you can expect → exact sizing almost never just works for mating parts
tbh you addressed most of my concerns in design updates (no more second spar)
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