I designed this close to 3" ground screw anchor to hold in place a tent that i have setup to provide shade for my chickens. It can get quite windy and the 9" aluminum tent stakes were coming out easily. I haven't load tested these to say really how strong they are but they have so far held up really well when screwed into soil with good grass coverage. They are designed to be printed in two halves and glued together to maximize layer strength. I used super glue without issue.
The author hasn't provided the model origin yet.