I'm writing a scientific paper and would like to ask my co-writer to write down the paper's outlining chapters.
Would it be possible to use the idiom (if indeed exists) - "Please start framing out the paper's outline" ?
It sounds quite unnatural to me, but I figured it wouldn't hurt asking.
I agree with you that "framing out the outline" is not a natural turn of phrase. You could say "sketching the outline." My recommendation would be "outlining the structure of the paper."