This root appeared as ᴱ√VELU “unroll” in the Qenya Lexicon of the 1910s with derivatives like ᴱQ. velunte “sail” and ᴱQ. velupantie “revelation” (QL/100). It had several Gnomish derivatives of similar meaning (GL/22), all beginning with “b” since initial voiced spirants became stops in Gnomish.
Neo-Eldarin: I think it is worth positing a Neo-Root ᴺ√BELU to salvage these early words. However, in The Etymologies from the 1930s, Tolkien glossed the Quenya verb ᴹQ. panta- as “to unfurl, spread out, open”, so it is possible the sense “unfurl” moved to the root ᴹ√PAT (unglossed), though most of this root’s other derivatives are closer in sense to “open” (Ety/PAT).
A verb appearing as belu- or belwa- in the Gnomish Lexicon glossed “unroll, unfurl (intransitively), belly (of sails), swell” in the Gnomish Lexicon of the 1910s (GL/22), clearly based on the early root ᴱ√VELU (or ✱ᴱ√BELU) “unroll” (QL/100).
@@@ maybe salvage belwa-?