14a It's in the sticks - make haste (8) I have ----P---
17a Bones made of 12 (6). I have 12 as SLICER so RELICS makes sense BUT I also have 5d as PERSEPHONE so there is a conflict! There are several alternate spellings of PERSEPHONE but none seem to fit. I'm pretty sure SLICER is right and was pretty sure about PERSEPHONE till I tried to enter RELICS!
26a In one variation, runner-up docked in front of spacecraft (4,4)
14a is CELERITY - it within celery
17a RELICS were often bits of bone
26a NOSE CONE (someone else answered that one in another question, though i'm not sure why, but it fits).