38mm delay lengths

38mm  8 sec
FS   99  1d=9.2s@kn274@11t@1x3.5x3/8c  v
WS   91  1d=11.0s@kn230@12t@1x3.5x3/8c  v
SD   91     v
STD  42  1d=17.5s@kn169@14t@1x3.5x3/8c  D16=125  16=100
F    42
BLU  42
BK   42  81=13/16d=23s@196kn  56=9/16d=13s@175kn   v

42 = 0.42 inches
1d = 1.00 inch delay
1/32" per second more if longer, less if shorter

Buttkicker load (BK) with a 0.42" delay is 8 seconds
+4/32" length (0.55" total) is 12 seconds delay
-4/32" length (0.29" total) is 4 seconds delay

Generally never set a delay below 2 seconds since the 
delay also acts as a bulkhead during the thrust phase.

FS=Firestarter
WS=Whitestar
SD=Stardust
STD=Standard
F=Fast
BLU=Bluestar
BK=Buttkicker
RED=Redstar
B=Basic
BLK=Blackstar
CLR=Clearstar

Fast is orange
Standard is brown
BK is black
WS and FS are silver