The Rationale in the Designs of the Arms

First and Fourth Quarters:
Arms:  Azure, on a bend Argent, a wyvern Gules.  Crest:  A wyvern Gules, charged on the wings, one visible, with a wheel Argent.  Granted by the Court of the Lord Lyon, 2006.  The rationale is discussed here.

Second and Third Quarters:
Arms:  Per pale Argent and Azure, three oak trees eradicated, counterchanged, fructed Or, a chief per pale Azure and Argent.  Crest:  A dragon passant Vert grasping in its dexter foreclaw an oak tree eradicated per pale Azure and Argent fructed Or.  Granted by the College of Arms, 1984. 

Aside from the obvious canting on the name Drake, the dragon in the crest symbolizes a connection to Isle of Wight County, Virginia, where my family first settled in America.

Sir Richard Worsley, Bart., bore for a crest a dragon vert. He was granted land in Isle of Wight plantation, and along with Christopher Lawne (as in Lawne's Creek, Virginia), was one of its first settlers. Sir Richard was from Appuldercombe in the Isle of Wight in England, and it was his place of origin and connection which inspired the name for the Virginia county.

The idea for the oak trees began as oak slips, representing the rank insignia of a MAJOR in the United Air Force, and commemorating my father's service in the Second World War. The idea evolved into trees because the combination of a dragon and a tree with golden fruit calls to mind the Garden of Hesperides (Hesiod, Theogony, 215; Milton, Paradise Regained, II, 357).

In Pretence:
Arms:  Azure three Chabots haurient Argent jessant de lis Or within a Tressure flory on the outer edge of Maple Leaves Or.  Granted by the College of Arms, 2004.  The rationale is discussed here.

The Combined Achievement:
Justification for quartering the arms granted by the Lyon Court with the arms granted by the College of Arms can be found in the Spanish certification here.