The third of three Charticon 2013 exclusives are homages to the Powermasters Hi-Test and Throttle, called Unleaded and Accelerator.
Original G1 toys:
These turn into guns, not engines, something explained by their biography, which somehow also taps into the Masterforce story of Buster and Hydra, the Takara recolors of Hi-Test and Throttle.
I initially had some trouble fitting them in the hands of my Universe Darkwind, so I clipped them to the wings.
However, they can be made to fit into the hands if you turn them right.