FCW cranks have 2 counterweights on each crank throw. The DD cranks are similar to the original Cox Killer Bee crank. They also have different cam and crank sprocket reluctor configuration. Cylinder bore and stroke was with a five bearing crank. It also incorporates a crank and connecting rod mechanism. They compress gas by utilizing a piston pushed by a crank shaft. It uses the M20B25 block with M20B27 crank and custom rods. Not all square taper crank and bottom bracket combinations are compatible. The spindle is permanently pressed into the right crank. This was achieved with a bearing surface machined onto the front end of the crank. The main landing gear is fully retractable by a hand crank. The bottom bracket shell is large to accommodate removal of this S-shaped crank. A pin on the hand crank engages these holes. It used a permanent magnet which was rotated by a crank. One Matilda had a damaged turret crank that allowed it to turn clockwise only.