Ejecting high pressure engine efflux into a channel (called an augmentor) causes additional cooler ambient air to accelerate through the channel and mix with the engine exhaust. At the exit of the augmentor, the combined flow produces more thrust than the input engine efflux; the net increase is the amount of augmentation. In laboratory tests, thrust augmentation of 1.5 to 2 times engine thrust was achieved. In reality, incomplete mixing, duct losses, unanticipated high weight and ram drag, and the huge volume required for the augmented jet ejector systems caused the theory to be difficult to apply to a possible operational concept.

Aircraft in this sub-category include:

Lockheed XV-4A

Rockwell XFV-12A

Return to the VSTOL Wheel