Having a fully reusable and efficient engine would also greatly reduce the cost of space flight, researchers claim.

The neo will come with a larger, more efficient engine that will cut fuel consumption by about 15 per cent.

This provided a very efficient engine, which won many awards both at home and abroad.

The thinner air will reduce air resistance and allow more efficient engine geometries.

This set-up should produce the most efficient engine setting / best glide speed equation (for the particular circumstance).