Old 10th Sep 2008, 03:40
  #93 (permalink)  
Modern Elmo
Join Date: Apr 2006
Location: Tullahoma TN
Posts: 482
Wrong to say slower takeoffs. I should have said "shorter."

How about this?:

By Karl Schwarz

„It was the high point of my career as a pilot,“ said Rüdiger Knöpfel of the Bundeswehr Aircraft Test Center (WTD 61) with enthusiasm, as he looked back on the first landing with the X-31A in extremely short take-off and landing (ESTOL) mode. In the critical minutes of the flight he had had virtually nothing to do, as it is only thanks to the unbelievably accurate position finding and automatic control functions of the complex software that the German-American experimental aircraft is able to perform extremely short landings.


„You don't have time to be nervous,“ adds Rüdiger Knöpfel, although the manoeuvre is extremely risky. „If the computer reduces the angle of attack too early, the nose landing gear could buckle under; if it acts too late or too little then the tail could hit the ground.“

Neither occurred, a major success for the small test team, which had to contend with a very tight budget. But what was the point of all this expenditure? On the last test flight the landing speed was 121kt (224km/h), down 31% from the normal 175kt (324km/h). Whereas on a normal conventional landing the X-31 requires some 2,400m of runway to come to a halt, all it requires now is 520m.

Such figures naturally depend on the aircraft type, but have the attraction of making landings on short temporary airstrips feasible. The reduction in landing energy is important for aircraft carrier-based operations. The aircraft structure could be lighter or it would be possible to set down with greater fuel reserves remaining or with unused weapons without overstressing the airframe. Again, the requirements regarding headwind on the deck would be less stringent if planes could land at a lower speed.


FLUG REVUE July 2003: X-31A demonstrates ESTOL landing

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