nz,
You're still not being clear- do you mean LEDs as found on modern Jets, in which case the answer is "3000psi of hydraulic power", or unpwered slats, as in a Tiger Moth, in which case the answer is "Spring Pressure".
If it's the latter, the slats are spring-loaded open. When there is sufficient airflow, the pressure forces them them shut. They can also be locked shut mechanically
Not going to happen a 160kts as the Tiger would have shed it's wings by then!
Someone mentioned the Sabre liner, and by inference the F-86 having unpowered slats? I wasn't aware of that, but would be interested to know if that is the case.
Last edited by Wizofoz; 24th November 2012 at 08:21.