We have a Lyco O-470 in one of our planes and keeping the flaps open we do steep descents from 12,000' to pattern using speedbrakes (ie. fast) and it doesn't seem to hurt the engine. There's no EGT gauge so I do not know what it does to it tempwise, but it seems to be ok for decades of this. One thing though, is we keep some power in to help heat the engine on the way down.
Last edited by Cubdriver; 07-23-2007 at 05:09 AM.