Originally Posted by peterh337
200kt TAS at FL180, ISA, is only about 147kt IAS.
The stock DA42 TDi will do that much at low levels so it's just a case of having enough turbo boost at FL180.
The usual plane salesmen's trick
But does IAS really matter in performance (except for people who've never been above 5000ft)? I always though TAS is the
only important figure for cruise (besides the fuel flow to achieve it) and IAS is just a number full of errors (compressibility, position, instrument, ...). I'm ready to be proven wrong.
Originally Posted by peterh337
Was your engine delivering the same HP at FL200? That would amaze me; no GA turbo installation delivers sea level MP at FL200. Most of them go to about FL150 or so, and drop off beyond that.
Thielert Centurion 2.0 (obviously not applicable to AE300, but the numbers are likely very similar) produces around 2,25 bar of manifold pressure at 100% load which is cca. 65". Obviously almost twice as much as normal turbo installation, where 40" seems to be the normal MP for maximum power. Given that, I think the turbo should be able to maintain at least sea level MP at FL200
