Actually Mr Boogie (Microjet powered F-35 thread here in Jets) and I had already decided to experiment a bit. Not so much with surface roughness as layout. His access to fast prototyping equipment should allow the reproduction of essentially identical ducting, to which we can make simple, controlled changes. His bird is so close to 1:1 t/w already, that I'm thinking flight testing should be sufficient to "measure" the results. If we get anything worth reporting we'll post a thread. Who knows, perhaps 3D AutoCAD is able to produce surface textures too, thereby allowing THAT area to be explored as well.
Meantime Ed, are you aware of any online resources on the topic? Again, sorry to stray OT. Feel free to PM if that seems more appropriate.
Originally Posted by Ed Waldrep
... Maybe someone will build two different versions of the same ducting and mount small turbulators in one to see if there's a difference in performance. The dynamic portion would be hard to test without a wind tunnel I suppose... Making the turbulators would be the hard part... My understanding has always been that turbulence is to be avoided in inlet ducting, but maybe stirring up the boundary layer is a good thing? I doubt it will have a huge impact on performance in though.