Sorry guys if this is a daft question !

Just starting the trimming process on a new 'plane. First flight with a 12x6 prop' was too quick for my style , around 4.6 secs.
The engine was turning at 8,600 rpm.

I'm going to swap for a 12x5 , so my question is :

Is it the norm when you reduce pitch that you launch at the same rpm , i.e 8,600 ?

Is there an rpm rule when reducing pitch guys  ?

Again , sorry if this is obvious to you all ,

regards from a drizzly Charente

Robin.

it seems that most instructions that come with new engines are out dated lately. most of the times i read that people are using lower pitch props than manufactures recommend. Is there some kind of starting point  with newer engines that is a starting guide. for example a 25 size motor  runs good with what size props 35,40,46 and so on.I am currently running a os 25 with a 10 x 4 prop and it pulls great but the speed is defiantly fast. I would like to lose some speed but not loss the amount of pull thru stunts.