scale effects

Hi All, There are a ton of you that build scale engines based on full size drawings of IC engine like the RR Merlin, Dusenberg Straight 8, Wasp Series Radials, etc. I am wondering how you handle scaling full size plans down to your desired scale? How on the world do you handle the...

Hello I am planning on building a 4" scale compound steam engine. Changing the linear scale by 1/3 affects area by a factor of 1/9 and volume scale by 1/27. Physics doesn't scale so I am concerned that changing the linear scale may require modifications to the steam path dimensions...