Quote from Drifteris :

Scawen, if you going to touch engines, could you add crossplane option for inline 4 engine? If it's not too hard

In addition, for V engines, a slider for V-angle. The maths to infer the firing intervals shouldn't be too involved.

For bikes we might need direct control of firing intervals in many cases, e.g. the various flavours of V4. V5s currently aren't allowed, even though that used to be the old crossplane V8 hack when the external tweakers were around, so at some point LFS could figure that out. V3s too

Even with inline 3 engines, for real production bikes that someone might want to reproduce, there are 3 different crankshaft arrangements to choose from. Things start to get potentially complicated for the UI.


A simple solution is to select the crankpin separation (it would use some default value for the cylinder count and configuration) and have the editor duplicate that up. E.g. for Triumph's "T Plane" triple, you would choose the inline 3 and change the crankpin separation from 240 degrees up to 270. This would cover the third configuration, too: the early Laverda triples - select 180 degree crankpin separation.

The same control would work for the V4s and parallel twins.

More fiddly subjects like the difference between 120, 90 and 60 degree V6s, including even firing and uneven firing, would probably not benefit from varying the crankpin separation. Perhaps for these larger engines a simple tickbox for even or uneven firing, whilst still being able to change the V angle in either case.


I think that displaying the firing intervals directly will allow people to get the correct sound even if the in-editor configuration isn't exactly right.