Boxkite wrote:I guess you are talking about max static RPM in the above examples?
Don't know anything about specifics, but I would guess that would be dynamic. Getting 2700 static on the ground would be interesting in the cruise!
I guess the difference is just where the red line is painted. Sometimes an engine limited to a lower RPM will have a longer TBO, but it's not that common.
Flying_john wrote:Compare a screaming Suzuki at 7000RPM producing 100hp and an 0-200 at 2200rpm. If you could make the 0-200 work at 7000rpm you would get more horses Some people run racing O-200s to something like 4000rpm
, but their TBO is much reduced!
Boxkite wrote:(strangely a DR400-140B has a 160hp engine!)
A 160hp engine will be higher compression.
It's interesting to see Lycoming's engine line-up, particularly for the 540 engine. This has (essentially, in common use) two compression ratings and two RPM limits.
The low compression engine with a 2450rpm limit makes 235hp. (e.g. Cherokee 235)
The high compression engine with a 2450rpm limit makes 250hp. (e.g. TB20)
The low compression engine with a 2700rpm limit makes 260hp. (e.g. some Cherokee 6s)
The high compression engine with a 2700rpm limit makes 300hp. (other Cherokee 6s, Extra 300s, etc).
These are off the top of my head, so forgive any errors...
Personally I like the higher compression engines as they're more efficient and give better fuel consumption, but they need higher octane fuel (i.e. won't run on standard 95 mogas).