Hi Andy, On the p51d fdm configuration, it looks like the substantial change was actually increasing the turbo multiplier from 2.0 to 5.5, and not reducing the cruise speed as stated in the CVS log of March 23. The cruise speed change does have an effect, but it is fairly small.
The problem with putting the turbo multiplier up in that range is the manifold pressure output is directly multiplied by that number. So full throttle produces an output of 164 inHG manifold pressure. We should be seeing about 61 inHG at sea level for this engine. Setting this multiplier lower to get the correct manifold pressure with turbo at sea level should reduce the maximum flight level for the aircraft since the second stage turbo cannot currently be modeled. On the other hand, using this lower value should NOT produce incorrect lower altitude performance since all the data I'm using is for below the 20,000 ft altitude where the second stage kicks in. The drag numbers calculated by YASim should be more or less correct up to at least up to 20,000 ft where the second stage would be kicking in. If there is a problem that setting the multiplier to 5.5 fixes, I suspect it is in the FDM design and not the P51D configuration. Any ideas how we can fix or work around this? Best, Jim _______________________________________________ Flightgear-devel mailing list [email protected] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
