Major A <[EMAIL PROTECTED]> said: > > If we're already talking about engines: has anyone looked at the 747 > fuel consumption yet? The 747-yasim model seems to need way too much > fuel. Even if I increase the fuel fraction to 1.0 in the XML file I'm > unable to fly the plane across the Atlantic properly. Try taking the > model from EDDF to KDTW, for instance, I guarantee you'll run out of > fuel. I ascend in steps (FL180, 240, 260, 280, etc. up to something > between 320 and 400, doesn't make a lot of a difference), keeping > airspeed constant to around M.82, I can't think of a significantly > more efficient way of conserving fuel. > > The real 747-400 can surely do better than that, even a 767 can!
If you could find a way to measure expected range and consumption rate that would be helpful. There is a parameter called tsfc (thrust specific fuel consumption factor) that can be added to each of the jet engine definitions in Aircraft-yasim/747.xml. <jet x="-2" y="12.65" z="-2.41" mass="8000" thrust="63737" tsfc="0.5"> Decreasing the tsfc should decrease fuel consumption. Adjust it up or down until it seems to be consuming at a correct rate. It'd probably be easy enough to estimate the rate you should see if you know the range of the aircraft and how much it should use to get up to cruise. Let me know what you get so I can add it to the config file in cvs. Best, Jim _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
