On Sun, 2007-02-04 at 18:07 +0100, Sébastien MARQUE wrote: > hi all! > > I really find the Piper Comanche pa24-250 from Dave Perry wonderfull! I > use it on cvs FG-OSG. > But as I come from c172p, I'm a little confused with the engine, > propeller and power controls... > > First for a 180 miles trip I use 3/4 of the available fuel (on the four > tanks, ~7.000 ft ASL, ~130 KTAS), I don't know if it is normal, or too > much, I personnally think it's too much, and I misuse the engine controls. > First thanks for the kind comments. Second, the comment from Hal Engel were right on.
Concerning the egt and leaning. About a month ago, I added to the pa24-electrical.nas code that models more realisticly the egt. With this change, you should be able to come very close to a real leaning procedure. If you slowly (a little at a time because the code models "thermal" delay) pull back the mixture until it peaks at about 300+ on the egt, then push it back in until the temp drops about 25 to 50. This should give about 12.5 to 13.5 gal/hr fuel consumption, as in the real pa24-250. You can browse the fuel flow in the properties list. I regularly get 155 to 160 knots tas in the model and in the real N7764P. If you are not "clean" (gear up and no flaps) or if you have poor stabilator trim and are chasing the desired altitude, then expect lower tas. I also added a working tas ring to the asi as well as an OAT on the left front window. To use this, get the outside air temp in deg. C, align your altitude with the OAT on the asi and the TAS in mph is indicated on the white scale on the asi. You should regularly get more than 180 mph TAS. The "rule of thumb" that was taught when the pa24-250 was new was to run power "square" at cruse and in all climbs run the manifold pressure "less" than the RPM/100. So 23 in manifold pressure and 2300 RPM cruse was common practice. Constant speed propellers (like on the pa24) are not well modeled in Yasim. After some discussion on the developers list, we compromised in modeling the prop control response. Anyone who has flown with constant speed props will notice that the RPM on the pa24 drops too soon as you pull back the throttle. Also, in constant rate descents such as on an ILS GS, I use about 1 inHG less manifold pressure in the fgfs pa24 than in the real AC. > here's the trip: > http://fgfs.i-net.hu/modules/fgtracker/?FUNCT=FLIGHT&FLIGHTID=10065&PHPSESSID=fde9c270fdb27c820fde750dd1c9a31e > > Indeed, I can't succeed to find the good way to use the mixture control > (on the c172 I used the fuel flow keeping its value at the minimum, > don't know if it is the good manner, btw). for now I keep it at the > maximum (except for switching off the engine). > > To climb or descend I was used to play with power control on the c172, > on pa24 it is not that simple ;). so I try to play with n/N key to > control propeller, putting the manifold pressure at 16 (for descent, as > described in README.pa24-250), but I don't understand the effects both > on propeller and rpm, and my descent is not very nice... > for climbing I push the propeller control to the maximum, manifold > pressure too, and I try to correct climb rate using the yoke and trim, > so I can't keep a constant speed... and climbing is not "smooth" > (neither descent) ;) I think of the prop control like a manual gear shift. When going up a steep hill, you need to downshift to get the full benefit of the power and not damage the engine, i.e. push the prop control forward. The throttle in both the pa24 and your car only determines how much power you are applying. > I'm not a real pilot, I only fly on FGFS, so sorry if I don't use the > good terminology for these controls (indeed I don't know it in English, > that is a problem to find infos over the Net). > > Any help is welcome to explain how to use these controls fine. > Thank you. > As Hal said, the pa24 rewards smooth control inputs and trim is very important. Just keep practicing! -- Dave Perry <[EMAIL PROTECTED]> ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Flightgear-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-users
