Melchior FRANZ schrieb: > * Georg Vollnhals -- Wednesday 14 June 2006 03:02: >> Take the BO105 and goo for a straight and level flight with 100-120 >> knts. Then push the collective down. [...] >> Try it with the BO105 - see what happens? >> You are not only able to hold height with pulling the stick back but to >> climb with up to 1500 ft/min until speed is low. > > That's "translational lift". You know, the thing people are claiming > isn't implemented. :-} It's not realistic (as Maik himself says), No. Translational list is an additional lift component related to helicopter speed against the air and will start at about 12 to 20 knts (depending on type of helo). This is a real big addition lift component together with (an unwished) roll and yaw component. > but I'm not sure about the "dropping like a stone" thing. Normally, > people compare a fully loaded real helicopter (because they are sitting > in them as passengers together with several other people) with an > unloaded sim helicopter. Put more weight into the bo, and it sinks > faster, as one would expect in RL. > > m. "falling like a stone" might be the wrong expression but was told me by a RL pilot and demonstrated afterwards in a "hot" autorotation for a short time from 2000 to 1000 ft. It is pretty impressive and the vertical speed naturally depends on the type and configuration (ie weight) of the helo that you fly, our BK117 should come up to more than 2000 ft/min, a BO105 will be have some other numbers but generally comparable. You understand what one is doing when reducing collective? You reduce the common blade-pitch angle to (nearly) zero (depending on the type of helo you are flying). Of course, going into a heavy flare will give you some lift for a short time until your horizontal kinetic energy (speed) is reduced. But when I asked one of our experienced RL pilots about this scenario and what would happen, he told me that he could (if ever) hold altitude for a *very* short time by pitching back but could not make the bird ascend remarkably (what our FG helo does).
OK, after all I want to say once again that I am not the real expert for this, we should have an *experienced RL helo pilot* who is also interested in flightsims to tell us what he thinks in general and detail about our FDM. But as I was very keen to learn all about helicopter flight behaviour and technics and comparing different helo sim flightmodels by checking the opinion of RL helo pilots I *just want to share* all I know with you. People simply should be advised that there are very diffent views regarding the actual helo FDM. I would feel pretty bad if we announce our helo FDM as "realistic" as we have some nice fixed wing aircraft with "real life pilots and a/c owners" approved flightdynamics, this would be bad for FG in common. Just my 2c, this discussion will probably never end :-) Regards Georg EDDW _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
