Andy Ross <[EMAIL PROTECTED]> writes: > David Megginson wrote:
>> 1. Sea level 35degC, 28.5inHG >> 2. Sea level -25degC, 32inHG > The "density altitude difference" (a butchered term -- the density > altitude that corresponds to the same ratio vs. standard sea level > conditions) that this corresponds to is about 11000 feet MSL. That's > a pretty hefty difference in density! :) > >> The C172 barely climbs out of ground effect, and eventually manages an >> anemic 200-300fpm climb at 70 KIAS >> [vs.] >> The C172 finishes the takeoff roll in seconds and shoots up like a >> rocket at over 1500fpm at 70 KIAS. >> >> These are the right types of effects, but I think that the magnitudes >> are a little excessive, at least for a sea-level airfield. I have done a substantial amount of flying at high altitudes, including training for and actual missions doing search and rescue at high altitudes (up to 13000+ feet). From my experience, I would say that the effects you are seeing with a density altitude difference of 11000 feet are pretty much in line with reality, for a 172. When flying at those altitudes, climb rate is minimal, and rate of turn is huge -- i.e. if you try to reverse your direction by 180 degrees, it takes you *much* longer to make that turn at 11000 feet than it does at 2000 feet. (Do the various FDMs model that characteristic of density altitude well or at all?) Cheers, Derrell _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
