This may appear twice - it didn't seem to get through first time so I'm re-sending it.
On Tuesday 11 December 2007 15:52, dave perry wrote: [snip...] > I took a look at the bleriot-XI-yasim.xml last night. The > dimensions in this file do not match the .ac file. After some > time with google looking for specifications, I found a few very > good sources. The wing span in the .ac file is for the final > configuration, not the channel crossing configuration. The .ac > has the 3 cylinder Anzani engine (rated 23 - 25 hp on various > sites at 1450 rpm). Also the wing incidence in the specs is 7 > degrees which the yasim solver had a lot of trouble doing. The > cruise with this engine was only 36 mph and only 48 with the 50 > hp gnome rotary. I also found the 22 mile channel crossing took > 36.5 min which implies a 47 mph ground speed (10 mph tail wind > perhaps). > > Anyway, I was able to get much more realistic performance with > some experimenting using the above data. I am not satisfied yet > as I still cannot get sufficient elevator trim and convergence > with the 7 degree incidence. I should have a satisfying config > file by this weekend. > > I don't want to offend the originator of this beautiful model. > So I ask, is it OK to submit a bleriot-XI-yasim.xml file that > better matches the specifications ? > > -Dave Perry I couldn't resist having a quick look at it:) I've attached a config for you to have a look at (tarred & gzip'd) I took your revised config and changed: approach aoa - now set to 3 deg - 15 deg value seemed much too high and just wouldn't have worked with the u/c configuration. This is probably a bit too low but it's difficult to say with such an early and primitive aircraft - movies clips will help here, if any can be found. wing incidence - now set to 7 deg wing camber - reduced this to 0.1 (from 0.11 - an apparently minor change but was needed to solve) wing aileron controls changed from FLAP0 to FLAP1 (I don't think this makes any difference but FLAP0 is normally used for non-split controls) wing aileron drag - increased by 0.1 to 1.5 so that it's greater than the lift. hstab stall aoa - reduced to 9 deg - looking at the design, I wouldn't expect much difference in stall behaviour between the wings and hstab. hstab FLAP0 drag - increased by 0.1 to 1.5 so that it's greater than the lift. This solves but I'm not sure if the Drag coefficient and Lift ratio are reasonable. Also, with the wing set at 7 deg incidence, but with a stall aoa of only 8 deg there's only one deg to play with - this doesn't seem right so I suspect that both the wing and hstab stall aoa settings should be pushed up by a few more degrees. I'd also expect an even greater ratio between the aileron & hstab lift & drag values. The hstab should probably have a camber value too, considering it's design. LeeE
bleriot-XI-yasim.tar.gz
Description: application/tgz
------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php
_______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
