HoHun

Hi Lis, >For the "super-turbo" distinction ... Ah, perhaps a slight misunderstanding - I merely meant to point out that the term "turbo-supercharger" is used to refer to a turbine-driven supercharger (more commonly called "turbocharger" today). "Turbo-supercharger" and "geared supercharger" are a distinct pair, but "supercharger" alone can refer to either of them. The attached example shows a description of the Republic P-47's supercharging system with this use of the term ... "Turbo-supercharger" was in fact coined fairly early on, as evident from this 1919 issue of Flight magazine: http://www.flightglobal.com/pdfarchive/view/1919/1919%20-%201084.html According to etymonline, "turbocharger" was first used in 1934: http://www.etymonline.com/index.php?term=turbine The same concept obviously, and I figure the long variant has since dropped out of common use. Regards, Henning (HoHun)

Hi Lis, Excellent research and very accurate article! Two minor comments on terminology: >Turbocharger, sometimes called power recovery device ... I've not seen "power recovery device" applied to turbochargers, but there are the "power recovery turbines" which exploit the otherwise lost power of the exhaust gases to add mechanical power to the drive shaft via a hydraulic clutch. This technology was used mostly on post-WW2 airliners to improve overall efficiency. >Supercharger, sometimes called turbosupercharger , is a type where compressor is driven directly by the engine. It's my impression that the term "turbo-supercharger" was never used for mechnically-driven superchargers but only for the familiar turbine-supercharger combination described above as "turbocharger". I believe "turbocharger" is just a convenient contraction of the original "turbo-supercharger". Regards, Henning (HoHun)

See also http://xplane.wikia.com/wiki/Engine_Specs#Tips_.26_Comments_on_Piston_Engines

Hi Tkyler, >OR use the plugin "dataref editor" where you can enter the frequency in using the keyboard. http://wiki.x-plane.com/DataRefEditor Very useful tool, thanks a lot for the hint! :-) I was able to set a 4-digit frequency that way, but I can't say for sure that X-Plane will work with such a frequency since prior to that, I had already followed Samen's advice and changed the "offending" NDB to a 3-digit frequency. It looks like I can't change it back within X-Plane since there is just a 3-digit entry field (and klicking the offending NDB for the first time actually sets the frequency to "999" automatically). I guess I could always change it back by manually editing nav.dat, of course. Regards, Henning (HoHun)

Hi Samen, >You can just change the frequency by going into Local Map> Edit and selecting the NDB and then changing the frequency Thanks a lot, that's a great workaround! :-) Regards, Henning (HoHun)

Hi everyone, Flying around over virtual Antarctica, I noticed that Palmer Station NDB is listed with the frequency of "1600". Is it possible to tune the ADF receiver to this frequency at all? The standard ADF console only displays three digits. I used data out to show ADF status including frequency, and it also shows only three digits. If it's impossible to tune to a 4-digit NDB frequency, is the listing for the Palmer Station NDB frequency in error, or does it really use such a frequency in real life, and it's only an X-Plane limitation that it cannot be tuned to? Thanks in advance! :-) Henning (HoHun)

Hi Zach, >Well, what do you think? Looks pretty good! :-) >I have NO information on any of the airfoils or prop used on the aircraft (I have the Hartzell prop's model number, but no information otherwise found online). Again, if anyone knows of an online resource for this information, shoot it my way. Unfortunately, the PC-21 is not on the most useful list I know when it comes to airfoil information: http://www.ae.illinois.edu/m-selig/ads/aircraft.html However, this list might prove useful in future projects, so I thought I'd mention it :-) >Also, I am curious as to how X-Plane calculates misc wings. I used small misc wings to make winglets and such, but doesn't X-Plane see a bunch of new wing tips? No. You can use the option "Output Flight Model" (or whatever it is called now) to write a text file regarding the current flight model. If you open that file, you'll usually see "Wing x joined to wing y" messages throughout the file, showing that X-Plane figured out where a logical wing is connected to another to form a "physical" wing. One thing where your model might be sub-optimal is the vertical stabilizer. Many X-Plane aircraft are built with a vertical "main" stabilizer and a second one in front of it to make it look like the real aircraft's strake. Austin on one occassion advised against that because this will be treated as two consecutive wings by X-Plane, causing the main stabilizer to be affected by the strake's downwash. The proper way according to Austin to build one lower vertical stabilizer that begins at the root of the stabilizer and runs up to the point where the strake ends, and an upper vertical strabilizer which consists of the strake-less part. (An additional disadvantage of the separate strake is that it's impossible to fair the strake properly into the stabilizer profile, while this is easy with Austin's method. The visual aspect doesn't matter if you're building a Blender airframe, of course.) Regards, Henning (HoHun)

Hi everyone, Has anyone tried to create a dual ducted contra-rotating fan "helicopter" as featured in James Cameron's "Avatar"? I like the looks of those things, but it was rather funny to hear them going "whop-whop-whop" in the movie ... probably because this sounds "realistic" to an audience associating the pictures with the Vietnam-era Hueys from "Apocalypse Now" :-) I tried to convert X-Plane's Osprey to an "Avatar chopper" configuration, but the contra-rotating fans did not respond to cyclic commands too well, with both fans on one side occasionally opposing each other (which would have lead to instant self-destruction in real life). From the way they are depicted in the movie, the Avatar choppers don't actually have cyclic controls (I suppose), as they appear to turn by vectoring the fans fore and aft. I don't think I have noticed any lateral swivelling, so I assume they'd use differential thrust to roll. I have no idea what they might do to achieve pitch control ... maybe a puffer in the tail? In any case, my (mostly unsuccessful) attempts to convert the Osprey seems to indicate that the Avatar chopper setup requires quite a bit more power to achive vertical take-off than the original Osprey setup :-) Regards, Henning (HoHun)