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Post by M.I.B. on Jun 20, 2016 20:59:18 GMT
Hi everyone, I was wondering what's the purpose (if it has any in FS) of the DC-9 "R NAV" AP mode. I did read the DC-9 panel installation and handling notes, but this function isn't mentioned anywhere. I understand the "NAV LOC" mode is the one that's used to follow a localizer as well as VORs, but I'm not sure what purpose "R NAV" serves, and I was just curious to know. Any input you can provide - greatly appreciated. Dóre
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Post by Klaus Hullermann on Jun 21, 2016 5:41:24 GMT
I can only guess, but perhaps it could mean 'Reverse Nav' aka the 'Backcourse'-function of the FS-autopilots. But only the experts here at HJG can clear this 'mystery' correctly.
Klaus
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Post by Herman on Jun 21, 2016 6:24:47 GMT
Perhaps r nav is for GPS navigation ??
Herman
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Post by aerofoto - HJG Admin on Jun 21, 2016 7:28:16 GMT
RNAV ? The following link may help/explain in the absence of any other/better information .... en.wikipedia.org/wiki/Area_navigationI never covered RNAV within my manual/"DC-9 PANEL INSTALLATION & HANDLING NOTES" .... simply because I didn't know enough about it .... I'm "NOT" a pilot Whilst featured within each of our DC-9 panel AP's .... I'm not sure that it's really all that significant/relevant .... given that the standard AP based flight, navigation, and approach to landing modes provided .... are more than adequate for most conditions within the virtual FS world environment. Mark C AKL/NZ
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Post by M.I.B. on Jun 21, 2016 11:46:50 GMT
Thank you so much, fellow crewmen, for your input! I'm not sure that it's really all that significant/relevant .... given that the standard AP based flight, navigation, and approach to landing modes provided .... are more than adequate for most conditions within the virtual FS world environment. Exactly the way I had inclined to think myself. I just noticed that function was "just standing there" with no apparent purpose and I was curious about it. This clears up the mystery, thanks again folks! Dóre
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Post by George Carty - HJG on Jun 21, 2016 12:09:19 GMT
You may want to get in touch with Stellan Hilmerby ( www.hilmerby.com), as the DC-9 autopilot gauge is unchanged from the original Hilmerby panel from which HJG's DC-9 panel series was modified. George
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Post by Mike Monce - HJG on Jun 21, 2016 12:55:48 GMT
A lot of smaller airports without LOC/ILS now utilize RNAV for instrument approaches. It is totally dependent on GPS technology; just program and follow that magenta line while paying attention to the altitude procedures. See this example from skyvector for my local GA airport; scroll down to the bottom of the page for RNAV approach plates for Rnwys 9/27: skyvector.com/airport/IJD/Windham-AirportIn terms of real world safety, this is a great leap forward for instrument approaches to small uncontrolled airports. For me using a simulator, I prefer to torture myself with circle to land procedures . However, if I was flying the real thing that magenta line would be the only way I would go. Mike
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Post by Falcon on Jun 21, 2016 17:33:59 GMT
We used RNAV navigation back in the late 1960's. It was a great way to go direct, bypassing many vor's that were not in a straight line. However the FAA revoked all RNAV routes in the contiguous United States due to findings that aircraft were using inertial navigation systems rather than the ground-based beacons.
It was called "random navigation" therefore RNAV. Falcon
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Post by M.I.B. on Jun 22, 2016 13:53:49 GMT
OK, I might be starting to get the hang of this thing. The way I see it, if we are to greatly simplify things, it's just another type of navigation out of so many others, no big deal. But it would seem to me that there are "2 versions" of RNAV, so to speak, the old one from the DC-9 era and the modern, GPS-related RNAV. I've just checked some YouTube RNAV tutorials and I've performed some very basic RNAV approaches with the default FS9 C172, and the default GPS. It looks similar to any modern-day FMC-controlled approach with SIDs, STARs and such. BUT, (a big BUTT here), this could not have been the case when the DC-9 roamed the skies, there was no GPS back then, no magenta lines on shiny LCD screens. It'd be very interesting to know how DC-9's basic AP RNAV mode would work, how it would pull this off, without GPS, FMC and such. This is, in my opinion, what makes RNAV so interesting (to someone like me, who knows next to nothing about it). If it were just another modern day type of navigation, associated with advanced systems like GPS and FMC, it wouldn't stand out to me, but this same type of navigation existed back in those days too, and I can't figure out how it used to work with no modern equipment, but only that basic RNAV AP mode. I think I'm gonna try and contact Stellan...
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Post by aerofoto - HJG Admin on Jun 22, 2016 20:49:27 GMT
I think that particular analysis is probably "right on the money" Dorel .... in an "FS CONTEXT" Since we first released the DC-9 panels (around 2009 I think it was) I've never used the RNAV function .... and I don't think anyone's missing anything (major) by not using it. Apart from the KLN90 GPS feature (part of the Radio Stack sub panel), our DC-9 panels don't feature the common FS type GPS (simply because GPS wasn't standard kit in regard to the "panel era" we've represented), so, if RNAV is practiceable, then, it'd require the old (non-GPS related) procedure .... since following a GPS displayed track .... or switching to GPS NAV .... isn't possible using this particular DC-9 panel series .... so far as I'm aware. Mark C AKL/NZ
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Post by dutchman2 on Jun 24, 2016 17:15:48 GMT
I believe the original RNAV was from the 70's. This was a method to "displace" the VOR station electronically and create a ghost station set at a given distance along a radial off the actual VOR station. Sort of a poor mans INS or OMEGA system. Anything to get off of the fixed airways or go to an airport without any navaids.
Thats the Cliffs notes version, the purist may have a more detail explanation.
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Post by Nathan Ford - HJG on Jun 26, 2016 3:06:31 GMT
Dutchman, that's pretty much exactly it. By displacing the VOR to a virtual point from the actual VOR, you where able to fly directly to a Fix, IAF or the FAF. The advantage of GPS over RNAV is that RNAV has to be in range of the VOR in order for it to establish a fix. Some GA aircraft still have RNAV computers fitted to them. Here is a link to the pilots guide for the KNS-80Cheers, Nathan
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Post by walterleo on Jun 26, 2016 12:49:01 GMT
Hi friends: When I learned to fly the last marvel was indeed the RNAV computer coupled with the VOR DME radios. It was a development which was similar to the military TACAN navigation system, which could lead a fighter exactly to the point where it should deliver its deadly load, flying evasive manuevers and not straight on. The Russians installed a similar more exact system already in its early jets like the Tu-104 and Tu-124. The system was called RSBN-2 ("radio navigation system two") but needed quite a good training as contrary to a VOR system its indictor showed only the radial and distance and no TO-FROM information. So for practical use a computer for course information was an important addition called SRP. So the system was even able to calculate "DME" ARCS for approaches and departures, also in the simulations, in real it could also be used for instrument landings. The steering information was visible as the course line on its KMMP indicator or on the HSI of the Tu-134. It was not coupled to the AP. Contrary to the VOR based systems its course information was aligned to the TRUE NORTH of the selected actual groundstation. The Russian simulations of the Tu-104, 124, 134, 154 and IL-62 all have systems like these onboard. RNAV systems for flying "direct" also are navigation systems like the western R-Theta and its Russian sybling NI (Tu-104, 124) NAS (TU-134 and 154) and PB-NV (IL 62). In the Tu-154 and the IL-62 systems the RSBN stations were used to update the NAS and PB-NV systems. Like INS systems the Russian systems even the ones with doppler radar drift and groundspeed senors over time drifted away from the real world, which GPS doesnt. To my knowledge in FS there exists no simulation of a VOR based Areanav. In the seventies existed airways which were only available to aircraft with "areanav capability" so flying from Nautla to Merida over the Gulf of Mexico. Aircrafts without that had to fly on other airways. Kind regards Walter
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Post by walterleo on Jul 1, 2016 8:49:46 GMT
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Post by gotto on Oct 12, 2016 18:16:24 GMT
I can only guess, but perhaps it could mean 'Reverse Nav' aka the 'Backcourse'-function of the FS-autopilots. But only the experts here at HJG can clear this 'mystery' correctly. Klaus Hello ! I was the one programming the Autopilot related to Stellan 's DC-9. When A/P is active and the Nav selector is moved to "RNAV" position, the A/C should be able to follow/track the flight plan providing a plan has been loaded. And yes, I know this is cheating ! Best regards, Geir
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