A few aviation questions

[Guest Adverse Yawn]

In mountainout terrain, if you are vally flying on GPS (which you wouldn't be in reality), you would only be able to see satalites above you, you position resolution could be pretty bad, not what you would want in such a situation. I also imagine (because I don't know for sure) that there must be some posibility of the UHF signal bouncing of the side of a mountain or two, increasing the amount of time it takes for the received to get the signal and this increasing the error still further.I reamin very sceptical over the reliability of GPS because the very weak signal strength. This is having seen my own Skymap IIIC telling me I was 5nm north of where I knew I was too!!

[Guest Adverse Yawn]

So why does the RAF (the bestest pilots in the world BTW :)) use Grob Tutors then?http://www.ukmfts.mod.uk/pages/current/platforms.shtml

[LAdamson 240]

>I reamin very sceptical over the reliability of GPS because>the very weak signal strength. This is having seen my own>Skymap IIIC telling me I was 5nm north of where I knew I was>too!!>I trust them a lot, at least in the U.S.. As an example, my Garmin 296 hand-held has 12 channels, usually pics up at least eight satelittes at a time, and requires four for a good fix.A Garmin 1000 glass panel uses two independent GPS's and uses the one with the best incoming signals. Last year, a friend & I, put about 29 hours of cross country on an airplane with a dual axis auto-pilot that relied on the panel mounted GPS for heading information. No problems at all, except when a thick "flight guide" was sitting on the antenna which is located under the windscreen on top of the glareshield. edit: these small solid state gyro auto-pilots are widely used in experimental aircraft. Reading as many experimental/kitplane forums as I do, I always read how well the A/P works for cross-country's & seldom any problems; keeping in mind, that the A/P depends solely on the GPS for guidence. When I say small, the gyro itself, will fit in a 1/4" cube. Quite different from the spinning motorized gyros of yesteryear. L.Adamson

[Guest]

The Grobs are not used in the role of primary trainer. They're used as pre-selection trainers. Aspiring pilots get a few hours of Grob time to determine whether they "have what it takes", "are naturals", etc. etc.In other words, to weed out those who want to but likely will fail in the actual training process.Those who succeed in this first step then go on to Tucano.

[michal 44]

>be some posibility of the UHF signal bouncing of the side of a>mountain or two, No, signals don't bounce of a mountain or two.>I reamin very sceptical over the reliability of GPS because>the very weak signal strength. With your understanding of physics you should be.Michael J.

[Guest JamesO]

Hey, I think I'm in the right place.. my previous experience has been hanging around the MSFS forum and the screenshot forum so I'm not too sure :) I've been an on-and-off simmer for around 4 or 5 or 6 years (I can't remember). Recently, I have began an undergraduate degree in Aerospace Engineering and have been pleasantly surprised, how much flightsim, with all its quirks, helped as background knowledge for this course (at least the flight mechanics bit anyway). I do have a few questions however, if anyone is willing to answer. I have been looking at aircraft performance mainly, and am wondering what VNE speed stands for, I think its the absolute maximum never exceed speed, but I'm not sure. Also, while looking up aircraft data, I have found that sometimes I cannot locate a cruise speed, maybe just a speed such as trimming speed range or a manoeuvering speed. Is there a reason for this? This may sound like a silly question, but is there a difference between a primary trainer, and a trainer aircraft? When looked up on the internet, they give different things. I would have assumed primary trainer would be your Cessna 150 or Piper Arrow type of aircraft. I would very much appreciate someone shedding some light on these questions! I'd also be interested to hear from anyone who is also studying this course (or similar) or has studied it! Many thanks, James:-wave

[Guest Adverse Yawn]

What the Garmin high end kit introduces is RAIM. The kit can't improve on the fundemental weakness of GPS signals, but the RAIM system ensure sufficient satelites are tracked and compared to each for errors with additional available for redundancy. If that is not the case then you get a warning, and those warnings are no infrequent. With stuff like the Skymap, there is no such system.

[Guest Adverse Yawn]

Hey professor! How are you doing?http://gpsinformation.net/multipath.htmhttp://www.estec.esa.nl/conferences/FPD/in...s-es011026.htmlhttp://en.wikipedia.org/wiki/Global_Positioning_Systemhttp://www.gmat.unsw.edu.au/snap/publicati...e_etal2000h.pdfOh my, it seems my knowledge of physics is sufficient to arrive at a reasonable hypothesis from first principles that is in fact correct.LOL!

[KevinAu 441]

>This is totally irrelevant to the post - but I've found that>I can fly in FS amazingly well in mountains with the FS GPS>displaying the terrain features.>>I can definitely see that technology as a major advantage and>lifesaver in the real world.We actually do. EGPWS is replacing GPWS on aircraft now. Enhanced Ground Proximity Warning System uses the GPS/FMS derived position of an aircraft in relation to a stored database of terrain in order to generate terrain warnings. The radar altimeter is out of the picture in many of the modes.

[Guest HotCharlie]

>The Grobs are not used in the role of primary trainer.>They're used as pre-selection trainers. Aspiring pilots get a>few hours of Grob time to determine whether they "have what it>takes", "are naturals", etc. etc.Not entirely true. The Royal Navy use the Tutor/Heron for "Grading" (preselection) before entrance to Dartmouth than Elementary Flying Training on the Firefly, but all RAF pilots now do just over 60hrs on the Tutor as their elementary flying training. At this point they are then streamed to Linton (Tucano), Shawbury (Squirrel/Griffon) or Cranwell (King Air) for the next stage of their training.