Looking for advice and opinions on learning navigation skills

On Thursday, March 21, 2013 2:31:55 PM UTC-7, son_of_flubber wrote:
I fly in a moderately difficult area with lots of landmarks, lots of woods and eastern USA scale hills and mountains and very few spots to land out. Flying into valleys and not having enough space to turn around is a possibility. To date, I've relied on eyeballing the glide path to the airport and getting back close to the pattern with plenty of altitude to spare. I'm a navigational newbie. I've just started getting into the approach of calculating in advance "safe altitudes" at landmarks; altitudes that guarantee a glide to the pattern at best L/D with a large safety margin. My plan is to study the chart and topo maps in advance, make a list of safe altitudes and landmarks (maybe on a 3X5 card) then practice picking out landmarks and observing altitude. Plan and execute some mini-tasks around the airport with altitude targets. I'm using one of the classic books that talks about how to do this. In short, develop navigational skills without a digital PNA. Once I have better "navigational sense" I will learn to use a PNA. I'll stand off or stay well above any valleys where I might have trouble turning around.. As I get into this and realize the difficulty and complexity of navigating on paper, I'm wondering whether my traditional paper-based approach is dumb. Would it make more sense to start using a PNA sooner rather than later? I'm not suggesting that I rely blindly on the PNA, more like a combination of traditional methods with the PNA. Is it smart or dumb to delay using a PNA for a season? Are there any books that teach navigation with a combination PNA and paper based approach?

On Monday, March 25, 2013 3:56:05 PM UTC-4, Ramy wrote:
All excellent advices.

What I think many don't realize based on various discussions I had, is John's point about the impact of MC setting on safety glide. Many PDA soaring software going through the extra effort to sync the MC setting with the flight computer, which is a bad idea. The first thing you need to do when configuring your PDA soaring software is to decouple the MC setting between the two. Otherwise, when you fly conservatively (low MC setting) it will calculate way overly optimistic glides. As such you want to set the MC setting in your PDA high for safety while the MC setting in your Speed To Fly computer low, especially when trying to stay within safe glide of a waypoint. John's article explains this very well.



Ramy

When I first got serious about XC and racing, I owned 1/3 of a Grob Astir CS with STF vario and no other electronic wizardry. I had a prayer wheel (old glide calculator), but I'm a rows/columns guy, so I set about building some simple glide calculations in Excel that I printed into a small booklet.. There were pages for 0, 10kt, 20kt headwinds (good enough increments for what I wanted). Going through that exercise lead to asking a lot of questions about what MC settings implied, arrival height "cushions" and stuff like that. It was hugely instructive, and lead to a lot of the MC insights that John and Ramy mention. In particular, it showed how marginal low MC glides are and that a fixed "cushion" altitude (arrival above pattern) can be way too little when you're 20 miles out and ludicrously conservative when you're 10 miles out.

In summary, I'd spend the time to understand how to make simple glide calculator in Excel and figure out what the underlying messages are on your own, then correlate with the other articles you can read.

One way of making a glide computer be more conservative about arrival heights is to enter a value for bugs.

How conservative you should be setting out on your final glide will depend among other things on how safe the terrain is on the way and how likely you are to find more lift on the way if needed.

I have no problems with the idea of using electronic aids from an early stage, but

Sense check what they tell you
Follow where you are on a paper map in case the electronics let you down
Learn your toys thoroughly when you are not flying
Know your settings, database, polar, safety height etc
Remember the idea of the electronics is to let you spend less time with your head down, not more

On Monday, March 25, 2013 1:26:18 PM UTC-7, Papa3 wrote:
In particular, it showed how marginal low MC glides are and that a fixed "cushion" altitude (arrival above pattern) can be way too little when you're 20 miles out and ludicrously conservative when you're 10 miles out.

This is one of the main point I found many pilots are not aware off. Whenever I bring the subject of the importance of degrading the polar sufficiently by at least 30% (either by using something like MC=4 or high bug factor as someone else mentioned), I often hear about marginal polar degradation (10-20%) and a hefty safety cushion which suppose to compliment the polar degradation, completely missing the above point.
The whole idea of adding safety cushion (margin) is silly IMHO. Most soaring software will turn your waypoint from green to red once you are one feet below your safety cushion, resulting of lack of visual indicator of how much you are below your safety cushion. Instead, I use MC=4 and zero arrival safety cushion (except for terrain clearance). This way I can decide which safety cushion to give based on comfort level (such as known airport with landable fields nearby vs unknown strip)and can monitor by how much my safety cushion increases or decreases.

Ramy