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C152Student 2nd Dec 2009 19:58

Navigation Exam
 
Hello Chaps,

Its my first post on this site because I seek information which I have not been able to find via search.

I have almost completed my flight training but have at this time only completed my R/T and Air Law exams.

I am preparing for my Navigation exam but I keeping having mental blocks, especially with the whizzy wheel.

I had committed to memory how to work out my track based on w/v and its resultant drift, then I open up the Confuser, to find that the first question flips that on its head and asks me to find the W/V.

I then learn how to do this, but then the first way is gone. This computer and my brain are completely incompatible.

Can anyone recommend a way to learn how to fully use and understand this, surely others must have faced the same problem.

Thanks in advance to anyone who replies :-)

Piper.Classique 2nd Dec 2009 20:11

As long as you get the answer right you don't have to use the whizz wheel. Try drawing the triangle of velocities on paper, or on a photocopy of the map you use. That way you can see what you are doing, rather than leaning by rote.

Aytonace 2nd Dec 2009 20:21

Hi

I did some practice ones using graph paper as well as using the computer. Its much easier doing it that way and then you can visualise it in your mind. Not sure what books you are using but I use the Jeremy Pratt books which shows you different ways of working it out. I find the Pratt books really good this way as he always gives you that little bit extra knowledge for each section of navigation.

Good luck with your nav exam - got mine coming up soon! Have you done your qualifying cross-country yet?

C152Student 2nd Dec 2009 21:05

Not done x-country yet, nor any nav solo - My instructor wants me to pass the nav exam first before I get into that, although he did make mention of allowing me to fly in and out of the zone solo as I am very familiar with the area.

I have the trevor thom books; but being honest. The Nav book is one that I can only read for a minute or two before throwing it down in blind rage because i simply cannot grasp nor understand what it is talking about.

The real confusing issue is, give me a chart, the winds, and a whiz wheel and I can work out my route, fairly accuratley and fly it as planned.

What gets me with the confuser is that it is asking me to work out elements that I would normally have provided, such as the Wind, and for some reason this throws my mind off.

I know that once this knowledge "clicks" I will have no problem, but my mind is like an old engine, it takes a while to fire.

Can anyone actually recommend any DVD/CD/Video based productions that might help me through this more.

Thanks in advance.

gasax 2nd Dec 2009 22:02

Young people!

The whizz wheel is a shorthand for the 'velocity of triangles' - look it up and try to sort out a method whihc makes snese to you.

A bit of searching on here will give you the 'wind up' and 'wind down' methods on the wheel. The critical element is it that the wheel is a visualisation of the triangle, 'get' the triangle and everything else is easy. Learning the answers in 'modern education', learn the underlying theory and you have it cracked.!!!!!

Gertrude the Wombat 2nd Dec 2009 22:19

Quote:

the first question flips that on its head and asks me to find the W/V
This I'm afraid is one of those completely stupid questions that have no bearing on anything you will ever do once you've passed the exam, like the one in Air Law that asks you what colour paper the Diet of Worms was printed on. Or the one where you're expected to remember whether some visibility limit is 1500m or 1800m (real life answer: "who cares, if the vis is less than 5km I'm staying on the ground anyway").

Yes in theory you could fly a heading, and work out from the map (or, more likely, the GPS) what your actual track and groundspeed are, and then get out the whizz wheel and calculate the wind velocity, but nobody does that - why would anyone want to?? Anyway nobody uses the whizz wheel in flight, not even those who use it for flight planning on the ground.

Besides ... my whizz wheel comes with a little booklet with worked examples of each type of problem - you'd use the booklet in real life, wouldn't you, nobody ever told me not to use it in the exam.

AlphaMale 2nd Dec 2009 23:35

Quote:

I am preparing for my Navigation exam but I keeping having mental blocks, especially with the whizzy wheel.
You're not the only one.

I've done my X-Country and currently just short of 37hrs. I can plan any route the normal way i.e. knowing the wind etc but like you my mind stutters when I am asked about other elements. The worst thing for me is that I'll revise for 3 evenings one after the other with a goal of sitting the exam on the 4th day (usually a weekend) but due to the weather the school has been closed causing a delay, by the time I get a clear day my confidence is low and I need to go back to the drawing board.

I'd like to get the Nav exam out of the way soon, I'll probably have to book a day off work next week if I can't sit it this weekend.

A.Agincourt 2nd Dec 2009 23:36

The not so palatable answer to your question is simply that you have to understand the mathematics. The 'Whiz Wheel' is nothing other than a basic table of relational values and it is intended as an 'aid memoir' and to save you the working out on paper, the mathematical solution. A circular slide rule.

If you do not understand the basic mathematical concept then the 'Whiz Wheel' is of no use to you. Sorry if that sounds hard and I realise that I am not offering you a simple solution, which is probably what you wanted but trust me here - learn the pure mathematical concept and then you will discover not only the answer to your dilemma but also in the process, an ability to do most of what you need to acceptable tolerances, in you head will become reality.

Best Wishes

BackPacker 3rd Dec 2009 07:48

What you will probably find is that if you are given a "straight forward" question (you are given the true track and TAS, and W/V, need to calculate true heading and GS), you need the whizz wheel since the possible multiple choice answers are very close together. Two degrees error in the calculation and you've got the wrong answer.

But if you have one of those "backward" questions (need to calculate the W/V from in-flight data) the possible answers are so far apart that you can just reason yourself to the correct choice, without breaking out the whizz wheel at all. And it's that reasoning they want to test, not a backwards way of using the wheel.

Something along the lines of "you want to travel due North. TAS is 100 knots. You find that you have to steer 353 degrees, and your GS is 89 knots. Calculate the wind velocity.
a. 45/15
b. 135/15
c. 225/15
d. 315/15"

Question like this, don't look at the actual numbers but look at their relation. TAS is 100, GS is 89? Must be a headwind. Scrap answers b and c. Heading is 353 while track is 0? Must be due to a wind from the left. Scrap answer a. So answer d is right.

So the first thing you need to recognise is when NOT to use the whizz wheel.
Quote:

Young people!

The whizz wheel is a shorthand for the 'velocity of triangles'
Old people!

It's actually a 'triangle of velocities'. You'll get far more results if you google for that.:ok:

C152Student 3rd Dec 2009 08:12

BackPacker,

Thank You! for that simple explaination, I just tried it on the confuser and the answer was obvious, I was becomming fixated on using the wheel to do a calculation that did not require it.

I am so glad I asked this question :-)

1800ed 3rd Dec 2009 09:14

I found the Nav exam to be a bit frustrating. The answers require you to be very accurate with your calculations, and if you have a bit of a cheap 'whiz wheel' then you might have problems. I borrowed an 'ATPL style' whiz wheel for the exam because it helped accuracy. In real life however, mine works perfectly well with its 2 degree resolution; seeing as the aircraft I fly has a DI with a resolution of 5 degrees.

Aytonace 3rd Dec 2009 09:57

Quote:

Quote:
Young people!

The whizz wheel is a shorthand for the 'velocity of triangles'
Old people!

It's actually a 'triangle of velocities'. You'll get far more results if you google for that.http://images.ibsrv.net/ibsrv/res/sr...ies/thumbs.gif
Brilliant - you beat me to it :)

C152Student 3rd Dec 2009 10:03

The flight computer i purchased is the Pooleys CRP-5 (Pooleys - CRP-5 Computer)

Is this a poor quality one?

C152Student 3rd Dec 2009 13:35

Thanks for the advice, I shall follow it confident that I am now thanks to previous advice able to work out the wind regardless, the skill will no doubt become useful when in the air to work out the true uppers.

I assume I use the wind(dot) down method, when selecting the wind I normally place the card / dot and 100knots and mark on my wind speed, so if its 15 I will mark 85 knots, so this is the opposite method to what you would recommend?

Cusco 3rd Dec 2009 13:54

Quote:

The flight computer i purchased is the Pooleys CRP-5 (Pooleys - CRP-5 Computer)

Is this a poor quality one?
The CRP 5 is a very good quality computer: My only thought is that for PPL study is a bit 'over the top'

Fine if you're going on to do commercial but it deals with higher speeds etc than you'll meet for PPL.

If you're only doing PPL take comfort in the fact that as soon as you pass the test, you'll never use it again and can flog it and put the money towards a small dedicated electronic flight calculator.

Job done.

Cusco

C152Student 3rd Dec 2009 14:25

Yes, I do plan on going electric, unfortunatley for the test I must use this old fashioned and innacurate technology.

I seem to be getting to grips with it, but looking foward to getting rid of it at the same time.

Gertrude the Wombat 3rd Dec 2009 20:13

Quote:

Two degrees error in the calculation and you've got the wrong answer.
Which is bollocks of course as you can't fly that accurately anyway.

I got one of those "wrong" in the IMCR written exam - what I measured came out exactly half way between two of the multiple choice answers, and I picked one at random, and got the wrong one.

Real life question: if I'd flown that route according to my plan would I have hit anything or infringed controlled airspace? No, so that should have been counted as a correct answer.

BackPacker 3rd Dec 2009 23:10

Quote:

I got one of those "wrong" in the IMCR written exam - what I measured came out exactly half way between two of the multiple choice answers, and I picked one at random, and got the wrong one.
Same for me on the PPL nav exam. Measured the true track between two aerodromes, found an answer that was right in the middle between the two most likely multiple choice answers.

Evidently I guessed right though.

boomerangben 4th Dec 2009 18:40

Quote:

Yes, I do plan on going electric, unfortunatley for the test I must use this old fashioned and innacurate technology.
As a member of the crew that did the longest range civvy SAR job which was planned using a whiz wheel, I can confirm that they are more than accurate enough.

I still fly with one in the pocket, gets used from time to time and even used it to work out the wind. But don't fret, most of the time the GPS works out the wind and to be honest one only needs to know the actual wind if one is flying over water for extended periods on minimum fuel.

The whizz wheel is a bit of a bone on contention and of course there is a miriad of alternatives once you get your ppl. But stick with it. There is something extremely satisfying planning (and indeed navigating) the old fashioned way - it works surprisingly well. Yes a computer and gps makes things easier, but somehow achieving something that the grey/black boxes told you that you can do is somehow less fulfilling.

C152Student 4th Dec 2009 18:43

I understand your point, and as I become more comfortable with the contraption I find myself using it more, it will likley be kept in my flight bag and I will use a PC based flight planning software at home for pre planning my routes.

Given the amount of effort it is taking to learn these skills it would be a shame to loose it after I have obtained the licence.


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