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Old 21st Jul 2018, 20:16
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Flight computer alternative PPL

Hi all,
Doing my first Nav Monday dual, was a while since I done the groundschool on navigation etc, so I’m just practicing myself at home before I meet with instructor, some small navs on the chart. My problem is I get frustrated with the whizz wheel, I don’t mind the wind side but the calculations side is annoying me. I’d like to use just basic math calculations instead. For example working out fuel consumption if I use x at 80nm how much will I use come 100nm. Do any of you just forget about using the flight computer? I know it’s a very good aid but it’s frustrating me.
Any better alternatives, calculations to use instead, jot it down on paper. My fuel one I used above just an example but if their is useful calculations that will aid me for PPL navs what’s the best ? If not I’ll just wait and see how the instructors do it. Thanks
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Old 21st Jul 2018, 21:00
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I learned to use the slderule type for my PPL in 1964. I bought one. After letting my PPL lapse for over 20 years, and becoming familiar with electronic calculators rather than trig and log tables and slide rules, I couldn't be bothered with the nav. sliderule, and passed the exams using my non-programable scientific calculator, which I was familiar with.
Programmable calculators were forbidden.
If you're familiar with trig, use it.
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Old 21st Jul 2018, 22:05
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if I use x at 80nm how much will I use come 100nm.
Simple; X/80 x100 but, fuel is burnt in unit time, not unit distance, which can vary considerably!
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Old 22nd Jul 2018, 11:50
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Certainly any of the calculations may be performed using basic math, and the wind drift/speed can be done with trig and vectors.
But, for calculations, the big advantage to the whiz wheel is that it "automatically" divides (or multiplies) by 60, vastly simplifying the steps needed for time calculations (fuel burn, nm/hr, etc.)
The conversions (pounds per gallon, nm to km, etc.) are simpler, as well, rather than having a list of conversion factors, one simply lines up arrows and reads the answer. Then if you're talking about the usual flight computer, those small windows used for true altitude, true airspeed, and density altitude are way easier than consulting tables of numbers (though, the tiny coarse number scales make it unrealistic to get very precise numbers). Remember, also, part of the elegant simplicity of the E6B is it's ease of use one-handed while flying in perhaps turbulent air. All that said, in reality, once through the exams as a licensed pilot, your trip calculations, as well as weight and balance, are most likely to be accomplished using one of the many excellent flight planning apps available for tablets or smartphones. But, personally I think use of those apps, or the dedicated electronic E6B calculators, at the student level of flight planning, may leave the student with a lack of understanding the fundamentals of a given problem, even though they may turn out a "correct" answer. IMHO, as a long-time instructor, my recommendation would be, at least through your training, to keep at the old-fashioned whiz wheel till it's easy for you to use.
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Old 22nd Jul 2018, 15:55
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The situation really depends on how good one is with mental arithmetic and basic concepts of geometry and mechanics. A seasoned engineer would do these calculations in his head faster than it takes to set the values on the whiz wheel.
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Old 22nd Jul 2018, 19:11
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A seasoned engineer would do these calculations in his head faster than it takes to set the values on the whiz wheel.
So would a seasoned pilot of course.
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Old 22nd Jul 2018, 21:25
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Thanks for the replies . Yes so I sat down today and done some calculations over and over on the whizz wheel, I finally understand, as they say the penny just dropped. I was way overthinking it and just lack of use where I lost my confidence with it. I sat all exams in February and just totally forgot it.

An instructor today went way over the top on the wind side of the wheel, completely exploded my mind and confused the hell out of me. So now I’m trying to figure this out since today lol.
May someone help maybe on a quick step by step. I watched videos but it wasn’t working for me. For G/S and heading.

Once i I have my wind and speed and TAS and track.
1. Apply wind direction on index.
2. Put in the TAS.
3. Dot down, is wind speed ?
4. From here I got confused, maybe above is wrong too.
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Old 23rd Jul 2018, 20:08
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It's been a while since I taught, or used, the famous whizz wheel. What sometimes helps is not just putting a dot on the grid, but drawing a complete arrow to show the wind vector. It may get easier to see the whole wind triangle that way.
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Old 23rd Jul 2018, 20:54
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The slide rule side is just proportions, so 10 over 20 you will see is the same as 40 over 80 and so forth.
So 95 kts over 60 minutes = 95 miles in 60 minutes or 9.5 miles in 6 minutes.
The numbers can represent anything.
So 5 apples over 10 (say £1) = 10 apples over 20 (£2).

For the wind side i always start by drawing the vector triangle on the chart, you don't really need the whizz wheel.
But then show how to draw the same on the whizz wheel.
Unfortunately there are one or two crap methods which totally confuse students, because some instructors don't understand it themselves.

So on a chart draw a line from A to B say 120 miles long. Your Track.
Then at point B draw a line from wind direction to scale so let 1mm = 1kt. So 25 kts would be 25mm long.
Call the end of the wind line point C.
Now measure out on the rule say 95mm to represent cruise speed of 95 kts.
Now place 95 at point C and rotate rule until it touches line A B and mark as point D.
All done. The angle formed is drift and the distance D to B is groundspeed.

Last edited by BigEndBob; 23rd Jul 2018 at 21:12.
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Old 24th Jul 2018, 12:14
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The nice thing about the whizz wheel is that once you have a ratio set, whether it be fuel consumption or distance / time or whatever, you can make very quick calculations that are accurate enough for practical purposes. That said, although I carry a whizz wheel in my flight bag, I don't think I have ever used it in anger. PPL and CPL navs were all about map reading and following valleys and now for airline stuff I just use a calculator for anything the FMS doesn't already calculate for me. A calculator is more prone to input error though.
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Old 24th Jul 2018, 13:58
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Sporty's Electronic E6B Flight Computer - from Sporty's Pilot Shop
This one is permitted to be used during FAA tests. I had to use the whizz wheel during my PPL examination flight back then. Possibly there are better mobile apps or similar that do the same today?
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Old 24th Jul 2018, 14:04
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Sanity check

Put the forecast wind on your map
It will probably be sort of right. Look out of the window to double check. Windsock, clouds, that sort of thing.
Your effective wind will be somewhere between the two.
Now draw your required track on the map.
You won't drift into wind
You won't go faster with a headwind
Find a few good waypoints along your route.
Do a quick and dirty calculation of TAS and heading, using whatever method you favour. Does it look reasonable bearing in mind the above?
Good. Go flying.
Use your waypoints to correct your heading and etas.
Job done.
PS Buy a fast aeroplane. Smaller drift angle.
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Old 24th Jul 2018, 15:58
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Seanmul89

Your complaining about the mysteries of the back of the whizz wheel not the wind side. Simply to be shown how to operate the wheel, without first ensuring you understand what it is you are doing, is akin to learning a foreign language without being told what the words mean.

Briefly, the earths atmosphere is defined by the International Standard Atmosphere (ISA). For any given altitude ISA determines the density and temperature and provides this throughout the whole Troposphere. All instruments are manufactured according to this standard. Of course, in the real world, the atmosphere is rarely ever the same as ISA. Therefore the pressure instruments will be in error. The atmosphere's temperature for any given altitude has the largest effect on the density. You need therefore to correct the indicated errors of the pressure instruments by calculation. The aircraft flight manual/POH will include graphs or arrays to calculate fuel consumption, climb rates, optimal altitudes and range variables.

You should read up on the atmosphere and understand how this affects flight. Also refer to your text books for the construction and mechanisms of the aircraft pressure instruments. All will become much clearer once you have done this. Not understanding "indicated" and "true" and instrument errors leads to many problems in aircraft handling also but this too is often ignored by instructors.
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Old 28th Jul 2018, 17:04
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Originally Posted by Fl1ingfrog
Seanmul89

Your complaining about the mysteries of the back of the whizz wheel not the wind side. Simply to be shown how to operate the wheel, without first ensuring you understand what it is you are doing, is akin to learning a foreign language without being told what the words mean.

Briefly, the earths atmosphere is defined by the International Standard Atmosphere (ISA). For any given altitude ISA determines the density and temperature and provides this throughout the whole Troposphere. All instruments are manufactured according to this standard. Of course, in the real world, the atmosphere is rarely ever the same as ISA. Therefore the pressure instruments will be in error. The atmosphere's temperature for any given altitude has the largest effect on the density. You need therefore to correct the indicated errors of the pressure instruments by calculation. The aircraft flight manual/POH will include graphs or arrays to calculate fuel consumption, climb rates, optimal altitudes and range variables.

You should read up on the atmosphere and understand how this affects flight. Also refer to your text books for the construction and mechanisms of the aircraft pressure instruments. All will become much clearer once you have done this. Not understanding "indicated" and "true" and instrument errors leads to many problems in aircraft handling also but this too is often ignored by instructors.
Thanks,
I understand ISA, I was just more asking for an alternative to the flight computer but I’ve done more than enough examples for my own sake to understand it and I’m confident with it now. Maybe I asked it in the wrong way. An answer I was looking for I’ve got it sorted and pretty simple, I over complicated it in my question because I wasn’t sure how to ask in text, the instructor over complicated too, but I’m happy now with it. Cheers for the reply.
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Old 29th Jul 2018, 13:53
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Originally Posted by Seanmul89
calculations side is annoying me
It's just a circular slide rule, with some useful constants.

OK, so not everybody used a circular slide rule at school. It's just like a linear one, except you don't have to worry about running off the end, you just automagically keep going round.

OK, so not everybody used a slide rule at school. It's just a way of doing multiplications by adding up logs. Less accurate than using log tables, but a hell of a lot quicker, assuming you don't, as indeed you don't, need the four or five figure accuracy.

Wot, you didn't use log tables in school either?? - what do they teach kids these days!

Use an electronic calculator, phone, computer, wha'ever. It quite likely won't have the magic constants marked on it (fuel density, US gallons per litre, etc) so you'll have to look them up somewhere.
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Old 29th Jul 2018, 17:57
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"Wot, you didn't use log tables in school either?? - what do they teach kids these days"
​​​​​​Ability to calculate has collapsed since navigation stopped using Roman numbers and the abacus, which served Pontius perfectly well.
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Old 30th Jul 2018, 15:28
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Thanks guys, well after a few days using it and sitting with a friend it’s fine. I was overthinking it and just some bad instruction on it which over complicated it.
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