Flight computer and navigation

[coodem]

Guys

Im still on my groundschool stage, just learning/studying for the nav exam. I have managed to get my head around the whizz wheel, It's as hard as I imagined it to be.

It lead me to wonder how many people actually use it to do their day to flying calculations. Seeing as there are so many electronic devices available these days

So how do you guys plot your route, calculate drift?

[High Wing Drifter]

I still do, but then again I am still in the training pipeline. Once I've popped out of the other side I am considering buying something like Navbox. However, once it clicks, it is not an onerous tool. I'l stick my neck out and state that if you make a point of using it for calculations and conversions too, you will find it a very handy device on which, in my opinion, it is harder to produce erroneous results than using a calculator.

However the clockface rule of thumb, although nearly but not quite as accurate, actually is just as effective for working out drift and G/S good enough to nav by. I am trying to find a link on Google for it, but it seems to down?? I'll edit later if somebody doesn't add it.

[FlyingForFun]

It's quite rare now that I need to fly long legs visually outside of the area I know extremely well - but on those rare occassions, yes I do still use the flight computer.

I think I am probably in the minority, but I'm certainly not the only one who still uses it. Once you know how to use it, it is very easy. I also like the fact that it is visual, making it easier for me to spot errors than many digital tools, it doesn't need batteries - and, most important, I already own it, so there's no need for me to spend money on another tool.

FFF
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[DB6]

You will use it maybe once or twice after you get your licence, then it will get put away and never seen again until it appears on ebay ;) . Whilst it is important to be able to understand the principles of VFR nav (which is what the whizzwheel does) it is simply not a sensible or practical piece of everyday equipment. You will do all your nav using VORs or GPS, and/or you will just use the clock code + max drift (do a search) for everyday use. And you can forget all the TAS/IAS calcs and all that stuff unless you are flying a Blackbird and then someone else will do it for you anyway.
That said don't ignore it just yet, you have a test to pass. And if you want to go commercial you'll have to do it all again on the CRP-5 which is even more expensive :eek:.

[nigelisom]

I disagree with DB6, I think it is still a useful and dare I say it an enjoyable tool to use. Yes you will probably end up navigating mostly by GPS/VOR but it is still useful to draw lines on a chart and calculate and fill in a plog as well, for the much greater situational awareness compared with just using goto on the GPS.
I may be perverse, but I also get a measure of enjoyment from planning my flights in advance and a great sense of satisfaction when all the headings and timings that I have calculated work out (maybe I should get out more). Lastly when the electrics all go out (it has happened to me) my plog, stopwatch and chart will still allow me to navigate home!
So I say stick with it and keep practising eventually it will all make sense and it them becomes quick and easy to do the planning.

Nigel

[Jamongris]

I haven't used it much since I passed, but it was something I enjoyed using. I really only use it now to calculte cross winds and occasionally when plotting courses.

In practice I use VORs and GPS as backups but find the stopwatch and wind observation during visual flights the most useful tools. The important thing is to develop a technique you are comfortable with.

Good luck with the exams anyway :ok:

[GroundBound]

Think of the whiz-wheel as a triangle of vectors. Draw a vector triangle, then see how is transposes itself to the whiz-wheel and it should help to understand it.
A. the aircraft position,
B. the end of the TAS and heading vector
C. the resultant position of the a/c.
Vector AB is the TAS and heading,
vector BC is the wind,
vector AC is the groundspeed and track.
Point A is an imaginary point at the bottom of the sliding scale.
Point B you mark yourself depending on your airspeed and heading, by sliding the scale, and turning the wheel to indicate the wind from direction.
Point C is the centre of the whiz-wheel.
If you are using the Wind Up method, then invert the meanings of points B and C. (point B is the centre of the wheel, and point C is the start of the wind vector)
After you have marked point B, draw the wind vector, it makes it all clearer.
Yes, I do use the whiz-wheel, as well as the electronic devices. Its a good fallback, and once you understand it, quick and easy to use.
GB.

[Piltdown Man]

They are very useful devices when you actually "use" a plane. Just for knocking a hole in the sky for an hour or so, they have very little value. But when you regularly travel from one place to another they are invaluable. No batteries, self contained formulae, useful units and conversions. Well worth the effort of learning how to use it.

[Genghis the Engineer]

I use it for drift/speed/planning calcs, but tend very rarely to use the reverse side for conversion calcs - on the whole I'd rather use a normal calculator for that.

G

[Superpilot]

An outdated bag of ****e in my opinion. Should be removed from the syllabus.

[astra]

Agree with superpilot.

Clockface rule of thumb works for me. You can do it in your head and is only a couple of degrees out from the dalton for drift calcs.

Is the wind ever as forcast? Is your HSI/DI accurate to within a couple of degrees? Who said flying was an exact science?

[coodem]

Thanks guys. It seems its all gonna be down to personal taste then. I guess I won't bother spending any money on an electronic device yet. Not until I have passed out and done a few journeys, and see how I feel about it then. So I''ll learn it as well as I can now and worry about making the choice later.

[Mike Cross]

I use NavBox ProPlan but if plans change I'm very happy with the whizzwheel.

I don't find it all difficult to use. As for the back of it, we used logs and slide rules at school so I have no problem understanding it, a minor skill that's all but extinct nowadays.

Mike

[coodem]

Mike What GPS unit do you use with the proplan, Looks really nice. And does not seem that expensive.

Does it plan your altitude to avoid restricted airspace. ie. tells/shows you to fly below/above or even around

[IO540]

The circular slide rule is a relic from WW1. It is taught because we beat the Germans with it (twice actually) so it must be the "proper" way to do flight planning. My grandfather went down the coalmine and my father did too, and YOU will too, my son.... much if aviation is like that, which is great if you don't want too many of the great unwashed coming into it.

Like the signals square, the overhead join, and a load of other cr*p.

It's a complete waste of time. It cannot be used in flight, unless you have a plane with an autopilot, and if you have one of those, as I have, then you will be navigating with more modern methods anyway. Women (who can do two or more things concurrently) might be OK with it :O

The time spent (wasted actually) learning how to use that damned thing would be better spent teaching how to use quick rules of thumb (which are just as accurate, given the typical error in the forecast, but your instructor won't tell you that - even if he knows it), and how to use a GPS. And use a decent flight planning program like Navbox. Come to think of it, Navbox Pro costs only a bit more than the CR&P-1 :O

I've done the FAA IR, and done the FAA PPL before that, and the FAA (which looks after a GA fleet about 10x bigger than the whole of Europe) doesn't require it. Some of the US instructors like it for sure but it isn't a requirement. You can use a PDA running an E6B sort of program if you want.

As for Navbox, no it doesn't provide (useful) vertical navigation, nor is the map quality and information content good enough for CAS or terrain avoidance. In Europe, they would have to increase the price an order of magnitude to pay the mapmakers' license fees (the VFR and IFR charts are free in the USA) so you have to use the printed chart for these things. It's really no big deal. What Navbox gives you is a dead fast plog, wind-corrected if you like, and a simple map to print out.

[Leezyjet]

Have to agree with you IO540.

I don't bother using mine either. Just do quick "back of a fag packet" calculations, and that works just as well.

Sometimes don't even bother doing that !.

:)

[Cricket23]

Few comments on here about rules of thumb, and I just wondered what people's favourites were. Mine are:
1) Distance from tip of thumb to 1st knuckle is 10nm.
2) Tip of thumb to tip of little finger when hand is outstretched is 70nm.
3) Max drift for around 100kts in a spamcan is wind/5 * 3 = max drift (eg wind 15/5*3 = 9 degrees max drift)
4) Use of the clockface to work out how much wind to allow for.
...any others.....?

Having said that I've just bought myself a Garmin 96C and was wondering whether Navbox or something similar would be a smart purchase as well. Any advice?

C23

[IO540]

Max drift = half the wind (100kt) or 1/3 of the wind (150kt). Anything more precise is wasted in the error in the winds aloft forecast.

Navbox Pro is the way to go for European VFR and "UK-style" (i.e. Class G mostly) IFR. You get 28-day updates and these come from the national AIPs, same as the vastly more expensive Jeppesen data (which I have used also). I am not aware of any other flight planning program for Europe which gets proper regular updates, and updates are crucial.

[englishal]

I dunno where mine is anymore, seeing as I haven't used it for 5 years :O I preplan properly on the computer which works out my CoG, SoG, Compass headings and all that stuff, then if I need to change it in the air I use rules of thumb, and GPS to give CoG, SoG, and actual winds......

I tried planning properly for my IR checkride several years ago, filed my flight plan which included a SID, then picked up my clearance and it took me a completely different route anyway......so now I just make sure I'm not going to run out of petrol and off I go. If I need to divert, there is always the Goto button :)

IO, are you now a member of the Elite then (if so, congratulations!) ? Are you back, I'm off over there on Wednesday......
Cheers

[drauk]

You can also try the too-lazy-for-a-whiz-wheel-when-you-can't-afford-navbox-or-don't-have-it-to-hand-or-are-using-a-Mac-or-a-PDA-or-need-to-plan-to-some-obscure-little-town-and-you-want-a-google-overhead-photo-of-it online tool: http://fly.dsc.net

[Whirlybird]

What I use depends on what sort of flying I'm doing. For a local bimble, I'll draw a line on the chart, maybe, and measure it, and that's about it. For something a bit longer, in light winds, I'll draw the line and do an approximate estimate of drift for the wind. If crossing France, with few ground features, I'll still draw my line, but I'll use VORs and GPS. But for a long trip in the UK, I'll use my whizzwheel. Why not? Once you're really in practise, it's as quick or quicker to use this than any of the approximations. It only seems complicated at the beginning. When you're used to it, it's fast, accurate, easy to carry around, doesn't need batteries, and doesn't go wrong. Those who disagree probably never learned to be that comfortable with it in the first place.

[MyData]

I use www.goflying.org to get a plan for my route - it is a free service provided by another PPrNer.

BUT - as all these services have disclaimers about accuracy and reliability I also double check the results with my whizzwheel - it takes literally seconds and as Whirlybird points out it is always there, no batteries, accurate etc.

I too found the whizzwheel quite difficult to get to grips with. Different lines representing different parts of a triangle etc. until an instructor showed me a short cut which I only promised to use once I understood the principles and could use the 'standard' method. ;)

e.g. following the example in Trevor T. Navigation, page 74.
TAS 97, W/V 320/25, TR 295

Take your CRP-1 or other...
1. Set the blue circle over the TAS (97)
2. Turn the inner circle so that 320 (Wind dir) is aligned with INDEX at the top
3. Mark a dot 25 (Wind vel) units BELOW the blue circle. I.e. a dot on the vertical centre line at 72.
4. Turn the inner circle so that 295 (TR) is aligned with INDEX at the top.

Your dot should now be on the 75 speed line, and 8 degrees to the LEFT of the centre line.

5. Move the 295 marker at the top to the LEFT so it is aligned with 8 on the drift scale.

Your dot should now be on the 73 speed line, and about 5.5 degrees LEFT.

6. Move the 295 marker on the inner circle so it is aligned with 5.5 on the LEFT hand drift scale

Your dot should now be on the 74 speed line, and about 6 degrees LEFT.

7. Move the 295 marker on the inner circle so it is aligned with 6 on the LEFT hand drift scale

Your dot should now be on the 74 speed line, and about 6 degrees LEFT.

You have reached your destination, the dot and the drift offset are the same.

8. Read off the heading below the INDEX mark: 301
9. Read off the speed on the speed line: 74

OK. So Trevor T. gets 301 and 73 but I'll allow the 1 knot due to the fatness of the dot on the CRP-1.

Basically - you are making smaller and smaller changes until the the two offset numbers meet. Remember that if the dot moves to the right side initially then work with the RIGHT drift scale. No lines, no triangles, nice and simple.

Using this method a HDG and GS calculation can be made in seconds which is mainly what you will need. Since the exam I've never had to worry about calculating W/V etc. in the air.


Saying all that - I'm now learning to use VORs and GPS much more and I make more use of them in future I guess.

[Andy_RR]

After flying my first nav exercise yesterday, I'd say that using a wizz-wheel is much easier than flying the headings that you've calculated!

Hopefully it will get better (and the viz was really poor, but that's making excuses!)

A

[Mike Cross]

Coodem

I use a Garmin 196. The way I do it is:-

1. Plan the route on the chart to avoid things that are best avoided.
2. Stick the route into ProPlan - it'll remember it so you can use it again in the future.
3. Get the wind off the Met Ofifce site and NOTAM from AIS
4. Stick the wind into ProPlan and print a detailed PLOG
5 Upload the route to the Garmin (if it's not in there already)
6. Print the en-route frequency list from ProPlan
7. Go Fly!

I subscribe to the ProPlan updates.

[Whirlybird]

Hopefully it will get better (and the viz was really poor, but that's making excuses!)

No that's not making excuses. Visual navigation in poor visibility is really, really difficult. I remember not being able to find Sheffield - and I mean the town, not the airfield!!! In good visibility, when you can see for several miles, you fly your headings, the ground beneath you matches the chart, and it's easy and fun. Once the vis is down to 7 or 8km (it doesn't have to be really bad) it's much harder, and you really have to be on the ball to notice if your heading isn't working. That may be because the wind has changed or whatever, not because you're not flying accurately. And then, IMHO, is the time to use VOR and GPS and anything else you've got as a back-up.

[Johnm]

I confess I have no idea where my whizz wheel is. I go with IO540, though I always draw a line on my chart, take my 10nm thumb with me and a stop watch. I also note headings on my PLOG though not usually times since unless I loose all the electrics and the spare handheld GPS I've usually got that readily to hand.

Crude knowledge of the wind, drift angle and speed together with a 10 mile thumb will give you a quick approximation to times on the fly if push comes to shove anyway.

[IO540]

For VFR, I draw a line on the chart too - may as well since already using it for controlled airspace and terrain planning.

Unless one is able to print out sections of the actual VFR chart, showing the route, which is possible (very expensively) with Jeppesen Flitestar ...

"And then, IMHO, is the time to use VOR and GPS and anything else you've got as a back-up."

Better to use the GPS as primary, with anything else you have as a backup. GPS is the best device by far. Otherwise, it's like travelling somewhere, on a bike, with a motorbike on a trailer in case the bike breaks. Aviation tradition says that the bike is the "proper airmanship" way to do it. Outside aviation, nobody would bother to make their life deliberately harder. Of course, these comments make instructors really mad.

[High Wing Drifter]

I'm a bit behind the time on this and referring to IO540's earlier post, I do enjoy reading his various diatribes :D

The usefulness and functionality of a device is not inversely proportional to its longevity, often the opposite! Nobody in their right mind would use a whizz-wheel in the cockpit, it is only a planning tool. Rules of thumb technique are necessary/essential knowlegde and I've never met an instructor who disagrees with this. Rules of thumb augment any navigation method be it VFR, IFR, GPS, RNAV, DR, etc.

My observation is that learning to use a whizz-wheel is really part of the process of ingraining the notion that you need to be vigilent with regards to the various metrics and conversions required in the flight planning process. I would argue that the use of one universally capable metrics tool in the training process helps structure and standardise the corresponding processes, rather than having to use this piece of software for this and that calculator for that, etc.

:8

[wsmempson]

Given that my last post (see "where the .... am I) was a tale about how I got confused about my position I almost hesitate to comment here, but here goes. I think that the whizz-wheel is a good tool for pre-flight planning if you are still pursuing the 'steam-driven' approach and also a good device for helping to teach the principles of navigation. I still do my pre-flight planning using one and, as long as the wind forecasts are reasonably accurate, is an enjoyable and satisfying process.

Arguably, one of the reasons I found my self in the ordure was that I hadn't done any planning and simply relied on my knowledge of an area I know well.

However, I seriously doubt that I could use a CRP-1 in the air with any degree of confidence - too much like riding a uni-cycle, blindfolded, around the rim of the pit of doom whilst reciting one's times tables.

[FlyingForFun]

Whirlybird said:Once the vis is down to 7 or 8km (it doesn't have to be really bad) it's much harder, and you really have to be on the ball to notice if your heading isn't working. That may be because the wind has changed or whatever, not because you're not flying accurately. And then, IMHO, is the time to use VOR and GPS and anything else you've got as a back-upAll very true. It's not impossible to fly visually in very poor viz (even down to 3km or less), but the whiz wheel and traditional ded-reckoning techniques are definitely not the way to go. In this kind of viz, use line features - the bigger the better. Follow the line features until you reach good position fixes on those line features, e.g. follow a motorway until it reaches the town, then follow the edge of the town to the destination airport.

If you're starting somewhere other than a line feature, then find a line feature to follow, and fly to it - but fly to one side of your first position fix. E.g. fly to the south of your position fix, then turn north to follow your line feature - that way you know that your first position fix will be in the direction you are going.

Definitely not the kind of navigation for student pilots or low-hours pilots to be attempting un-aided, but certainly not impossible, and (like a lot of difficult things) very rewarding when it goes right! And if the weather is that bad, you'll probably be using up some of your capacity simply keeping the aircraft the right way up and maintaining VMC, too.....

Alternatively, follow Whirly's suggestion and use any nav-aids available!

FFF
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[boomerangben]

The Whizwheel is a good tool you would be surprised how many commercial pilots use them. Until recently many North Sea helicopter flights were planned using the whizwheel and they are still used for fuel planning long range SAR sorties.

[S-Works]

biggest pile of pap going and more prone to errors than an ADF on a stormy night........

Managed to fly 1500hrs without one and the to do the JAR IR had to learn to use a VFR flight tool again. Still hate it and if I passed the last exams really will throw it in the bin or put iton eBay this time.

ASA Electronic calculator for me and guess what you can actually use that one in the air assuming that I had a total electric failure and the backup batteries on the GNS430 and the 296 both failed........ Of ocurse of the batteries went flat on the ASA as well, I really would be having a bad day.....