Whizz Wheel CRP1

[night hawk 150]

Hi its me again

Can anyone shed any light on some website that explaines the use of the whizz wheel or if anyone has any information they can e-mail me that too would be good.

I am starting to use the whizz wheel and would like to get a bit more knowledge before lessons and ground school.

Thanks in advacne
Craig

[Whirlygig]

I found it so much easier to have someone sit down with me and SHOW me how to use it. Can you try to arrange a one-to-one with an instructor?

Cheers

Whirls

[EGTC]

I learned using the Trevor Thom Navigation book. Along with preparing you for the Nav exam, it gives good detailed tutorials on how to use both sides of the Wizz Wheel.

[night hawk 150]

thank you for your answers gentlemen i have just e-mailed the club as they get a discount on this sort of thing and have ordered the Thom book and naviagation computer CD Rom.

Craig

[FingersR]

Hi Craig,

Im in the same situiation as you. I have just got the Oxford Aviation Whizz Wheel CBT and its great!!!

Cheers

Ben

[night hawk 150]

thanks fingers (nice name)

i look forward to when i get mine

Craig

[TheOddOne]

Craig,

Just a personal thing, but I found learning the CRP1 (and later, the CRP5) much easier than reading Thom! Some people get on with his books, but I was brought up on Birch & Bramson, which was much more practical and down-to-earth. Thom, I find, is a bit impenetrable and dry in style, though no doubt very thorough and accurate.

If you can, get someone, doesn't have to be an instructor, to go through the CRP 1 with you (so long as they get it right, of course!) I found that much the best way of getting my head around what is arguably the hardest part of learning to fly (apart from paying for it all!)

Oh, and do insist on learning the 'wind down' method. See another thread on this subject.

Cheers,
The Odd One

[soay]

Oh, and do insist on learning the 'wind down' method. See another thread on this subject.
If this (http://www.pprune.org/forums/showthread.php?s=&threadid=188043&highlight=wind+down+method) is the thread you were referring to, it was inconclusive about which method was "correct". However, there's no doubt that the wind up method is easier to use and comprehend - especially if you get a CRP with a wind arm.

[foxmoth]

Just remember where everything goes and put what you have in the right place - don't know if it works for wind up because I have never used it that way.
Start with the wind if you have it - wind direction at the top, wind speed below the center dot and mark with a cross or other indication.
TAS under the center dot, heading at the top (where it says "True Heading"!). You now have your drift & GS under the wind cross and can read track off under the same drift angle at the top of the computer.
Of course you often do not have the heading to put at the top in which case you put a guestimated or approximate heading at the top (many people start with their track) and just keep adjusting it until the drift at the top (under your track), and that under the wind arrow, match.
If you learn it like this and just put in the elements you have, you can solve almost any wizz wheel problem that has 4 elements given.

[BigEndBob]

Why is the use of the crp made so complicated.

Set wind dir at top.
Draw line down to ctr. dot from above=wind speed (3 headed arrow toward dot).
Set track at top.
Place the tail end of wind arrow on TAS arc.

Read off drift (tail end of wind arrow) and apply correct sense.
Read off ground speed under ctr. dot.

To find w/v from TMG and groundspeed some of the above have to be reversed..think about it.

[HGFC1]

Try this from Jim Nich which he posted a couple of years ago in this forum.

posted 20th June 2003 06:48
--------------------------------------------------------------------------------

Pinks,

here is my whizz wheel ditty, it was written quite a few years ago for someone who had never seen one before so I'm sorry if I am teaching you to suck eggs. I had it saved ti disk and have just cut it and am now trying to paste it so I hope it works.

Enjoy

The Whizz Wheel

Okay, the first thing to remember is that all of the calculations done on this infernal machine for VFR Nav are APPROXIMATIONS! The wind you will use for planning can (and will) be very different from the wind you will actually experience once airborne. So, don’t get too hung up on it. Don’t spend years trying to get an incredibly accurate plog when the ambient conditions will only make a complete nonsense of it.

Secondly, remember that the wind you are using to plan with (generally from the spot wind chart, met form 215, we will use 240/24 for our demo) will be orientated to TRUE North. This North represents the point around which the Earth rotates whilst your aircraft compass points to Magnetic North. These two Norths are not co-located and depending on where you are in the world the difference will vary in amount (variation). Suffice to say that in our part of the UK we generally use 6 degrees of variation and always ADD it to a true heading (explained later) to get a heading on which we can fly (Heading Magnetic).

Now, look at your map. It is overlain with a grid which is oriented to True North. So, any angles that are measured will be in Degrees TRUE. Right, first things first. Draw a line on your map joining two points you wish to fly between. Now take your protractor and lining up the North on your protractor with the Map North, ensure the centre point of your protractor is somewhere on the line you have drawn, usually at your start point. Where your line passes through the outer edge of your protractor is the angle of your drawn line in degrees TRUE. If you were to point the aeroplane in this direction in would be a TRUE HEADING.

Let’s say that the reading you got was 335 degrees. This means that the track you wish to travel along the map is 335 degrees true! (this is your track true). You can write this figure in your plog. Next you can measure the distance. Make sure you are using the correct scale (this is the most common error with students) as your ruler may have two or three different scales. Lets also assume that you found the distance to be 48 nautical miles (a nautical mile is longer than a statute mile but I can’t be @rsed to explain the difference, it just is okay!). You can also put this down on your plog.

Now the fun begins because we now have to account for the wind (because just like a boat in the water the wind will try to blow us in the direction it is travelling) and to help us do this we have the whizz wheel (CRP 1 or 5). So, here are some steps to help us.

1. First mark the wind on. This is the side with the big round window in the middle. Simply rotate the inner wheel until the wind direction under the arrow at the top (in our case 240).
2. Put the little blue circle in the middle of the window on 90 which should be on a rectangular card which should slot through the middle of your whiz wheel (we use this as our true airspeed………….because we can) then count down from 90 the wind speed and put a little dot with a felt tip pen on the figure (our wind speed was 24 so a little dot on 66 would be correct).
3. Next, rotate the inner wheel until your track (the angle from your map) is under the arrow. You will now see that your little dot has moved.
4. The dot tells us we have 15 degrees of starboard (right) drift. This means if we did nothing and just pointed the aeroplane 335 degrees we would actually be pushed by the wind 15 degrees to the right, we would TRACK (our path over the ground) 350 degrees. Clearly this is undesirable so we have to change heading in order to offset this wind and maintain our track of 335.
5. Now comes the clever bit. Because we have right (starboard) drift we must turn to port (left) so therefore our numbers will decrease (any turn to the left numbers get smaller, to the right, numbers get bigger). The question is, by how much.
6. Initially rotate the inner wheel by the amount of drift you have (in this case 15 degrees left to 320). The dot has moved almost to the 16 degree line so now move the wheel another degree to 319.
7. You now have the situation where your drift is 16 degrees and your change of heading is 16 degree, the two match up. Ensure you do this for every drift calculation. It will only be correct when your change of heading from the original track and the new drift angle agree. You may have to jiggle it a bit but it will be close enough.
8. So, you now have a TRUE heading which if you point your aeroplane it will TRACK 335 across the ground. You also have a groundspeed (the curved line that your dot is now closest to) in our case 89 knots.
9. As already said, we cannot fly true headings in our aircraft so this is where you add your variation (6 degrees) to come up with a MAGNETIC heading of 325 degrees. Fly this and with that wind you will track 335 degrees true across the ground.
10. flip your whiz wheel over, put the big black arrow on the inner scale against 89 on the outer, then go to 48 (our distance) on the outer scale and read the time it is going to take on the inner scale (32 and a bit minutes).

All that is left now is to enter all this information onto your plog and go and fly it (but that’s another story).

[Pronto]

S~C150~I

When I was learning to fly - many years ago - I was shown a very simple method of using the CRP1 by an ex-RAF Meteor pilot. This wasn't the way that was in the handbook (which came with the computer) but it works and works well enough for me.

A few years ago, a friend who was learning to fly in foreign climes emailed to say he was having problems with the computer. I put together a quick guide - with digital photos - and emailed it back. Problem over!

I probably still have the guide but - due to the photos, it isn't small. So, if you have broadband (or don't mind a long d/l) PM me with your email and I'll send it to you.

Regards

P

[IO540]

When one starts flying for real (i.e. using a GPS for primary navigation) one never looks at the silly slide rule again.

They can't be used in-flight (unless one has an autopilot and if one has one of those....) and down on the ground the accuracy is limited by the accuracy of the forecast wind aloft. The errors in that, factored into the wind triangle calculation, are typically greater that any human could hold a heading for for any length of time.

And if you forget to restart the stopwatch, you are stuffed.

If aviation was invented today we would never waste time on these silly ex-WW1 gadgets.

What keeps this stuff going is tradition, tradition, tradition, the clapped out planes people have to train in, and tradition. Oh and I forgot to mention resistance to change :O

p.s. forgot to mention one more: the CAA is run by a bunch of ex RAF navigators who love this stuff.

[bletchleytugie]

Quote

"When one starts flying for real (i.e. using a GPS for primary navigation) one never looks at the silly slide rule again."

One would hope that one looks out the window and practices good airmanship ratherthan watching the numbers change.

As one of Mrs Thatchers incomprehensives who was taught to navigate by the ex RAF Navigators at the CAA, I bet my pre planning leaves me in a better position to formulate a plan when it starts going pear shaped rather than trusting too a fading screen and some dodgy software.

Discuss

[BigEndBob]

Why not just draw out triangle of velocities on map and save 50-70 quid or how much crp costs these days.
This is how i ususally start to explain whats going on to student.

[IO540]

That's right, and equally to the point, the simple rules of thumb for the wind correction (say, max drift is half of the crosswind, good enough for anywhere near 100kt) yield as accurate a heading as any more apparently precise method.

[PAPI-74]

I am doing my ATPL and have got a copy of the CATS (Cranfield Aviation Training Schoool) CRP-5 video. It will cover what you need for the CRP-1 and some. Look them up and e-mail them. You may get through Pilot Warehouse. Well recommended.;)

The problem with the cheap GPS is you won\'t always know if it is working on a good enough RAIM (Rx Autonomous Integrity Monitoring), meaning your equipment may not have the brain power to detect a failed source within the see satellites. This will put you miles off track and you would never know. Never, ever rely on it.
The performance required must detect and allert you to errors. You may think, "so what?" but mountains and Airliners on a SID in a TMA will bite.
My advise is train well and don\'t let bad, sloppy short cuts be the way you fly. CFIT and Weather are still the bigest killers and as for poor planning.....:(

[IO540]

PAPI, you may be doing an ATPL course but have you actually done any flying yet, without (and particularly WITH) a GPS?

Do you know what RAIM actually does?

[Droopystop]

IO540,

I am not sure that extolling the virtues of GPS is appropriate here. The PPL system does not allow for GPS at the moment. Whether that is right or wrong is another thread. There is no doubt in my mind that use of the CRP ensures a rigourous method of flight planning, which I think we all agree is of utmost importance. To do the same on a GPS requires that it is a) hand held ie can be taken into the flight planning room, b) has some form of moving map function so that plans can be gross error checked and c) unless it contains an upto date ICAO chart, you still need a paper chart and a line. Of course these things are available, but at a price which not everyone is prepared to pay. So please don't discourage newbies with the perception that high technology is the way to go when the PPL course doesn't allow for it and it is not absolutely necessary.

Student in Ipswich,

There are many out there who still use the CRP and that includes professional aviators, including North Sea and SAR helicopter pilots. In practiced hands they are not significantly slower than electronics. In some respects CRPs are better because it is easier to pick up mistakes. On the other hand, GPS can be more accurate and provide more information. Whether the increased accuracy and information is necessary is debatable. Learn it, try to enjoy the experience - the circular slide rule is a truely amazing bit of kit. If once you get a PPL, you decide to get a GPS by all means get one, they are definitely useful tools. But remember to use it in the same way as a CRP. In other words do all your flight planning on the ground first, set the route up before getting into the aircraft (or at least before you start up in the case of a fixed set) and don't get distracted by it once airbourne.

Good luck and happy flying

[Paris Dakar]

Student~C150~Ipswich,

I got a little booklet with my whizz wheel - and it might as well have been written in Martian scrawl for the use it was.

The ww does look complicated when you first see it but (as has been said before in the thread) if you can sit down with someone who can give you a guided tour, you will soon realise that it's a really remarkable bit of kit.

As for "When one starts flying for real (i.e. using a GPS for primary navigation) one never looks at the silly slide rule again" I can't really agree with that. I sat a mini GFT earlier this year (long lay-off from flying), and the examiner requested a demonstration of how I used my ww to work out my calculations.

PD

[HGFC1]

Something to bear in mind (http://www.pprune.org/forums/showthread.php?s=&postid=2120908#post2120908) for those who dislike, don't understand the Whizz Wheel or are too lazy to bother and just rely on gps.

[IO540]

retired RAF Air Commodore and president of the Royal Institute of Navigation, said the GPS signal is more fragile than many users might suppose. "Too many people don't understand its foibles and vulnerabilities," he added.

One must listen to a "retired Air Commodore", of course :O

Any single system can fail, so a backup for a GPS is dead reckoning, or (much better) tracking a VOR.

So, what is supposed to be a backup for DR? 121.50? That is another thread....

Better to start with a 99.99% reliable method (GPS), and have a backup plan, than to start with a 90% reliable method (DR) and have no backup plan (which is what a PPL is taught).