CRP-1 Computer

[biffo28]

Hi all,
Just started my navigation theory for the PPL and its my understanding that a "slide rule" type computer such as the CRP-1 must be used for a number of calculations.

I have an I phone "app" that gives the same answers as the crp-1 and is a lot easier to use (admittedly I am not very experienced with the CRP-1). I guess that there are a number of other "bespoke" digital devices available too.

Was wondering what experienced PPs use? i.e. Are pilots moving away from the old slide rule type machine in favour of electronic calculators? And if they are, why are the training protocols sticking with the old slide rule approach?

Cheers,

Biffo

[JOE-FBS]

I think I am correct in saying that only a circular slde rule, of which the CRP1 is one type, is allowed for the nav' calc's in the PPL and IMCR exam's. You can take an electronic calculator into the exam's but not a programmable one so that's going to preclude your app'. The Whizz Wheel is a fine thing and not terribly difficult once you know how to use it. I know lots of people drop them the minute they have passed the exam's but it appeals to me being simple, sufficently accurate and not needing batteries. It also requires that you have an idea what the answer should be before you do the calculation which acts as an error check.

PS you will find plenty of threads here and on the other place telling you both that the WW is rubbish which no sane person will use one in real life and the complete opposite. You'll get the same sort of very polarised arguments when you first mention GPS as well!

[nick ritter]

Biffo,

Good luck with your navigation exam and ppl training

I am certain that you will receive a number of views on this and ultimately it is for you to decide what suits you best

Personally, I used the whiz wheel thing when planning my navigation routes during my ppl training, as my instructor would not let me use my Iphone even though applications like flight plan reduce the work load hugely. I would however check the results that I obtained through the whiz wheel against the I phone to ensure that for future use I was actually doing everything correctly

For the actual exam, you need to talk to your instructor in advance. I am sure that there are certain rules and regulations on this, but most of these guys are reasonable people and if you are up front with them and express an interest to use an I phone during the exam to help save time with these calculations you may be surprised with what they come back with. If you don’t ask, you will never get, that is for sure

As for my flying currently, I use my I phone to get the basic weather (Aero weather application is free and fantastic for this) and I use the flight plan for a number of the conversions and any calculations etc

Although to be honest even this isn’t necessary once you start planning with software like Sky Demon (which does 99pc of all this for you as far as I can tell)

The only time I used the whiz wheel was when I needed to plot a route during my written IMC exam just before Christmas and I had nothing to measure the track of my route, so I ripped the front dial off my CRP computer and used that. Without it I would have been ruined. So don’t throw it in the bin too early is all I will say

Good luck which ever direction you go

Nick

[PompeyPaul]

I didn't think you could take an electronic calculator in with you ? I thought it was all slide rule. It would make sense if you could take a calculator, because the slide rule doesn't have the resolution required to do some of the long division required (awaiting correction from some old timer) and so has to be done by hand (a nostalgic trip down memory lane to the long division of school days).

I used my slide rule for the first year after qualifying, then moved to a flight calculator on iPhone and now have moved onto computer software.

My own personal advice, which is no more than opinion, is that I'd rather be able to go in doing the exam purely with a slide rule, just in case you find the calculator is taken off you before you attempt the exam.

Certainly if you were allowed a calculator it would explain why I finished my nav exam with like 2 mins remaining, where as all the other exams I had around half the exam time remaining when finished.

[The Flying Chicken]

I still enjoy using my flight computer. I used to struggle, but I can generally out-calculate someone on a calculator. Also, it's easier to recognized "input crud, output crud", as the figures are there in front of you.
For tests such as the navigation, you will need it. A simple scientific calculator is always useful too, especially when working out moment arms.

Anyway, back to topic. I find most people ditch their CRP or ARC after they pass, and they seem to do fine.

[soay]

You'll need a CRP-1 type sliderule for your exams, but get one with a wind arm (http://www.pooleys.com/prod_detail.cfm?product_id=566&PageNum_rs_product=1&product_category_id=0&product_sub_category_id=0). They are much easier to use.

[24Carrot]

Conduct of the CAA PPL exams is described here: http://www.caa.co.uk/docs/33/srg_lts_StdsDoc11_v9.pdf

The relevant sections for calculators are:

2.7.9 NEVER allow the use of programmable electronic calculators (this includes those calculators that contain Flight Calculation software).

2.7.15 NEVER permit applicants to take a mobile phone or other electronic device (apart from a permitted calculator) into the examination room.

"Non-programmable" still allows quite a decent calculator. I recently took some CAA exams at Gatwick, and the "standard A-level" calculator fx-83GT did not trouble the CAA invigilator.

[Slopey]

if you are up front with them and express an interest to use an I phone during the exam to help save time with these calculations you may be surprised with what they come back with.

That's an easy one - the reply you'll get is - NO!

[IO540]

The silly slide rule is required for the exams. You have to learn to use it, end of story.

Very few pilots who fly to places for real use it. Most use programs on a laptop or similar, where you drag/drop the route and it knocks out the plog.

I used mine only in the PPL and iMCR exams - never again. Gave it to somebody, I think...

[peregrineh]

US navy pilot Dalton invented the WW (E6B) and I believe he was a genius in his time with the 'computer' being one of the most significant developments in aviation in the last century. However I think that is where it belongs - ever since the US opened up GPS to the world after the first Iraq war, navigation was always heading in a different direction. Whilst I think it is important to be able to read a map and track a course whilst flying and hence learning the basics of navigation, it is now time to go with technology. I thnk it is irresponsible of the CAA not to have any GPS training in the PPL - nick ritter (posted above) and I passed our PPL at roughly similar times and both spent mcuh effort trying to learn and programme mobile GPSs - being the way naivigation is going I really think this should be in the course.

As per apps - I know plenty who have used some of the very helpful apps over the WW in the exams but I think you need an understanding examiner, as the CAA is very clear they are not allowed, I would not advertise the fact if you use them. But they are certainly more relevant. Speaking form my own experience - I have not used the WW since the navigation exam and would have no idea how it worked any more, slightly worrying considering I am going to start reading for the IMC..... My advice would be use the iphone and find a friendly examiner - it might be bending the rules but long term a lot more practical for you.

[24Carrot]

biffo28, I expect you will also start flying Nav exercises soon, and I am sure you will be 'encouraged' to draw lines on the chart, one for each leg. Once you have gone to that trouble anyway, you may find a "wind protractor" is faster than anything when it comes to calculating wind corrected headings and ground speed for that detailed plog the FIs and examiners like to see.:ok:

[mikehallam]

IM(notso)HO.

One really needs to master spatial knowledge of the triangles of wind speed, track and the two norths (M & True), so if in flight one day all else fails, you still have your head & can visualise the needed triangles & navigate by dead reckoning !

Learning the basic CRP-1 is easy and the exam demonstrates this straightforward ability. What you do later is your business, but for 40 years mine still lives in my flight bag instantly ready to do service [without requiring i/p signal or batteries].

mikehallam

[mixsfour]

Still using my CRP-1 a year after passing the exam and skills test - perhaps the novelty is yet to wear off! But then I'm old enough to have used a slide rule in my A level exams!

[nick ritter]

It is an interesting question and one that i am sure will split opinions

Many on this forum ask for advice on their PPL exams and the often given reply is to buy the PPL confuser

*I would say that this book is as close to cheating as you can legitimately get

I bought it and passed all my exams after going over the questions 3 or 4 times each and thanked my lucky stars that a cheat sheet like this was so openly available, if only one existed for that A level history exam I wondered?

The vast majority can pass the exams without any real under standing as to why if they just gave this 20 pound book a quick once over on the way into work every morning for a week. No real effort needs to go into it, the confuser will sort you out. A Fantastic quick result for some, terrible in the eyes of others

Now, there is no question, an iPhone app that will do say all the calculations for your wind star in 5 seconds, is a very useful and practical tool to have in the real world. Is it cheating? For you exam, Yes, by the letter of the law it is. But IMHO no more so than the confessor, in fact less so I would say

The same applies in the real world. No one in finance sits down an writes out the Black Scholes model to price every option. Once you are aware of how certain inputs and their change will impact others, the F9 key will do the hard work for you, in less than a second

Now of course you will get hundreds saying, it is precisely because you have no idea how to price these things that the world of finance is in such a mess. And perhaps they have a point

There can be no true substitute for education and actually knowing your stuff, especially if you want to be serious about your hobby or trade or passion or whatever it is

It is for this reason that I fully respect others wishes to use the WW, but personally, it isn't for me



*

[Johnm]

The WW is needed for exams, but for VFR flying it's the equivalent of doing arithmetic to two decimal places on data plus or minus 20%.

For IFR you can't do a lot without cockpit electronics

In either case over short distances the clock rule of thumb and the 1:60 rule are a good enough approximation for most things in my experience, but only if all the GPS, VOR and DME kit expires.

[The500man]

What is the CAA action in such an instance?


Probably nothing unless they can charge you for it.

From my perspective the whizz wheel is sufficient for the job so why waste money on tech that does the same job? You have to buy a CRP-1 for the exams anyway.

[PompeyPaul]

Learning the basic CRP-1 is easy and the exam demonstrates this straightforward ability. What you do later is your business, but for 40 years mine still lives in my flight bag instantly ready to do service [without requiring i/p signal or batteries].
This is an interesting point, and I still have my WW with me at all times. Realistically though I think it would probably be more dangerous for me to attempt to plog with the WW, whilst being out of practice in a theoretical emergency, than it would be inconvenient to find batteries / computer terminal / ip etc etc

It reminds me of the night qualifaction. I earned mine and was told never to use it, only in emergencies if I get caught out. The thing is, if I ever DID need to use it, due to emergency, it'd probably go wrong because I'd be so out of practice.

If I was retired, and had time on my hands then keeping WW skills up to date, flying at night regularly, going through how to inflate the life raft in the aircraft etc etc are all things I could do and would like to. In reality I just don't have the time to keep all of those "emergency" skills going.

I guess that's the difference between me the amateur, and the pros ?

[biffo28]

Thanks to all for the illuminating replies.

For clarification, i will not use any form of calculator in the exam that is not expressly permitted by the regulations, "sympathietic" examiner or not.

I think i will try to master this device and if successful continue to use when (if ever) qualified. If I end up having diffs with it i will go "electronic when qualified.

Thanks again to all for a truly interesting and educational debate!

Biffo

[IO540]

Contrary to what some might claim, almost nobody can use the slide rule when airborne.

What is one going to do with it??

The wind calculator side is useless unless you know the actual wind. One can use it backwards to work out the wind knowing one's heading, track, etc, but you won't know your track unless you have a GPS ;) in which case why work out the wind? It will be as much use as knowing yesterday's FTSE100.

The other side is just a straight multiply/divide slide rule, bent around into a circle. I used those at school in the 1960s. But a £5 calculator will do that job and with much less chance of an error. I do carry a calculator but, FWIW, in 10 years of flying I have never had to calculate anything when airborne, flying with a GPS. I use it only after a fill-up to check the fuel totaliser error against the pump.

[Maoraigh1]

If you're current with simple trig and a non-programmable scientific calculator, use that. Otherwise learn the WW.
I used a scientific calculater and trig in 1987, resitting my exams after a 20+ year break from flying. In 1964, I had no choice but the circular compurter.

[Genghis the Engineer]

I don't often use it when airborne, certainly - but I've used the Dalton Computer regularly for flight planning on the ground.

G

[mikehallam]

CRP's main function is pre-flight planning, with a chart. Of course any computing aid or even pencil & paper will do. That's why it lives in my bag.
i.e. Used before, without a care, you fly off in the general direction of 'x'.

As per se it's unknown how good the applicant's trigonometry is, the CRP test presumably demonstrates that one understands the basic 'rules' and thus better knows how to visualise the effects of wind, on drift & velocity.

[Rather than wholly believing a digital read out from some random piece of kit the P1 has decided to use.]

mikehallam.

[BackPacker]

I think i will try to master this device

Don't try to master the device. Try to master the theory behind it. Start with constructing a wind triangle on the chart itself. I learned how to do that for a nautical exam (using current and drift instead of wind, but the idea is the same) and it's really, really simple.

Then you realise that, with the typical speeds of a light aircraft, your chart is often simply not big enough to construct a 1-hour wind triangle, and that working in smaller increments, say 30 or 15 minutes gets too confusing. So you make the leap to using the wind side of the CRP-1. Which is really nothing more than a one-hour wind triangle but in a smaller and more convenient package. And slightly more accurate too.

As far as the circular sliderule side is concerned, think of it as a straightforward calculator that only does multiplications and divisions. Start with (I'm not kidding) multiplying 2 and 3 together on the sliderule. Try to understand why the answer is 6 according to the sliderule, and do a few other of these very, very basic calculations. Then do divisions.

Then setup the slide rule according to the booklet for doing, say, a fuel weight calculation. You will find that once you've got the scale set up properly, one of the main indicators (opposite of the "1" usually) is simply pointing to the specific gravity of the fuel you're using (in whatever units you choose to use). Same for time/speed/distance calculations. You are simply setting it up so that the "1" (or the "60" for 60 minutes in an hour) is against your multiplier (ground speed).

Once you've mastered the basics, using the CRP-1 is easy and probably faster than using an electronic calculator. Plus, it will give you a mental check on whether the answers are more or less correct.

All the intermediate electronic stuff, like electronic flight computers, home-grown spreadsheets and such, are not really useful as far as I'm concerned. In fact, to a large extend I consider them GIGO systems: Garbage In, Garbage Out. It's too easy to input a wrong value, but use the output as gospel. And fly in a completely opposite direction without knowing or understanding why.

If you want to get rid of the CRP-1, make sure you get rid of it all the way. And that means to get either a PC package like SkyAngel, PocketFMS or JeppView where you simply click your whole route together with your mouse and then upload it onto your GPS/iPhone/whatever, or a proper aviation GPS which essentially does the same thing. You then enter the upper wind, airspeed, fuel flow and a few other values, and the device calculates the whole plog for you. The mental check of the CRP-1 is now replaced with the very simple fact that the magenta line runs from your origin to your destination.

[biffo28]

Thanks Backpacker.

You advice on "get rid of it all the way" was very timely. Posed the CRP-1 question to my instructor today and he showed me SkyDemon - I am now sold on that type of software!