Question with the CRP-5 Windarm edition

[math341c]

Hello, again dear pilots, I finally got my PPL and have a lot of hours to fly out alone, and I am about to put my full focus on ATPL. The first subjects I want to pass are Navigation, meteorology and Human performance.

I have a question about the CRP-5 Wind-arm edition that i can't find anywhere on the internet. I bought the wind-arm edition, because it is better for me, and it does not get so much weared, when you write on it and delete it with your eraser all the time.

The problem is that the ATPL books only explain using the CRP 5 without the wind-arm. I can 90% of the things on it, but there is one thing i never found out.

It is when you for example have a task like this one:
TH: 100 degrees
Wind speed: 30 kt
Wind direction: 170 degrees
TAS: 150 kt

How can I find the true track, giving this information? WIth CRP-5 Wind-Arm.
I have pounded my head on it for hours and failed every time and I tried youtube etc, but can't find it anywhere.

Thanks in advance.

[paco]

Why don't you get the Jeppesen CR-3 or the E6B circular comnputer. Much easier and you can do convergency and grid on it.

[math341c]

Because you are only allowed to have the CRP-5/W at the EASA ATPL exam. :)

[Banana Joe]

The CRP-5 should be renamed CRaP-5. What a piece of junk.
As Paco said, the CR-3 or ASA current offering are so much better.

[paco]

You might want to petition for its use - we had to do that with the CAA here

[math341c]

Can you elaborate :) ?

What petition? EASA is not some democratic organization where we students can dictate what flight computers we may use for the exams.

They have a complete list of what you exactly may/may not use for the ATPL Exams.

[Genghis the Engineer]

Because you are only allowed to have the CRP-5/W at the EASA ATPL exam. :)

Untrue. I used an Aviat 617, with no difficulty, and passed.

They all work basically the same anyhow, just slight variations like constants, Mach window or a wind arm.

[Genghis the Engineer]

math341c

Where you'd have previously marked something with soft pencil on the facia, turn the wind arm to that position and note where on the scale it is, then use that point.

All else remains the same.

[paco]

It is up to each country as to what they use - EASA does not really dictate. We (as a school) requested that the UK CAA allowed the use of the CR-3.

[Banana Joe]

Where I sat my ATPL exams everybody used the E6B, if you did not have one with you this is what the inspectors would give you. I had no issues with my CR-3.

[Tinstaafl]

Where did you get the idea that only the CRP5 is permitted? The UK's CAA website states:

"Approved flight computers – CRP-1; CRP-5/CR-3/CR-6; ARC-2; E6B"

[paco]

Apparently in Norway at least you have to use what they give you

[math341c]

Hello again guys, I found a solution. I searched and searched for hours and finally found a video on how to solve for Track and GS with the CRP-5 Wind arm edition.

And I do not agree, CRP-5 is not crap, it's very effective. A circular flight computer is completely unnecessary and would be a waste of money. CRP-5 or CRP-5W is all you need for EASA ATPL.

Question banks and ATPL books use the CRP-5 When explaining the calculations of the different things, so I am pretty sure that the CRP-5 Is the main flight computer that is used for ATPL exams.

Take care :)

[Banana Joe]

You haven't even started and you don't know what you're talking about. With the CR-3 I could answer some questions in Radio Navigation or General Navigation that otherwise would require some calculation. Definitely not a waste of money, considering the price of the CR-3 and the over price of the CRP-5. Waste £80 I've ever spent. The CR-3 was just 25 euro.

[paco]

What Banana Joe said - I've seen how they make the crap 5

Before JAA the UK CAA used three of them to check the answers in their questions as the quality was so variable.

[math341c]

Paco could you please elaborate what type of things the circular computer can calculate compared to the CRP-5?


BTW the CR-3 you are both talking about, at least the Pooley's one. Seems to be made for American pilots, as I can't not find it in any european store.

I can't not even find it on transair, i can only find the E6B Circular computer, is is the same as the CR3?

[paco]

The E6B circular is a clone of the CR-3 which isn't made any more.

You can do grid and convergency for one thing, time to station. The slide rule is pretty much the same with a more elegant solution for conversions.

http://www.captonline.com/CR3.jpg (http://www.captonline.com/CR31.jpg)

As an example for convergency, say from York (roughly 54°N), you need to find a ship just East of the Isle Of Man, which is more or less on the same latitude, but 3° to the West, or 180 minutes, which at the Equator would be 180 nm. The black band represents cosines, which stop at 45°, but the cosine of 54° is the same as the sine of 36° so, looking opposite, you have 106 nm to go.

For grid, at 40W, a true track of 50 degs makes for a grid track of 90 and vice versa (just treat it like variation):
http://www.captonline.com/easagrid1.jpg

[math341c]

You mean CR-3 is not made any more? The E6B is sold as new, pretty many in stock? Transair has more than 60 in stock?

[Tinstaafl]

Pooleys' CRP6 & CRP9 aren't the same as a Jepp CR type. Biggest difference is their wind side is just a cut down modification of a slide type solution. Jepp CRs use trig. to solve the wind triangle. Slide types, including Pooleys' supposedly CR equivalent, use vector addition. The Pooleys' one seems to be missing some scales on the calculator side eg recovery coefficients etc. You don't get the benefits of a true CR type with the Pooleys job.


APR industries used to also make a Jepp CR equivalent. Not sure if they still do.

[maximus610]

You mean CR-3 is not made any more? ...

On ebay plenty of them...

[math341c]

okay guys never answered back, i decieded to give the CR3 a shot, i was wrong with my first posts your are right. I went into some new Aviation Exam questions that actually used and recommended the CR3 as an example for solving such type of tasks. I got it on Amazon pretty cheap, so i can't wait to try it out. I just hope i can use it for the EASA exams!

Thank you.

[bafanguy]

What happened to the YouTube video posted by the guy who was showing how to use the CRP-5 ? I was going to watch it to see how much I've forgotten (Hint: a lot :)).