Backontrack,
Basically, there are 4 types of operation that the CRP5 does for you.
1. Multiplication and Division and Conversions, just like any slide rule. I agree, for these, you are probably better off with an electronic calculator.
2. Distance, Speed and Time (and fuel-flow calculations). You can do these with a calculator, but it's actually quicker with a CRP5, once you get good at it. With a question like "You are doing 220 knots groundspeed, so how long will it take you to cover 57 nautical miles?", if you use a calculator, you get the answer in hours. You then need to multiply it by 60. By the time you've done that, you could have already had the answer on the CRP5, in terms of minutes, which is what you want, not hours. On the other hand, if the question is "Your groundspeed is 320 knots, so how far will you travel in 13 minutes?", then you need to divide, not multiply, by 60. With a calculator, decisions as to which way round to do the calculation, and slight loss of speed. No such problem with the CRP5. With that big black triangle on the inner scale, you work in base 60. It gives you the answer in the form you need it.
3 TAS and Altitude Calculations. To calculate these by numerical methods on an electronic calculator requires specialist formulae, which are too complicated for everyday use - especially TAS from FL and temp, and Compressibility correction. The CRP5 solves them simply and accurately.
4 Wind Calculations - the relationship between Heading, Track, Drift, TAS, and Groundspeed. These are vector problems and would be too complicated on a normal programmable scientific calculator. You have been able to get specialist aviation calculators with the formulae already programmed for years, but these have never really caught on because the presentation on the CRP5 wind face, as well as solving the numerical problem, gives you an instant intuitive picture as to whether the wind is giving you mainly head/tailwind component or mainly crosswind, and a visual picture of whether it's head or tail and which direction the drift is in.
Three other observations:
Firstly, if your instructor hasn't explained it to you, he's not doing his job properly. Ask him. You may find he doesn't know it himself.
Secondly, the little book that comes with the CRP5 is excellent! You can use it to teach yourself very easily, if you want to.
Finally, the Oxford/Pooley CRP5 Computer Based Training (CBT) CDROM will be available in February. You can get it from Pooley's. It is so clear in its explanation. In the meantime, if you want to, you can get the CRP1 CBT CDROM. It's pretty similar to the CRP5, but without the same number of facilities.
All the best,
Paul
[ 08 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]
[ 08 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]
[ 08 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]</p>