Need help with using slide rule on Citizen BJ7019-62E "Nighthawk"
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Thread: Need help with using slide rule on Citizen BJ7019-62E "Nighthawk"

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  1. #1
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    Need help with using slide rule on Citizen BJ7019-62E "Nighthawk"

    While i am learning how to do time speed and distance calculations on the slide rule of my (recently purchased) Citizen BJ7019-62E "Nighthawk" using the instruction booklet that came with it and the ASA E6B flight computer instruction manual, I am unable figure out how to use the FUEL LBS and OIL LBS markers that appear on the outside, rotating dial of the Nighthawk.

    There aren't any instructions to this effect in the standard user manual that came in the box.

    The E6B instruction manual can't be used in this case since the mechanism is slightly different on a true E6B flight computer (instructions reference "arrow line up") vis-a-vis the Nighthawk (can't line up arrows by virtue of construction).

    Since i'm at it, I'd appreciate if you could point me to a resource that enlists *all* the various types of calculations that can be performed on this Citizen Nighthawk.

    Thanks in advance and have a great day ahead!

  2. #2
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    Re: Need help with using slide rule on Citizen BJ7019-62E "Nighthawk"

    You have me stumped. On an E6-b, the procedure is to line up "fuel lb" or "oil lb" on the outer scale with a liquid volume (e.g. US gal) arrow on the inner scale. This way you can find your fuel or oil quantity around the inside and see how much it weighs on the outside.

    By the looks of it, the Nighthawk's dial is missing the necessary markings on the inner bezel for the calculation, but it has all of the necessary markings on the outer dial. I suppose if you find the fuel or oil markings on the outer bezel and lined them up with 12.8 (corresponding to US gal) on the inner bezel, you could still do the calculation...but you might as well just multiply at that point.

    I suppose I'll have to buy a Nighthawk to try to figure it out

    To help with your other question, aside from picking calculations out from an e6-b instruction manual, the only thing I would know is to look up instructions for a regular slide rule. An e6-b is just a specialized slide rule made more convenient for cockpits. The scales on the bezels of a slide rule watch are just like the logarithmic "C" and "D" scales on a slide rule. These scales were designed primarily for multiplication and division, so calculations that involve multiplying by a conversion factor (eg. currency or length conversion) or using a ratio (eg. miles, hours, and miles per hour) will work.

    As of now, what all do you know how to do with it?
    Last edited by FunkySteve; July 25th, 2012 at 15:14.

  3. #3
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    Re: Need help with using slide rule on Citizen BJ7019-62E "Nighthawk"

    Quote Originally Posted by FunkySteve View Post
    You have me stumped. On an E6-b, the procedure is to line up "fuel lb" or "oil lb" on the outer scale with a liquid volume (e.g. US gal) arrow on the inner scale. This way you can find your fuel or oil quantity around the inside and see how much it weighs on the outside.

    By the looks of it, the Nighthawk's dial is missing the necessary markings on the inner bezel for the calculation, but it has all of the necessary markings on the outer dial. I suppose if you find the fuel or oil markings on the outer bezel and lined them up with 12.8 (corresponding to US gal) on the inner bezel, you could still do the calculation...but you might as well just multiply at that point.

    I suppose I'll have to buy a Nighthawk to try to figure it out

    To help with your other question, aside from picking calculations out from an e6-b instruction manual, the only thing I would know is to look up instructions for a regular slide rule. An e6-b is just a specialized slide rule made more convenient for cockpits. The scales on the bezels of a slide rule watch are just like the logarithmic "C" and "D" scales on a slide rule. These scales were designed primarily for multiplication and division, so calculations that involve multiplying by a conversion factor (eg. currency or length conversion) or using a ratio (eg. miles, hours, and miles per hour) will work.

    As of now, what all do you know how to do with it?
    Hi FunkySteve,
    Thanks for your response. I'd highly recommend that you buy the Nighthawk. You'll love it I have the euro/asian version with the black ion coating. Honestly, the black looks a very deep chocolate brown to my eyes. But nonetheless its a fantastic piece of equipment. I wash it daily, it's been splattered with light rain already and has had one small bump on the clasp side with a door (my neglience, obviously). But no sign of any scratch or ding. It's awesome.

    As of now I can just find out the speed and distance traveled given the appropriate data i need. Progressing slowly, but surely.

    I'm certain the scales can do more than just TSD (Time, Speed, Distance) and other aeronautical calculations. Like you correctly said, these are just scales and can be used to do more. Just curious about what else they can calculate.

    Thanks and have a great day ahead!

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  5. #4
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    Re: Need help with using slide rule on Citizen BJ7019-62E "Nighthawk"

    i recall one fellow WUS member commenting that he cleverly uses his bezels for currency conversions. If you line up a currency conversion rate (e.g. 1 dollar = 1.228 euros), then all of the numbers around the bezel act as euro to dollar conversions.

    Also, in an aviation context, I use the basic e6b bezels to do fuel burn calculations. If you have a fuel burn rate (gallons per hour) over a certain period of time in hours, you can calculate gallons burned. A similar idea can be used to determine fuel mileage in a car

    From there, I would say a good start is to learn simple multiplication and division, if you haven't already. Once you can do that hundreds of everyday calculations like tips and percentages can be done. I can't wait to get one so I don't have to constantly pull out my calculator in class (your description makes it even harder to resist!)
    getkaizer likes this.

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    Re: Need help with using slide rule on Citizen BJ7019-62E "Nighthawk"

    Quote Originally Posted by FunkySteve View Post
    i recall one fellow WUS member commenting that he cleverly uses his bezels for currency conversions. If you line up a currency conversion rate (e.g. 1 dollar = 1.228 euros), then all of the numbers around the bezel act as euro to dollar conversions.

    Also, in an aviation context, I use the basic e6b bezels to do fuel burn calculations. If you have a fuel burn rate (gallons per hour) over a certain period of time in hours, you can calculate gallons burned. A similar idea can be used to determine fuel mileage in a car

    From there, I would say a good start is to learn simple multiplication and division, if you haven't already. Once you can do that hundreds of everyday calculations like tips and percentages can be done. I can't wait to get one so I don't have to constantly pull out my calculator in class (your description makes it even harder to resist!)
    Thanks FunkySteve!
    Making a list and then maybe i shall put up a post on what can be done with this piece of equipment (apart from telling the time).
    While the calculator may be quick, this baby won't die on you (provided you wear it regularly) since it's eco-drive.
    -------
    Thanks to Watchuseek and the good people there, I am the proud owner of a Citizen BJ7019-62E Pro Master "Nighthawk" Euro / Asian version with standard bracelet and black ion coating.

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