E6B Questions .... And more to come?

[Lomcevak]

Greetings, all! First post. I'm getting ready to do my flight training, and just picked up an E6B (mechanical). I love my calculators, but man, I can see how this thing can be faster than a calculator when you learn to use it proficiently. Alas, that is the trouble at the moment...I have questions! Many questions.

I found a couple vids on YouTube that helped quite a bit, but for the most part the other vids weren't very clear.

Anyway, one of the questions I came upon was in regards to divot (D=VT Distance = Velocity x Time). For the most part I thought I understood how to use the E6B in these situations, however, it appears that a question came up that left me a little befuddled.

The question gave the following:

Distance: 13 NM
Time: 6.8 mins

The solution that generated the correct result was to align the 8th tick mark past the "60 Rate" (which on other E6Bs is simply depicted with the large triangular pointer) pointer with 13 on the "A" scale. The rate marker then roughly points to "11.5" on the "A" scale; which represent 115 knots.

However, I thought that the "C" scale (hours) could also be used as minutes and seconds. So I aligned 6:48 on the "C" scale (41.25 on the "B" scale) with the "13" on the "A" scale. When I read off the rate at the rate marker, it indicates "19.2".

What have I done wrong? What was my incorrect assumption?

Thanks for your help!

 

[John Collins]

The second calculation is 13 NM / 6.8 Min, which yields 1.91 NM/Min. Most folks want to know Knots, or NM/Hr. To convert 1.91 NM/Min into Knots, multiply by 60 Min/Hr and get 114.7 Knots or 115 Knots rounded to the nearest Knot.

 

[Lomcevak]

John, thank you for the quick response.

So, what you're saying is that the "C" scale turned to minutes and seconds when I wasn't looking! You know what I mean, sometimes it can be used as hours and minutes, and other times it can be used as minutes and seconds.

I understand what you're saying that it was actually functioning as minutes and seconds, but, how do I recognize when it has changed like that? I guess the very fact that I had declared (in my mind) that 6:00 = 6 minutes, eh?

Then, how did the 8th tick mark past 60 = 6.8 MINUTES?

Does that then mean that, on the "B" scale: "55" = 5.5 minutes, "40" = 4.0 minutes, "12" = 1.2 minutes and "10" = 1 minute?

Does "95" on the "B" scale equal half a minute (If the black 10 = 1 minute, then going backwards to the 95 would be 1 - 0.5 minutes which equals 0.5 minutes, correct)? Or 95 seconds? Or 9.5 Minutes? Does "75" equal 75 seconds, and if so, how did that happen? Or does it equal 7.5 minutes?


I think the problem is my fundamental approach to this. How should I be approaching this?

 

[John Collins]

I don't own an E6B, so it is somewhat difficult to comment on various scales, other than to say that an E6-B is a circular slide rule and the scales are logarithmic. To multiply two numbers, you add their logarithms and to divide one number by another, you subtract the logarithm of the divisor from the dividend. There are no units provided on the scales, so the user has to determine powers of 10 that are being used. On a simple scale, it is repeated on the movable part and the fixed part, so setting the pointer (10's position) to a place on the movable scale to one number being multiplied and reading the other number off on the movable scale to mark the answer on the fixed scale, has the same effect as adding the two logarithms, or in other words, it reads off the multiplication of the two numbers. If you use the 60 mark as the pointer, then the answers will be multiplied by 60, so it all depends on what the units you are using to make the calculations with. In high school physics, we were supposed to learn about dimensional analysis, but this is not always remembered. With dimensional analysis, you note the dimensions of each of the operands and the answer will be in those units. If you want to change the units, you have to multiply or divide by the ratio of the desired units to the units you have as presented in the problem

So to calculate the velocity, the equation is D/T. Your dimensions are 13 Nautical Miles for distance and 6.8 minutes for time. So the result is in NM/Minute. To change this to NM per hour that your IAS is marked in, there are 60 Minutes/hour, so multiply by 60 Min/Hr to get the correct dimensions of NM/Hr.

 

[jnmeade]

Most E6Bs have the formulas printed right on the dial. The calculations are just like cross-multiplying. Labels can't quite be anything you want them to be, but as long as they are consistent all you are looking at is relationships so call them anything consistent and appropriate.

 

[John221us]

There are E6B apps available for most smart phones. Just saying...

 

[cherokeeflyboy]

John, thank you for the quick response.

So, what you're saying is that the "C" scale turned to minutes and seconds when I wasn't looking! You know what I mean, sometimes it can be used as hours and minutes, and other times it can be used as minutes and seconds.

I understand what you're saying that it was actually functioning as minutes and seconds, but, how do I recognize when it has changed like that? I guess the very fact that I had declared (in my mind) that 6:00 = 6 minutes, eh?

Then, how did the 8th tick mark past 60 = 6.8 MINUTES?

Does that then mean that, on the "B" scale: "55" = 5.5 minutes, "40" = 4.0 minutes, "12" = 1.2 minutes and "10" = 1 minute?

Does "95" on the "B" scale equal half a minute (If the black 10 = 1 minute, then going backwards to the 95 would be 1 - 0.5 minutes which equals 0.5 minutes, correct)? Or 95 seconds? Or 9.5 Minutes? Does "75" equal 75 seconds, and if so, how did that happen? Or does it equal 7.5 minutes?


I think the problem is my fundamental approach to this. How should I be approaching this?

"

1. 1. The numbers along the outside of the stationary portion are referred to as the OUTER SCALE
      1. The outer scale is used to represent distance, fuel, groundspeed, true airspeed, or corrected (true) altitude, depending on the calculation being performed.
      
      
   2. The numbers on the edge of the rotating portion are referred to as the INNER SCALE
      1. The inner scale is used to represent time, calibrated or indicated airspeed, and calibrated or indicated altitude, depending on the calculation being performed.
      2. The number "60" on the inner scale has been replaced with a triangular-shaped arrow, referred to as the Index (
         
         ).
         1. This arrow is used as a reference to a rate, such as knots (nautical miles per hour) or gallons per hour.
         
         
   3. In the center of the rotating portion are three "holes" (windows) used to compute corrected (true) altitude, density altitude, and true airspeed.
   
   
2. Scale Values
   1. The numbers on the outer and inner scales represent multiples of 10 of the values shown.
      1. EXAMPLE: The number "20" on either scale may represent 0.2, 2.0, 20, 200, or 2,000.
   2. On both the outer and inner scales you will notice that the number of tick marks, or graduations, vary between numbers.
      1. EXAMPLES:
         1. The first tick mark to the right of "10" may represent 10.1, 101, 1,100, etc.
         2. The first tick mark to the right of "17" may represent 1.72, 17.2, 172, etc.
         3. The first tick mark to the right of "35" may represent 3.55, 35.5, etc. The second tick mark to the right of "35" may represent 3.6, 36, 360, etc.
   3. On the inner scale, minutes may be translated to hours and minutes by reference to the hour scale, which is below and inside the inner scale.
      1. EXAMPLE: 120 min., or "12" on the inner scale is also 2 hr. as indicated by "2:00" below the "12."
   4. On the hour scale, the tick marks represent either 5 min. or 10 min.
      1. EXAMPLE: Between "1:50" and "2:00" the tick mark represents 5 min. Between "4:00" and "4:30" each tick mark represents 10 min.
      2. The tick marks on the inner scale can be used to supplement the hour scale.
3. The calculator side of the flight computer is constructed so that any relationship, or ratio, between a number on the outer scale and a number on the inner scale will remain constant for all other numbers on both scales.
   1. Rotate the inner circle so the "10" is opposite the "10" on the outer scale, and note that all the numbers around both circles are identical.
   2. Next, rotate "20" under "10" on the outer scale; now all numbers on the inner scale are double those on the outer scale.
   "

 

[bobmrg]

Greetings, all! First post. I'm getting ready to do my flight training, and just picked up an E6B (mechanical). I love my calculators, but man, I can see how this thing can be faster than a calculator when you learn to use it proficiently. Alas, that is the trouble at the moment...I have questions! Many questions.

I found a couple vids on YouTube that helped quite a bit, but for the most part the other vids weren't very clear.

Anyway, one of the questions I came upon was in regards to divot (D=VT Distance = Velocity x Time). For the most part I thought I understood how to use the E6B in these situations, however, it appears that a question came up that left me a little befuddled.

The question gave the following:

Distance: 13 NM
Time: 6.8 mins

The solution that generated the correct result was to align the 8th tick mark past the "60 Rate" (which on other E6Bs is simply depicted with the large triangular pointer) pointer with 13 on the "A" scale. The rate marker then roughly points to "11.5" on the "A" scale; which represent 115 knots.

However, I thought that the "C" scale (hours) could also be used as minutes and seconds. So I aligned 6:48 on the "C" scale (41.25 on the "B" scale) with the "13" on the "A" scale. When I read off the rate at the rate marker, it indicates "19.2".

What have I done wrong? What was my incorrect assumption?

Thanks for your help!

14 nautical (I'm guessing) miles in 7 minutes? The answer has to be two miles per minute/120 knots without breaking a sweat. Use that kind of rounding-it-off thinking to solve written test questions and one of the answer choices should jump out at you.

Bob Gardner

 

[AggieMike88]

There are E6B apps available for most smart phones. Just saying...

Tru, but ya can't take them into the written exam. So learning the mechanical E6-B can be a worthy exercise.

 

[BillTIZ]

There are E6B apps available for most smart phones. Just saying...

You can't take that into the written test. Last I checked.

 

[Jeanie]

I recommend you buy or borrow an E6B calculator, the kind that uses batteries for the written test. It makes some of the problems easier. The regular manual whiz wheel is easier in the plane.

 

[John221us]

Tru, but ya can't take them into the written exam. So learning the mechanical E6-B can be a worthy exercise.

Your right, you can't take a smart phone. You can take an electronic E6B, though (1970's style calculator that they get too much for). I did use the mechanical for that (basically a sliderule, 1950's technology). On my oral for the practical, my DPE didn't care and after that I switched to online flight planning tools and an iPad/iPhone with Foreflight and never looked back.

 

[GCA319]

There are E6B apps available for most smart phones. Just saying...

I love when student's show up with those. Makes my job alot easier;however, if they ask me which one to buy, I usually tell them to get the mechanical one to save some cash versus spending $65 on an electronic one. Usually after they've mastered flight planning the traditional way, I introduce them to online flight planning (DUAT, AOPA etc) to show them how most flight planning is done in the real world of flying. I also require the use of computer flight planning for Commercial students since most commercial operators will want it to be done as quickly as possible.

 

[Bobcat1]

Just live with your E6b for the next week or so and it'll be second nature to you. I still find it really handy for converting lbs of fuel to kilos when fueling up in foreign countries, checking ETP solutions, fuel burn, even currency exchange rates. You can even use it for wt/balance load shift problems. You just have to get really familiar with it. You can do pencil and paper flight planning almost as fast as the online planning if you're used to the tools.

Just remember where you leave your decimal points and you'll do OK.

 

[gprellwitz]

And for those looking to take an E6B into the test, the test application actually has one built into it that you can use. Of course, unless you've practiced with it it may be a bit cumbersome, but it's there, at least on the LaserGrade up until 2 years ago.

 

[GCA319]

And for those looking to take an E6B into the test, the test application actually has one built into it that you can use. Of course, unless you've practiced with it it may be a bit cumbersome, but it's there, at least on the LaserGrade up until 2 years ago.

All sporty's calculators are approved. I'm not sure about the apps though...I think testing centers are prohibited from having Wi-fi, but one could potentially pick up a wi-fi signal from another nearby location...

 

[gprellwitz]

All sporty's calculators are approved. I'm not sure about the apps though...I think testing centers are prohibited from having Wi-fi, but one could potentially pick up a wi-fi signal from another nearby location...

I'm not sure it was clear that what I meant is that the testing application itself has a built-in electronic E6B that you can bring up on screen. You don't need to provide anything yourself. (Though it makes a lot of sense to bring one that your familiar with, be it Sporty's, ASA, a mechanical one, etc.)

 

[GCA319]

I'm not sure it was clear that what I meant is that the testing application itself has a built-in electronic E6B that you can bring up on screen. You don't need to provide anything yourself. (Though it makes a lot of sense to bring one that your familiar with, be it Sporty's, ASA, a mechanical one, etc.)

Ok, understood. I thought you meant an I-Phone app...That's what I get for just glancing over the post prior to posting. CATS does not have anything built in, but I don't consider it a bad thing as long as it's use were optional.

 

[MBDiagMan]

Tru, but ya can't take them into the written exam. So learning the mechanical E6-B can be a worthy exercise.

Yes, and it might even come in handy some day while flying the plane! I've yet to see the battery go dead in a Whiz Wheel.

To the OP,

Basically you are setting up a ratio in the Whiz Wheel. If 14NM in 7 minutes means two NM per minute, then the wheel is set and you can look at any distance to see how much time it will take or any time to see how much distance you would cover.

Hope this helps.

I'm old enough that I went through college, with a slide rule. I can see where it would be less than intuitive for a younger person who grew up with an electronic calculator.

 

[airdale]

I have questions! Many questions.

I have one or two PDF copies of E-6B instruction books. If you PM me an email address I'll dig 'em up and send them to you.

 

[somorris]

I have one or two PDF copies of E-6B instruction books.

This struck me as funny. I also went through college with a slide rule, Doc.

 

[MBDiagMan]

This struck me as funny. I also went through college with a slide rule, Doc.

Now that you point it out I do indeed see the humor in it. Sort of like reading the owners manual for your Model T on your laptop.

 

[airdale]

Sort of like reading the owners manual for your Model T on your laptop.

:wink2: Exactly. I took the E-6B along on a cruise just as a toy and had the instructions on my Sony E-Reader. Kind of fun to figure out how to use the thing again. Little practical value, but fun.

I have two or three of the really nicely made older ones with engraved markings, including one of the CPU-26A/P half-size computers. In comparison, the current silk-screened gaggle is all junk. I have one of the round Jepp computers too but have never really warmed to that one.

 

[MBDiagMan]

:wink2: Exactly. I took the E-6B along on a cruise just as a toy and had the instructions on my Sony E-Reader. Kind of fun to figure out how to use the thing again. Little practical value, but fun.

I have two or three of the really nicely made older ones with engraved markings, including one of the CPU-26A/P half-size computers. In comparison, the current silk-screened gaggle is all junk. I have one of the round Jepp computers too but have never really warmed to that one.

I had a distant relative who was a B17 navigator during WWII. He had a really neat government issue E6B that I saw as a child. After his death, it was never found in his belongings, at least that is what I was told. I sure would like to have it.