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Dead reckoning computer

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Butcher Boy
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2006/10/28 14:05:54 (permalink)
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Dead reckoning computer

Hello,
 
I feel a bit embarrassed, as a Navy officer, to ask a question about how this navigation computer works but I just can't get a way with it...
 
I have a TYPE E-6B flight computer, aerial, dead reckoning with the original issue plastic grid card. First of all, which side of the card should be facing upwards when the computer's open side is pointing upwards too.
Secondly, how does it works and what is it used for?
 
When turning the computer to the other side (as pictured), how do you have to work with it?
 
Finally, was this type of computer issued for navigators onboard bombers or did (fighter) pilots used it too?
 
I hope someone can help me out (a veteran perhaps)? A theorethical version would be fine but a practical exercice would even be better
 
Thanks a lot for your help!
Regards,
 
Michael

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22 Replies Related Threads

    Huey
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    RE: Dead reckoning computer 2006/10/28 15:31:19 (permalink)
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    Michael,

    Ah, the E-6B "whiz wheel".

    It's been a long time since I've used one but the idea is to take indicated air speed (IAS) the aircraft is flying and convert it to ground speed - taking into consideration the heading of the aircraft and the wind direction and velocity. Ground speed is needed to calculate time from Point A to Point B.

    A simple illustration will suffice. Step 1A - turn the outer bezel to where 0 degrees (North) is at the top - this indicates the aircraft is flying due North (0 degrees). Step 1B - slide the wheel up the graph so that the little circle in the window - the little circle represents the aircraft -  is over the 100 Knots Indicated Airspeed (KIAS) marker. Comment: This hypothetical setting means the aircraft is flying 0 degrees due North at 100 KIAS.

    OK now we'll factor in the wind speed and direction and how that affects the aircraft's ground speed; say the forecast winds are 10 knots out of the North, i.e. the aircraft is flying directly into the wind.

    Step 2A - from the little circle in the window over the 100 K marker go up to the 110 K mark and make a little dot with a circle around it - the 'wind dot' - with a pencil. The reason you make the mark at 110 K is that 110 K - 100 K = 10 K - the forecast wind speed. Step 2B - now slide the wind dot down to the aircraft's IAS i.e. 100 K. Step 2C - now look at where the little black circle in the window is now - it's over the 90 K mark. When you think about it what the whiz wheel has calculated for you is that if you're flying due North (0 degrees) at 100 KIAS - and the wind is coming directly out of the North (0 degrees) at 10 K - that will slow up the aircraft's ground speed (the little black circle) to 90 K.

    To see how the wind affects the aircraft's ground speed if the aircraft were flying due South (180 degrees), turn the outer besel until 180 degrees is at the top. The wind dot will stay on the 100 KIAS mark but the little circle in the window - representing the aircraft - swings around to where it is now over the 110 K marker indicating that what is now a 10 K tail wind has increased the aircraft's ground speed to 110 K.

    The same methodology applies for any magnetic heading the aircraft is flying. Turn the outer bezel to the aircraft's magnetic heading, place the wind dot over the aircraft's IAS mark, and the circle in the little circle in the window will provide the aircraft's ground speed. Additionally the wind dot will indicate the amount of correction - L or R - needed to fly into the wind (crab) in order to maintain the correct ground track.

    Hope that helps.

    Take what you like and leave the rest....

    Andy
    post edited by Huey - 2006/10/29 10:38:10
    danodenweller
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    RE: Dead reckoning computer 2006/10/28 21:23:51 (permalink)
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    Michael,
     
    Either side of the slate is correct, as I recall there is a nautical mile grid and a statute mile grid.  At least on the civilian version.  The slate is used for wind vector (deflection) calculations.  All answers are based on the recollections of a fading memory! 
     
    Try this site for a copy of the manual:
     
    www.cgaux.info/g_ocx/missions/auxair/E6B_manual.pdf
     
     
    Dan B. Odenweller
    Butcher Boy
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    RE: Dead reckoning computer 2006/11/10 04:34:58 (permalink)
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    Hi,
     
    Thanks a lot Andy and Dan! Couldn't wish for a better explanation. Still another question regardng the "whiz wheel"... was this instrument part of the navigator kit or from the pilot kit as well?
     
    I found another computer recently, COMPUTERS, TIME and DISTANCE, TYPE D-4 in original issue carton. This carton reads pilot, kit, flying. So I assume this computer was only used by pilots?
     
    How does this one work? Similar to the E-6B?
     
    Again, thanks a lot for your wonderfull help guys!
    Regards,
     
    Michael

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    Guest
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    RE: Dead reckoning computer 2006/11/10 07:58:13 (permalink)
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    The E-6B was also used by the navigator and bombardier and was a part of their kit's.
    #5
    Paolo Italy
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    RE: Dead reckoning computer 2008/01/29 05:04:37 (permalink)
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    Michael,
     
    the E-6B flight computer is still used today and they teach how to use it in PPL courses; they come from a variety of suppliers including Jeppesen. My best bet is to look for it from a pilot as they come with a comprehensive instruction booklet that you can copy, or get a PPL course manual and likely you will find a whole section on how to use it.
     
    They work exactly as 70 years ago with a calculation side and the sliding wind/speed scale on the other.
     
    Paolo
    Paolo Italy
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    RE: Dead reckoning computer 2008/01/29 11:17:17 (permalink)
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    Hi Huey,
     
    Just a minor comment, the idea on the wind/speed side is to get the GS (ground speed) from the TAS (True Airspeed). The IAS (Indicated AS) or CAS as it is on the E6B is found on the calculation side; give a IAS or CAS with the Pressure Altitude and the Outside Air Temperature you can find the TAS or viceversa if the flight manual gives you the TAS you can find the CAS or IAS.
     
    Ciao
     
    Paolo
    Paolo Italy
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    RE: Dead reckoning computer 2008/01/29 11:19:28 (permalink)
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    Michael,
     
    do you want a copy of the EB6 instruction booklet; with a little patience I can scan one for you.
     
    Paolo
    sandruckd
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    RE: Dead reckoning computer 2008/01/29 16:17:56 (permalink)
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    So the E6B was part of the navigators equipment I take it, not the pilots?

    Dave Sandruck, USAF Ret
    Nephew of Irvin Wentz, KIA 9 Dec 1944
    99 BG, 347 BS
    Tortorella (Foggia), Italy
    sandruckd
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    RE: Dead reckoning computer 2008/01/29 16:19:15 (permalink)
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    Sorry, I forgot to ask how much a vintage E6B would cost?

    Dave Sandruck, USAF Ret
    Nephew of Irvin Wentz, KIA 9 Dec 1944
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    ng19delta
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    RE: Dead reckoning computer 2008/01/29 17:01:59 (permalink)
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    All depends on the seller, and what you want to spend. /there are at least two WWII USAAF models- Aluminum(early & prewar) and plastic- during the war. I have examples of both in my set...

    Robbie
    P40 Petey
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    RE: Dead reckoning computer 2008/01/29 17:03:09 (permalink)
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    So the E6B was part of the navigators equipment I take it, not the pilots?

     
    Pilots use the E6B.  If I remember correctly, it was designed by the US Navy for their pilots.  I learned how to use one when I was trained to fly an airplane.  I would imagine that pilots in WWII would have their own E6B.  Not every airplane in WWII had a navigator.  The pilot in command is the ultimate navigator on his ship.  I would imagine single engine pilots probably would actually have one on board.  You can calculate distance, time, gallons per hour, etc.   Convert mph to knots, convert statute miles to nautical, etc.  If you order a new E6B from Sporty's Pilot shop, it comes with an instruction booklet. 
     
    P-40 Petey
    Terry T.
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    RE: Dead reckoning computer 2008/01/29 17:25:52 (permalink)
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    Intersting thread..I have a Jeppessen CR-3 flight computer still in its orginal box..price sticker says  $13.95..
     
     
     
    Terry T.
     
     
    .
    Anthony J. Mireles
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    RE: Dead reckoning computer 2008/01/29 18:32:51 (permalink)
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    Some of the newer pilots think the manual E6B a quaint relic of a long gone era.  They have the new electronic E6B flight computers.  I still use the old E6B.  Batteries go out, equipment fails, but the old E6B will be there for you.  You can drop it on the ramp and nothing happens to it; you can spill a drink on it and it will still work; and it never needs batteries.  You can run a plastic (or cardboard) E6B over with a B-29 and it will still work.  Try that with an electronic E6B. 

    TonyM. 
    post edited by Anthony J. Mireles - 2008/01/30 01:05:57
    Anthony J. Mireles
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    RE: Dead reckoning computer 2008/01/29 18:40:24 (permalink)
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    So the E6B was part of the navigators equipment I take it, not the pilots?


    Also, Aviation Cadets during World War II are taught to navigate an airplane.  They will not get their wings and qualify as a pilot if they cannot.  Any WWII AAF pilot knows just as much about navigation as the rated navigator.  (Not sure if AAF pilots are taught to use sextants and shoot star fixes like rated navigators)  And as was said before, the pilot in command is the ultimate navigator on his airplane. 

    The E6B was designed by the US Navy for their pilots to use in navigation.  Navy pilots had their own little portable desks to take on board so they could do their own navigating.  There was no navigator on single engine Navy airplanes but the pilot.  TonyM.
    Paolo Italy
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    RE: Dead reckoning computer 2008/01/30 00:24:09 (permalink)
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    ORIGINAL: sandruckd

    So the E6B was part of the navigators equipment I take it, not the pilots?

     
    Dave,
     
    every one was issued an E6B since it a full comprehensive tool for flight planning (visual flight) as it can be deduced from the name "dead reconing" computer.
     
    This has nothing to do with death of course but is an abbreviation of "deduced reconing" which in essence means flight by visual references.
     
    Apart from Ground/True/Wind Speed calculation (on one side), the calculator side can do a wealth of conversions/calculations including altidude, speed, temperature, consumption, time, quantity.
     
    I still use it for flight planning and bring it with me when I paddle around with my Stearman.
     
    Paolo
    ng19delta
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    RE: Dead reckoning computer 2008/01/30 04:17:15 (permalink)
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    Like glass cockpit instruments, I have no interest in an electronic E-6B. Give me steamer gauges and a whiz-wheel any day: Part of the joy of flying is learning to do the real work- True piloting is with a map on your knee, and sight of the ground, and flying by map and compass. I'd rather dead reckon than follow the GPS line. Works well, takes skill, and presents a nice challenge. Same reason my Tom-tom nav device in my car (which was a prize I won at a raffle- not something I purchased) is just along for backup, nd fun- not something I depend on to get A to B.  That said, I know that there is a place and use for all those electric gadgets- but preferably not in my cockpit! When the batteries die, the screen cracks, or something else wipes out the system, and you can't recall how to use the real instruments of flight, then you are stuck...

    I use the E-6B and love it: I have several I use, from WWII and up.

    Robbie
    Anthony J. Mireles
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    RE: Dead reckoning computer 2008/01/30 12:18:40 (permalink)
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    Like glass cockpit instruments, I have no interest in an electronic E-6B. Give me steamer gauges and a whiz-wheel any day: Part of the joy of flying is learning to do the real work- True piloting is with a map on your knee, and sight of the ground, and flying by map and compass. I'd rather dead reckon than follow the GPS line. Works well, takes skill, and presents a nice challenge. Same reason my Tom-tom nav device in my car (which was a prize I won at a raffle- not something I purchased) is just along for backup, nd fun- not something I depend on to get A to B. That said, I know that there is a place and use for all those electric gadgets- but preferably not in my cockpit! When the batteries die, the screen cracks, or something else wipes out the system, and you can't recall how to use the real instruments of flight, then you are stuck...

    I use the E-6B and love it: I have several I use, from WWII and up.

    Robbie

     
    Amen, Robbie, Amen.
     
    TonyM.
    Ken a B24 Fan
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    RE: Dead reckoning computer 2008/02/02 01:19:04 (permalink)
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    Dad received a "computer" (Circular Slide Rule) E-6 at some point in his pilot training on his way to fly B-24 bombers in Italy.

    On one mission, the navigator was out of commission and dad had to go down to the nav's desk, grab his maps and dead-recon his way from Vienna to Vis in the Adriatic. The plane was hit by flak right after bombs away sending all four engines into flat pitch. They dropped 9000 ft and fell behind the formation. They got the propeller pitch corrected while the No. 3 engine was knocked out and the prop froze in flat pitch. The nose turret plex was gone and there were over 50 fist-sized and larger holes in the fuselage. The waist gunner was hit badly in the shoulder.

    He got the plane to Vis and landed as the number four engine quit on touch down, the gas gauges reading zero.

    It behooved the pilots to be able to navigate almost as well as the navigator. Because you never knew...

    I always marveled at the single-seaters' ability to fly, fight and navigate their way back to base if they got separated from the others during the action. The compass did help.

    Ken

    Ken Alexander
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    Vage Rot
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    Re:Dead reckoning computer 2009/02/03 15:49:44 (permalink)
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    Hi Gents,
     
    Can anyone remember how to use the whizz wheel to work out intercepts?
    Given
    the cse/spd of tgt
    range/brg from interceptor to tgt
    speed of interceptor
     
    I was taught this 22 years gog at Nav school but too many brain cells have died between then and now!
     
    Cheers
    vage
     
     
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