In 1981 I bought one of the first electronic calculators that was designed specifically for aviation related calculations


It could compute density altitude, wind correction angles, even CG position, amongst other calculations


The calculator I purchased was brown in color, quite bulky and incorporated lots of red lights to indicate the relevant functions, as a gadget lover then and now I thought it was very cool


Does anyone remember this calculator, who made it and even better do they have a picture ?

I’ve found an answer to my question, anyone who likes gadgets or vintage calculators might find it of interest


It was called a ‘Navtronic 1701TR’

Very cool, worth a google

One for $30 on eBay here:
https://www.ebay.co.uk/itm/324836243473 ... BM1LOCgadf

I see that, looks good but it does say it doesn’t turn on !

I should read the description

Max Q wrote:

I see that, looks good but it does say it doesn’t turn on !

They had 3 “AA” size rechargeable batteries, if it hasn’t been used for a while they would not longer be good. It wouldn’t take much effort to make a new battery pack for it.

I too came from the mechanical E6B world but never used the electronic kind. Do I remember correctly that electronic E6Bs were not allowed during exams? Was it considered cheating? As a flight instructor in the late 1980s I was still teaching the manual device. Doubtful, but do student pilots still learn it today?

The “Circular Slide Rule” was a fascinating tool.

zeke wrote:

Max Q wrote:

I see that, looks good but it does say it doesn’t turn on !

They had 3 “AA” size rechargeable batteries, if it hasn’t been used for a while they would not longer be good. It wouldn’t take much effort to make a new battery pack for it.

As long as corrosion hasn’t caused terminal damage to the electronics !

26point2 wrote:

I too came from the mechanical E6B world but never used the electronic kind. Do I remember correctly that electronic E6Bs were not allowed during exams? Was it considered cheating? As a flight instructor in the late 1980s I was still teaching the manual device. Doubtful, but do student pilots still learn it today?

The “Circular Slide Rule” was a fascinating tool.

Yes, it is still taught today, unless things have changed in the past few years.

If memory serves in the US I could use an electronic E6B.

For the EASA exams you have to use a mechanical CRP-5 or equivalent. Electronic is not allowed, nor is a programmable calculator. If memory serves, the E6B was no good for EASA because it is missing a few of the needed speed conversions facilities.

Max Q wrote:

As long as corrosion hasn’t caused terminal damage to the electronics !

Dont know if you remember those little plastic battery holders with two cables coming off it, thats what I remember. You can still buy them.

PCBs back then look like a kid built them.

Starlionblue wrote:

26point2 wrote:

I too came from the mechanical E6B world but never used the electronic kind. Do I remember correctly that electronic E6Bs were not allowed during exams? Was it considered cheating? As a flight instructor in the late 1980s I was still teaching the manual device. Doubtful, but do student pilots still learn it today?

The “Circular Slide Rule” was a fascinating tool.

Yes, it is still taught today, unless things have changed in the past few years.

If memory serves in the US I could use an electronic E6B.

For the EASA exams you have to use a mechanical CRP-5 or equivalent. Electronic is not allowed, nor is a programmable calculator. If memory serves, the E6B was no good for EASA because it is missing a few of the needed speed conversions facilities.

I learned on the manual E6B and we teach it as a skill for PPL students. Circular slide rules are pretty nifty, gets you around a lot of the gross errors that you end up with if you fat-finger something on a calculator. I always tell students to guesstimate the output before calculating, then seeing if they're within 30%. If it's off by an order of magnitude, it's likely that there's an input error.

What did EASA not like about the E6B? You can do any speed conversions on the whiz wheel side aslong as you know the appropriate conversion (e.g. 1.852 for nm/km).

LH707330 wrote:

Starlionblue wrote:

26point2 wrote:

I too came from the mechanical E6B world but never used the electronic kind. Do I remember correctly that electronic E6Bs were not allowed during exams? Was it considered cheating? As a flight instructor in the late 1980s I was still teaching the manual device. Doubtful, but do student pilots still learn it today?

The “Circular Slide Rule” was a fascinating tool.

Yes, it is still taught today, unless things have changed in the past few years.

If memory serves in the US I could use an electronic E6B.

For the EASA exams you have to use a mechanical CRP-5 or equivalent. Electronic is not allowed, nor is a programmable calculator. If memory serves, the E6B was no good for EASA because it is missing a few of the needed speed conversions facilities.

I learned on the manual E6B and we teach it as a skill for PPL students. Circular slide rules are pretty nifty, gets you around a lot of the gross errors that you end up with if you fat-finger something on a calculator. I always tell students to guesstimate the output before calculating, then seeing if they're within 30%. If it's off by an order of magnitude, it's likely that there's an input error.

What did EASA not like about the E6B? You can do any speed conversions on the whiz wheel side aslong as you know the appropriate conversion (e.g. 1.852 for nm/km).

Hazy memory as it has been a few years, but IIRC you can do compressibility corrections on the CRP-5, which you can't on the E6B, and you need them for EASA exams.

Also I found wind calculations on the CRP-5 easier, but that's more of a style thing.

Starlionblue wrote:

LH707330 wrote:

Starlionblue wrote:

Yes, it is still taught today, unless things have changed in the past few years.

If memory serves in the US I could use an electronic E6B.

For the EASA exams you have to use a mechanical CRP-5 or equivalent. Electronic is not allowed, nor is a programmable calculator. If memory serves, the E6B was no good for EASA because it is missing a few of the needed speed conversions facilities.

I learned on the manual E6B and we teach it as a skill for PPL students. Circular slide rules are pretty nifty, gets you around a lot of the gross errors that you end up with if you fat-finger something on a calculator. I always tell students to guesstimate the output before calculating, then seeing if they're within 30%. If it's off by an order of magnitude, it's likely that there's an input error.

What did EASA not like about the E6B? You can do any speed conversions on the whiz wheel side aslong as you know the appropriate conversion (e.g. 1.852 for nm/km).

Hazy memory as it has been a few years, but IIRC you can do compressibility corrections on the CRP-5, which you can't on the E6B, and you need them for EASA exams.

Also I found wind calculations on the CRP-5 easier, but that's more of a style thing.

Compressibility is quite a useful one to have, that makes sense. I'll have to look up how the wind side behaves differently, I've always found the E6B to be pretty straightforward.

LH707330 wrote:

Starlionblue wrote:

LH707330 wrote:

I learned on the manual E6B and we teach it as a skill for PPL students. Circular slide rules are pretty nifty, gets you around a lot of the gross errors that you end up with if you fat-finger something on a calculator. I always tell students to guesstimate the output before calculating, then seeing if they're within 30%. If it's off by an order of magnitude, it's likely that there's an input error.

What did EASA not like about the E6B? You can do any speed conversions on the whiz wheel side aslong as you know the appropriate conversion (e.g. 1.852 for nm/km).

Hazy memory as it has been a few years, but IIRC you can do compressibility corrections on the CRP-5, which you can't on the E6B, and you need them for EASA exams.

Also I found wind calculations on the CRP-5 easier, but that's more of a style thing.

Compressibility is quite a useful one to have, that makes sense. I'll have to look up how the wind side behaves differently, I've always found the E6B to be pretty straightforward.

Compressibility correction is useful indeed. but in this case, it was useful to me because it was needed for the exam, not for any in-flight application.

For the wind, I think the CRP-5 and the E6B are pretty similar conceptually. But for some reason, I found things simpler on the CRP-5. I might have to dig them out and do a side by side comparison.

Interestingly, the CRx style whizz wheels use a different kind of wind calculation entirely. I never learned to use one, though. No point relearning when I already knew the CRP-5/E6B method. Here's a comparison of the two methods: http://www.stefanv.com/aviation/flight_computers.html

Starlionblue wrote:

LH707330 wrote:

Starlionblue wrote:

Hazy memory as it has been a few years, but IIRC you can do compressibility corrections on the CRP-5, which you can't on the E6B, and you need them for EASA exams.

Also I found wind calculations on the CRP-5 easier, but that's more of a style thing.

Compressibility is quite a useful one to have, that makes sense. I'll have to look up how the wind side behaves differently, I've always found the E6B to be pretty straightforward.

Compressibility correction is useful indeed. but in this case, it was useful to me because it was needed for the exam, not for any in-flight application.

For the wind, I think the CRP-5 and the E6B are pretty similar conceptually. But for some reason, I found things simpler on the CRP-5. I might have to dig them out and do a side by side comparison.

Interestingly, the CRx style whizz wheels use a different kind of wind calculation entirely. I never learned to use one, though. No point relearning when I already knew the CRP-5/E6B method. Here's a comparison of the two methods: http://www.stefanv.com/aviation/flight_computers.html

Thanks for that article, it was a good read! Using the CR5 seems straightforward enough, but I think it's probably harder to explain to students than the wind triangle method on the E6B. Whatever helps people fly the airplane proficiently instead of relying on magenta lines and ForeFlight nav logs....