Motocalc or Ecalc?

[SIMON CRAGG]

I am fairly new to electric flight, but am getting there.

I more or less know my way round my Wattmeter, but am keen to learn more!.

As far as I can see there are really only two Calculator Templates, Moto calc and e.calc.

I have had a play with both free versions, and I prefer e.calc.

Before I purchase the full version of either, has anybody any experience of both, and the pros and cons please?

[Trevor]

There's also Drivecalc:

http://www.drivecalc.de

Trevor

[Ace]

Drivecalc - Talk about comprehensive with data overload ---- WOW

Thanks Trevor

[Alan H]

I've been using Drivecalc for several years and have found it gives a pretty good idea of what to expect from a given motor/battery/prop/ESC combination.

[SIMON CRAGG]

Posted by Trevor on 17/10/2019 08:12:53:

There's also Drivecalc:

http://www.drivecalc.de

Trevor

Thanks for that, but (as a novice at electric), did not find it as easy to use as e.calc.

Will certainly persevere with it though.

[Dickw]

I use both DriveCalc and MotoCalc and have found both to be very useful and reasonably accurate at predicting performance - provided you put decent data in to start with!

Dick

[SIMON CRAGG]

Anybody tried e.calc?

[PeterF]

I have MotoCalc and eCalc and have used both for many years, MotoCalc right back to the days of brushed motors and Nimh batteries. Whilst I believe that both are pretty accurate, my view is that eCalc is the more flexible and has a better database of motors and props. To that extent, I have pretty much given up on MotoCalc. I bought a new PC in July and have not yet loaded MotoCalc onto it because I have not missed it yet. I also have a few EDF models and eCalc also covers these in their FanCalc module. The only thing with eCalc is you do not have a program and your data recorded, so if eCalc goes belly up, then you have to start anew.

I have used eCalc from 300W small hand launch models through the 1600W power system on the 1/4 scale Tiger Moth in my avatar, which was chosen using eCalc up to a 2500W 80in wingspan CAP232 aerobat and twin 90mm EDF jet running 2 x 3000W motors, all with acceptable accuracy.

Edited By PeterF on 17/10/2019 12:30:24

[Bob Cotsford]

I use eCalc and tend to rely on it for initial settings for new models but I have to admit to not being familiar with the others mentioned above. I have eCalc, it works and it has a comprehensive database of prop, battery and motors that hasn't let me down - yet! The only thing I'd like added to it would be a simple way to save motor setups, you can give your configuration a name but I've yet to find out how to save it!

[PeterF]

Posted by Bob Cotsford on 17/10/2019 13:01:33:

The only thing I'd like added to it would be a simple way to save motor setups, you can give your configuration a name but I've yet to find out how to save it!

Bob,

When you have completed a calculation, press the "Share" button, this then puts a web address in your browser with all of the inputs in the address. You just then bookmark that page in your web browser. Then when you want to go back to a saved configuration, click on the saved bookmark and it repopulates eCalc with the saved configuration and then you press calculate to get back to the results where you left off.

Screenshot showing where the "Share" button is located.

For example, here is a link for my 1/4 scale Tiger Moth setup, click here to show how the system works.

Edited By PeterF on 17/10/2019 13:31:55

[Bob Cotsford]

Thanks Peter, I was expecting to be able to save to my PC where it would be easy to find with File Explorer. So is there a link to browse shared setups? I can't immediately see one, I'll take a closer look later.

[PeterF]

There is no save option to the hard disk, just saving a link / bookmark / favorite to your browser, but it contains all the input details so you can completely get back to where you were and continue with a series of calcs. I am pretty methodical about this, here is a snapshot of Chrome bookmarks and under my Mosquito I have 2 bookmarks, links / favorites saved for ecalc with different prop sizes as I was deciding on what I wanted to go for.

There is no link to shared set ups, eCalc do not save your setup if you press share. The purpose of the "Share" button is to create a web address that you can copy and then send to someone else so that they can see your setup and recreate it quickly via email, or as I did in my post above, by putting the link on a forum. However, to save it for yourself, you need to bookmark it, or perhaps even keep a document where you paste the links in.

If you are not familiar with bookmarks / saved links / favorites then there should be general help online for your particular browser.

[Bob Cotsford]

Thanks Peter, it would be easy enough to setup a new bookmark group in Firefox, pity about not being able to browse other's shared setups all the same.

[Geoff S]

I must admit that despite doing a lot of glow to electric conversions I've almost never used any of the s/w aids to do it. I merely start with a propellor and (usually) deciding on 10,000 rpm wot I design the drive train by rule of thumb, measurement and experience. They all seem to work OK. As electric motors are lighter than their glow equivalents I tend to over specify both motor and esc which I think helps reliability as well as balance.

Using one one of the eflight calculators is OK provided the motor (or one similar) is already one of the choices. If it isn't, then finding the detailed spec is very difficult because often all that's supplied is the kv, the physical dimensions and, if you're lucky, the maximum current. That's often not sufficient for the s/w.

Having said that, this thread reminded me that I have a copy of Moto Calc somewhere. It certainly is'nt on this 8 year old PC or wasn't until I downloaded it from MotoCalc's website. It asked me to register with a number or from a disk. I found my disk - a 3.5" floppy (with a few back-ups) that i bought from Gordon Tarling in 1998 (over 20 years ago) for £21. Fortunately I have a 3.5" FDD which connects to a uSB port. Within seconds I was reregistered and fully updated to run on Win 10. So at least you know that Motocalc honour their commitment to fully up date the s/w for ever (or at least after 20 years)

Geoff

[Trevor]

Geoff, I agree. I used ElecriCalc (also off a 3.5in floppy) back in the brushed motor/NiCd days, when sorting out a viable power setup was much more critical than it is nowadays. However I can’t remember when I last used one of these programs.

I keep a note of the setups on each plane I’ve got and when building something new, can usually find a previous model which can give me a good enough guide to pick out a suitable battery/ motor/prop combo. Truth is, modern brushless motors have such a wide efficiency band And LiPos are so much lighter than the old NiCds that it’s not so tricky as it used to be. Also, with so many motors to choose from, it must be hard for the writers of the calculators to keep their databases up to date.

[SIMON CRAGG]

I have got the stage where I need to establish which prop to use on my PT-19.

First question, do I have to use "e" rated props or can I use one of the hundreds of IC props I have collected?

Second question, when reading the watt meter and comparing props, am I right in thinking I need maximum Watts and minimum amps? Or is it a balance between the two?

Exciting times!

[Frank Skilbeck]

Simon, no problem in using IC props, just that they are slightly less efficient as they are thicker, especially at the hub, to accommodate the power pulses from an IC engine.

As for watts and amps, remember the watts = volts x amps, so max watts occur at max amps, if you are exceeding the amp rating of a motor or ESC and you aren't getting enough power then you need more volts and probably a different prop. This is where programs like Ecalc come in, you can experiment with different set ups without risking releasing the magic smoke.

BTW I have not used Motorcalc but do use Ecalc and drivecalc and like them both.