eCalc ??? Is it any use ??? ... and will this thing fly ???

[roycruse]

Hi guys

Im looking at eCalc and wondering if it has any meaning in the real world.

It doesnt seem to have a setting to choose between a Hexa and a Y6 or an Octo ands an X8

Im not sure the same calculations make sense when mounting motors side by side and one above the other.

In an X8 or a Y6 the under over motors will be assisting each other - the top prop supplying moving and pressurised airflow to the bottom prop and the bottom prop in turn providing a low pressure void below the top prop.

So does all the calculations go out the window in Y6 and X8 configurations.

I have finally got a couple of motors and speed controllers arrived in the post today and will start taking some real world readings tonight but I was just interested in seasoned multi rotor builders/flyers opinions of this software.

This is the kind of thing I'm hoping to build as an Aerial Photography / Videography platform to carry a Canon550D and 24mm wide angle prime lens... (total weight of camera = about 800g)

http://www.ecalc.ch/xcoptercalc_e.htm?ecalc&weight=3500&rotornumber=6&elevation=500&airtemp=25&batteries=lipo_2100mah_-_20/30c&s=3&p=4&chargestate=normal&esc=max_30a&motor=turnigy&type=sk2836-11&propeller=apc_electric_e&diameter=13&pitch=6.5&blades=2

 

[roycruse]

oh - i see the link generator thing doesnt work on it...

 

[jes1111]

Markus (of eCalc.ch) has not put any facility in there for coaxial setups because there are too many variables to be able to calculate the result with any reasonable accuracy and little scientific test data to verify against. The net loss you will experience between a coax pair and the same two motors in a side-by-side arrangement depends on diameter, spacing, the respective pitches, the respective diameters, the respective prop "styles", the profile/frontal area of the arm in between them, which way the wind is blowing, etc. What we do know is that there is some loss and that it's likely to be between 10 and 50% depending on your setup. What I tend to do for coax calculations is enter the average pitch of the top and bottom - so, for example, if I have 14x4 on top and 14x5 underneath, I'll enter 4.5 in the pitch field.

I view eCalc as indispensable, even without coax-specific calculations

The URL generator only works properly when eCalc is embedded in a commercial site.

 

[Bartman]

550D with wide angle.....easy.....I had an original MK Okto II with Robbe Roxxy motors that carried that camera/lens with enough power to spare.....motors are 110W each and had 10" props.....also had two 5000 mah 4S batteries, video Tx, MKTR camera mount

flight times were 7 to 8 minutes with outside temps at 90+ and 10 to 11 minutes with cooler temps.

Currently using a DW frame and heavier Avroto motors and a heavier camera mount I'm getting 9 to 10 minutes of flight time with the same batteries. Mikrokopter electronics on both examples.

Hope that helps.
Bart

 

[Bartman]

Is this your first attempt with RC stuff? If so, I'd suggest you buy a cheap quad and get a feel for things so the bigger stuff comes more naturally.
Have fun,
Bart

 

[roycruse]

thanks for you replies - all useful info.

not my first attempt at anything rc : but is my first attempt at a multi rotor - started flying slope soarers when I was 14 (which was 24 years ago now) and have had many many planes both ic and electric. I also fly helis but less confidently which is why I like the idea of a more stable platform of a quad for Aerial Photography than using a heli.

I find that when flying a heli far to much of my brain power is used up keeping the thing where i want it and not enough brain left over for the photography part. - I like the idea of a quad and its auto stabilising mode to leave me to concentrate on getting the shots.

on top of that I love learning new stuff and discovering things by trail and error and im looking forward to slowly putting something together.

I could never buy something like this ready made - would seem to defeat the object for me - must be home made... Im the kind of person who would rather take a day off work and have the washing machine in bits all over the living room to fix it rather than pay someone to come out

 

[Bartman]

I hear ya! I'm all for DIY but when analysis paralysis sets in you have to just put bit to material and start cutting something.

Good luck with it, we'll be looking forward to seeing what you come up with.

Bart