Torque roll


#1

Hi there,

I've watched a number of the youtube videos with the OpenRovs' in action. What i have picked up is the slight tendancy of the unit to torque roll.

I'm assuming this is because of the force exerted by the twin propellers spinning in the same direction?

In order that this can be eliminated, i'm planning on purchasing equivalent sized contra rotating props and swapping the wires on the ESC > brushless motors.

1. "The prop shop". Bespoke propellers, approx £40, lead time 3 weeks.... http://www.prop-shop.co.uk/

or2. Cornwall model boats, COTS propellers, http://www.cornwallmodelboats.co.uk/acatalog/propellers.html

Has anyone tried this?

Best regards,

Phil


#2

Hey Phil,

We're planning on switching to a different propeller as well: the Graupner 2308.60 and 2308L. Earlier, I did a blog post about some testing we did with these new props where I reported that the efficiency of a similar but slightly larger prop, the 2308.65 was more then 200% as efficient as the original Delta V-15's we've been using!

You can get the 2308.65 and the 2308.60 in both left-handed and right-handed configurations (just look for an "L" after the name for the left handed version, otherwise it's right-handed). The 2308.60 and 2308.60L are also very close to twice the efficiency as the original props, but because they're smaller, they deliver slow speed thrust a bit better which is more useful for our needs. We'll be including both left and right rotation 2308.60 props in our "v2.5" kits to reduce the torque roll you've described.

Thanks for the comment!

Eric


#3

Hi Eric,

Thanks for that, just had a read of the blog, really interesting stuff!

Looking forward to getting my v2.5 kit :slight_smile:

All the best,

Phil


#4

Hi Eric,

Do you have an approximate idea of the following?

  1. Motor stall current.
  2. Motor peak current.
  3. Motor operating current.

Best regards,

Phil