# Weedless Propeller Specs

**URL:** <https://discuss.bluerobotics.com/t/weedless-propeller-specs/17165>\
**Category:** Thrusters and Motors\
**Created:** [June 13, 2024, 4:36pm UTC](https://discuss.bluerobotics.com/t/weedless-propeller-specs/17165 "2024-06-13T16:36:45Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![EliotBR](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/eliotbr/32/6937_2.png) [@EliotBR](https://discuss.bluerobotics.com/u/EliotBR)\
**Post date:** [June 21, 2024, 5:27pm UTC](https://discuss.bluerobotics.com/t/weedless-propeller-specs/17165/4 "2024-06-21T17:27:18Z")

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> [@EliotBR](#):
>
> I’ve asked internally to see if I can get confirmation on the value, in which case we can hopefully include a value in the technical details.

Following up on this, I’ve been told my approach was indeed correct, but apparently the public CAD model has the blades slightly modified for IP reasons. The measurement from the actual design file has been confirmed as 14°, which I’ve now added to the technical details on the product page 🙂

> [@Matt\_D](#):
>
> This is a flawed way of measuring pitch as it does not account for slip, although, at the time this was the easiest way I could think of.

This is effectively a re-arrangement of my approach in [this T200 comment](https://discuss.bluerobotics.com/t/flow-rate-s-for-t200/4117/9), but with an included efficiency estimate (so you’re not the only one doing such calculations) 🙂

> [@Matt\_D](#):
>
> Pitch Angle = TANH( Pitch/ Circumference\_D\_0.75 )  
> **Pitch angle** =TANH( 124mm/(84mm\*PI) ) = 25 degrees

I’m assuming you meant \arctan here (i.e. \tan^{-1}), not hyperbolic tangent (\tanh)? That matches your calculated value, and makes follows your triangle logic description.

> [@Matt\_D](#):
>
> I’m not sure how to get notation into the post.

There’s a formatting section in the [How to Use the Forums](https://discuss.bluerobotics.com/t/how-to-use-the-blue-robotics-forums-please-read/10521) post, which covers the basics - the maths is essentially handled by LaTeX syntax, if you’re familiar with that 🙂

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