Symmetric Propellers?

The only propeller options that Blue Robotics sells are asymmetric and I was curious if they could make a symmetric propeller? Many applications and thruster layouts could benefit from having equal forwards and backwards thrust. While it may not achieve as high of an efficiency in a particular direction, it could improve overall efficiency in a something like a two front facing, two back facing propeller configuration. In addition, this could make the control software easier to implement accurately.

Hi @sergmister, welcome to the forum :slight_smile:

Design and testing time as well as injection moulding machinery time and moulds are quite expensive, so mass-manufacturing and selling multiple propeller variations is likely not economical unless there’s a significant demand for different options in different use-cases. I will register your interest in the idea, but I don’t expect we’ll be selling an extra propeller option in the near future, unless perhaps it’s more efficient and is switched to as a replacement for the existing design.

It’s also worth noting that the thrust asymmetry is partly from the nozzle design, not just the propellers. You’ll notice that our new T500 Thrusters are extra forward-biased, which is partly due to the nozzle tapering that speeds up and guides the water flow in the forwards direction.

From a small-batch / individual standpoint, you could potentially 3D print custom propellor and/or nozzle designs, or 3D print custom moulds that could be used to make a few from one mould. I understand that’s quite limited in terms of the people who have access to the skills, knowledge, and equipment to do that effectively. There’s some possibility we could make a design and provide some CAD files, but it’s not a high enough priority to divert our limited R&D and testing resources to above our variety of other active projects, so it would only happen if someone decides it’s fun and worthwhile enough to do in their spare time (which would likely not be able to include any testing beyond fitment).