> For the complete documentation index, see [llms.txt](https://docs.freeflysystems.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.freeflysystems.com/astro/maintenance/standard-maintenance-procedures/replacing-components/replacing-propellers.md). # Replacing Propellers {% embed url="" %} {% hint style="warning" %} Ensure rotation direction is correct. Always replace propellers with a set intended to rotate in the same direction (clockwise or counter-clockwise). We suggest replacing one propeller assembly at a time to minimize potential for mix-ups, rather than removing all propellers at once. {% endhint %} {% hint style="info" %} Always replace both propeller blades as a set. They are a matched and balanced pair, with matching serial numbers. This is to reduce vibration. {% endhint %} #### Astro vs Astro Max Motors Before you consider replacing props, it is important to identify the which Astro motors you have. The **Astro** is equipped with Freefly *F45* motors, where the **Astro Max** has a newer Freefly *7010* motor. In addition to providing more thrust than the prior generation motor, the Astro Max 7010 motors have a different mounting pattern for props than the F45 motor. Reference the image below to identify which one you have.
#### Identifying your current props Legacy props are 21" long and marked with "2170". High efficiency props are 22" long, and marked with "2270". Example of a 2270 CCW prop:\ ![](/files/5MhNBVGwJQ0qhMQuNbhc) #### **Which props do I need?** * Since we no longer sell the 21" (2170) props, we only carry the high-efficiency 22" (2270) props. * Depending on the motor you have, the 22" props will come with the appropriate mounting hardware. * If you have the Astro with F45 motors, you have the legacy Astro and will need to get the [Astro Legacy Spare Props](https://store.freeflysystems.com/collections/astro/products/astro-legacy-spare-propeller-set-2270-high-efficiency) (2270) * If you have the Astro with 7010 motors, you have Astro Max, and will need to get the [Astro Max Spare Props](https://store.freeflysystems.com/collections/astro/products/astro-max-spare-propeller-set-high-efficiency) (2270)
#### How many props do I need? 1. If you want to upgrade your legacy Astro (F45 motors) to maximize flight time, you'll need to purchase two sets of the 2270 props. We recommend a third set to have a spare set in your kit. 2. If you just need a replacement prop (CW or CCW) and have 21" props on your Astro marked with "2170" on the blade, you'll need to purchase two sets of the 2270 props so you can replace the props on all four motors. 3. If your Astro already has 22" props marked with "2270" on the blade, just purchase what you feel comfortable having for spares. Most people have one set (one each CW & CCW) in their kit. #### Steps to replace props on legacy Astro (F45 motors) 1. Remove fasteners between the prop hub and the motors: (x4) M3x10 bolts. 2. Remove the old propeller assembly. 3. Fit the new propeller assembly. 4. Apply Loctite 243 or equivalent to all screws before installing. torque to 1.5 Newton meters. 5. Reinstall (x4) M3x8 bolts.

Propellers are labelled with their orientation, Clockwise (CW) or Counter-clockwise (CCW).

The correct direction of the propellers is shown below. Please note the arrow indicating the front of the Astro, which is easily identified by the cylindrical antenna. ![](/files/BRUuYk5sXAuwnorbwKJv) ### Prop Tension Each blade of the propeller assembly should move freely with a small amount of resistance. It should not be difficult to fold the prop manually, and the force of gravity should be enough to pivot the blade at the bolt if the aircraft is rotated. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.freeflysystems.com/astro/maintenance/standard-maintenance-procedures/replacing-components/replacing-propellers.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.