# Blades-on Scale Factor Calibration {% hint style="danger" %} These directions require that you have already assembled, charged, and configured your power meter shaft. All necessary steps are covered in the [Getting Started](/2.1/kayak/getting-started.md) section. {% endhint %} ## 1. Place the paddle onto the calibration jig * Place the paddle onto the calibration jig, note if the left or right shaft is being calibrated. * The blade should be supported near its centre. * The shaft support should be approximately at the top hand position. ## 2. Measure distances and weights for calibration {% hint style="info" %} We recommend all lengths are recorded using millimetres, and weights using kilograms. {% endhint %} 1. **tipToDatum:** The distance from the blade tip to the datum of the shaft being calibrated. 2. **weight1, weight2:** The weight is measured in kilograms. Weight one will be lighter than weight 2. For reference, when we calibrate in the workshop we use 13kg for weight 1, and 26kg for weight 2. 3. **datumToDatum:** The distance between both datum points. 4. **tipToBlade:** The distance between the blade tip and the blade support. 5. **tipToShaft:** The distance between the blade tip and the shaft support. 6. **tipToCalWeight:** The distance between the blade tip and the location of the calibration weight hook. ## 3. Enter measurements into the calibration URL We'll need to take those measurements you just recorded and plug them into our calibration API via a special URL. The URL will look similar to this when we are done. #### The URL will always begin with : **?** The rest of the URL will need to be modified with your measurements from the previous step. The URL is sectioned into 'Key:Value' pairs, we have supplied the keys, you just need to enter your measurements as the values. Follow the table below if you need help. {% hint style="warning" %} All lengths are entered as metres, all weights are entered as kilograms {% endhint %} | Key | Value | | ----------------- | ------------------------------ | | shaft= | left, right | | \&tipToDatum= | your **tipToDatum** length | | \&weight1= | your **weight1** weight | | \&weight2= | your **weight2** weight | | \&datumToDatum= | your **datumToDatum** length | | \&tipToBlade= | your **tipToBlade** length | | \&tipToShaft= | your **tipToShaft** length | | \&tipToCalWeight= | your **tipToCalWeight** weight | All together your specific URL will look similar to the one below, all the value locations with your measurements are **bold**. \*\* ## 4. Connect using your specific URL 1. Connect to your power meter to our Web App via Bluetooth. 2. Enter your modified URL into the browser address bar and refresh. ![](/files/-M4NXljzljV1tpyUaZf1) ![After refreshing with your URL the calibration screen will appear](/files/-M4NoTunbh4UfeZJ37zL) ## 5. Record the Zero weight values Now we are all set to start recording our calibration data. First, we have to record a zero weight calibration. Before attaching any weight, click the **0** on the left-side of the fourth row from the top, shown below in the yellow box. This should update the fourth row with values in the **A, B,** and **C** columns, shown below in the purple box. ![](/files/-M563GwA13Vcr9UpPHN9) ## 6. Record the weight 1 values Attach the first set of weights (**weight1**) at the location designated in your earlier measurements. The first thing you should notice is a slight increase in the **Output** row values. To record these values we just click the **weight1 value** on the left side of the fifth row from the top(yellow). In the screenshot below, the **weight1 value** is **12.69**. After a successful click, the **weight1** values for the **A, B,** and **C** columns should all be updated(purple). ![](/files/-M563UblcTOv4uWwW7TT) ## 7. Record the weight 2 values Attach the second set of weights (**weight2**) at the same location as **weight1**. Check there is a slight increase in the **Output** row values. Click the **weight2 value** on the left side of the sixth row from the top(yellow). In the screenshot below, the **weight2 value** is **25.37**. After a successful click, the **weight2** values for the **A, B,** and **C** (purple) columns should all be updated. ![](/files/-M564ZCcKGs8SCwk0l_t) ## 8. Check the values and remove the weights Double check that all the weight values have been stored properly in the **Zero weight, weight1,** and **weight2** rows. Then go ahead and remove any weights that are still attached. ## 9. Update the Scale Factor values Now that you have all the values necessary for calibration, you'll need to update the scale factor. First, last check all the numbers look right. The **R**² row, fourth from the bottom (orange), should show the value of **1** for the **A**, **B**, and **C** columns. If everything looks good, click the **Scale F.** (yellow) text on the left side of the fifth row from the bottom. This will update your current scale factor values (purple) and ensure your power meter is calibrated and accurate for use. ![](/files/-M566K1-fwiWQbkTnTey) {% hint style="danger" %} If your **R**² values don't display properly, or if there are any other issues encountered during the calibration, please contact us at . Be sure to include a screenshot of your calibration and a brief explanation. {% endhint %} --- # Agent Instructions: 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: ``` GET https://support.onegiantleap.co.nz/2.1/kayak/calibration/scale-factor/dev-scale-factor-calibration.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.