The PB‑3 is a sophisticated electronic device that measures the vibration produced by an out of balance propeller or rotor and sends that information to an Android™ smartphone or tablet using Bluetooth® wireless technology.

The Propeller Balancer App is an Android^† app that provides the user interface for the PB‑3. It features 4 main views:

Polar chart	Spectrum display
Used when balancing	Used to diagnose vibration problems
Numeric display	Graphical Display
Simple readout of vibration level	Another diagnostic tool

The PB‑3 can be used on a wide variety of propellers, engines and airframes - from Microlights to Warbirds, 2-strokes to Turboprops. Take a look at the customer photo gallery to see examples of the PB-3 in use.

^†The app is not compatible with the iPad or iPhone.

Intelligent Polar Chart Provides Balance Solution

The "Polar Wizard" tells you the adjustments required to balance a propeller.

Similarly, when balancing a rotor, the app suggests the adjustments required to improve the spanwise and chordwise balance.

Here is an example of using the polar wizard to balance a propeller.

Spectrum Display and Analysis

The vibration spectrum can be displayed and analysed.

Persistent Tagged Data

Vibration data is grouped by job and tagged with a job name (e.g. the aircraft registration).

Data Export

Vibration data can be exported as SQL or CSV (for incorporation in spreadsheets, etc.).

Image Export

All of the views can be exported as images which may then be shared by Bluetooth, email, etc.

Wireless Connectivity

You are not tied to the aircraft with cables when balancing.

Inbuilt Optical Tachometer

Simplifies setup and reduces the number of cables required.

External Tachometer Input

For applications such as gyroplane rotor balancing, an external tachometer is used.

Micro USB Charger Socket

Compatible with modern mobile phone chargers.

The PB-3 propeller balancer kit comprises:

• PB-3 device incorporating an optical tachometer.
• Dual-axis accelerometer and cable^†.
• Retroreflective tape.
• Balance weights (stainless steel washers)
• USB cable for charging and firmware upgrades.
• Printed manuals.
• Carrying case.

^† standard length for the propeller balancing kit is 3M - other lengths available on request.

The kit does not include a charger (the PB-3 requires a 5V USB charger as used by mobile phones). If you need (yet another!) charger, one can be supplied for free (UK or European style mains plug only).

The rotor balancing kit also includes a Red LED Tacho Sensor & cable.

This sensor is designed specifically for measuring the RPM of rotors.

Features of this sensor are:

• Robust, splash proof design.
• Utilises Digital Signal Processing to enhance noise immunity.
• The use of a visible light source makes alignment easy.
• Detects retroreflective tape from 1cm to 100cm away.

BTW, if you think the PB-3 is expensive, consider this: the price of a PB-3 + the cost of a new, good quality, Android tablet is still only about 1/4 of the cost of the cheapest alternative brand of dynamic balancer product (with similar features) currently on sale worldwide.

An Android device is not supplied with the PB‑3.

A mounting bracket for the vibration sensor if it cannot be directly attached to the front of the engine. Often this is simply a strip of metal with a couple of holes drilled in it. Exactly what is required depends on the engine type and installation.

For rotor balancing, one or two mounting brackets are required to mount the accelerometer and the tacho sensor. Often, only one bracket will be required for both sensors as shown here in this picture of the sensors mounted on the rotorhead of an ELA gyro:

Here's another photo showing the sensors mounted on a Dynali Helicopter using a simple "L" shaped bracket.

Full details of how the PB‑3, tacho sensor and the app are used can be found in these documents:

• PB-3 Propeller Balancer User Manual (last updated 6/11/2013)
• Red LED Tacho Sensor Manual (last updated 16/11/2013)
• Propeller Balancer App User Manual (last updated 07/08/2016)

Before you can install the app, you need to tell your Android device that it's OK to install non-Market applications. Go to Menu > Settings > Applications and make sure that the Unknown Sources checkbox is checked. Using a barcode scanning app, you can download the latest version of the propeller balancer app directly to your Android device using the QR code on the right. Alternatively, click on the QR code to start the download.

You must accept these permissions for the app to be installed:

Storage

To export images to the device's external storage (SD card).

Network communications

To communicate with the PB‑3.

System tools

To request enabling of Bluetooth and adjustment of the screen timeout.

The app release history is here.

The Propeller Balancer app uses the services of a 3rd party File Manager app, the OI File Manager - you can install that app from either the Android Market or directly from Open Intents.

The PB‑3 firmware is easily updated - when they become available, firmware updates can be downloaded from here.

The Android device must be running version 2.1 (Eclair) or higher and support Bluetooth SPP.

At this time, all Android devices have screens that are not easily viewed when directly illuminated by bright sunlight. Some are better than others in this respect. So, before you buy an expensive Android phone or tablet for use with a PB‑3, you are advised to check how visible its screen is in direct sunlight.

It is strongly recommended that you use a device that has a capacitive touch-screen as they are much easier to use than devices that have resistive touch-screens. This is especially true for small screens. For larger screens, the insensitivity of resistive screens is less of a problem (but still annoying!)

For propeller balancing, the app is quite usable on small screens (e.g. phones). For rotor balancing, the 7" tablet format is ideal because the screen is large enough to be easy to use but the device is not so large as to be unmanageable.

The PB‑3 should work with many different Android devices. Here are a few it is known to work with:

Finally, if you obtain an unlocked Android phone, you can then use a pay-as-you-go SIM card in it thus avoiding the need to sign up for an expensive monthly contract. In the UK, one of the cheapest options is giffgaff.

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