Home About Vibration Dynamic Balancing

Welcome to the home of Precision on-site propeller balancing and vibration analysis for UAVs, drones, autonomous aircraft, both civilian and military

This is where you can find the most precise, accurate analysis and balancing of your propeller/motor combination. We're a mobile service and will travel to your company or to an airport conveniently nearby.  We're fully insured to work on UAV/drone power units and that is our specialty.

Our technician's hands-on aviation technical experience spans almost 50 years and a wide range of aircraft from cold-war era jet fighters and bombers to modern airliners and general aviation (GA) propeller-driven aircraft. A concurrent career in both electronics and software design spanning more than 35 years have added diagnostic and problem-solving skills second to none. Click here to see a few of the aircraft he has years of experience with ...

No more balancing for GA aircraft
We no longer perform balancing on general aviation aircraft (Cessna, Piper, Beech etc). However, havng successfully balanced well over 600 of these GA aircraft, over a 14 year span, we have a wealth of knowledge about the intricacies and tricks and traps associated with both static and dynamic balancing. We've seen all the different situations that can cause vibration in power units and propellers.

Why specialize in UAVs, drones, autonomous aircraft?
Because this is the new wave of aviation - a rebirth of aviation in another form - autonomous aircraft delivering cargo and people where they need to go without the need to first travel to an airport. It is exciting and we enjoy the challenge that this type of technology brings and are uniquely qualified to solve the special vibration problems that come with these versatile aircraft.

The next several paragraphs will give you a quick overview of diagnosis and balancing....

Why are typical UAV/drone propellers more challenging to balance?
Unlike those regular, fixed-wing aircraft, which cruise at about 2400 RPM, drones and UAVs are more difficult to balance because, for example during hover, the speed of each motor is constantly varying through a wide range of speeds in order to maintain a level attitude.

It takes many runs to bring the imbalance of each UAV or drone motor and prop down to close to zero. It also takes many judgements by a skilled expert during these runs in order to get these propellers to be in balance throughout their wide speed range.

So it's nothing like balancing the propellers of regular aircraft, where there is a steady cruise speed at which we need to have a smooth motor and prop. Dynamic balancing propellers on UAVs, drones, autonomous aircraft requires that the person doing the balancing be expert at tricking the assembly into complying.

Why is it so difficult to diagnose and fix the vibration?
Because vibration comes from a variety of sources and is difficult. but not impossible, to cure.

Just looking at a mass imbalance, for example, when you apply a corrective weight to the propeller hub this weight is only good for a specific narrow range of RPMs.
For example, putting a 12 gram weight somewhere on the hub might be the perfect amount of balancing weight at 2000 RPM but it could easily be too much or too little at a higher RPM. Also there will often be not just one but several mass imbalances around the hub, each requiring a corrective weight. These can and will interact with each other to give you a situation that is very difficult to resolve - unless you've seen hundreds or thousand
s of these and have developed the skills to get around the laws of physics enough to make the propeller assembly useable for your purposes.

First, however, the various sources of vibration must be clearly identifed and each must be remedied differently....and that's where we are head and shoulders above any other propeller balancing company.

How big a problem is vibration anyway?

An out-of-balace propeller wastes a lot of power!
This is crucial for an electric vehicle!
At 2400 rpm, an out of balance propeller is lifting and dropping the entire motor and prop assembly 40 times per second. You can imagine how much power that takes - instead of all the power going to traction, it's being wasted.

You probably have at least .4 ips of vibration occurring within your operating range
- that's over 40lbs of oscillating force at the front bearing
Amazingly, many start out with even more vibration! 
You need to get the total vibration down to .2ips or below throughout the operating range in order to have a smooth platform for your avionics and other equipment on board.

What's causing all this vibration?
Most of it is usually caused by prop/spinner mass imbalance.

However, other things can come into play too - blade tracking errors, pitch divergence between the blades mounted in a hub, even aerodynamic interaction between blades on a hub. These will play hell with the balancing equipment's readings, fooling it into asking for weights to try to eliminate vibration that's not caused by mass imbalance at all, but perhaps by pitch or tracking errors.

You can waste days, weeks, months trying to discover the cause and the cure for each of these and end up with nothing - or you can call us to come to your facility and cure it for you - a very wise choice.

What about static balancing?
Even if you carefully static balanced the propeller before installing it you will have serious vibration occurring somewhere in your hover or cruise speed range.:
A new prop is 'statically' balanced at rest, on a shaft which is placed on a set of parallel rails, not spin-balanced - there's a huge difference! - Static balancing cannot detect how the assembly will behave once it is spinning at high speed. Resonance plays a major role too - harmonic resonance of the blades, motor, mounting system and airframe can cause vibration spikes in various RPM ranges.

Static balancing gives your prop assembly a basic starting point, making sure the blades weigh the same at rest.

What skills are required to do multi-speed dynamic balancing?

It requires a set of special skills and experience that only someone with many years of experience can provide.Theoretical analysis won't work here - you need to have the assembly spun and the vibration diagnosed by someone with long practical experience. It can make the difference between success or failure of your entire project.

It typically takes 4-6 hours to dynamically balance a UAV prop assembly because we need to run it at many different speeds.

When we Dynamically balance your propeller assemblies you'll see a BIG improvement
We can completely eliminate vibration in most cases, or vastly reduce it.

Expert diagnosis
As well as balancing we can most certainly pinpoint the precise cause of any vibration and give guidance to ensure that you can identify and eliminate manufacturing, mounting and procedural errors.

GIve your UAV, drone or autonomous aircraft project the very best chance to succeed
Expert propeller balancing for unmanned aircraft - we'll help make your project fly right and on time.

Call (831) 331-3660 or email for an appointment.

You'll see why we're the best in the business, bar none!

Please explore these links for further details:
Home About Vibration Dynamic Balancing


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Last modified: April 04, 2018