Hop Up Science #2

It is rare to go to a game day, and not see people tinkering with their hop-up’s at the end of their guns in between rounds. Hop-up has come in many forms, and materials and ask any player their preferred brand and they will give you a host of names/makers and places to buy from.

However, if you do not know what a hop-up is, or - what it does, you may just end up spending your hard earned coin on a product that may not be suitable, or does not work with your type of gel blaster.

So first, up – what is a hop-up and what does it do? A hop-up applies backspin to the ball, as it is coming out of the barrel. Essentially, instead of the gel travelling a certain distance and then falling to the ground in an arc shaped trajectory, the backspin enables the pellet to fly further on a straighter flight patch. This occurs due to the influence of three factors:

The Magnus Effect, occurs when a spinning spherical or cylindrical object has air moving over it transverse (across) to the axis of rotation. One side is opposing the flow of air which ‘slows’ the airflow, and causes a higher-pressure air build up to occur. Because the other side of the ball is rotating in the same direction of the air, and either has no effect, speeds it up via skin drag, lowering the pressure. Which leads us to….

Bernoulli’s Principle. This principle states, in part, that restrictions cause things to flow faster, and faster fluids have lower pressure. (A good example of this is to put your finger over the end of the hose. The water pressure increases due to the restriction, causing the flowing water to move faster past the point of the restriction.)

Finally, The Coanda Effect, which is the tendency for a fluid to be attracted to a nearby surface, and by extension, follow a curved surface. This is important because the gel ball is spherical.

The tongue inside a gelball hop-up acts as the bucking found in airsoft style hop-ups. Here's a good example of how it works: 

The combination of the ‘restriction’ of the barrel, combined with the changing pressure, acts to create a pressure difference across the spherical pellet, which in turn imparts a force upon it.

So how do you use this to your advantage? Adjusting your hop-up for peak performance takes patience and a small amount of precision, it’s certainly not something you want to be adjusting on the fly if you can help it, and especially if it’s your first time trying to tune it in,.

We recommend having a play around at home with the hop to try to get an idea of what you gun is capabale of, and finding the sweet spot for getting a low, flat trajectory, as this is what you’re aiming for. 

Adjustments to your hop-up can result in three different outcomes, too much, not enough, just right. Here is what to expect from the three, and how to identify them.

Too Much Hop – The purpose of backspin is counteract gravity, however too much backspin will make your gel travel along a relatively straight path, and then start to fly up as the backspin takes effect. This will result in a strange almost vertical trajectory.

Not Enough Hop – If you are starting to apply backspin, you should begin to notice your gels range increasing and travelling along a floating trajectory. If you are not applying any backspin, the path the gel moves will just be a short arc, starting at the barrel and slowly working to the ground.

Just Right – It is worth testing both the too much, and too little ends of the spectrum to get a gauge of how your blaster fires with each, so you know what to look for when you find the sweet spot. If you are testing adding maximum backspin, look for when the gel would start to travel upwards, this should be the point where the backspin effect kicks in, and holds the gel level in the air. A flat trajectory that gently lifts to a floating trajectory is the end goal, and will provide the best results for range and accuracy.

There is near no situations where a hop up would be a disadvantage, more range and accuracy is a dream come true for most players, however achieving it is not simple, and does require some finesse.

With a basic understanding of the forces and physics at play, and a little experience, you will find tuning your hop-ups for maximum performance a breeze!
 
SEE YOU ON THE FIELD!
- Grant / "THURISAZ"