After seeing How the Gearbox works and the Air groupin this article we explain what Hop up a replica from is and how it works Airsoft which for those who are at the beginning, often turns out to be an unknown component.

It is a small mechanism present in the ASG that came into force in the 90s, which allows for a more precise trajectory during the release of the pellet.

The physical phenomenon

At the basis of the operation of the Hop up, there is the physical principle discovered by the scientist, Heinrich Gustav Magnus, lived in the 9th century. It is called the Magnus Effect and it is the variation of the trajectory of a rotating body in a moving fluid.

Practically, when the pellet is ejected and undergoes the rotation given by the Hop up rubber, the speed given by the fluid (air) increases more or less according to the direction of rotation of the body. This happens precisely due to the dragging of the fluid (air) around the pellet.

How hop up works

There are different models of Hop Upwhich vary according to the type of replica used, but in this article we will focus on the model that we find inside the M4, even if the operating logic remains unchanged.

The Hop Up system consists in inserting a rubber inside the barrel, which has the task of “containing” the pellet so that this, based on the adjustment given through the various wheels and levers, gives a “turn” to the pellet in able to lengthen and improve the outgoing trajectory.

So what happens?

The rubber gives the cue ball an angular velocity, as explained by the aforementioned physical phenomenon Magnus effect.

Hop-up operation

How do you adjust the hop up

Hop Up can be adjusted manuallyso as to choose which pressure to impress on the dot, by means of a pusher and gears. The choice is up to us because, depending on the friction, we will impart a different rotary motion to the cue ball.

In the image below showing the famous “T” of the Hop up with all its components, it is possible to notice the 3 main holes:

T Hop Up
“T” Hop Up
  • The one that points downwards from where the pellets enter and which connects directly to the magazine, widening the tab of the latter which unlocks the advancement of the pellets towards the inside of the “T”.
  • The rear hole into which the nozzle which carries one pellet at a time inside the barrel.
  • The front hole in which the barrel is housed complete with rubber. In a very precise point of the barrel there is a hole which allows the rubber, with the push given by the presser, to pop up inside the barrel, so as to give the “round” to the pellet.

Hop up replacement

Replace the Hop-up is a very simple operation which consists in extracting the “T” and the barrel from the front, simply by sliding it out.

Once you are holding the “T” with the barrel joined together, just peel the “C clip” remove the barrel from the “T” and it will come off together with the rubber. To replace the rubber just remove it from the barrel, being careful not to lose the presserand insert a new one, remembering to also reinsert the presser inside the Hop Up.

Furthermore, in the rubber, there is a small strip of embossed rubber that runs along the entire length of the rubber, this must be inserted into the groove on the barrel.

Hop up care and maintenance

As for the hop up the most delicate part is definitely the rubbersubject to wear. There are different types of rubber pads on the market and they can generally be divided into the softer ones and the harder ones (the former are those that require more maintenance). It may be useful to use it silicone spray to keep the eraser moist.

A damaged hop-up can cause many problems in a replica, among which

  • Power loss
  • Loss of accuracy
  • Loss of range
  • Pellets that are deflected at the exit

The cause, for the first two, could be due to the wear of the rubber which, if punctured, loses air outside the barrel. For aiming problems you must always check if the rubber inside the barrel is perfectly straight, in fact even a slightly displaced position deflects the dot in the opposite direction.

As always, our advice for beginners is to consult a trusted mechanic before proceeding with disassembly.

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By airsoft