A+ Studio Hop Up Rubber

[DipTwit]

Jimski, all you're saying is that you'll get better range from "more power" which means more fps... which is not at all what I'm trying to refute (that you could get more range at the same muzzle velocity from some change in hopup)

Better accuracy... now you're agreeing with me

[ThunderCactus]

Actually its field proven fact that long flat patch rubbers (like the rhop and orga flat hop for ptw) give you a flatter trajectory.
Your guess is as good as mine as to why, I dont even have a decent guess. As far as I know spin is spin, more spin makes bbs fly up and less spin makes them hit the ground faster, but somehow the rhop and orga flat get you the same range with much less hump in the flight.
Ive also noticed, messing around with different diameter rollers on the ptw, that smaller diameter rollers produce more hump than larger diameter rollers when targetting the same distance.
Again, no idea why, it just works that way. So theorize away, but dont try to theory away a fact =)

Weight of bb is inconsequential to the trajectory of the bb, you can get any bb to fly straight, but heavier ammo will travel further, and you inevitably need more muzzle energy to use heavier ammo. So indirectly, fps does affect range, but only if you use heavier ammo to match.

[Spike]

[Drakker]

One hypothesis put forward as to why the trajectory is flatter with longer hops is that they don't need to push as much on the BB since the contact is longer. This means that the initial point around which the BB spins is closer to the center of the BB, while regular bump hops push harder on the BB (and the BB against the bottom of the barrel), making it spin away from it's center mass when it is suddenly released. While the BB is in flight it would progressively start spinning around it's center mass, but that would cause the BB to slowly fly up while it stabilizes, resulting in a less flat trajectory.

I'm no physicist but I think this makes some sense.

[ThunderCactus]

You just gave me a good idea!
If a BB is properly balanced, it has no choice but to spin around it's center mass, but perhaps it's not always round, and the center of mass changes when it goes through the hop rubber.
The added pressure of forcing the BB to skid through a short section of the barrel wall may deform the BB, or change the balance just enough to cause it to move its center mass ever so slightly.
That would account for better accuracy and range on the low pressure flat hops, but I'm not entirely sure just how it would affect the magnus effect.

But the skid mark could change the grip of the BB, causing it to fly up sooner. And applying less hop obviously gets rid of the hump, but having a smoother surface would cause the magnus effect to show later in the flight path and come on more gradually, giving you a flatter trajectory and more range.
The magnus effect gets stronger as the forward velocity is reduced, a reduction in surface smoothness could cause the BB to slow down faster and get more lift...
I like the second idea better lol

[Drakker]

As far as I know no one ever postulated that strong hops would deform the BB (but alas, I don't know every hypothesis out there). That is quite an interesting idea. Also, the quality of the barrel might play a part here, as a smoother, high quality finish barrel is less likely to scratch the BB, again affecting accuracy.

This would be quite simple to test, fire say in a pool from far away so make sure that no impact deforms or scratches it, and check the BB with the most accurate measuring tool you have access to and a microscope to check for scratches.

Considering the BB rides on top of the barrel, and that it will still pick up spin from contacting the surface, which is what LRB (slightly curved down barrels) used to exploit, if the BB is not spinning around it's center mass, it's going to hit the ceiling of the barrel erratically, and any defect in the barrel means even more erratic path inside the barrel, which results in lower accuracy with a regular hop, but not as bad of a loss with a flatter hop.

Also, people have speculated that when the BB stabilizes to spin around its center mass, it is actually bleeding energy and it reduces the spin rate faster, affecting the magnus effect at range, which directly affects how far the BB will fly.

[KenTsui]

If I remember correctly, HS5 hypothesized that the R-Hop does well because it aligns or encourages the alignment of the geometric center with the actual rotational axis. He called it the "Wobble Hypothesis".

https://sites.google.com/site/hsarmo...effectiverange

He theorizes that R-Hop reduces excess up and down movement, allowing it to maximize forward distance.

Perhaps this is why similar hop-up systems seem to have flatter trajectory, because it is more "efficient" and you don't need to over-hop it to get the same range.

[ThunderCactus]

Originally Posted by Drakker

As far as I know no one ever postulated that strong hops would deform the BB (but alas, I don't know every hypothesis out there).

Well, we've all been using the same style or similar variation of hop rubber until recently. It's just not something that's come into question....


I've done many reclamations of BBs from soft targets, haven't noticed anything really absolute apart from the odd ding, but those have been written off as metal air nozzle marks (from ptw)
I'd have to take a closer look at them if I try it again...

Anyway, used bioshot and BB bastard between tests and found the same thing occurred on both. I'm leaning towards an issue in physically altering the BB rather than how they're affecting the flight dynamics of the BB purely through spin and applied force. But, you know, I'm open to ideas lol

[Drakker]

It might actually be a combination of both.

[DipTwit]

Very curious - somehow it intuitively seems unlikely that you could deform the bb with something so soft as a hopup patch...

Noting that not all bb's are perfectly balanced though - could bring all kinds of mess into the equation, and *if* they weren't balanced around centre mass, their range would certainly suffer as the air resistance would go way up from the "wobble"

The thing is, though, I'd have to look it up, but I'm pretty sure bb will *always* adjust to spin around it's centre of mass to minimize wobble, all by itself. This is the same reason when you spin a hard-boiled egg on a table, lengthwise, it will actually stand up on end. Of course, a bb turning sideways in mid-air would do terrible things to its trajectory, but this is all a result of non-perfect bb's... not what hopup gave them their spin.

So I'm still not sure if we can say that better hopups actually extend range... but I'm still content to find the best one, cuz consistency = accuracy = more hits! I just installed an orga flat-hop, guess I'll see if I can tell the difference.

[chaz]

What about having dimples in the BB like golf balls? Dimples in golf balls reduce the drag on them allowing further shots? I know golf balls are not being "spun" like airsoft BBs but has this ever been looked at by manufacturers as a way to make better BBs?

[ThunderCactus]

The dimples would increase drag from the magnus effect, causing them to hit you in the back of the head.
Think of how much the stitches on a baseball affect it's direction.
There's nothing wrong with the design or shape of the ammo. The manufacturing could always improve, but it's pretty damn good as is.
And before anyone says it, rifled or shuttlecock rounds wouldn't be effective past 60ft or so. Rifle rounds are designed to perform at high velocity, without the magnus effect you just can't get any decent range out of a very low velocity projectile.

And I'm not saying the hop rubber is what's deforming the BBs, I'm saying its the PRESSURE of the hop rubber that causes it to be deformed by the BARREL.
You might think the barrel is polished, but look right below your hop patch, there's always a patch of BB residue.

[RDX672]

I switched thé modify nub for a Maple leaf ohm, now thé
G36c with reaps shoot at 240 feets. I ll have to get .32 bb to sée if it perform better than .3