A question about barrel length

[Floreos]

I don't see how the bernoulli effect is supposed to have any correlation to a BB rolling in a tube. You're comparing wings and balls here. And obviously when a wing touches the ground and changes angles it's going to send whatever it's attached to in a different direction. It's like you're saying if a planes wing fell off or was damaged mid flight that it's some how comparable to a ball spinning. This ball is being held to the top of the barrel via "the magnus effect" and pressurised air or Gas that it is rideing on.

You would be better off comparing it to a wheel.

[Ricochet]

Didn't BB Bastard or someone test these theories with lexan barrels and high speed cameras?

[ThunderCactus]

The magnus effect doesnt even work at high speeds, in the way we're using it.
And the high barrel pressure keeps he BB centered, and the magnus effect not working.
If the magnus effect was strong enough to lift the BB in the barrel, then it would start acting immediately as it left the barrel, but the magnus effect doesnt come into play until about 50ft out. Then its a very gradual increase in effect as the BB slows down and its able to move more air around to generate an airfoil.

But what makes it really impossible in high pressures is the BB is being PUSHED by the air. Air is pushing past the BB and bleeding past faster than he backspin can move air. At 400fps on a short barrel, a BB would have to be spinning fast enough to push air backwards PAST a 90-120psi compression wave in order to start generating lift.

The magnus effect only works at certain speeds where the BB can actually grip and move air in the direction it needs to in order to create that effect.
If the BB is travelling faster than it can generate an airfoil effect, then it wont generate an airfoil.
The slower the BB is going, the more the magnus effect will affect it.

If you look at a wing at high speeds, it generates lift up until it goes supersonic. Then the aerodynamics change.
If a BB were to go supersonic, it wouldnt matter how fast it was spinning, it would never generate any lift.
And if you have a pressure wave flowing back to front over your wing which outpressures anything in front of the wing, its never going to generate any lift.

[pestobanana]

The point is
1. If the BB rolled on the top of the barrel, it would cut off the airflow required to push the BB upward. Otherwise you could drive a car on a ceiling if the Magnus effect applied to wheels touching a surface.
2. The Magnus effect applies to objects moving through air, not object being propelled by air.

Read less bullshit on tech forums, learn more about physics and use rational thinking.

[Red Dot]

At OP, no barrel length isn't a big factor in the accuracy equation of airsoft. The hop-up unit and BB quality have more to do with that.

[Ricochet]

...I want supersonic BBs.

[cetane]

Originally Posted by Ricochet

...I want supersonic BBs.

https://youtu.be/98Zg8ZhwYqQ

[Floreos]

Well then why does every wide bore barrel manufacturer claim that it does what this guy is saying.

[pestobanana]

Every wide bore barrel manufacturer claims to give a better air cushion. I don't recall any manufacturer claiming that bbs ride the too of the barrel. If they did, TK twist barrels would have had really fucked up trajectories.

[Floreos]

I'm just going to concede the argument here. I've probably been swindled by some bad information.

[Ricochet]

Most of those opinions were cultivated out of subjective information. The wider the bore the stronger the cushion required to stabilize the BB, so wider bore barrels do work, but so do ones that are tighter. Really tight barrels can have varied results on stability though. Barrel length can have an affect on distance/accuracy, but it isn't the go-to dynamic to improve those things, it might make things worse as well.

[ThunderCactus]

Originally Posted by Floreos

Well then why does every wide bore barrel manufacturer claim that it does what this guy is saying.

Gotta market it somehow.
The truth of widebores is they just lose accuracy more slowly over many shots due to fouling.
But most people dont even clean their barrels more than once a year, so what do they care about lessened fouling?

A 6.23 is supposed to be more accurate. But a 6.03 and 6.23 have the same accuracy. People claim a 5.98 or 6.01 is more accurate. Again, no different than the 6.03 or 6.13 or 6.23.
The tighter barrels foul faster, thats about it.
I got a one shot kill at 300ft a few weeks ago with my M14; its using a 300mm pdi 6.05 with a suppressor. Heres the kicker; theres more empty space in front of the barrel to the end of the suppressor (310mm) than there is actual inner barrel in the gun.
I know a guy with a bolt action rifle with a 550mm 6.01 barrel that can make the same shot, but one has to wonder; whats the extra 250mm of barrel really doing? Its just more length for something to go wrong.

The barrel industry has many examples of bullshit theory being used to sell barrels;
-edgi 5.98 barrels
-TK twist barrels
-prometheus delta strike
-those new one piece inner/outer barrels

Fact is, the BB and hop rubber you use is going to have way more effect on accuracy than the barrel.
The worst thing a barrel can do to your accuracy is obstructing the BB; if it hits something in the barrel on the way through, it knocks the rotational axis of the backspin off centerline.
But beyond that, the barrel makes very little difference in accuracy at 200-300ft
All it does is send the BB out in a straight line and hopefully not affect the rotation.
The BB ideally never touches the wall, so bore doesnt matter.
The BB is stabilized to the center of the barrel in the first inch or so, so length doesnt matter except for ease of acceleration.
The only really important qualities are the consistency of the bore and the finish, so as to reduce any turbulent air flow in the barrel.
At 200+ft accuracy is almost entirely determined by BB weight, quality, and how consistent and perpendicular to the ground the backspin is.
Because using a king arms .30g BB over a madbull .30 is going to have way more effect on accuracy than using a stock marui barrel over a prometheus 6.03 at 250ft

[lurkingknight]

Originally Posted by pestobanana

Every wide bore barrel manufacturer claims to give a better air cushion. I don't recall any manufacturer claiming that bbs ride the too of the barrel. If they did, TK twist barrels would have had really fucked up trajectories.

I have a tk twist barrel... it gives super wild trajectories.