Sewdhull
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Posts posted by Sewdhull
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1 hour ago, Pseudotectonic said:
500C heatgun didn't seem to remove the springiness on the compressed coils on my m90
Not even if I tried to get it to settle afterwards by compressing it for a week inside a torch
It was nowhere near cherry colour tho, it did darken the bright shiny metal a little (could just be surface grease)
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I guess the 20 FPS loss from removing the bearing is actually because the rotational friction on the non-bearing side is slowing its decompression
Try playing with a spring by hand, but twist it or keep it from spinning, the twisting itself is going to affect it wants to expand/compress, in fact you can try to compress/decompress the spring by the twisting alone
You need 800+Celcius to anneal springs, stainless is higher.
The 20FPS loss is because the spring is less pre compressed, there's no extra friction in having 1 bearing instead of 2. I'm going to explain why because it's come up before.
If you compress a spring one end will rotate with respect to the other and if you have a bearing at one end, that end will rotate freely because bearings have less friction than the spring rubbing against another flat surface and once the bearing is rotating there is not enough force to rotate at the other end. The whole spring is not rotating, the wire is repositioning itself as it is put in torsion, so if it is fixed at one end the other rotates.
In Airsoft we have bearings not for friction issues, but so that the spring maintains its shape and does not bend to one side or the other when it gets compressed. You could fix the spring at both ends and have no frictional losses but you would still have the spring deforming as it compresses.
If you put a bearing at both ends and lets say, one bearing is a bit stiffer than the other, then the bearing with the least friction will rotate first, but the other bearing will not rotate because the force to rotate it never gets high enough since it is relieved by the first bearing to rotate. This is essentially what happens if you have just one bearing.
Remember that if the spring is fixed at one end there are no frictional losses, as it doesn't move.
Friction also doesn't care about area, only the force and coefficient of friction. So if you have a bearing at both ends the friction is double that of one bearing, since the force at both ends of the spring is the same. If only one bearing rotates, the friction is halved. Because the angle the spring rotates is double with 1 bearing the same amount of losses occur. Both bearings need to rotate of course for this to be true.
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312 xt95324 xt100
356 Xt105
That was on the MP5 and I lost just under 20FPS going to one bearing from 2 so they would be a bit higher with the 2 bearings.
Progressive springs are designed to have the coils close up and (they would not be progressive if they did not) you will end up with a spring that wants to bend in the middle if you heat up the middle of it to remove the springiness.
If you really want to shorten a spring don't cut any off, pop it in a cup of water leaving the 15mm( or whatever you want to shorten the spring by) poking out and heat up the end with a propane o butane torch nice and quickly to a cherry red colour. Let it cool in the air. Then compress it on a long bolt to shorten it. You can repeat the process if you need to. I've never really understood why people cut the spring at all.
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Ultimately the thing that determines the strength of the spring is the force needed to compress it when installed and compressed in the cylinder.
You can have a long weak spring that gets pre compressed on installation and will be the same rating as a short strong spring which gets pre compressed less. They are all of similar length with variations of up to 25mm from those I have.
2 minutes ago, DanBow said:No.
Then that option is not available to you.
It's not the length that matters but how it's used.
I bought a selection of AKs springs when I was trying to get the right fps on the MP5
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A certain rated spring takes into account the length of the spring to arrive at the strength the spring will be used at.
For example you can increase the strength of a spring using spacers to pre-compress it or it can be longer than another spring with same spring constant which ends up pre compressing it when installed. In fact all the springs seems to have a degree of pre compression when installed.
For springs that are the same length they need to be stiffer, thicker wire or some such. Looking at the springs I have what seems to happen is that some springs are just longer than an otherwise identical spring, until you need to use a stiffer material because you'll run out of room to compress it.
Springs are cheap enough, I wouldn't bother cutting one. Take off a bearing at the guide end if you have one on the cylinder head perhaps, you don't need 2 bearings.
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Are all those bearings the same width? I use some 3x8x3 bearings and they do protrude and the one under the selector plate needed the plate relieving, but yours look wrong. One flush and one not is weird. i think you'll need to open it up again...
Select 3mm ID and you'll see 2, 2.5, 3 and 4mm widths.
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LOL, it's not weight, it's mass. Then yes, 2k extra for you. Altho the hop works to counter the weight of the BB so i guess either would work...
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1 hour ago, Lozart said:
I'm not sure I get this - a heavier BB leaves the barrel at a lower velocity, the energy on impact would be higher because they carry more momentum but I don't see how an object travelling more slowly will get there quicker.
The reason is that the average speed of the bb is higher if it is heavier. With greater mass the bb slows down more slowly and the force due to drag is less because of the reduced speed from the outset.
So you have less deceleration all the time for the same speed (.2 vs .4 is half of the deceleration due to drag of the .2) and more drag for the same energy for the .2, because its going faster and drag is exponentially increased with speed.
The result is that the .2 has a high force slowing a light bb which reduces it's speed much more than the lower force on a heavier bb. The heavy one overtakes the light one in effect and arrives sooner than the light one.
The graph above from the Airsoft trajectory project shows the time and mass relationship.
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Yeah time to target will be less with a heavier BB. Clearly at first, 15 to 20m if I recall correctly, the lighter BB will arrive first but the amount of time you are looking at is neglible. Only once the distance increases does time difference become a factor and then in favour of the heavier BB.
Range is dictated by the hops ability to spin the BB and this uses energy so if you keep the same spring etc and try to spin a heavier BB you will lose some FPS but not necessarily any range, but you might.
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A heavier BB will go further and quicker than a lighter one if it has the same forwards energy.
The issue comes when you add hop to impart more of the springs energy to the BB to make it spin in a similar way to a lighter BB which leaves less energy to make it go forward, so it's slower out of the barrel not only because it's heavier, but also because some of the pushing energy got used up getting it to spin.
Normally we would adjust the spring to add some FPS to compensate for the hop rubbing more.
Joule creep happens because a heavier BB takes longer to speed up and exit the barrel than a lighter BB so the force acting on the BB can do so for a longer time (potentially the pressure will be higher too). This only works if the lighter BB wouldn't have used all the energy.
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You should get a couple of clips for the trigger and ARL. Makes a significant positive difference to putting the gearbox back together.
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4 hours ago, Pseudotectonic said:
Actually, why not invite him in here for a chat
Yes this.
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I'm not deaf, so i can't say how it affects someone.
Here we are( sorry) ranking the problems we perceive that a deaf a person would have in our game and how it affects us and them. Only the deaf person can say really.
One of the main issues I have seen is social isolation, get him out playing a game, if he cant hear his hits (that tickled me) shoot him again for example. Speech to text is widely available so he can read the chat going on around him at lunch or whatever. I'm sure he can figure stuff out, its clunky compared to just speaking but perfectly serviceable.
Nothing wrong being out of a comfort zone... unless you don't want to be.
- Tackle, Shamal, Tactical Pith Helmet and 1 other
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Have a look on Reapers Air soft, he has a table he has done for various motors and their mAh per shot.
Go to 43 mins to see that table, but long story short around 1mAh a shot is the highest. Depending on the motor you may get from 900 to 5800 bbs for each 1000MAh. There are lots of variables tho, and data measurement can vary with method so it's going to be ballpark.
8 minutes ago, DanBow said:5000 shots!!! Jesus!
What started me looking in to this is the last time I played i got through a fully charged 450mAh in a morning and estimated that id only shot about 500 shots. That figure came from google and i thought that if its right, then a full battery in the morning was about right.
You will get more shots from a good ( low IR) battery of the same capacity and a good battery running at a fraction of it's current giving ability will give you more shots than a smaller one running closer to it's limit.
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If his only issue is that he can't hear, then it's down to the 34 year old man what he does. Not his sister.
If there's more than the deafness things might be different, but there's nothing to suggest that.
I mean his mum, your sister....
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His deafness isn't an issue is it? Reasonable accommodations can be made, visual signs rather than audible etc. It's no big deal in something like Airsoft.
If he can read, he can understand a briefing, or perhaps lip read. Most Comms issues I've seen with the deaf are the non deaf persons issue.
Worried about him not calling his hits?
A proper briefing seems like a good idea.
Some of the stuff above is patronising rubbish.
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Yeah you'll need to look inside. Jams can damage stuff way back.
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It's useful to know how your own setup performs if you like to fiddle. I'm the same
It's difficult to remove that smacking, some used an airbrake but it's very difficult because of the way the guns work.
If the cylinder maintained pressure maybe you could do it, but it might rebounding anyway so I dunno
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The shape of the metal bit spreads the load inside the stock too.
I wonder how easy they are to make, I might have a go since I have a couple of mp5s
Blue dust coming out of gearbox
in Electric Guns
Posted · Edited by Sewdhull
The only corrosion that's blue I know of is that of copper.
But it could be ground up thread lock