Some easy simple Airsoft Maths that I think work

[Sitting Duck]

I'm sure these easy ways to work stuff out is pretty damn accurate & no calculator
or degree in mathematical engineering required

I have checked them and the gears ratio saves a major headache indeed

(unless you love counting up tiny teeth - 21 22 23 23 - no crap start again 1 2 3)

Count amount of turns on bevel gear to rotate the sector gear 1 full revolution & multiply by 3

checked this against stock, high speed & high torque gears - works out very well

and finally figured out wtf all them 100:200 & 100:300 gears bloody mean as well

Then just recently noticed how the port on cylinder kind of works out right without
all that Pi r ² crap working out volumes of cylinder & barrel and ratios etc....

So please have a look and if your own gun is running well see if the cylinder port bit makes sense
eg: length to port minus 12mm aprox = say 30mm....
multiply that final figure by ten - yeah I think you shouldn't need calculator for that one
= 300mm barrel for that port position

yes there a few variables eg: Tight Bore & Bore up kits but in general these will only throw out figures
on volume ratio by about 1% to 1.5% max on each variable....

I have checked this against a few cylinders that are for certain barrels and it works out very well indeed

(it is that simple to me I dunno why peeps bother with old π r ² x cylinder/barrel length)

plus some programs for calculating ratios are not easy to understand or don't seem to work out right to me

(bit where you enter or measure cylinder length or port is a little unclear to me)

plus people saying oh yeah a 3/4 cylinder is for 363 to 410 - wtf ?

3/4 is not exactly very pinpoint accurate and range of nearly 2 inches is also a little wide too ffs

I think it is nigh on there with the 12mm figure subtraction is about correct - but the cylinder should have AOE done

(Should really do AOE anyway is the general feeling)

This adds aprox 4-5mm to say 6mm on cylinder head inside the cylinder itself - never mind go with 12mm for now ffs

(O-ring sits aprox 2mm back from piston and is what creates the seal really so just go for 12mm - trust me)
anyway here are the pics that should be speak for themselves

give us any feedback if you can though chaps.....

&

cheers for any feedback even if I am talking out of my ar$e one more

Just thought if anybody was putting together a gearbox these could come in handy
to suss out what gear ratio you putting in there (in case you forgot or lost the packet they came in)
and also if you got a cylinder knocking about but unsure what barrel it is supposed to be used with etc....

Yes they ain't 101% accurate but imho these 2 quick tests are bloomin' close without all the maths

EDIT - make that figure aprox 15mm NOT 12mm - my very bad

12mm is piston but aprox 3mm further back from piston is center of O-ring which in effect is where the compression is created

or rather not created until it passes the end of port - therefore it is the O-ring's start & finish or travel is what we are trying to work out

So measure front of cylinder to port and subtract 15mm not 12mm - then multiply by 10 = ideal barrel range chaps

EDIT - 2018, after reviewing my crap I revised this to 15mm for 0.20's and say 20mm subtraction for say heavier 0.30's

 

[SeniorSpaz87]

And who said you wouldn't need math outside of high school...

 

[Sitting Duck]

I'm all for doing stuff properly when it has to be

but if there is an easier simpler method that works I'll deffo use that

but sod doing an Open University Course just to figure out some stuff in my toy gun

(I get bored at work sometimes and kept doing all these maths and wtf - that simple crap works as well)

 

[DEDSEC]

Ugh regret failing maths back in school...

Don't suppose you could use your genius mind to create a time machine to go back to the 80/ 90's?

 

[Sitting Duck]

Just a week would be perfect to win last week's lottery = MY OWN AIRSOFT ARMY

Seriously the maths on ratio does work BUT - for "general" chrono/airsoft setup's

eg: this is the maths that in effect gives you the 1.5~1.6 ratio's for the "normal" 0.20's and maybe 0.25's

All this bollox can really change when using heavier 0.30's and will be off for say DMR's using .36's

The heavier bb's will need a great ratio of 1.8 to 2.0 perhaps to shift the heavier mass of bb correctly

Airsoft Ed made a post about this over volume and there are many articles saying heavier bb's need higher volume ratio

As it stands the basic quick check does work I reckon - for 0.20's at the chrono and how most stuff is shipped to run with

However for those players seeking better performance with slightly heavier bb's the number 12 will not work for them

These heavier bb's or higher volumes may need a larger number subtracted - eg: 16 instead of 12mm

(42mm - 16 = 26 or 260 barrel with higher volume to push out heavier bb's - but I am guessing this bit atm coz I dunno)

Heck I'm no expert mofo but just the numbers adding up or correlating on the 1.5/1.6 ratio and thought I'd inform you chaps

and gear check thingy is coz I hate counting tiny gears and all that crap multiply this n that divide by wtf etc...

I'm throwing this out there and if anybody looks into it and gives us some feedback we might all be able to arrive at a good

all round quick ratio checker for normal bb's AND if we get some feedback adapt change the magic number 12 according

to what bb's people use and we may be able to perfect it more for all weights of bb's

(might be increase 12mm by 1.5 or 2mm for each .05g increment etc... but am open to any feedback like I said)

 

[Lozart]

And who said you wouldn't need math outside of high school...

"maths", "secondary school". Where did you grow up, America?

 

[SeniorSpaz87]

"maths", "secondary school". Where did you grow up, America?

although I am American, I have been living elsewhere since I was 12. Math was a typo, or mybe autocorrect. And its just habit to call it high school, as my US and Singapore schools both called it that, and my current IB school has PYP, MYP and IBDP, not primary and secondary school.

 

[Lozart]

although I am American, I have been living elsewhere since I was 12. Math was a typo, or mybe autocorrect. And its just habit to call it high school, as my US and Singapore schools both called it that, and my current IB school has PYP, MYP and IBDP, not primary and secondary school.

fair play then! Where in the US are you from then? How come Singapore, forces parents? Just being nosey like....

 

[SeniorSpaz87]

haha, not forces. my dad works for Abbott Labs, which is a big pharmacutical (pardon my spelling, my ipad doesnt do autocorrect) company, and he keeps getting promoted, so we move every two years or so. I lived in five states by the time I was five, but we set up in Tennessee for 8 years. Singapore was our first overseas move, and now we are about to start our fourth year here in the UK.

 

[Lozart]

So how do you like it here? Are you near Maidenhead then? I'm assuming as that's where Abbots are....

 

[SeniorSpaz87]

Im in Sunningdale, as you should know Lozart (think UGL). Its nice here, and I dread moving back to the US for uni, as I dont wnt to lose my sport

 

[Lozart]

Im in Sunningdale, as you should know Lozart (think UGL). Its nice here, and I dread moving back to the US for uni, as I dont wnt to lose my sport

Oh yeah.....duuurrrrrrrr. Sorry having a bit of a "slow" day today

Can you not do uni here then?

 

[SeniorSpaz87]

based off my career options and wants, I am torn between Richmond uni here, and either FIT or UCF in Florida. Also, I have an open offer for an internship in florida, but whether I decide to do that year-round, or just over the summers, i do not yet know

 

[Lozart]

What are you looking at going into as a career then?

To be fair if you already have an internship offer I can see why you're torn!

 

[SeniorSpaz87]

im big on CAD/CAM and computer design manufacture. Based my IB diploma around it as well, and have been doing it with Autodesk Maya, ProDesktop, and Solidworks for four years in Singapore and here. Also, as some of you will probably like to hear, I have been to the main Safariland plant in Florda and met with the designers there (thats why I know Bill Rogers amd have so many Safariland products).

 

[Sitting Duck]

Oi - do you two wanna flirt somewhere else or something

jeeeez thought there was gonna be some new findings/results

And I thought I was the main thread derailer or hijacker

 

[SeniorSpaz87]

haha, I was thinking we had kinda disrupted the thread....

 

[Sitting Duck]

haha, I was thinking we had kinda disrupted the thread....

lol- no worries - it is normally me doing that as it is what I do best

(or majored in if we talking in US english)

 

[Lozart]

Oi - do you two wanna flirt somewhere else or something

jeeeez thought there was gonna be some new findings/results

And I thought I was the main thread derailer or hijacker

Yeah....sorry about that

 

[BrightCandle]

Lets assume that there is a magic ratio of air volume for the barrel verses the cylinder, that is the current theory that if we maintain this ratio then we get the best performance. We can define that ratio as follows:

MagicRatio = VolumeOfBarrel / VolumeOfCylinder

I make a 453mm 6.05mm barrel volume of 16580.93mm^2

I make the volume of a non ported cylinder as 8111.17mm^2

Making the ideal ratio 16580.93 / 8111.17 = 2.044

The volume of cylinder is radius ^ 2 * length.

Lets assume a 6.05mm barrel for simplicities sake and a variable length we get VolumeOfBarrel= 36.6025 * BarrelLength

The VolumeOfCylinder uses the same equation for the volume of a cylinder. A full length cylinder has 58.75mm of usable length but this varies with the port but its inner radius is going to be 11.75mm (not a bore up). So we get 138.0625 * LengthOfCylinder

If we substitute those into the equation:

MagicRatio = 36.6025 * BarrelLength / 138.0625 * CylinderLength

The MagicRatio we know from the considered optimal setup so we can use that to eliminate the term:

2.044 = 36.6025 * BarrelLength / 138.0625 * CylinderLength

Now we need to rearrange it a bit

138.0625 * CylinderLength * 2.044 = 36.6025 * BarrelLength

282.19975 * CylinderLength = 36.6025 * BarrelLength

And divide by 36.6025

7.71 * CylinderLength = BarrelLength

BarrelLength = 7.71 * CylinderLength

So your equation is off a little bit, but it may all depend on cylinder volume estimates and the thus the magic ratio. Still 10x is only about 25% off of the actual magic value I derive from the underlying volumes and in this case we can see the volumes of each is linearly scaled with each other, so we don't technically need to use R^2 in the end so long as we can fix both the inner barrel radius and cylinder radius. The later is basically fixed and the differences in volume from a 6.01mm inner barrel and 6.08mm is just 2.3% so its a small factor we can ignore. A 6.23 is actually quite a difference, more like 7.4% but its still a relatively small error when we consider we have to choose between 293mm and 353mm barrels which has a much larger difference.

(PS nothing cool about not knowing how to read the above derivation, its the sort of thing any 16 old that isn't failing maths can do, which is the majority of them. If you can't follow it you should consider a trip back to school not trolling me. It only reflects badly on you that you read this. There is a serious ignorance culture in the UK around mathematics and that concerns me greatly considering how much our economy and businesses depend on it. This isn't rocket science, I would know. The above however could still be wrong, I make mistakes like any human)