Help me with my pressure washer launcher-Getting no distance

[Blitzen]

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Okay, right down to business, here are some pics of the launcher itself:
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Additional Information/Problem
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* It is a powerwasher launcher, put inside a wooden stock.
* The barrel is 1.5"
* The air flow goes as follows: Air source (was using 12 grams today)-->Remote Line-->Brass Piping-->Powerwasher valve-->Braided Steel Hose-->Barrel

When I am shooting grenades/sabots, My problem is that I am not getting any distance with this launcher. Currently I am getting about 8 yds. I have heard from other people (more specifically a member on here named goathunter) that they can get about 50 yds (with grenades). Originally I thought that I didnt have a big enough air chamber behind the valve, but I thought that adding a remote line would fix the problem. Though a lack of a bigger airchamber could be the problem, I think I might be doing something wrong with the grenade/sabot as well. I say this because I have shot grenades with this launcher (which has a much bigger air chamber) and I still didnt get alot of distance.

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Here are some pics of the Grenade/Sabot:
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(Size comparison)

(Size comparison)

(In the barrel)
My sabot works like this: The grenade fits on the pvc capsule. That is put into the barrel, yet the lip of the capsule permits it from sliding all the way into the barrel. You shoot the launcher, the capsule stays and you "eject" it, and then slide in another capsule. I have tried this capsule method, and just firing grenades, and I still dont get alot of distance. Though it looks like there is a tight fit it was able to wiggle out some. However I have tried it with bigger grenades, and it still dosent go far.

So....Any ideas?

Three things I think I need are:
1. Longer barrel (the barrel is only 11.5" at the moment)
2. Bigger hose running from the valve to the barrel cap
3. Bigger air chamber...(Dont really know how to do that one just yet)

[hi]

there is no flow. get a bigger valve, a bigger air chamber and a longer barrel.

[bigbob12345]

as hi said it is all the valve
replace the valve witha QEv or something similar and you will get the power you want.

[Blitzen]

Well, I have heard of good results from others who have used a powerwasher valve, so for the moment lets keep "getting another valve" out of the solution box please.

[MrCrowley]

Look at the launchers that seem to get the results you want, and then write down the differences between yours and theirs.

If you can't find the problem from that, post the differences here and we should be able to work out what's the problem.

[psycix]

It might be just me, but as far as I can see, there is NO chamber on your gun exept a bit of copper pipe trough the stock?
You should get a large chamber (the volume of your barrel) and then try it again, if it fails then, it is your valve wich is crappy.

Also, what pressure do you use?

It seems like you are just trying to feed the air to the barrel directly from the 12g bottle??
One word:
Dont.

[Daegurth]

800psi through a pressure washer? sounds dangerous to me. or is it regulated to something the valve can take?

either way, what you're essentially trying to do is use a blowgun valve as a primary valve. i think it's it's releasing the CO2 far too slowly- you probably need a regulator, say 80-120 psi, and a separate chamber; then use the pressure washer valve to pilot a good valve, say a 1/2"-3/4" QEV.

i'll have a look for this "goathunter," and see what he used, but it would have been much easier if you'd posted a link to a thread on a fully working model of what you're attempting.

ok, i've got the thread: http://www.spudfiles.com/forums/goats-mcs-t12488.html

hm. apparently it works. i'm just not sure what the difference is. wait. you are using the hosing as a chamber, with a BV to stop the supply, right?

it's odd, because it seems as though it should work. maybe you need to extend the barrel, give the pressure anough time to build. it's the only thing i can think of right now...

[grumpy]

i still say, your problem is all the airline you have used is to small and is constricting airflow, get rid of the remote and mount the co2 so that it is fed directly into the power washer handle, and replace the braided line going to the endcap with a larger diameter one. also a longer barrel will let the pressure expand more giving the grenade time to get up to speed, play around with different barrel lengths to find what is optimum length for you. the sabot should make a tight seal or gas will escape around it, i suggest the dixie cups or foam sabots.

[DYI]

800psi through a pressure washer? sounds dangerous to me. or is it regulated to something the valve can take?

You do realise that most pressure washer handles are rated for AT LEAST 2 000 psi, right? There is nothing unsafe about the current setup, it just isn't working because there's no chamber, and very little flow through the valve.

As far as suggestions, you could try upping the pressure to whatever the valve is rated for, but it might start leaking due to the use of gas rather than liquid. When I tested a 4 000 psi pressure washer handle with unregged nitrogen (2 400 psi) it made a very pronounced hiss from the output end. Another idea would be to use a metal barrel, and feed liquid CO₂ through the pressure washer handle. It would expand to a huge volume, and would be the equivalent of using a large chamber.

So you can try a larger chamber, longer barrel, liquid CO₂, and/or more pressure. When that doesn't work, get a valve with more flow.

[TurboSuper]

Instead of using the pressure washer as your main valve, use it as the pneumatic trigger on a modified sprinkler valve.

It's the best way to get the performance you want without using insanely high pressures and the like.

Goathunter used an 800 PSI pressure source, a smaller barrel (for a paintball shell, apparently), and a longer barrel. That combination is probably why it worked better.

[clide]

Looks to me like you may have issues with too much blow-by. To test if this is the case find a nice solid projectile that is a really good fit in the barrel. If you can't find anything that fits really good then use something that fits decent and use a plastic bag as wadding. For now I would suggest muzzle loading it since your breech may be part of the problem (usually male fittings have a smaller ID than SCH40 pipe). If you can get a different projectile to fire well out of it then you have found your problem and you can take steps to address getting the grenade to fire better. If nothing else will fire very well then it is either a problem with your valve or lack of chamber.

[ALIHISGREAT]

you should lube your ammo as it looks rubbery? and also put a chamber on it between the 12g and the trigger although pressure washer handles have low flow so maybe you should use a ball valve?

[Blitz]

That's a nice stock -- did you make that yourself or mod it from a toy gun or something? Would be a nice quick-add to something I'm building.

[Blitzen]

I made the stock from wood. All done by me

[elitesniper]

You should sand around the edges of the stock to give it more authenticity.