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Posted: Mon Aug 29, 2011 2:50 pm
by Labtecpower
My calculation was as following:

(chamber length*(pi*r^2)=(10*(pi*1.4^2)

That makes the chamber volume 61 ml.

HGDT says the chamber volume is about 30 milliliters, wich one is right? :scratch:


I certainly caught the hybrid bug :D the power increase when compared to a pneumatic is very nice.

I will continue playing with this for a while, and when im back in school I can machine something better.

Posted: Mon Aug 29, 2011 2:59 pm
by jackssmirkingrevenge
Labtecpower wrote:My calculation was as following:

(chamber length*(pi*r^2)=(10*(pi*1.4^2)

That makes the chamber volume 61 ml.
Damn Euro decimals ;)

Posted: Mon Aug 29, 2011 3:24 pm
by Labtecpower
ah, now I understand :D
thank you!

I guess I just have to use high mixes for moah powah! :)

This thing has about 3 times the power of my copper spudgun according to HGDT and GGDT...

Posted: Mon Aug 29, 2011 4:28 pm
by jackssmirkingrevenge
Labtecpower wrote:ah, now I understand :D
thank you!
No worries, I have this exact same problem everytime I need to use excel in Spain :roll:
I guess I just have to use high mixes for moah powah! :)
While I've never had a serious blowout since the mini hybrid fail, I have noticed that most of my projects over time develop small leaks between the epoxy plugs and the chamber. I would suggest going for bigger chambers as opposed to higher mixes when using this style of epoxy construction.

Posted: Tue Aug 30, 2011 4:35 am
by Labtecpower
While I've never had a serious blowout since the mini hybrid fail, I have noticed that most of my projects over time develop small leaks between the epoxy plugs and the chamber. I would suggest going for bigger chambers as opposed to higher mixes when using this style of epoxy construction.
This school year i'll probably learn how to use the CNC lathe, so when school starts again, I don't think I will be using epoxy for large pieces of the structure.

I don't know what to build first, because it has to be slightly portable.
My first plan was for a 30 mm 2.30 meter long "rifle" style hybrid, but a shotgun is also very appealing, and more suitable for smoothbore.

Posted: Tue Aug 30, 2011 5:04 am
by jackssmirkingrevenge
Labtecpower wrote:a shotgun is also very appealing, and more suitable for smoothbore.
My 3/4" hybrid was certainly very powerful even at "low" mixes like 9x, at that bore 12 gauge sabots fit perfectly (thought really with lathe access you can easily make your own out of UHMWPE or Delrin) so you can fire pretty much anything that fits.

A suppressed "no country" style hybrid shotgun is still on my to-do list :)

Posted: Tue Aug 30, 2011 5:16 am
by Crna Legija
OMG I started to make a hybrid it looks almost exactly like yours and is 63ml chamber, how loud is your one? at 5x. All i need to do now is get a good igniter because my spark gap is about 1mm and i don't think i can close it up.

Posted: Tue Aug 30, 2011 5:38 am
by Labtecpower
Crna Legija wrote:OMG I started to make a hybrid it looks almost exactly like yours and is 63ml chamber, how loud is your one? at 5x. All i need to do now is get a good igniter because my spark gap is about 1mm and i don't think i can close it up.
Almost exactly the same! 2 ml chamber size difference :D

At 5x mix it is loud enough to make your ears hurt, when not wearing protection. At 8x it was loud enough to frighten my uncle when I shot it in the garage, while he was in the living room.


If I make a shotgun, it will be one with a piston valve, I hate changing burst disks. I also want a removable stock , and changeable barrels.

Posted: Tue Aug 30, 2011 5:52 am
by Crna Legija
Labtecpower wrote:
Crna Legija wrote:OMG I started to make a hybrid it looks almost exactly like yours and is 63ml chamber, how loud is your one? at 5x. All i need to do now is get a good igniter because my spark gap is about 1mm and i don't think i can close it up.
Almost exactly the same! 2 ml chamber size difference :D

At 5x mix it is loud enough to make your ears hurt, when not wearing protection. At 8x it was loud enough to frighten my uncle when I shot it in the garage, while he was in the living room.


If I make a shotgun, it will be one with a piston valve, I hate changing burst disks. I also want a removable stock , and changeable barrels.

dam i will need a big suppressor then because i was hoping for 15x.

Posted: Tue Aug 30, 2011 5:56 am
by Labtecpower
What is your chamber material? It looks like aluminium, and I don't know if you want to use thin-walled stuff at 15x mix. Don't forget it can generate 1500 psi, or 115 bar.

I don't care about a lot of noise, but as this is a JSR-style mini hybrid, I will recommend a JSR style supressor over the whole length of the barrel :D

Posted: Tue Aug 30, 2011 6:24 am
by jackssmirkingrevenge
Labtecpower wrote:If I make a shotgun, it will be one with a piston valve, I hate changing burst disks.
Burst disks are definitely a pain in the buttocks. A piston needs to be accessible for servicing though, piston hybrids have high temperatures to add to the list of abuse which the seals have to suffer.
as this is a JSR-style mini hybrid, I will recommend a JSR style supressor over the whole length of the barrel
JSR agrees :D
Crna Legija wrote:All i need to do now is get a good igniter because my spark gap is about 1mm and i don't think i can close it up.
Looking at the picture, it seems your electrode is too close to the schrader outside the launcher, so no matter how strong the ignitor is the spark will still perfer to arc externally at higher mixes.

Posted: Tue Aug 30, 2011 6:41 am
by Crna Legija
Labtecpower wrote:What is your chamber material? It looks like aluminium, and I don't know if you want to use thin-walled stuff at 15x mix. Don't forget it can generate 1500 psi, or 115 bar.

I don't care about a lot of noise, but as this is a JSR-style mini hybrid, I will recommend a JSR style supressor over the whole length of the barrel :D

Yeah it is aluminium, walls are 2.3mm. The epoxy plugs are 20mm thick and there are two pins going the whole width of the plugs.
jackssmirkingrevenge wrote:Looking at the picture, it seems your electrode is too close to the schrader outside the launcher, so no matter how strong the ignitor is the spark will still perfer to arc externally at higher mixes.
peace of wire is connected to the schrader and was use to hold the valve up while I casted. It also extends the spark gap to 1/3 the way in

Posted: Tue Aug 30, 2011 6:53 am
by POLAND_SPUD
piston needs to be accessible for servicing though
His design is accesible... though I am not sure if he can raplace the sealing face / rubber washers on it

It's basically a pressure relief / pop-off valve

EDIT
uhmm or maybe that wasn't labtec who mentioned this type of valve :?

Posted: Tue Aug 30, 2011 7:02 am
by jackssmirkingrevenge
POLAND_SPUD wrote:uhmm or maybe that wasn't labtec who mentioned this type of valve :?
I was wondering :D

Were you thinking of Lockednloaded?
piace of wire is connected to the schrader and was use to hold the valve up while I casted. It also extends the spark gap to 1/3 the way in
Ah ok, though it was the other way round and the gap was between wire and schrader.

Posted: Tue Aug 30, 2011 3:33 pm
by Labtecpower
Second explosion in two days :D

The front connector decided to fail at a 9x mix. The bang was loud enough to make my ears ring under my ear muffs, but the reaction from my mom was more frightening :roll:

Luckily I have a stainless steel connector, wich should be able to survive the pressure. I used a burst disk with a 35 bar burst pressure.

Image

You can see the connector in the picture above. I just need a way to connect the barrel.