TBMA-230 V2.0

[jackssmirkingrevenge]

and to a few chat conversations lol.

... about my sibling? behind my back?! *gasp*

[jrrdw]

About PS doing SB15's little sister lol.

[SpudBlaster15]

What is the maximum ROF of this system, without loading projectiles? I can't imagine it would take more than about 5 seconds per shot!

Probably around 6RPM if the chamber is vented between shots. Venting alone takes about as much time as the rest of the process.

Leaving the post combustion atmosphere in the chamber would likely bump the maximum ROF up to 10-12RPM, at the cost of some power.

[jackssmirkingrevenge]

With cartridges on the other hand...

*ahem*

[SpudBlaster15]

With cartridges on the other hand...

*ahem*

When somebody figures out how to effectively mass produce and transport 80in³ hybrid cartridges, let me know.

[POLAND_SPUD]

@SB15
can't you use a mechanical spring instead ?
and purge teh chamber with compressed air ?

[SpudBlaster15]

@SB15
can't you use a mechanical spring instead ?
and purge teh chamber with compressed air ?

The chamber is purged with compressed air, but it's not an instantaneous process. A 3-5 second burst from an air compressor was sufficient for my original design.

Not sure where you're suggesting the use of a mechanical spring...

[POLAND_SPUD]

Not sure where you're suggesting the use of a mechanical spring&A 3-5 second burst from an air compressor was sufficient for my original design

well it would use less air per cycle. though I guess it's better to keep the system as it is


ohh btw I really really like the way you designed it...
after the shot the main valve is in open position so you can purge it, but as soon as you switch the DCV to the first position (fuelling) the main valve closes

[mark.f]

Excellent streamlining operation, SB15. The use of a 5-way for air and fuel is a great touch... Sgort would be proud. Glad to see another person realizing pneumatics aren't the only place to apply such technology.

[jackssmirkingrevenge]

When somebody figures out how to effectively mass produce and transport 80in³ hybrid cartridges, let me know.

A multishot means you don't need as much power, think submachinegun vs shotgun, so cartridges could be significantly smaller...

[pneumaticcannons]

I didn't think that was very funny. This cannon is pretty kick ass and I never at all hinted at the superiority of a pneumatic version.

whu whu whu what?

[Gun Freak]

You all are under the wrong impression... I don't think hybrids are stupid, I just don't want to build one. That's all... I'm aware of the power differences between pneumatic and hybrid...

[SpudBlaster15]

So I went to go test this launcher the other day, and I quickly realized that despite the modifications I had made, it was still too long for my current transportation situation. That's when I decided to change a few more things around.

Firstly, the barrel is now 48" long, which should improve portability and reduce the deflection/elastic deformation caused by recoil. Muzzle energy is estimated to be around 3000ft-lbs (~4000J) with an 80g projectile at an 8X mix.

Secondly, I had an industrial supply outlet custom make a 2"x12" SCH40 galvanized steel pipe nipple to replace the stupid looking coupled setup on the previous version. This significantly increases the strength of the chamber, and also eliminates two potential leak pathways.

Thirdly, I repositioned the ball valve to mount directly to the chamber, which increases the meter volume (Calculated meter pressure is now ~8PSI/X), and isolates several threaded joints from the combustion pressure. As of now, there are only 8 connections which will be exposed to high pressure upon firing; this is a massive improvement over the 16 found on the TBMA V1.0.

Fourthly, MOAR push-to-connect fittings, which should cause POLAND_SPUD to [redacted in an attempt to maintain G rating of forum].

Fifthly, the pictures:





The new configuration allows for a more comfortable firing position:



Videos will be posted when I find some interesting targets to demolish.

[Gun Freak]

Way to push the gas cylinder up against your bicep

[Lockednloaded]

I'm not much of a DCV guy, but couldn't a hybrid be fueled using only a 3/2 way and two regulators?