Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 51 users online :: 5 registered, 0 hidden and 46 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

New hybrid (w.i.p.)

Built a hybrid cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
Sponsored 
  • Author
    Message

Unread postAuthor: Labtecpower » Sat Dec 24, 2011 2:44 am

As it seems now it holds pressure very well, but i'll do some tests with water.
The elecrode is in the right place, with a 1-1.5 mm gap.
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: jackssmirkingrevenge » Sat Dec 24, 2011 3:15 am

What's your ignition source? I found that less than 0.5mm was needed with a piezo.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: Labtecpower » Sat Dec 24, 2011 3:51 am

I use the ignition box seen in my youtube video.
I'm able to pull 4cm sparks.
If you were using gaps that small i'm going to bend the electrode closer to the wall, but that doesn't exlpain why I got reliable ignition yesterday morning :?
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: jackssmirkingrevenge » Sat Dec 24, 2011 5:04 am

Labtecpower wrote:If you were using gaps that small i'm going to bend the electrode closer to the wall, but that doesn't exlpain why I got reliable ignition yesterday morning :?


That was just for the piezo, with a more energetic spark you can get by with a larger gap.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: Labtecpower » Sat Dec 24, 2011 5:46 am

Found the problem.
When I pump the chamber to the desired pressure and let it sit for a while, it shoots without problems.
Is there a way I can mix the fuel in my hybrid?

The chamber of this thing is much longer than my previous one, so I think that bugs the mixing...

I'm thinking of adding a few BB's to the chamber, and shaking it before firing :roll:
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: jackssmirkingrevenge » Sat Dec 24, 2011 5:49 am

I don't think this is your problem. You're pressurising the thing, it doesn't need agitation.

Are you venting properly between shots? That includes the pump volume :) I like to cover the mouth of the chamber with my thumb and pump air a couple of times before refilling.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: Labtecpower » Sat Dec 24, 2011 6:08 am

I tested it:

with proper venting, first click ignition, but with a very dull "pop"

second time I vented it, and I added a tin foil ball to the chamber.
I shaked it a few times, and this time I got a very loud bang :)

Let's make some holes :D
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Sponsored

Sponsor
 


Unread postAuthor: SpudBlaster15 » Sat Dec 24, 2011 12:44 pm

Labtecpower wrote:Found the problem.
When I pump the chamber to the desired pressure and let it sit for a while, it shoots without problems.
Is there a way I can mix the fuel in my hybrid?


Ah, this reminds me of why I came up with the air through meter fueling system when I first started experimenting with hybrids...
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: Labtecpower » Sat Jan 07, 2012 10:52 am

I can't get this thing to work reliably as a hybrid, so I just filled it up with a mixture of hydrogen and oxygen from a small electrolysis cell.
I just needed some bangs :roll:

[youtube]http://www.youtube.com/watch?v=onctZMEgWKs[/youtube]

Guitars disapproving in the background :D
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: Labtecpower » Tue Jan 10, 2012 4:39 pm

Finally working flawlessly :)
I added an extra connector so I could shake the chamber before firing, hopefully mixing the gas :roll:

Fus Ro Fail Dah :D

[youtube]http://www.youtube.com/watch?v=G8BQiRDvo6A[/youtube]
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: jackssmirkingrevenge » Tue Jan 10, 2012 5:02 pm

Finally :D

I still don't think mixing is your problem though, rather achieving the right mix. Can you explain your exact fuelling procedure and calculations?
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: Labtecpower » Tue Jan 10, 2012 5:43 pm

calculating the chamber volume; (104 ml)

I calculated it by filling from a syringe.
First I emptied two 50ml syringes, and for the last bit I went to a 5ml one.

then (104*0.03230)*mix number

I measure the butane in a syringe, then gently inject it in the chamber.
Before fueling I vent the chamber thoroughly.
After injecting the butane I quickly put masking tape over the chamber opening.

Then I fill it to the right pressure, I use a valve that closes with a spring, it pops open at a pressure of 3 psi.
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: jackssmirkingrevenge » Tue Jan 10, 2012 5:50 pm

What are you using to pressurise though?

I calculated my shock pump has a dead volume of 1.75mL between pump check valve and schrader attachment, I add this to chamber volume when calculating fuel - indeed none of my hybrids worked before I realised this (because I was dealing mostly with small chamber sizes and this was significant).

Also, obvious and stupid question but I have to ask it, for say a 5x mix, you are pumping to 4 bar, right?
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: Labtecpower » Tue Jan 10, 2012 7:03 pm

Pumps dead space doesn't count with my gun I believe, the filling valve works as a check valve. There is no open connection between the chamber and the pump. :)
And yes, I pay attention to that :wink:
Good to point out tough :D
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: jackssmirkingrevenge » Wed Jan 11, 2012 1:09 am

Labtecpower wrote:Pumps dead space doesn't count with my gun I believe, the filling valve works as a check valve.


I would not be too quick to assume that, if it were mine I would do some tests taking this volume into account.

You said it worked reliably with hydrogen, hydrogen has a massive range of concentrations it can ignite (5-75% if I recall correctly) so proportion is not so important. Butane on the other hand has a 2-8% concentration range, so it is a lot more sensitive for reliable operation.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

PreviousNext

Return to Hybrid Cannon Database

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

cron
Reputation System ©'