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 58 users online :: 5 registered, 0 hidden and 53 guests


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

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

The Team
Administrators
Global Moderators
global_moderators.png CS

A Few Hybrid Questions

Post questions and info about hybrid (compressed gas with fuel) powered cannons here. This includes discussion about fuels, ratios, ignition systems, build types, safety, and anything else relevant.
Sponsored 
  • Author
    Message

Unread postAuthor: Hubb » Tue Jan 08, 2008 6:56 am

spanerman wrote:move the scrader to the fuel input...this way the air injection will force the propane into the chamber


Yeah. In my first designed (sketched on notebook paper), that's where it is. I don't know why I put it like that in the above diagram. I guess I was just trying to get it on the diagram.
  • 0

User avatar
Hubb
Major General
Major General
 
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Reputation: 2

Unread postAuthor: Hubb » Wed Jan 16, 2008 5:54 pm

Bumping because I have another question and don't want to start another thread:

I began construction on the hybrid. I thought about using the spark plug but, once I realized I could not secure it without drilling a hole into the chamber, I scratched the idea. Instead, I built another "spark plug." It is made from a 1/2" pipe cap, pipe nipple, and coat hangers. The hangers are sharpened and secured through the cap with epoxy, where it is screwed onto the nipple, allowing 1/2" threads, which means no drilling through the chamber.

I hooked this up to a piezo and, although it made a good spark (the electrodes have a gap of about 1 mm), I am concerned with it igniting in 6x or more mix. I have recently disassembled a camera to use. BTW: It hurts like a b!tch when it discharges through the thumb.

My question is, has anyone ever used a piezo in a hybrid with 6x or more? If it doesn't work, can the camera sparker be used without running it through an ignition coil or equivalent?
  • 0

User avatar
Hubb
Major General
Major General
 
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Reputation: 2

Unread postAuthor: Fnord » Wed Jan 16, 2008 9:19 pm

I think nova uses a piezo at 8x. A gap of 1 mm will be fine for a typical grill igniter.

I don't think there's any way of using a camera flash in a hybrid without a coil of some type. The voltage is just too low.
  • 0

Image
User avatar
Fnord
Major General
Major General
 
Posts: 2244
Joined: Tue Feb 13, 2007 9:20 pm
Location: Pripyat
Reputation: 7

Unread postAuthor: Novacastrian » Fri Jan 18, 2008 3:49 am

_Fnord wrote:I think nova uses a piezo at 8x. A gap of 1 mm will be fine for a typical grill igniter.


Yes I do use a piezo at 8x mixes. I run about a 1.5mm gap so it would probably still work at 16x mixes at a .75mm gap. After i buy a shock pump i plan to build a 16x Hybrid :twisted:
  • 0

America, the greatest gangster of all time. With 200 million odd foot soldiers at it's whim and call.
When you fill your car with refined oil remember that it has been paid for with blood and guts, some from your own countrymen, most not.

Novacastrian
Major General
Major General
 
Posts: 1604
Joined: Sat Aug 11, 2007 6:59 pm
Reputation: 0

Unread postAuthor: Hubb » Mon Jan 21, 2008 9:29 am

Yesterday, I tested my hybrid. It fired at 4x so far, however, I had to hit the piezo several times for it to do so. There is still a small leak somewhere on the chamber that needs to be fixed so as soon as I fix it, I'll mount it on a stand (it's a pita to hold and fire because of its weight).

I was going to put JB Weld around all the threads and stuff to get a good seal. I let you guys look at it (although it's nothing special) when it's finished. Thanks guys.

Edited for a question: As mentioned above, I had to click the piezo several times before it fired. Do you guys think that if I extended the spark moreso into the chamber, that it would ignite faster? The attachment is how my current setup is:
  • 0

Attachments
current setup.jpg
current setup.jpg (8.39 KiB) Viewed 556 times
User avatar
Hubb
Major General
Major General
 
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Reputation: 2

Unread postAuthor: Novacastrian » Tue Jan 22, 2008 1:15 am

Are you sure that the wiring isn't shorting out on occasion?
  • 0

America, the greatest gangster of all time. With 200 million odd foot soldiers at it's whim and call.
When you fill your car with refined oil remember that it has been paid for with blood and guts, some from your own countrymen, most not.

Novacastrian
Major General
Major General
 
Posts: 1604
Joined: Sat Aug 11, 2007 6:59 pm
Reputation: 0

Unread postAuthor: SpudBlaster15 » Tue Jan 22, 2008 1:32 am

Ah, yet another person who is using my hybrid design, what is this, the 5th or 5th time its been used? :lol:

Your leak is likely originating from the union to burst disk seal, this area is notorious for developing leaks. My setup had to be extensively modified in order to seal properly at up to 8x mixes. I can post a picture if you'd like.

How large is your spark gap?
  • 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

Sponsored

Sponsor
 


Unread postAuthor: Hubb » Tue Jan 22, 2008 6:07 am

Spark gap is about 1mm. The leak was coming from the nipple that connects the union to the reducer. This probably had a lot to do with me not being able to find my pipe wrench.

As far as the gap shorting out, the wires running into the cap are insulated and testing revealed it sparking every time.

I plan on rebuilding it and making the wires longer to reach more into the chamber. I also plan on removing all the teflon tape and just putting JB Weld on the threads to permanently seal it.

@Spudblaster: A picture would be nice. If you're referring to my spark idea, I thought it was original. Apologies.
  • 0

User avatar
Hubb
Major General
Major General
 
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Reputation: 2

Unread postAuthor: SpudBlaster15 » Tue Jan 22, 2008 9:45 pm

I was referring to the whole launcher design.
  • 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: Hubb » Fri Jan 25, 2008 1:45 pm

SpudBlaster15 wrote:I was referring to the whole launcher design.


That's just how a pictured a hybrid to look. I guess yours would be considered the standard in hybrid design :wink:


Anyway, I fixed the leak except one, that FREAKIN' burst disc :x

I used so many pieces of aluminum foil trying to get it to seal (as in trying 2 layers, 3 layers, 4 layers, etc about 15 or 20 times each, wasting about 6 hours of my day) but it would not. I then used pieces of a ziploc bag but it wouldn't hold pressure past 2x.

I took the union and put a bead of that liquid gasket material stuff around it and it is curing now (to create an o-ring type seal). Maybe that will work. Any other help is appreciated.
  • 0

User avatar
Hubb
Major General
Major General
 
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Reputation: 2

Unread postAuthor: DYI » Fri Jan 25, 2008 2:22 pm

So it wouldn't seal with a simple butyl rubber gasket on the union? That seems kind of strange, because the union on the SCTBDC seals at up to 500 psi fairly well with alu. foil disks.
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

Unread postAuthor: Hubb » Fri Jan 25, 2008 2:55 pm

Then I guess I got a bad union. You see, the one I bought didn't have any kind of seal in it.
  • 0

User avatar
Hubb
Major General
Major General
 
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Reputation: 2

Unread postAuthor: DYI » Fri Jan 25, 2008 2:57 pm

Oh, mines didn't have a gasket either, I had to make one. So you're saying that you expected to seal without any sealing material?
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

Unread postAuthor: Hubb » Fri Jan 25, 2008 3:05 pm

I guess so. I've never used one before with this. Besides, I managed to seal it earlier and achieve a 4x.

But don't eat me. That seems to be the only thing (and hopefully is) I've messed up with the hybrid so far. Do you think the liquid gasket material will work okay?
  • 0

User avatar
Hubb
Major General
Major General
 
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Reputation: 2

Unread postAuthor: DYI » Fri Jan 25, 2008 3:54 pm

I have no idea, I've only ever used butyl rubber gaskets. If it's a gasket material though, I see no reason that it shouldn't work if applied properly. Alu. foil disks are a lot easier to seal than sheet alu. disks.
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

PreviousNext

Return to Hybrid Cannon Discussion

Who is online

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

Reputation System ©'