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 43 users online :: 3 registered, 0 hidden and 40 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Placement of Spark Gap

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

Placement of Spark Gap

Unread postAuthor: frocksie » Sun Feb 24, 2008 9:45 am

I am thinking about making a hybrid in the near future, and I have a question on the safest place to put the spark gap.

The chamber will likely be 2"x12", and I am wondering whether I should put a hole in the chamber wall, tap it, and then put in a homemade sparkplug, or whether I should put a tee in front of the chamber, and put the sparkplug in that.

Thanks.
  • 0

Attachments
hybrd spark.JPG
hybrd spark.JPG (27.08 KiB) Viewed 486 times
“He who controls the present, controls the past. He who controls the past, controls the future.”
-George Orwell
User avatar
frocksie
Sergeant
Sergeant
 
Posts: 91
Joined: Fri Mar 23, 2007 2:05 pm
Location: Maine
Reputation: 0

Unread postAuthor: SpudFarm » Sun Feb 24, 2008 11:44 am

look how i did it on my hybrid (posted) almost same chamber volume also.

check it out! i did it that way to be able to change the part if ruptured. the chamber is a little more expensive. but the middle is the safest point when you think of DDT.

and 2" by 12" is a big chamber :twisted: how about the barrel?
  • 0

User avatar
SpudFarm
Donating Member
Donating Member
 
Posts: 2563
Joined: Sat Nov 04, 2006 9:39 am
Location: Norway Trondheim area
Reputation: 0

Unread postAuthor: DYI » Sun Feb 24, 2008 12:05 pm

You really don't have to worry about DDT in this design no matter where you put the spark gap, and the structural integrity of the chamber will be improved by not having holes tapped in its walls. Just attach your homemade spark plug with normal threaded fittings, and don't tap any holes anywhere on the chamber.
  • 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: SpudFarm » Sun Feb 24, 2008 12:20 pm

do you mean like place a small TEE fitting on the back or something?
  • 0

User avatar
SpudFarm
Donating Member
Donating Member
 
Posts: 2563
Joined: Sat Nov 04, 2006 9:39 am
Location: Norway Trondheim area
Reputation: 0

Unread postAuthor: psycix » Sun Feb 24, 2008 1:10 pm

In the middle would be optimal, but in the tee could be more safe, as you wont need a hole in your chamber.
Ive heard once that the placement of the gap isnt really important in hybrids.
The burst disk makes up for bad placements and also the chamber is smallish compared to combustions.
  • 0

Till the day I'm dieing, I'll keep them spuddies flying, 'cause I can!

Spudfiles steam group, join!
User avatar
psycix
Donating Member
Donating Member
 
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands
Reputation: 0

Unread postAuthor: SpudFarm » Sun Feb 24, 2008 1:23 pm

yeah you dont need rapid combustion in a hybrid since it wont go until the burst pressure of the disk is reached : )
  • 0

User avatar
SpudFarm
Donating Member
Donating Member
 
Posts: 2563
Joined: Sat Nov 04, 2006 9:39 am
Location: Norway Trondheim area
Reputation: 0

Return to Hybrid Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot]

Reputation System ©'