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 81 users online :: 5 registered, 0 hidden and 76 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

hybrid fueling

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

hybrid fueling

Unread postAuthor: sw5amped » Sun Dec 01, 2013 2:03 pm

So y'all
I read ur posts all the time and im blown away by the knowledge. I've been building for a few years now and I've built some really nice combustion guns. I've done a lot of research on hybrids but i need a little help on the fueling. If i have a 55 cubic inch chamber and a2.2 meter pipe, and i wanna make a 3x mix. How do i do the math. Please help
Thanks guys
  • 0


sw5amped
Specialist
Specialist
 
Posts: 59
Joined: Tue Apr 16, 2013 8:11 pm
Location: CT
Reputation: 11

Re: hybrid fueling

Unread postAuthor: Ragnarok » Sun Dec 01, 2013 2:29 pm

It depends on how you're fuelling. There have been several different approaches.

However, the maths for two common approaches is already addressed here: hybrid-cannons/topic13602.html
  • 0

Does that thing kinda look like a big cat to you?
User avatar
Ragnarok
Chief of Staff
Chief of Staff
 
Posts: 5339
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK
Reputation: 8

Re: hybrid fueling

Unread postAuthor: sw5amped » Sun Dec 01, 2013 2:37 pm

Im using a 13 inch half inch meter pipe with 100psi gauge
  • 0


sw5amped
Specialist
Specialist
 
Posts: 59
Joined: Tue Apr 16, 2013 8:11 pm
Location: CT
Reputation: 11

Re: hybrid fueling

Unread postAuthor: Ragnarok » Sun Dec 01, 2013 3:30 pm

Sorry, I can't actually do the maths for you.

I'll check your answer if you post one, but it's important that you understand how to do the maths yourself.
  • 0

Does that thing kinda look like a big cat to you?
User avatar
Ragnarok
Chief of Staff
Chief of Staff
 
Posts: 5339
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK
Reputation: 8

Re: hybrid fueling

Unread postAuthor: advancedspuds » Thu Dec 05, 2013 7:43 am

Fuel Charge Pressure (In PSI)
1x 0 (normal combustion firing)
2x 14.7
3x 29.4
4x 44.1
5x 58.8
6x 73.5
7x 88.2
8x 102.9

This is the air pressure in the chamber used with different charges. I don't really want to guide someone on how to do meters as it is a topic in and of itself, plus if you are even thinking of venturing into hybrids, one really should have a solid grasp on how the other things work and know how dangerous they can be.
  • 0

User avatar
advancedspuds
Private
Private
 
Posts: 15
Joined: Thu Dec 05, 2013 6:01 am
Country: United States (us)
Reputation: 0

Re: hybrid fueling

Unread postAuthor: sw5amped » Thu Dec 05, 2013 9:33 am

Thank u but i could have just gone to advanced spud guns site and copied the same chart.... i think there was a miscommunication here. What I'm trying to figure out is.... let's say i wanna use a 3x Mic. My meter pipe is 2.3ci in vol. My chamber vol is 56ci. At a 3x mix i think i should be injecting 44 psi of propane. I'm frustrated!!!! @ a 3x mix multiply the amount of fuel in chamber normally by 3 or not.
Then for the air do i just use 14.7 x my mix number?????
  • 0


sw5amped
Specialist
Specialist
 
Posts: 59
Joined: Tue Apr 16, 2013 8:11 pm
Location: CT
Reputation: 11

Re: hybrid fueling

Unread postAuthor: advancedspuds » Thu Dec 05, 2013 10:03 am

whoops, sorry for the misunderstanding. There is a fueling hybrid 101 in the stickies at the top. It is more accurate, but on a basic combustion spudgun it works like this:

http://www.burntlatke.com/lp.html

To use on hybrids, simply put the mix in 3 times for a 3X mix, etc. The Fueling 101 would be much more accurate as the fuel adds some pressure in a closed chamber like on a hybrid. It's close and will work up to about 6x mixes, after that I don't know as I have only went 6X at the highest. I couldn't get 7X to fire and TBH it was probably due to the problem with the fuel throwing off the chamber pressure measurement.

I used to have a calculator thing, many computers ago, I no longer have it but that site is one of the best for explaining it and giving you formulas to use. I forget the brand of regulator I used to use but it went from 0-60psi and was made for BBQ grills.
  • 0

User avatar
advancedspuds
Private
Private
 
Posts: 15
Joined: Thu Dec 05, 2013 6:01 am
Country: United States (us)
Reputation: 0

Re: hybrid fueling

Sponsored

Sponsor
 


Re: hybrid fueling

Unread postAuthor: Ragnarok » Thu Dec 05, 2013 11:01 am

sw5amped wrote:I'm frustrated!!!!

Getting worked up over it is not a good thing - hybrids and getting yourself into a frame of mind where you act irrationally are not a great combination.

My meter pipe is 2.3ci in vol. My chamber vol is 56ci. At a 3x mix i think i should be injecting 44 psi of propane.

In all seriousness, the thread link I posted earlier has all the necessary maths for that (other than a reminder that atmospheres are 14.7 psia, but you seem to know that) and it's not difficult.

But you are close.

Then for the air do i just use 14.7 x my mix number?????

If you're measuring by absolute pressure, yes. However, gauges don't do that, so you need to remember that the 14.7 psi of the first mix number is provided by normal atmospheric pressure.
  • 0

Does that thing kinda look like a big cat to you?
User avatar
Ragnarok
Chief of Staff
Chief of Staff
 
Posts: 5339
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK
Reputation: 8

Re: hybrid fueling

Unread postAuthor: sw5amped » Thu Dec 05, 2013 12:18 pm

Awsome!!!! Thanks bro!!! I think i just needed to hear it from someone els. I appreciate all ur help. I tend to act like a prick when i get confused. Esp when it comes to building launchers!!!! Ill run my numbers and hit u back later. Thanks again
  • 0


sw5amped
Specialist
Specialist
 
Posts: 59
Joined: Tue Apr 16, 2013 8:11 pm
Location: CT
Reputation: 11

Re: hybrid fueling

Unread postAuthor: burstmewideopen » Thu Jun 05, 2014 5:38 pm

hi i have built over 20 combustion launchers now im venturing in two hybrids now i have a sch 40 steel pipe as my combustion chamber and it holds 38.6 ml i was wondering if you could provide me with the math equations so i could work out my fuel to air mix please i have read just about everything there is to no and im still lost
  • 0


burstmewideopen
Private
Private
 
Posts: 1
Joined: Sun Apr 06, 2014 10:30 pm
Country: Australia (au)
Reputation: 0

Re: hybrid fueling

Unread postAuthor: jackssmirkingrevenge » Wed Jun 11, 2014 7:25 am

burstmewideopen wrote:i was wondering if you could provide me with the math equations so i could work out my fuel to air mix please i have read just about everything there is to no and im still lost


Have you had a read through this?
  • 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

Return to Hybrid Cannon Discussion

Who is online

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

Reputation System ©'