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 39 users online :: 6 registered, 0 hidden and 33 guests


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

Registered users: Bing [Bot], Exabot [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

A question about metering pipes...

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

A question about metering pipes...

Unread postAuthor: D_Hall » Thu Apr 10, 2008 10:49 pm

Do people use metering pipes for additional air or do they just pressurize directly from their air source?

If they use metering pipes, is it the same pipe used for the fuel or do they have a second pipe for air?
  • 0

Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
D_Hall
Donating Member
Donating Member
 
Posts: 1759
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Reputation: 6

Unread postAuthor: Lentamentalisk » Thu Apr 10, 2008 10:57 pm

The only reason people use metering pipes is because the amount of propane needed is so minute that it wouldn't show up accurately on a gauge if put directly into the chamber. There is not that issue with the air, since you are putting large amounts in, and it doesn't have to be so accurate.
The simple answer: People just pump it straight in, though pumping through the metering pipe would terbulize (yes that is a word. *shifty eyes* ...well now it is) the propane better in the chamber.
  • 0

Do not look back, and grieve over the past, for it is gone;
Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
User avatar
Lentamentalisk
Brigadier General
Brigadier General
 
Posts: 1202
Joined: Tue Aug 07, 2007 5:27 pm
Location: Berkeley C.A.
Reputation: 0

Unread postAuthor: D_Hall » Thu Apr 10, 2008 11:09 pm

I realize the issue with injecting fuel. I was just curious if people worried about similar precision with their air. I mean, it may have a larger margin of error, but it DOES matter. ;)
  • 0

Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
D_Hall
Donating Member
Donating Member
 
Posts: 1759
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Reputation: 6

Unread postAuthor: Lentamentalisk » Fri Apr 11, 2008 12:02 am

nobody to my knowledge is that nitpicky, unless you were to say, use O<sub>2</sub> from a tank, then maybe?
  • 0

Last edited by Lentamentalisk on Fri Apr 11, 2008 7:28 pm, edited 1 time in total.
Do not look back, and grieve over the past, for it is gone;
Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
User avatar
Lentamentalisk
Brigadier General
Brigadier General
 
Posts: 1202
Joined: Tue Aug 07, 2007 5:27 pm
Location: Berkeley C.A.
Reputation: 0

Unread postAuthor: DYI » Fri Apr 11, 2008 10:37 am

There are a few incidences that come to mind of this being used, but both were metering pure O<sub>2</sub>. Spudblaster's oxy/MAPP hybrid, and Dumbascii's Taternator II.

My metering system uses gauges to measure chamber pressure, one for propane, which is then closed off before the air is added. With accurate enough gauges, it would be far cheaper than the monstrous meter pipes that would be required for the Pipe Dream.

Considering the budget of this project, I don't imagine that precision gauges would be that bad. If it is only going to be used at a maximum of 3x or so, you could just use a grade 1A or better 0-3 psig gauge for the propane, and a similarly accurate 0-45 psig gauge for the air. If you could afford even higher accuracy gauges, it could be more accurate than a regular meter, and either way involves far less hassle.

Here's a picture of my metering setup:

Image

The ports, from left to right are: chamber connection, air input, fuel input, air pressure gauge (0-300psig, grade 1A), propane pressure gauge (0-15psig, grade 1A).
  • 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

Return to Hybrid Cannon Discussion

Who is online

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

Reputation System ©'