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 67 users online :: 6 registered, 0 hidden and 61 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

Hybrid User Quiz

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: spanerman » Sun Sep 23, 2007 11:42 am

100% in new quiz :twisted:
  • 0

Image

spanerman
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 438
Joined: Sun Sep 17, 2006 2:54 pm
Reputation: 0

Unread postAuthor: Hubb » Sun Sep 23, 2007 11:51 am

I'm still ready (100 in new quiz).
  • 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: jimmy101 » Sun Sep 23, 2007 11:57 am

There are too many errors in the quiz to make it of much use.

Question 3:
Question is poorly worded and there is no correct answer. If gauge pressure is the question then the answer is about 45 PSIG. If absolute pressures is wanted then the answer is about 60 PSI. Since the pressure scale is not specified in either the question or the answers there is no correct answer.

Question 4:
1. You don't need to avoid DDT. DDT is not always a problem. It depends on when DDT occurs and how much fuel detonates.
2. Nobody knows enough about DDT to say what the correct answer is. DDT depends on many factors, not the least of which is the pressure in the chamber. In some systems, DDT occurs in at fairly low pressures, such as a pipe open at one end. In other it requires high pressures and/or temperature. To think you understand what causes DDT is pure hubris.

Question 5:
Besides the spelling errors…

It would be better if the answer used the standard EE or physical description of a spark gap. The maximum spark gap is dependent on the breakdown voltage of the gases. Propane + air at elevated pressures has a slightly higher breakdown voltage. This is partly due to the number of molecules between the electrodes but that is not the only factor. In addition, besides the difference in the breakdown voltage, the amount of energy required for sustained combustion is a function of the pressure of the combustible mix. It is entirely possible to create an electrical spark that will not ignite a flammable mixture.

Question 6:
A is wrong. A hybrid could produce only 100 PSIG or so.
B is wrong. You have no idea how far "most" hybrids can launch a projectile.
C is wrong. So what? Hybrids as a class are not dangerous because some can exceed the speed of sound. Besides, the velocity of the projectile tells you nothing about how dangerous it is. It is the kinetic energy that causes the damage. A light supersonic round will do less damage than a massive subsonic round.

Question 7:
None of theses are correct (see answer to question #4). There are situations where A, B, C or D are true. There are situations where A, B, C or D are false.

Question 9:
Question is poorly worded and not very clear.

Besides, the "correct answer" is wrong anyway. If you have the compressed air inlet plumbed in such a way that it flows through the meter pipe then 100% of the fuel originally in the meter pipe ends up in the chamber. The mixture will not be at equilibrium as air is flowing though the meter pipe and esentially all of the propane in the meter will end up in the chamber. Assuming the meter pipe is not part of the volume that is combusted, then the gases in the meter pipe are 100% air with no propane.

Question 10:
The correct answer depends entirely on the characteristics of the gun and the ammo. A 1" plywood fence might be adequate. Or, a mattress backed with 1/4" steel might be inadequate (and suicidal).

Besides, the best backdrop for any firearm is generally dirt (or sand) or simply a very large open space.

You would have to be an idiot to fire a high powered rifle at a mattress backed with steel. Same for a high power hyrbid firing a sufficiently hard and dense round.

To say that any one of these answers is "the best backdrop for a hybrid cannon" is incorrect.
  • 0

Image

jimmy101
Lieutenant General
Lieutenant General
 
Posts: 3130
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7

Unread postAuthor: silverdooty » Sun Sep 23, 2007 12:45 pm

this is as bad as taking an online IQ test. most of the time google has the answers. here you merely scroll down to see your "friends" results and all the questions/answers are posted. i'm not saying people looked intentionally, but it happens. the results should not be accessible prior to taking the "quiz".

Old mattress with 1/4" steel plate behind it


are you serious?

while several questions are open to interpretation, this one is not. a lot of you guys are shooting hard projectiles looking for bigger,badder damage.

ignoring standard firearm safety just befuddles me.

billybob: hey jimbo, i just shot a tater thro' a piece a steel
jimbo: cool billybob
neighbor: omg someone shot my dog
billybob and jimbo: coooool
  • 0


silverdooty
Staff Sergeant
Staff Sergeant
 
Posts: 102
Joined: Mon Aug 06, 2007 8:52 pm
Location: old folks home
Reputation: 0

Unread postAuthor: noname » Sun Sep 23, 2007 1:37 pm

About Question 3, I see where you're coming from. I should have specified, but seeing as you won't be satisfied if I edit it (again), I might as well not.
Q 4, OK, maybe you do want DDT to happen every time you fire. It may not be a problem, but it also may be. DDT is capable of wearing out almost any kind of pipe, and that's enough reason (for me, at least) to avoid as best as possible.
Q 5, there aren't any spelling errors. Maybe I should have been more descriptive. I tried to, but was unable, because I was already at the maximum character limit. I made it as long as possible.
Q 6, a hybrid could only produce 100 psi, but it also can produce over 400 psi. I hav a great idea as to how far a hybrid can launch a projectile. Using a small, aerodynamic, finned dart, I'm very sure my gun could shoot over 1 1/2 miles. Most other hybrids, using the same small, aerodynamic, finned dart, could do the same thing. As for C, you're saying a supersonic projectile at least 1/2" in diameter isn't going to do damage, even if it isn't as much damage as a more massive, subsonic projectile?
Q 7, it's possible for DDT to be perfectly safe. It's also risky nonetheless, and should be avoided.
Q 9 was worded well enough to be understood, according to me, SB15, and spanerman, who have all built hybrids that fill from the propane meter. iPaintball, Hubb017, and Mopherman also got it right, and they haven't made hybrids yet. If you didn't understand it, it's not my fault.
Q 10, I've shot my gun at my friend's house loads of times, usign an old mattress with steel behind it as a backstop. Using anything from 2" potatoes and apples, to 1/2" steel ball bearings, darts, and anything else we could find to shoot, nothing went through or came back out. I can put almost anything through a 1" plywood fence, or a 2 x 4. 1/4" steel plate would cause ricochets. Also, I never said, "What's the best backstop?" I said, "What would be the best backstop," implying you should choose the best of the 4.

Maybe you're taking the scientific approach. I'm going with simple logic.[/i]
  • 0

User avatar
noname
Lieutenant General
Lieutenant General
 
Posts: 2699
Joined: Mon Apr 10, 2006 9:19 pm
Location: Bay Area, CA
Country: United States (us)
Reputation: 9

Unread postAuthor: JDP12 » Sun Sep 23, 2007 2:14 pm

well i got a 90, i got number 7 wrong. From what I had researched, none of those were truly correct, so I chose none of them, but you said it was wrong. Oh well
  • 0

"Some say his pet elephant is pink, and that he has no understanding of "PG rated forum". All we know is, he's called JSR. "
User avatar
JDP12
Major General
Major General
 
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm
Reputation: 0

Unread postAuthor: Pilgrimman » Sun Sep 23, 2007 2:16 pm

100% wOOt! :lol:
  • 0

Yeah, we wouldn't want to anger the bees, now would we??

I HATE YOU BEES! I HATE YOU BEES! I HATE YOU BEES!

LMAO Classic!!!! I love Family Guy!
User avatar
Pilgrimman
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 481
Joined: Thu Jun 28, 2007 1:10 pm
Location: Grants Pass, OR
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: jimmy101 » Tue Sep 25, 2007 11:22 am

noname wrote:Maybe you're taking the scientific approach. I'm going with simple logic.[/i]


It is harder to write a test than you thought isn't it? Just ask a teacher, everything has to be exactly correct, someone will find the piddly little problems.

The problem with simple logic is it is frequently wrong. Just take a look at any of the noobie posts ..." well I figured if I just ..." followed by a description that either won't work or is incredibly dangerous.

I still think you should remove any references to what a "typical hybrid can do" or what a high ratio hybrid could do and explicitly state the conditions ("for a 4x hybrid the ...").

I still think the backdrop answers are wrong enough to be dangerous. A hybrid could easily be producing muzzle energies comparable to a high powered rifle. Given the crappy accuracy of an unrifled barrel, people frequently fire at targets that they are way to close to. You would never fire a high powered rifle at a steel target (the mattress will have essentially zero affect on a small dense round) at ranges of less than a hundred feet or so. Since the chances of actually hitting anything smaller than a barn at a range of 100 feet with any kind of spudgun are pretty slim you need to take that into account when you propose a suitable backstop. Really don't want some noobie blasting away with say a golf ball in a high ratio hybrid, at a steel plate, at a range of 20 feet. Even with the mattress that golf ball is still coming back at the shooter with significant energy.
  • 0

Image

jimmy101
Lieutenant General
Lieutenant General
 
Posts: 3130
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7

Unread postAuthor: mark.f » Tue Sep 25, 2007 6:59 pm

I took the test, and I also found some "glitches" with it. I got the answer on the air injection through the meter question right, but that is not a very good question for "hybrid builders". That would be a good question for "people who build SB15's hybrid design".

Also, your DDT remarks aren't very valid. Most research into that topic has been fairly recent, (think the last 200 years or so). Most concrete postulations have been in the making for hundreds of years more than that. There's not enough data on the subject, we can just say what might happen based on ours and other's experiments.

And the backdrop question would be very circumstantial. If I were shooting glass marbles, I would have no qualms about firing them at a steel plate. If I was shooting carbon steel bearings, I wouldn't even begin to consider such a dangerous thing.
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3465
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Unread postAuthor: FordGtMan » Sun Dec 09, 2007 12:36 am

Wow I just took the quiz and got a 90 on it and i just found out how a hybrid worked a little more than a week ago. This just tells me to stay the **** away from them.
  • 0

User avatar
FordGtMan
Captain
Captain
 
Posts: 314
Joined: Thu Oct 25, 2007 9:15 pm
Location: southlake Tx
Reputation: 0

Unread postAuthor: PVC Arsenal 17 » Sun Dec 09, 2007 12:55 am

Haha I got one wrong. I don't know squat about hybrids.
  • 0


PVC Arsenal 17
Major General
Major General
 
Posts: 1762
Joined: Mon Mar 27, 2006 4:18 pm
Location: United States
Reputation: 1

Unread postAuthor: Novacastrian » Sun Dec 09, 2007 1:01 am

FordGtMan wrote:Wow I just took the quiz and got a 90 on it and i just found out how a hybrid worked a little more than a week ago. This just tells me to stay the **** away from them.


Hey dude i only got 90% and i am in the proud owner of two Hybrids. :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: MrCrowley » Sun Dec 09, 2007 1:20 am

Ah I got 90%, it wasn't exactly the best test ever written but meh I doubt I will be builidng a hybrid anytime soon while in NZ.
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: Novacastrian » Sun Dec 09, 2007 1:30 am

MrCrowley wrote:Ah I got 90%, it wasn't exactly the best test ever written but meh I doubt I will be builidng a hybrid anytime soon while in NZ.


That sounded as if someone is moving soon :D
Is it the great south land MrC?
  • 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: MrCrowley » Sun Dec 09, 2007 1:35 am

I'm not moving to Aussie :wink:

The reason I don't want to build one here is because everything cost so f'in much.
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

PreviousNext

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 ©'