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D_Hall · Fri Jan 09, 2009 4:11 pm

psycix wrote:Well, mixing is done in a hybrid by the air pressure flowing in and venting can also be done that way.

I can't discuss details, but I will say this: I've seen evidence that counters this statement. Fuel mixture in a hybrid is NOT a given.

Moonbogg · Fri Jan 09, 2009 4:27 pm

D_Hall wrote:
psycix wrote:Well, mixing is done in a hybrid by the air pressure flowing in and venting can also be done that way.
I can't discuss details, but I will say this: I've seen evidence that counters this statement. Fuel mixture in a hybrid is NOT a given.

With such a huge chamber with all the volume it has, I would gander a guess that the fan would help with the mixture and combustion rate.

psycix · Sun Jan 11, 2009 4:28 pm

@dave & jimmy101
My statement was made on what was generally believed by most people. It is assumed that a hybrid cannon does not need a fan. But since this is not yet confirmed by an experiment, "most people" could be wrong.

I think the effectiveness of mixing by air pressure depends on flow rate and size of chamber. In some cases a fan may be unnecessary, in some cases it WILL make a difference.
A fan may mix better then the air pressure, though this depends on the situation.

Moonbogg · Tue Jan 13, 2009 1:44 am

Design Update.

Thanks for all your input. I have made the following changes. First of all, I changed the chamber wall thickness to 3/16" from 1/8" due to strength loss from the holes in the chamber. I made the gusset larger. It extends half way across the chamber, transmitting all the recoil. If you held the cannon vertical, you could hang 800lbs from the rear end where the barrel starts with a factor of safety of 3.7. If anything breaks from recoil, its going to be me.
I added a small orifice flow control adapter, rather than a needle valve to protect the gauge. It was the smallest orifice McMaster had (2822T189).
I changed gauge and inlet locations. I got rid of all pipe clamps and used wide shaft collars to connect the barrel support to the chamber. I shortened the chamber by 2" because the volume was enormous and ridiculous.
The long gusset got in the way of the spark strip screws so I placed the screws on the bottom of the chamber, out of sight. I will be making myself a custom plexi box that either connects with stainless clips by using the spark strip screws for mounting, or a separate plexi mount plate attached with hi strength, yet removable and in no way permanent modelling glue (excellent stuff, I use it a lot). Its a strong rubber cement/sealer.
Current total weight: 16.5lbs. If you guys have any other comments or suggestions, I am all ears, however, I ordered the material today, so nothing TOO major can change. THANKS!

EDIT: Oh! I almost forgot....she has a name. "The Scorpion"

Check out my YouTube SpudGun Channel! · Tue Jan 13, 2009 1:58 am

Looking great, can't wait to see this puppy finished.

BTW, the name Scorpion has already been taken, well kind of:
http://www.spudfiles.com/forums/scorpio ... t4125.html

starman · Tue Jan 13, 2009 2:02 am

Oh yeah!! Looking good Moon. There's only one thing I can think of at the moment...just to be aware of. You're going to have access to your chamber from only one end so unless you have really really thin hands and arms, getting to the rear spark strip mount to screw it down is going to be a real challenge.

Just be thinking about how you're going to tie it down in the rear.

Moonbogg · Tue Jan 13, 2009 2:13 am

starman wrote:Oh yeah!! Looking good Moon. There's only one thing I can think of at the moment...just to be aware of. You're going to have access to your chamber from only one end so unless you have really really thin hands and arms, getting to the rear spark strip mount to screw it down is going to be a real challenge.

Just be thinking about how you're going to tie it down in the rear.

My hand can fit in there. I did a little mock test and it will be OK. Good eye though. A lot of people don't think about stuff like assembly etc. I really wanted to use a smaller chamber to have the whole thing be really sleek and streamlined looking, but there was no way my arm was getting in the back of a 3" pipe lol.

Moonbogg · Sat Feb 28, 2009 6:53 pm

Just wanted to update to show manufacturing progress. it's not done and they made a couple errors so they are now fixing them. But its on its way! It has yet to be heat treated and anodized as well.

psycix · Mon Mar 02, 2009 1:19 pm

Oooh shinyyy

What errors did they make? I hope that this wont create weak spots...

Moonbogg · Mon Mar 02, 2009 3:20 pm

psycix wrote:Oooh shinyyy
What errors did they make? I hope that this wont create weak spots...

The errors don't effect safety. What they did was make the gusset too long and too high, when it should taper down nicely to the chamber rather than be left sticking up like it is. Plus, there is not enough room to twist the camlock on. They just didn't use the CNC cutout file I gave them for whatever reason. Instead they eyeballed it appearantly.
Also, they didn't round off the pipe plugs square corners. Its alright though, they are on it.
It will be anodized blue.

psycix · Mon Mar 02, 2009 3:47 pm

They just didn't use the CNC cutout file I gave them for whatever reason.

If your file contained a mistake that could damage the machine, they wouldnt like it. If they made their own CNC file, made a mistake and ruined the machine, its their own fault which could have been avoided.

Moonbogg · Mon Mar 02, 2009 5:28 pm

psycix wrote:
They just didn't use the CNC cutout file I gave them for whatever reason.
If your file contained a mistake that could damage the machine, they wouldnt like it. If they made their own CNC file, made a mistake and ruined the machine, its their own fault which could have been avoided.

They are a client of mine and I make DXF files for them to use for programming their machines often. The geometry was clean, they just appear to have not used it.

MRR · Sat Mar 07, 2009 7:20 am

The front grip should be able to move from the left to the right of the gun.
Some people out there are left handed (me included) and it would be a nice
gimmick if you could customize it.

Moonbogg · Sat Mar 07, 2009 4:32 pm

MRR wrote:The front grip should be able to move from the left to the right of the gun.
Some people out there are left handed (me included) and it would be a nice
gimmick if you could customize it.

I was just making this one for myself. But if I made more of them they could be fully customized with colors, size and configurations.

Moonbogg · Thu Mar 19, 2009 7:01 pm

Here is the finished fabrication of the parts! Of course, I have PLENTY of work to do myself now. I am very pleased with the quality of work. I realize how difficult it must have been to get things to align properly. The welding process, stress relieving and then heat treating to T6 condition caused significant warpage and movement, which is to be expected. So for them to have accomplished it with this degree of quality really grants them my appreciation.
from what I see there is some minor misalignment of the barrel in regard to the main chamber however, so if this doesn't straighten out once the camlock is fully tightened, I will have to find some shaft collars with allong for misalignment, or use a more flexible material to connect the barrel support to the chamber, and then clamp it. I'll figure it out. They sell shaft collars with machinable bores for misalignment of axis if all else fails. This would be the last option however because it would only create additional cost. The fab cost along, not including the material at all, was about $2,000. So I will be taking care of this baby for a long time.
Anyway, what do you guys think so far!?!?
It looks very much like the CAD files!

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