Page 2 of 3

Re: My last mini machine gun

Posted: Mon Feb 10, 2014 7:52 am
by Spaderman17
I recognize that you have reason firepower! And your idea is certainly more efficient than mine.
But if I built something similar, I'm afraid to find difficult opponents!
In my mind, I seek only to "mark" my opponent, not "destroy"
Even if we use the Chinese electronics, my friends will want to play with me! :sad3: :sad3: :sad2:

I am fascinated by Warbirds, and they did not "Braaaaaaapp" But "Ratata Ratata :lol:
My idea of aerial combat, ammunition is limited, and the "windows shot" are carefully chosen beings.
Of course, the aircraft used for this type of combat, are quite slow.

Spad

Re: My last mini machine gun

Posted: Mon Feb 10, 2014 8:26 am
by CS
First off I must say your machining skills are amazing. It is a joy to see talented work like this, even better you combined your machine gun with an rc plane. Very cool stuff. As a lot of kids are, I was, and am, interested in the theatrics of war. I had a vivid fantasy of full fledged rc combat. Planes, boats, tanks, defenses... the whole nine yards. That would be a cool tv series, a lot more appealing then battlebots I would think. o' fantasy land.
In my mind, I seek only to "mark" my opponent, not "destroy"
I see your point, however... could you not shield the electronics/ engine with a thin piece of sheet metal? Leaving the propeller and foam body to be disposable?

For instance a 2.4384m x 1.2192m x 38.1mm piece of foam costs $15 here in the USA.

Re: My last mini machine gun

Posted: Mon Feb 10, 2014 8:43 am
by jackssmirkingrevenge
Spaderman17 wrote:In my mind, I seek only to "mark" my opponent, not "destroy"


Booooooooooooooo!!!!

Boring! :P :D
Even if we use the Chinese electronics, my friends will want to play with me! :sad3: :sad3: :sad2:
Fair point...
I am fascinated by Warbirds, and they did not "Braaaaaaapp" But "Ratata Ratata :lol:
My idea of aerial combat, ammunition is limited, and the "windows shot" are carefully chosen beings.
Of course, the aircraft used for this type of combat, are quite slow.
Your user name should have been an indication of course :)

Image

I have done some ratatatata experiments...

[youtube][/youtube]

I think your electric drive is a good idea for what you want, I think it can be optimized though.

This is how I would do it:
suggestedimprovement.png
The dead space is reduced and I have made the valve stem "balanced", this means most of its area does not have the full pressure from the firing chamber and therefore you need a much weaker spring to knock it open, this means you can use a smaller, lighter motor with lower electricity consumption.
CS wrote:I see your point, however... could you not shield the electronics/ engine with a thin piece of sheet metal? Leaving the propeller and foam body to be disposable?
I think the damage would come from hitting the ground as opposed to the actual BBs... maybe a parachute system?

Image

Re: My last mini machine gun

Posted: Mon Feb 10, 2014 1:08 pm
by Spaderman17
CS,
As a lot of kids are, I was, and am, interested in the theatrics of war. I had a vivid fantasy of full fledged rc combat
When I was 20 and I did my military service, I would not have missed a single episode of Papy Boyington! and 35 years later, I am still a fan .....
So, after having practiced hunting banner for 5 years, I try another approach to fight ....
The fight with gun seems quite realistic as the next step!
jackssmirkingrevenge wrote: Booooooooooooooo!!!!
Boring!
Not boring, just more technical and realistic
Your user name should have been an indication of course
Not exactly! my user name comes from "Simply Plastic Airplanes Design" and my fighter is built on the basis of http://www.spadtothebone.net/ Fighter in Coroplast

Thanks you for drawing balanced valve ! I understood

Spad

Re: My last mini machine gun

Posted: Mon Feb 10, 2014 4:20 pm
by jrrdw
Thread cleaned! :|

Re: My last mini machine gun

Posted: Tue Feb 11, 2014 9:55 am
by jackssmirkingrevenge
Spaderman17 wrote:Not boring, just more technical and realistic
Indeed, I was being facetious ;)
Not exactly! my user name comes from "Simply Plastic Airplanes Design" and my fighter is built on the basis of http://www.spadtothebone.net/ Fighter in Coroplast
A happy coincidence then hehehe
Thanks you for drawing balanced valve ! I understood
Great, I think it would be worth incorporating into your next prototype. You can make a gun that is technically interesting as well as efficient and lightweight :)

Re: My last mini machine gun

Posted: Tue Feb 11, 2014 12:37 pm
by Spaderman17
I always thought of a "rotary", but I like your animated concept and I may experience your concept ....
You are right, the simplicity and probably a good solution!

Unfortunately, even if I start with a simple concept, on arrival, I always complicated! this is stronger than me! :dontknow:

This time, I'll try to do better! :D

Re: My last mini machine gun

Posted: Wed Feb 12, 2014 6:24 am
by jackssmirkingrevenge
Spaderman17 wrote:I always thought of a "rotary", but I like your animated concept and I may experience your concept ....
You are right, the simplicity and probably a good solution!
Sometimes it's better to spend time thinking about a simple solution than making a complicated one.
Spaderman17 wrote:Unfortunately, even if I start with a simple concept, on arrival, I always complicated! this is stronger than me! :dontknow:


You have no idea how much I know that feeling hehehehe

Re: My last mini machine gun

Posted: Sat Feb 15, 2014 3:29 am
by Spaderman17
Hello
Here is the drawing of my next project!

Maybe one or two errors, but I think I got what I want .... :idea:
- Large valve opening
- Direct injection
- Balanced valve (I think so) :scratch:
- No containment (I hope) :bounce:
- and Injection just after stuffing the ball on the hop up, the reverse thing my first gun.....

(I hope my Chinglish is sufficiently understandable!)

Image

Re: My last mini machine gun

Posted: Sat Feb 15, 2014 8:55 am
by jackssmirkingrevenge
"Don't Panic" BB
:D :D :D

A bit convoluted but it looks like it would work :) The small spring next to the air input needs to be finely tuned in order to counterbalance the pressure. Too little force and it will leak, too much force and it will need too much hammer strength to open.

One thing you have to be careful about is "dead volume", I marked it below and compressed the design to reduce it:
volummort.png
More dead volume means the air has more time to expand and lose pressure before pushing the BB, so it will decrease efficiency.

Re: My last mini machine gun

Posted: Sat Feb 15, 2014 1:52 pm
by Spaderman17
I am well aware that the dead volume is detrimental to the operation! and I will try to improve the concept...
But this drawing is the first jet (or first rush)to define the movements and shapes...

soon pictures of the first pièces, after changing the drawing, :bounce:

PS : Thanks for drawing !! :wink:

Spad

Re: My last mini machine gun

Posted: Tue Feb 25, 2014 9:48 am
by Spaderman17
Hello all,

A lot of work right now, and little time for leisure ....But I'm still here ! :lol:
I continued to think about my project ....
I hope to bring news soon... :bounce:

Spad

Re: My last mini machine gun

Posted: Tue Feb 25, 2014 10:25 am
by jackssmirkingrevenge
Nous attendes avec impatience :)

Re: My last mini machine gun

Posted: Wed Feb 26, 2014 1:16 am
by Spaderman17
Whaoooo
friendly little word in French! :)

Spad

Re: My last mini machine gun

Posted: Wed Feb 26, 2014 8:19 am
by jackssmirkingrevenge
Je vis au Québec maintenant, je dois pratiquer!