CafeenMan

I think I just had a great idea. But then I just had it and haven't thought about it yet.

This isn't to fire projectiles. It just makes machine gun smoke come out of the barrels with some velocity.

Let's say you're flying a fighter with a couple guns in each wing. The firing mechanism is compressed air. In a tube someplace there is a ball like what is inside a helicopter ball link. The ball is a inside a metal tube. There is a shaft going through the ball and tube that is 90 degrees to the existing hole. The shaft rotates the ball which opens and closes the air line.

The shaft is hooked up to a small motor that can turn an RPM approximately the same rate of fire as the gun.

A small box holds charcoal dust or other black powder as is Teed into the airline after the valve.

Poof! Poof! Poof! Poof! from 4 barrels at the same time. Would be cool for a close in strafing run.

There's probably something out there that already works like this but the valve may be entirely different.

abufletcher

Before I proceeded I'd would want to know a lot more about what happens to a poof of smoke coming out of the leading edge of an aircraft flying at up to 400mph!

Bright flashing LED's in the gun tips might provide a more realistic effect.

CafeenMan

We can have both.

If you watch war documentaries you can see smoke coming out of the guns when watching a dogfight not too far away.

fireplug1111

My Feedback: (21)

CAFEENMAN:

DUDE.............
That is awesome. I got to think about this. I understand what you want and the idea is something that I think will work. If you guys have ideas then post them.

Edwin

My Feedback: (2)

Been working out a system for a vulcan gatlin gun on an A-10. Was thinking about using smoke with a baffle looking disc (like a revolver cylinder) driven by an electric motor. The motor would turn on with the smoke. Not sure the smoke will make it out the barrells though when flying at speed. And havent gotten to the sound yet.
Edwin

das20v

I dont think you would need powder or smoke....copressed gas like CO2 makes enough vapor when discharged......you just need to pulsate a soleniod valve and run the discharge lines up to the barrels. Maybe a small speaker in line to an I-pod or similar MP3 device can provide a pre-recorded sound...lightweight too. Just some ideas.

khodges

My Feedback: (1)

I think it's a cool idea, but I think the relative wind will disperse the smoke the moment it exits the gun tubes. Remember that along with the smoke on the full-scale planes, a tracer projectile is helping create the smoke trail. If you consider a rate of fire of 600 rounds per minute per gun, times three guns per side, and a tracer every 5th round per gun, that is 2 tracers per second per gun, which made pretty good smoke. The gunpowder itself was smokeless.

I wanted to figure a way to "fire" a bazooka rocket from my L-4 without actually launching a projectile. I played with baby powder through a tube using a puff of compressed air from an airbrush compressed air can, and "fired it" toward a window fan, but the breeze immediately dispersed the "smoke", instead of it making any sort of trail.

As far as the sound goes, RAM makes a machine gun sound module, programmable for the rate of fire and gun type sound. I've never heard one working, so I don't know how loud or real it sounds.

jlkonn

My Feedback: (1)

Edwin,
Don't know if you've ever heard an A-10 firing.
I saw them a couple times at Capability Demonstrations at Fort Sill.
They sound more like a buzzer than a machine gun firing.
I have also seen A-10's make flying demonstrations at airshows.
Half Cuban Eights, loops, rolls, etc...
They look like they are very good flying planes.
JLK

abufletcher

With firing rates at well over 2000 rounds per minute I've heard the sound described as more like a mechanical SCREAM! On a practical note, I doubt there is any way you could make even an amplified sound hearable over the sound of twin glow model engines. Maybe you could hear something on a close pass with a small ducted fan electric model but even then I have my doubts. All in all, other than the fun of a challenge I'd imagine there are about 1001 things that might make a model more scale than sound and/or visual effects on the MGs.

Still we build for the fun of figuring out how to build and I'd love to see (and hear) what someone comes up with.

CafeenMan

abufletcher - Wasn't it you who said a wheel might be better than my ball idea? Whoever said it, I've thought about it and it really is a better idea. The ball would require way too much precision to work at all. The wheel can be completely sealed against leaks and nothing more than a drill press and scroll saw are needed.

The wheel can be like a helicopter cooling fan - basically a round plate with blades on one side. The flat plate part would be thicker and on the outside edge have a notch on the edge at about 45 degrees to the face. The wheel will seal the blade part from the other part.

Two tubes come in. The one on the blade side is regulated to determine RPM (rate of fire) and the other side is full pressure. That side goes into the notched wheel side. When the notch isn't aligned with the feed tube that tube is basically blocked. When the notch aligns, there is a hole in the box that is parallel to the wheel having the output tube that goes to the guns. If you want the guns to fire alternately, then you need something different - maybe more in-feeds and out-feeds that are staggered. I think I would go with the guns all firing at once just for simplicity.

Edwin

My Feedback: (2)

Watching some A-10s at an airshow is what got me hooked. I've only heard the guns on TV during wings or other shows. For sound I was thinking about an electric motor beating against a drum type of gizzmo. Would be fast, but dont know how loud it would be. I bought some A-10 plans from Dean Lassik that are 115"ws and am gonna shrink them down to about 96" and use a couple of dynamax DF. Cant afford turbins.
Edwin

jlkonn

My Feedback: (1)

It's a very deep sound...kind of like a semi-truck going over rumble strips....
JLK

wcc963

Here is a video of an A-10 gun on a test stand. this one is for windows media player but he second is an avi so you need real player. maybe this can give an idea of what the smoke shoul look like and an idea of the sound you should shoot for,

http://www.alexisparkinn.com/photoga...test_stand.WMV

and heres a video of what the iraqi's are up agianst. steel rain is the way i can describe it.

http://www.alexisparkinn.com/photoga...fing%20Run.avi


hey if anyone get their gun working working and post some vids. it should be awsome to watch.

viper1

First Video shouldn't give problems.


converted the bottom one (strafing run) to WMV for you.


[link=http://media.putfile.com/A10-Strafing-Run-1]http://media.putfile.com/A10-Strafing-Run-1[/link]


EDIT: OOPS! after re-reading your post I think you meant get the machine gun to work , initially I thought you meant the video.
Anyway, I leave it as it is for those who don't have Realplayer (like me...)