Airsoft Canada
http://triggerairsoft.com/shop/

Go Back   Airsoft Canada > Discussion > Upgrades & Modifications > Showcase
Home Forums Register Gallery FAQ Calendar
Retailers Community News/Info International Retailers IRC Today's Posts

Whee! New MadMax ROFinator!

:

Showcase

Reply
 
Thread Tools
Old January 30th, 2007, 17:43   #16
dontask
 
Join Date: Jan 2006
Location: Vancouver
Send a message via MSN to dontask
you gotta love LiPo
dontask is offline   Reply With Quote
Old January 30th, 2007, 18:01   #17
Tankdude
 
Join Date: Jan 2005
Location: East Coast, New Brunswick
For a cut off there is a little circuit involving a opamp and diodes, OR get a speedcontroller for a model airplane. I'm sure you can hot wire it to fire and they (most) come with a battery cut off.

If your interested in the optamp I have the parts here but lost the diagram.
Tankdude is offline   Reply With Quote
Old January 31st, 2007, 17:09   #18
Renegade)
A Total Bastard
 
Renegade)'s Avatar
 
Join Date: Apr 2006
Location: Tottenham, Ontario
That, Carl my friend, is COOL!!! Really insane lol, show us more when you replace whatever parts you fried haha.
__________________
W1-5
Renegade) is offline   Reply With Quote
Old January 31st, 2007, 17:32   #19
Kid
 
Join Date: Feb 2005
Location: Moose Jaw, SK
Quote:
Originally Posted by Renegade) View Post
That, Carl my friend, is COOL!!! Really insane lol, show us more when you replace whatever parts you fried haha.
Show us the parts you fried, too. Maybe a macro shot to show the damage.
Kid is offline   Reply With Quote
Old January 31st, 2007, 17:34   #20
MadMax
Delierious Designer of Dastardly Detonations
 
MadMax's Avatar
 
Join Date: Dec 2001
Location: in the dark recesses of some metal chip filled machine shop
Quote:
Originally Posted by Tankdude View Post
For a cut off there is a little circuit involving a opamp and diodes, OR get a speedcontroller for a model airplane. I'm sure you can hot wire it to fire and they (most) come with a battery cut off.

If your interested in the optamp I have the parts here but lost the diagram.

I think I can work something out with the MOSFETs. Perhaps a comparator arrangement which compares the battery output voltage stepped down through a voltage divider against the output from say a 6v regulator.

Basically when the output of the battery drops below 12v across a 50% voltage divider (6v) it drops below the 6v reference provided by a regulator output which is also fed by the battery output.
__________________
Want nearly free GBB gas?

MadMax is offline   Reply With Quote
Old January 31st, 2007, 17:35   #21
MadMax
Delierious Designer of Dastardly Detonations
 
MadMax's Avatar
 
Join Date: Dec 2001
Location: in the dark recesses of some metal chip filled machine shop
Quote:
Originally Posted by Kid View Post
Show us the parts you fried, too. Maybe a macro shot to show the damage.
Not much fun really. The first 3 teeth on the piston wore off.

The burned out switch doesn't look like much. It just doesn't go continuous when it clicks.
__________________
Want nearly free GBB gas?

MadMax is offline   Reply With Quote
Old January 31st, 2007, 17:52   #22
Renegade)
A Total Bastard
 
Renegade)'s Avatar
 
Join Date: Apr 2006
Location: Tottenham, Ontario
Quote:
Originally Posted by MadMax View Post
Not much fun really. The first 3 teeth on the piston wore off.

The burned out switch doesn't look like much. It just doesn't go continuous when it clicks.
Ya... we want more video!
__________________
W1-5
Renegade) is offline   Reply With Quote
Old February 1st, 2007, 01:56   #23
MadMax
Delierious Designer of Dastardly Detonations
 
MadMax's Avatar
 
Join Date: Dec 2001
Location: in the dark recesses of some metal chip filled machine shop
Well, I figured out the dying piston problem today.

I mangled two more pistons before looking at the problem really hard. I found that CA makes their piston heads differently from TM. They're shorter than the usual piston head so the piston sits about 1mm too far forward. This makes for crappy pick up engagement so the first sector tooth makes a mess of the first piston tooth and subsequently prangs the 2nd and 3rd tooth.

I changed the piston head and piston and managed to fire off about 2000rnds in very long bursts before ROF dropped considerably and I was treated to the stink of burning insulator.

I think I fired the stock CA motor on a 300-500rnd (hard to tell except for the shredded zone of cardboard) burst.

I really want a SAW which doesn't even notice that's working, but I think I'm hitting the practical limits of the AEG design. Maybe I have to go to brushless motors which have the coils on the motor casing so I can remove heat with conduction. Brushed DC motors have always had the problem of heat removal. The coils on the armature can only shed heat to the air in the can so they can overheat. Maybe I can make a water cooling jacket for a brushless motor and bolt on a radiator like a water cooled Vickers gun.

I may also have a heat buildup issue in the cylinder. Air can heat up when it's compressed rapidly so I'm wondering if I could be making the cylinder really hot when firing long bursts. It's an issue with aircompressors which are on for many minutes at a time.
__________________
Want nearly free GBB gas?

MadMax is offline   Reply With Quote
Old February 1st, 2007, 02:01   #24
takatorikku
UnVerified
 
takatorikku's Avatar
 
Join Date: Sep 2006
are you using polycarb pistons or aluminum ones? would that even make a difference?
__________________
takatorikku is offline   Reply With Quote
Old February 1st, 2007, 02:07   #25
MadMax
Delierious Designer of Dastardly Detonations
 
MadMax's Avatar
 
Join Date: Dec 2001
Location: in the dark recesses of some metal chip filled machine shop
I'm trying to avoid aluminum pistons. Aluminum is not a very good material as it sheds particles pretty fast when it wears. When this starts to happen, the particles can get welded back on making a crummy galled surface which wears even faster. Also, if the piston jams, it would be strong enough to lock up the gears and stall the motor.

While Al pistons are strong on the whole (teeth don't rip off), they kill other stuff (and themselves ) with their shedded aluminum flakes.

Conversely, polycarb pistons just get torn to bits when they bind with the sector gear. They shed bits which the gears don't even notice. Up until now, the tradeoff of a consumable piston has been worthwhile in most of my AEGs as it protected more expensive components. However, if this gun eats up pistons too fast, I'll have to try a piston with a steel rack (e.g. deepfire).

At the moment, I'm more concerned with the motor heat issue. I think the current piston may last just fine, but if I can't beat the heat buildup problem in the motor I won't be able to make the gun of other peoples nightmares.
__________________
Want nearly free GBB gas?

MadMax is offline   Reply With Quote
Old February 1st, 2007, 02:24   #26
takatorikku
UnVerified
 
takatorikku's Avatar
 
Join Date: Sep 2006
how about heatsinks? or would they not fit into the handgrip?
__________________
takatorikku is offline   Reply With Quote
Old February 1st, 2007, 02:28   #27
MadMax
Delierious Designer of Dastardly Detonations
 
MadMax's Avatar
 
Join Date: Dec 2001
Location: in the dark recesses of some metal chip filled machine shop
heat sinks wouldn't work as the heat buildup is on the armature (where the coils are) which has poor contact with anything else in the motor (it's spinning). Heat sinking the can can remove heat from the magnets, but they don't heat up much. Heatsinking the brush housings might help cool the brushes a bit, but it would do nothing for the coils which are the major heat loads.
__________________
Want nearly free GBB gas?

MadMax is offline   Reply With Quote
Old February 1st, 2007, 02:46   #28
takatorikku
UnVerified
 
takatorikku's Avatar
 
Join Date: Sep 2006
well Carl, if anyone can figure it out, better you than me. I'd prolly somehow turn the thing into miniature nuclear device...
__________________
takatorikku is offline   Reply With Quote
Old February 1st, 2007, 02:47   #29
Lisa
Looking for form T-whatev
 
Lisa's Avatar
 
Join Date: Jun 2004
Location: Trenton
Fan? lol. not sure where you would stick it though
__________________
Nothing to see here
May you live in interesting times.
ASCMART, your smart choice
Lisa is offline   Reply With Quote
Old February 1st, 2007, 03:02   #30
MadMax
Delierious Designer of Dastardly Detonations
 
MadMax's Avatar
 
Join Date: Dec 2001
Location: in the dark recesses of some metal chip filled machine shop
Quote:
Originally Posted by Lisa View Post
Fan? lol. not sure where you would stick it though
I'm actually considering that. I'm thinking of shoehorning one just behind the pinion gear to improve airflow thru the motor
__________________
Want nearly free GBB gas?

MadMax is offline   Reply With Quote
ReplyTop


Go Back   Airsoft Canada > Discussion > Upgrades & Modifications > Showcase

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Airsoft Canada
http://triggerairsoft.com/shop/

All times are GMT -4. The time now is 19:04.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.