will a carb/pump work off exhaust pressure?
01-25-2005, 02:12 PM
#1
Senior Member
Thread Starter
Join Date: Dec 2002
Location: La Paz BCS, MEXICO
Posts: 1,986
Likes: 0
Received 0 Likes
on
0 Posts
will a carb/pump work off exhaust pressure?
I think there is a problem with my current project. see http://www.rcuniverse.com/forum/glow...582644/tm.htm#
Thought one solution might be to use the 'front' half of a carb (like a DIY smoke pump) to supply the glow carb. Would not solve the gravity flow.....?put tank on bottom side of wing?
It has me confused as this is first glow engine encounter for me.
Thought one solution might be to use the 'front' half of a carb (like a DIY smoke pump) to supply the glow carb. Would not solve the gravity flow.....?put tank on bottom side of wing?
It has me confused as this is first glow engine encounter for me.
01-25-2005, 04:29 PM
#2
RE: will a carb/pump work off exhaust pressure?
hi Mike,
the walbro type pumps need pulses in order to work not just pressure. a much better option is to use the regulator part of the carb and to pressurize the tank by tapping into the crankcase. this would be the same as using a cline or iron bay regulator. if you're interested i can probably dig up a link that shows how it's done...
another simpler option might be a uniflow type tank as used by control line fliers. in this setup the pressure line is tied to the clunk so that it is always submerged in the fuel and another regular vent is also used to allow fueling but is plugged for running. basically works like one of those water hoppers used in bird cages and won't allow the fuel to siphon out of the tank no matter how high it is above the spraybar.
dave
the walbro type pumps need pulses in order to work not just pressure. a much better option is to use the regulator part of the carb and to pressurize the tank by tapping into the crankcase. this would be the same as using a cline or iron bay regulator. if you're interested i can probably dig up a link that shows how it's done...
another simpler option might be a uniflow type tank as used by control line fliers. in this setup the pressure line is tied to the clunk so that it is always submerged in the fuel and another regular vent is also used to allow fueling but is plugged for running. basically works like one of those water hoppers used in bird cages and won't allow the fuel to siphon out of the tank no matter how high it is above the spraybar.
dave
01-26-2005, 01:18 AM
#3
Senior Member
Thread Starter
Join Date: Dec 2002
Location: La Paz BCS, MEXICO
Posts: 1,986
Likes: 0
Received 0 Likes
on
0 Posts
RE: will a carb/pump work off exhaust pressure?
ZAGNUT
Thanks for the lead / guidance. Googling gave me several sites but liked this one the best as it directly related to Uniflow tanks setup for heli use and the narrative and pics were good. I have added to the referenced thread as well.
http://www.fraserker.com/heli/uniflo...flow_works.htm Setup for use with exhaust pressure for helis
How the 'Uniflow' Fuel System Setup Works
by Nigel Fraser Ker
Found the Iron Bay site as well.
Thanks for the lead / guidance. Googling gave me several sites but liked this one the best as it directly related to Uniflow tanks setup for heli use and the narrative and pics were good. I have added to the referenced thread as well.
http://www.fraserker.com/heli/uniflo...flow_works.htm Setup for use with exhaust pressure for helis
How the 'Uniflow' Fuel System Setup Works
by Nigel Fraser Ker
Found the Iron Bay site as well.
01-26-2005, 12:08 PM
#4
Member
Join Date: Jan 2002
Location: Hermon,
ME
Posts: 81
Likes: 0
Received 0 Likes
on
0 Posts
RE: will a carb/pump work off exhaust pressure?
From many years ago and in land far away.... I remember reading in Cycle mag that someone had adapted a couple of walbros to a four stroke motorcycle, and ran the pulse port to the exhaust pipe. Said it worked like fuel injection. That being said, the magnitude of the pressure pulse in an exhaust pipe from a 500cc cylinder might be considerably more the our little 40 - 50 cc engines.
Steve
Steve
