boolat

Hello,

could you tell me why the modified cover Walbro carburetor?
do you have any example photos ?

Thank you

w8ye

My Feedback: (16)

The little hole is a atmospheric static pressure vent reference for the metering valve of the carb

When wind blows over the hole or the carb is inside a pressurized cowl, it makes the engine run unusual.

The trick is to attach a nipple to the vent hole and route the static vent source inside the fuselage of the plane or to a source where the atmospheric pressure is normal.

This makes the engine run correctly at all attitudes and speeds

boolat

So if I understand.
for proper engine operation is important?
by looking on google I found this:
http://www.thunderboltrc.com/tutoria...ial_seven.html
we have the choice to modified cover ....

w8ye

My Feedback: (16)

Many people get by fine without doing this modification.

You may or may not need this?

Rear carb engines are unlikely to need this modification.

Eganwp

My Feedback: (1)

The choice is yours as w8ye mentioned. Personally I do it to all my gas engines as I've found certain manouvers to pressurize my cowls differently, and have even resulted in a stalled engine. By doing the mod you guarantee consistant atmospheric pressurization on the diaphram.

Please note that if you do end up doing the mod that you need to make sure you seal your firewall/motor box of holes where possible. If you don't and you have no fuse vent holes cut, that you'll place positive pressure during flight in the fuse again affecting your diaphram. Try to keep your fuse intake/exhaust air pressure to be close to 0 for best results.

The other positive to this mod that most people don't realize is it allows for 95% accurate tuning on the ground. It will match your in-flight tuning nearly identically other than cooling which can very slightly affect it.

Egan

closetguy

My Feedback: (13)

hear is what i learn from doing this mod.don't run the line into the fuse,to much of a pressure change from ground to the flight.run the line outside of fuse into unobstructed air.use a piece of brass tube and on one end crimp it shut,then drill or cut two small holes in it.now put that in the end of line running from carb cover and mount it outside the fuse.

rfk1381

My Feedback: (7)

So, should we route the extended static vent line to the inside of the fuselage or should we route a brass line to the outside of the fuselage? I am ready to install my rear-carburetor RCGF 45cc in a 28% aerobat. The carburetor opening will extend through the firewall into the fuselage. So will I need to route an extended static vent line inside/outside  the fuse, or is it not required with a rear carb configuration?

w8ye

My Feedback: (16)

Why don't you try to run and fly it and see what you have as far as performance and controllability goes? If you have trouble, then you know a few things you can try?

captinjohn

NOT A REPLY For you guys that get all shook up about soldering a tube to the carb cover...you can use silicone fuel line...cut on a slant...line up ID of tubing and use clear GE silicone rubber to hold the line in place. Make sure the cover is first cleaned with silicone spray. It wll be hard to pull the vent tube off if done right. EASY Capt,n

RJConnet

rfk1381
I have been running my RCGF 45 that way for a couple years now and have had no problems at all. The carb sticks almost 3/4 of the way through the firewall so the vent hole is inside the fuselage, no tubing at all. It is in a AW 35cc Extra 300 and to get the proper cowl to engine prop drive distance had to bring the engine way back. Good luck with yours..........RJ

closetguy

My Feedback: (13)

i do it on all my gas engines now after seeing the difference it made on a Yak with a DLE55 in it.
i think the big opening on the Yak cowls is where you find the most trouble,i have flown Edges and
Extras with no prblem at all not using the line.

boolat

I made ​​this piece:

soon I will test in flight