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Fuel vent

Started by lbpa18, December 16, 2010, 12:41:57 PM

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lbpa18

Every time I put wing covers on I worry about the fuel vent getting snagged and broken off. There must be some compelling reason I have four tanks but only one fuel vent, but damned if I can figure out why. Any reason I cant add a second one on the other side? If the one gets bent and /or crimped, it may prevent the flow of fuel.

mrhelio

The main tank is on the right inboard fuel cell, this is where everything goes to..I see no reason to worry about damage to that vent, if you are careful it should be no problem

391stol

" If you are careful there will be no problems"   Is what is scary. I would add another vent and not mention it to anybody if you know what i mean.

45°

Just my 2 cents...

There is one fuel vent by design for an important reason... the vent on the left side is to help compensate for the longer fuel line runs (restricted fuel flow) with the primary system being located on the right. If you add another vent closer to the right you will create a new "path of least resistance" in the vent system and the fuel will draw much more readily from the right tank especially during high fuel burn like takeoff and possibly not at all from the left? I would highly recommend that you fully understand the fuel system before considering making any modifications to it. The vent is an integral part of the design and just as important as the fuel lines themselves.

Louis

#4
On the 800, i have three vent.  One for each outboard, located under the wing, one for the two inboards on the top.  The system is inboard to the motor, outboard transfer to inboard by fuel pump.

I made my wing cover so they don't touch the vent on the top

Louis


Louis

Quote from: lbpa18 on December 16, 2010, 12:41:57 PM
I have four tanks but only one fuel vent,.

Do you have the military version with the four valves ?  If not, and you have two outboard tanks with pumps, i am surprise you have only one vent

Louis

Louis

My 295 that is the serial number one for a 295 had those two underwing vent for the outboards ( pumps too)  Same as the 800 except for the inside clips.  Kind of hard Velcro for the 800

Louis

Neil

Quote from: Louis on December 22, 2010, 05:28:30 PM
My 295 that is the serial number one
Louis

Hi Louis
You have picture of your H295 # 1201

Neil

mrhelio

#8
Here we have serial # 1224 which is a 1967/8 H-295 model that clearly shows the single fuel vent. The H-800 had a new design with the improved Brent wing, the fuel system was also updated with additional vents as previously mentioned.


drmatt

The single fuel vent makes me nervous too.  We had ours break off in flight during some turbulence, a few days after we bought it and were flying it home.  Turns out it was only held in place by some bubble gum.  Fortunately the turbulence turned us around before the lack of fuel flow did...

Ken Berger

This thread seems confusing because the issue of what venting system is on 800s got mixed up with the questions of what venting is on the 295s when it has aux tanks.  This is my belief:

The venting on the 295 with aux tanks is the same as the 800s.  There are two vents on the aux tanks, one on each wing on the lower side, just outboard of the aux tank.  These lower vents are easy to miss because they just barely protrude below the wing skin.  The main tanks are both vented from one rather delicate cane shaped tube above the pilot's head on the outside of the fuselage.

Please show photos if you believe otherwise.
Ken

Louis

Quote from: Ken Berger on January 29, 2011, 07:55:43 PMThis is my belief:

My Helio 295 serial 1201 ( first one i think) was installed as you describe.  (electric transfer pump model, not the military four valves system).  My 800 was the same arrangement , and almost the same tanks (  the kind of clip that holds the bladder was different).  Two other 800 that i saw were the same.

Louis

Louis

Quote from: mrhelio on December 23, 2010, 12:28:19 AM
Here we have serial # 1224 which is a 1967/8 H-295 model that clearly shows the single fuel vent.

On a 60 gallons helio or 120 gallons ?

Louis

Neil

#13
Quote from: Louis on January 30, 2011, 02:14:28 PM
Quote from: mrhelio on December 23, 2010, 12:28:19 AM
Here we have serial # 1224 which is a 1967/8 H-295 model that clearly shows the single fuel vent.

On a 60 gallons helio or 120 gallons ?

Louis

Hi Louis 1224 is N61MU
is 120 gallon  is my first Helio raide in 1988 in Florida ( at this time N61MA)
Neil

Louis

#14
295 manual gives a three fuel vent system as standart for 120 gallons model.  All serial numbers.  As described by Ken Berger, two underwing vent for outside tanks ( number 16 on this page on auxiliary tank), plus one single overhead goose neck for the two inside tanks are shown on another page .

Louis