Today's Message Index:
----------------------
1. 01:09 PM - Re: Fuel valve (Chuck Jensen)
2. 01:46 PM - Re: Fuel valve (Stein Bruch)
3. 01:48 PM - Re: Nosewheel shimmy (Chuck Jensen)
4. 03:03 PM - Re: Fuel valve (cgalley)
Message 1
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--> RV9-List message posted by: Chuck Jensen <cjensen@dts9000.com>
Cy,
You wrote this this a few weeks ago. I was interested in the fuel
starvation issue with low wing and fuel flow from 'both' issue. Would you,
or someone be so kind as to expound on what must be shared wisdom given your
brief reference.
Chuck
-----Original Message-----
From: owner-rv9-list-server@matronics.com
[mailto:owner-rv9-list-server@matronics.com]On Behalf Of cgalley
Subject: Re: RV9-List: Fuel valve
--> RV9-List message posted by: "cgalley" <cgalley@qcbc.org>
With a low winged plane you DON'T want a both. Causes fuel starvation
problems.
Cy Galley
Safety Programs Editor
Always looking for ideas and articles for EAA Sport Pilot
----- Original Message -----
From: "Konrad Werner" <klwerner@comcast.net>
Subject: Re: RV9-List: Fuel valve
> --> RV9-List message posted by: "Konrad Werner" <klwerner@comcast.net>
>
> Dear Steve,
> The current valve has 3 Fuel Ports plus OFF. One of the fuel ports (your
choice) is not used with the standard 2-Tank setup.
> There is no "Both" on this valve.
> do not archive
> ----- Original Message -----
> From: Steve Sampson
> To: rv9-list@matronics.com
> Sent: Monday, August 23, 2004 12:39 PM
> Subject: RV9-List: Fuel valve
>
>
> --> RV9-List message posted by: "Steve Sampson"
<SSampson.SLN21@london.edu>
>
> Could someone remind me about the positions on the VANS supplied valve.
> One position is L Tank, one R Tank. Am I correct in thinking the other
two
> are both 'OFF' or is one 'Both'? I am just getting some labelling made
up
> and cant get to the valve.
>
> Thanks, Steve.
>
> #90360
> UK
>
> ---
>
>
Message 2
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--> RV9-List message posted by: "Stein Bruch" <stein@steinair.com>
Usually with a low wing airplane a "Both" selection is a "no-no"
There are a couple of reasons
#1) reason is that because of the venting/pressurization issues with the
tanks, you can and will most likely end up with one tank being pressurized
more than the other tank. This is a reality with our homebuilt airplanes,
the difference in venting pressure only has to be in fractions and then here
you go:
With a seletor in "both", the tank with the higher pressure in it (because
remembering that both aren't 100% equal) begins to feed fuel to the lower
pressure tank. This tank then will dump the fuel out of the vent and this
whole process will go on until one or both tanks are completely empty.
Even some high wing airplanes with a fuel system that doesn't have a
"common" or "interconnected" vent line can suffer from the same problems.
#2) The next problem is gravity. Assuming you can get the vent pressures on
the tanks to be 100% equal (by running a common tie between the vent lines
or something), you still have to worry about gravity. Gravity will always
move the fuel to the lowest tank, and if you are using a "both" valve while
the fule drains to the lowest tank, the system will then start drawing air
from the other tank.
Bad Deal all the way around. I've seen some people try to "roll their own"
BOTH selection by usine two boost pumps and elaborate check valves, but in
the end it's just easier to switch tanks every once and awhile. Fuel
systems are not something to take lightly, and I would strongly discourage
anyone from taking on modification of these systems lightly!!
One could write pages on the differences in design of fuel systems between
high and low wing planes, but that's the short version of it!
Cheers,
Stein Bruch
RV6's, Minneapolis
-----Original Message-----
From: owner-rv9-list-server@matronics.com
[mailto:owner-rv9-list-server@matronics.com]On Behalf Of Chuck Jensen
Subject: RE: RV9-List: Fuel valve
--> RV9-List message posted by: Chuck Jensen <cjensen@dts9000.com>
Cy,
You wrote this this a few weeks ago. I was interested in the fuel
starvation issue with low wing and fuel flow from 'both' issue. Would you,
or someone be so kind as to expound on what must be shared wisdom given your
brief reference.
Chuck
-----Original Message-----
From: owner-rv9-list-server@matronics.com
[mailto:owner-rv9-list-server@matronics.com]On Behalf Of cgalley
Subject: Re: RV9-List: Fuel valve
--> RV9-List message posted by: "cgalley" <cgalley@qcbc.org>
With a low winged plane you DON'T want a both. Causes fuel starvation
problems.
Cy Galley
Safety Programs Editor
Always looking for ideas and articles for EAA Sport Pilot
----- Original Message -----
From: "Konrad Werner" <klwerner@comcast.net>
Subject: Re: RV9-List: Fuel valve
> --> RV9-List message posted by: "Konrad Werner" <klwerner@comcast.net>
>
> Dear Steve,
> The current valve has 3 Fuel Ports plus OFF. One of the fuel ports (your
choice) is not used with the standard 2-Tank setup.
> There is no "Both" on this valve.
> do not archive
> ----- Original Message -----
> From: Steve Sampson
> To: rv9-list@matronics.com
> Sent: Monday, August 23, 2004 12:39 PM
> Subject: RV9-List: Fuel valve
>
>
> --> RV9-List message posted by: "Steve Sampson"
<SSampson.SLN21@london.edu>
>
> Could someone remind me about the positions on the VANS supplied valve.
> One position is L Tank, one R Tank. Am I correct in thinking the other
two
> are both 'OFF' or is one 'Both'? I am just getting some labelling made
up
> and cant get to the valve.
>
> Thanks, Steve.
>
> #90360
> UK
>
> ---
>
>
Message 3
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| Subject: | Nosewheel shimmy |
--> RV9-List message posted by: Chuck Jensen <cjensen@dts9000.com>
I don't know much about RVs (well, make that nothing, actually) but Velocity
aircraft have had some of the same issue about nose wheel shimmy...with
equal resolution--marginal. However, you're issue about the shimmy
associated with braking may be a somewhat different and may be related to
harmonic vibrations through the gear legs that are caused by braking action.
The harmonic vibration can be easily mistaken for shimmy in the nose wheel.
Just an alternative thought.
Chuck
-----Original Message-----
From: owner-rv9-list-server@matronics.com
[mailto:owner-rv9-list-server@matronics.com]On Behalf Of Dale Larsen
Subject: Re: RV9-List: Nosewheel shimmy
--> RV9-List message posted by: "Dale Larsen" <slickrock@been-there.com>
Axle bolt tension is good, breakout tension is adjusted per plans with a
fish scale. Tire pressure is good, and wheel rotates freely.
On closer investigation, it only occurs at the end of the rollout, when you
start to brake hard. If you don't brake at all, it dosent shimmy. I would
think that if it were due to a balance condition that it would be
poportional to the speed of the wheel.
No shimmy on takeoff.
> --> RV9-List message posted by: "fcs@jlc.net" <fcs@jlc.net>
>
>
> > It moves 1 to 1-1/2 inches at about a 3 Hz rate.
> > Maybe the wheel is out of balance?
> > Dale
>
> Wow, and you say you can't feel this?!? I suppose it is possible that
> your tube is folded or pinched inside the tire, causing major imbalance.
> If you think this is the case, you should immediately take the wheel apart
> and check. Trust me, you don't want to experience a flat tire. Some
> degree of bouncing is to be expected with a spring type nose gear leg, but
> that's way more than I have seen. Check your axle bolt tension while
> you're at it and make sure your wheel is rotating freely. Also check your
> nose fork breakout tension. If it is too loose the wheel can wobble
> violently from side to side just as it touches the pavement. Use a
> fish-scale to actually set it per Vans instructions. The fork must have a
> good bit of tension and not just swivel freely. If you can't find the
> culprit, I would give Vans a call and see if they have any further clues.
>
>
Message 4
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--> RV9-List message posted by: "cgalley" <cgalley@qcbc.org>
Take two straws and put them in your mouth. Place one of the straws in a can
of pop and suck.
How much pop did you get?
I'll bet none because air is easier to suck than pop. Close off the straw
that isn't in the pop and voila, you can suck the pop.
If you use a both tank position, then when one tank empties, no matter how
much gas is in the other tank, you will suck air and the engine will quit.
Cy Galley
EAA Safety Programs Editor
Always looking for ideas and articles for EAA Sport Pilot
----- Original Message -----
From: "Chuck Jensen" <cjensen@dts9000.com>
Subject: RE: RV9-List: Fuel valve
> --> RV9-List message posted by: Chuck Jensen <cjensen@dts9000.com>
>
> Cy,
>
> You wrote this this a few weeks ago. I was interested in the fuel
> starvation issue with low wing and fuel flow from 'both' issue. Would
you,
> or someone be so kind as to expound on what must be shared wisdom given
your
> brief reference.
>
> Chuck
>
> -----Original Message-----
> From: owner-rv9-list-server@matronics.com
> [mailto:owner-rv9-list-server@matronics.com]On Behalf Of cgalley
> To: rv9-list@matronics.com
> Subject: Re: RV9-List: Fuel valve
>
>
> --> RV9-List message posted by: "cgalley" <cgalley@qcbc.org>
>
> With a low winged plane you DON'T want a both. Causes fuel starvation
> problems.
>
> Cy Galley
> Safety Programs Editor
> Always looking for ideas and articles for EAA Sport Pilot
>
> ----- Original Message -----
> From: "Konrad Werner" <klwerner@comcast.net>
> To: <rv9-list@matronics.com>
> Subject: Re: RV9-List: Fuel valve
>
>
> > --> RV9-List message posted by: "Konrad Werner" <klwerner@comcast.net>
> >
> > Dear Steve,
> > The current valve has 3 Fuel Ports plus OFF. One of the fuel ports (your
> choice) is not used with the standard 2-Tank setup.
> > There is no "Both" on this valve.
> > do not archive
> > ----- Original Message -----
> > From: Steve Sampson
> > To: rv9-list@matronics.com
> > Sent: Monday, August 23, 2004 12:39 PM
> > Subject: RV9-List: Fuel valve
> >
> >
> > --> RV9-List message posted by: "Steve Sampson"
> <SSampson.SLN21@london.edu>
> >
> > Could someone remind me about the positions on the VANS supplied
valve.
> > One position is L Tank, one R Tank. Am I correct in thinking the other
> two
> > are both 'OFF' or is one 'Both'? I am just getting some labelling made
> up
> > and cant get to the valve.
> >
> > Thanks, Steve.
> >
> > #90360
> > UK
> >
> > ---
> >
> >
>
>
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