Author: Clifford Dow <cdowjr@...> Time: Wed Jan 2, 2002 12:01 pm PST Link
January 2, 2002
Could someone direct me to where I get the fuel pick
up for the RV-7A quickbuild wing – I’d like the type
for inverted flight in both tanks – the best rig
available. I don’t see it in the Vans catalogue and
I’d like not to order one which then does not fit and
have to return it.
Also, my fuel selector has Right and Left – no BOTH
setting. Why in heck wouldn’t it have “Both”? On a
cross country flight I’d like to not have to worry
about remembering to switch the tank once one was low.
Cliff Dow, Jr.
Cdowjr@Y...
Maine RV Builder
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Author: Mark Ruddock <mruddock_2000@...> Time: Wed Jan 2, 2002 12:26 pm PST Link
I am not sure of the reasons, but with the low wing
and venting and arrangement of tanks, a "both" would
not be good as I understand it for the RV.
IMHO, it may not be best to have the flop in both
tanks. The flop is good for only about 30 secs of
inverted anyway (as I remember and switching inverted
won't extend the time) and unless intentionaly flying
straight an level inverted, you don't get this much
negative in aerobatics much.
The flop tube may lower the useable fuel just a bit
too since the pickup is not always gonna be at the
lowest point in the tank.
The 30 secs is due to the negative dihedral when the
wing is inverted ( the fuel flows through the vent
holes in the tank ribs out away form the pickup).
Mark Ruddock
--- Clifford Dow <cdowjr@y...> wrote:
>
> January 2, 2002
>
> Could someone direct me to where I get the fuel pick
> up for the RV-7A quickbuild wing – I’d like the type
> for inverted flight in both tanks – the best rig
> available. I don’t see it in the Vans catalogue and
> I’d like not to order one which then does not fit
> and
> have to return it.
>
> Also, my fuel selector has Right and Left – no BOTH
> setting. Why in heck wouldn’t it have “Both”? On a
> cross country flight I’d like to not have to worry
> about remembering to switch the tank once one was
> low.
> Cliff Dow, Jr.
> Cdowjr@Y...
> Maine RV Builder
> __________________________________________________
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> Send your FREE holiday greetings online!
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> ------------------------ Yahoo! Groups Sponsor
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Author: "Greg Young" <gyoung@...> Time: Wed Jan 2, 2002 12:31 pm PST Link
Cliff,
Hate to start your year off with bad news, but there is no inverted pick-up
that installs in place of the normal pick-up. You'll have to modify the
tanks to put in a flop tube. It enters the tank at a fitting near the
leading edge and has a SS braided flex hose with a weighted end extending to
the aft bulkhead. This lets it flop around following gravity and the fuel.
It also flops around in the space normally used by the float-type senders
which means you've got to move the sender to the 2nd bay. There are a few
other details and in the whole scheme of things it's not a big deal, but
it's certainly not plug-and-play.
As to the fuel selector, the short answer is BOTH in a low wing, non-gravity
feed, aircraft could allow you to unport one of the pick-ups and start
sucking air. It can happen because of uneven feeding, uncoordinated flight
or other conditions. It's no fun when the engine goes quiet. Check the
archives for the RV-List - there has been tons of discussion there.
Regards,
Greg Young
RV-6 N6GY RIP
searching for Navion...
> -----Original Message-----
> From: Clifford Dow [mailto:cdowjr@y...]
> Sent: Wednesday, January 02, 2002 2:01 PM
> To: RV-7A YAHOO GROUP
> Subject: [RV7and7A] Fuel Pickups & Valves
> January 2, 2002
>
> Could someone direct me to where I get the fuel pick
> up for the RV-7A quickbuild wing Id like the type
> for inverted flight in both tanks the best rig
> available. I dont see it in the Vans catalogue and
> Id like not to order one which then does not fit and
> have to return it.
>
> Also, my fuel selector has Right and Left no BOTH
> setting. Why in heck wouldnt it have Both? On a
> cross country flight Id like to not have to worry
> about remembering to switch the tank once one was low.
> Cliff Dow, Jr.
> Cdowjr@Y...
> Maine RV Builder
[Non-text portions of this message have been removed]
Author: "Greg Young" <gyoung@...> Time: Wed Jan 2, 2002 3:08 pm PST Link
You're limited to the amount of fuel trapped in the first bay (couple
gallons) so you should get 5-10 minutes at least. The long flop tube can
almost reach all aft corners of the bay so unusable is small either normal
or inverted. There's also a trap door between bay 1 & 2 to keep more fuel in
bay 1 when you go inverted.
The argument for only 1 inverted tank is in case the flop tube gets hung up.
This is a personal risk assessment - what's the chance it will get hung up
on even 1 let alone both tanks at the same time?
Regards,
Greg Young
RV-6 N6GY RIP
searching for Navion...
> IMHO, it may not be best to have the flop in both
> tanks. The flop is good for only about 30 secs of
> inverted anyway (as I remember and switching inverted
> won't extend the time) and unless intentionaly flying
> straight an level inverted, you don't get this much
> negative in aerobatics much.
> The flop tube may lower the useable fuel just a bit
> too since the pickup is not always gonna be at the
> lowest point in the tank.
>
> The 30 secs is due to the negative dihedral when the
> wing is inverted ( the fuel flows through the vent
> holes in the tank ribs out away form the pickup).
>
> Mark Ruddock
[Non-text portions of this message have been removed]
Author: Mark Ruddock <mruddock_2000@...> Time: Wed Jan 2, 2002 4:44 pm PST Link
What Greg says sounds good, my tank with the flop tube
is still in another person's garage somewhere (had to
sell the kit 5 years ago) so I was going on memory.
5-10 min of inverted stuff is more than enough for
anything I can imagine, I have done it for a few
minutes in a Super Decathelon and it was more than
plenty, I much prefer immelmanns and loops and Cuban
8's (no neg g's there).
Retrofit of the QB is documented somewhere in the
archives.
Mark
--- Greg Young <gyoung@c...> wrote:
> You're limited to the amount of fuel trapped in the
> first bay (couple
> gallons) so you should get 5-10 minutes at least.
> The long flop tube can
> almost reach all aft corners of the bay so unusable
> is small either normal
> or inverted. There's also a trap door between bay 1
> & 2 to keep more fuel in
> bay 1 when you go inverted.
>
> The argument for only 1 inverted tank is in case the
> flop tube gets hung up.
> This is a personal risk assessment - what's the
> chance it will get hung up
> on even 1 let alone both tanks at the same time?
>
> Regards,
> Greg Young
> RV-6 N6GY RIP
> searching for Navion...
> > IMHO, it may not be best to have the flop in both
> > tanks. The flop is good for only about 30 secs of
> > inverted anyway (as I remember and switching
> inverted
> > won't extend the time) and unless intentionaly
> flying
> > straight an level inverted, you don't get this
> much
> > negative in aerobatics much.
> > The flop tube may lower the useable fuel just a
> bit
> > too since the pickup is not always gonna be at the
> > lowest point in the tank.
> >
> > The 30 secs is due to the negative dihedral when
> the
> > wing is inverted ( the fuel flows through the vent
> > holes in the tank ribs out away form the pickup).
> >
> > Mark Ruddock
> [Non-text portions of this message have been
> removed]
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Author: "rvator30" <r250@...> Time: Thu Jan 3, 2002 12:00 am PST Link
I am in the process of installing a flop tube in my left tank.. I
have one little question (literally).
There are two large holes in the second inboard rib. You are
supposed to cover one of them and make a hinge door for the other..
There are also a couple of other small holes near the top of the
rib.. Should I cover these also??? I dont plan on going inverted for
too long so it shouldn't matter but wondering if others have done
this.. the trap door wont be exactly airtight anyway... Thanks for
any responses...
Bob Hasch (RV7A wings in Maine)
Author: "Freddie Hegler" <MaxHegler@...> Time: Thu Jan 3, 2002 4:20 am PST Link
Bob,
I put flop tubes in both my tanks and did not plug the small holes. One of
the holes is where the vent tube goes through, so it will be plugged by the
tube...
Take Care,
Max
>From: "rvator30" <r250@h...>
>Reply-To: RV7and7A@yahoogroups.com
>To: RV7and7A@yahoogroups.com
>Subject: [RV7and7A] Re: Fuel Pickups & Valves
>Date: Thu, 03 Jan 2002 08:00:24 -0000
>
>I am in the process of installing a flop tube in my left tank.. I
>have one little question (literally).
>There are two large holes in the second inboard rib. You are
>supposed to cover one of them and make a hinge door for the other..
>There are also a couple of other small holes near the top of the
>rib.. Should I cover these also??? I dont plan on going inverted for
>too long so it shouldn't matter but wondering if others have done
>this.. the trap door wont be exactly airtight anyway... Thanks for
>any responses...
>Bob Hasch (RV7A wings in Maine)
>Van's Air Force - World Wide Wing
>www.vansaircraft.net
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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