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Flop Tube - Which Side ?.

P

Pittsartist

Well Known Member
My '6 will be fitted with Inverted Oil and F.I. Sooo, I need to have a flop tube in at least one tank.

The plan as it stands is to fit the flop tube in the Right Hand tank only and leave the left with a "plans" setup.

My logic in fitting to the right side is that '6 aeros are only legal one up, and the "one" in question will sit on the Left - so best to have the fuel on the right for lateral balance (I'd generally Aero with minimal fuel on the left for best performance).

Just looking around it seems that a lot do this the other way around i.e. flop tube on the Left.

Am I missing something ?. Is there a particular reason why left is best ?.

:confused:
 
There is no particular reason to choose either tank. Your logic is as sound as any other.
 
I fly a lot of aerobatics in my RV-8. If I were to do it again, I would put flop tubes in each tank. I never know well in advance when I an going to do aerobatics. Sometimes the left tank has significantly more has than the right and vice a versa. I can't think of any reason to not put flop tubes in each tank except it is tecommended to replace them every 5 years.

Jerry Esquenazi
RV-8 N84JE
FLYING since 2007, 800 hours.
 
the flop gets stiff...

The recommended replacement is based on a loss of flexibility from prolonged exposure to a single direction of 'flop'...

If your really need it.. it is probably worth having a look at it as it ages to ensure that it remains flexible
 
trap door...

I have a flop tube in a single tank... in hindsight if I were to do it again I might go ahead and instal it in both.

Regardless, I would definitely install the trap door in both tanks to help contain fuel in the cell closest to the root.

When I am running a tank down there is quite a difference in getting the last drop with the trap door... it helps keep the fuel contained in turbulence and really makes a difference when slipping where you can send several gallons out of the reach of the standard tank pickup.

With a single trap door and flop tube I always plan low fuel to switch to that tank for landing.
 
Tad-
I asked Van's about the expected service life of their flop tubes when I installed mine last year.

Here is what they said:

Me: Hello all-
Just a quick, simple question... I've heard of a lot of the "flop
tube" fuel pickup lines get "stiff" over time & don?t flop J What do
you think the reasonable life expectancy of your brand flop tube is?
I?ll probably only be using 100LL. I Just kind of wondering if it?s an annual, bi-annual, five year replacement item.


Vans:
We do not have any actual testing data on this but we believe a service life of five to eight years is reasonable.
 
Both sides

My -4 has flop tubes in both tanks, first flight May 1983, after purchasing the airplane in 2005 I had the tanks off to repair leaks, the flop tubes where still flexible and in fine shape (braded SS Teflon) I left them in and their still flopping and passing fuel.

My vote is for both sides, one less thing to worry about and or forget before putting the dirty side up.
 
I was told that my 1996 RV-6 had them in both sides. Never replaced, no indication of any trouble.

I'll be pulling them this winter to fix weepy cork gaskets on both tanks, i'll get to find out then, and also find out what kind of fuel senders are in there! :p
 
Flop tube

I may be way off on my train of thinking but the reason for the flop tube is to be able to pick up fuel in unusual attitudes. I guess one would have to make sure you are only pulling fuel then via the selector switch from the tank with the flop tube when doing aerobatics so you do not introduce air into the system? As I would think if you were set to both and one tank did not have the flop tube you would suck air? is this correct? Ken
 
GoingHawgWyld said:
I may be way off on my train of thinking but the reason for the flop tube is to be able to pick up fuel in unusual attitudes. I guess one would have to make sure you are only pulling fuel then via the selector switch from the tank with the flop tube when doing aerobatics so you do not introduce air into the system? As I would think if you were set to both and one tank did not have the flop tube you would suck air? is this correct? Ken
Click to expand...

We don't use/have a both position on our selectors in RVs or most low wing airplanes because if one tank ran out first you would be sucking nothing but air when upright.
 
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