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  #1  
Old 09-07-2023, 01:06 PM
Treedy Treedy is offline
 
Join Date: Oct 2022
Location: Winter Garden, FL
Posts: 3
Default Flop tube installation in RV-14

Iíve searched this forum without success. Has anybody installed flop tubes in the RV-14 tanks? If yes, what brand / supplier did you use? Any modifications to the standard tank?

It appears to me that the fuel gauge sending unit would interfere with a ďregularĒ flop tube.

Thanks
Tom Reedy

RV-14
Tail complete
Fuel tanks next
Waiting on LCP issue resolution!
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  #2  
Old 09-07-2023, 02:13 PM
RV8JD's Avatar
RV8JD RV8JD is offline
 
Join Date: Jan 2005
Posts: 1,072
Default One Thing to Consider ...

Quote:
Originally Posted by Taltruda View Post
I would really ask yourself if you REALLY need a flop tube.. unless you are intending extended negative aerobatics, they are must not needed. Are you also planning inverted oil? Flop tubes are rubber and need to be changed every few years.. I donít know anyone who really changes them as preventative maintenance, but over time, theyíll get stiff and reduce your usable fuel. You can still do all the good aerobatic maneuvers without flop tubes, the engine wonít quit from just a momentary negative maneuver.
+1. From this post by Jon Thocker: https://vansairforce.net/community/s...65&postcount=1
"A data point for anyone considering fuel tank flop tubes.

Decided to see how long my engine would run while inverted and on the NON inverted tank.

I have a flop tube in the right tank and a standard pickup in the left. From "experience" I've noticed I can fly for quite some time inverted and on the wrong tank!

Today, I decided to find out just how long! With only 4 gallons in the left tank and the left tank selected, I rolled inverted and started a timer. At 25 seconds I rolled upright and at the 30 second mark the engine stumbled for about 2 to 3 seconds then it smoothly regained power.

Hope this will convince guys to bite the bullet and install that inverted oil system. There is absolutely no need to put in a flop tube unless you intend to fly inverted for more than 20 seconds."
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  #3  
Old 09-07-2023, 04:10 PM
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wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 6,626
Default Flop tube

Check the 7 plans. The float moves to the baffle.
If the tank is similar, the Vans flop tube might work. If not, TS Flightlines can fab the hose. You would just need the weight fitting for the end.
I just happen to have one if you want it. The flop tube timed out before she is airworthy so I swapped it for a standard pickup. The hose isn't useable but the weight is fine. I haven't checked but it should come off like any other fitting.
You pay shipping and its yours.
Shoot me a PM.
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Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/2022, plus a little extra.
RV-7A #73391, N511RV reserved
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
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  #4  
Old 09-07-2023, 05:45 PM
Treedy Treedy is offline
 
Join Date: Oct 2022
Location: Winter Garden, FL
Posts: 3
Default RV14 flop tube

Quote:
Originally Posted by RV8JD View Post
+1. From this post by Jon Thocker: https://vansairforce.net/community/s...65&postcount=1
"A data point for anyone considering fuel tank flop tubes.

Decided to see how long my engine would run while inverted and on the NON inverted tank.

I have a flop tube in the right tank and a standard pickup in the left. From "experience" I've noticed I can fly for quite some time inverted and on the wrong tank!

Today, I decided to find out just how long! With only 4 gallons in the left tank and the left tank selected, I rolled inverted and started a timer. At 25 seconds I rolled upright and at the 30 second mark the engine stumbled for about 2 to 3 seconds then it smoothly regained power.

Hope this will convince guys to bite the bullet and install that inverted oil system. There is absolutely no need to put in a flop tube unless you intend to fly inverted for more than 20 seconds."

I am definitely installing inverted oil but after reading this Iím reconsidering inverted fuel. Donít plan extended inverted - 25 seconds is more than enough!
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  #5  
Old 09-07-2023, 05:46 PM
Treedy Treedy is offline
 
Join Date: Oct 2022
Location: Winter Garden, FL
Posts: 3
Default

Quote:
Originally Posted by wirejock View Post
Check the 7 plans. The float moves to the baffle.
If the tank is similar, the Vans flop tube might work. If not, TS Flightlines can fab the hose. You would just need the weight fitting for the end.
I just happen to have one if you want it. The flop tube timed out before she is airworthy so I swapped it for a standard pickup. The hose isn't useable but the weight is fine. I haven't checked but it should come off like any other fitting.
You pay shipping and its yours.
Shoot me a PM.
Thanks Larry - I appreciate the offer. Iíll keep you in mind but based on the other post Iím rethinking the inverted fuel
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  #6  
Old 09-08-2023, 02:22 PM
Ralph Inkster Ralph Inkster is online now
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 2,142
Default

Just measured up a 7 & 14 tank side by side.

The 4/6/7/8 flop tube are about 13" long, reasonably allowing it to flex enough (noting it gets stiffer with age) to reach both the top & bottom tank skins.

The 14 tank has a forward tank mounting bracket which is part of it's structure, this would be an obstacle inside the tank to mounting a flop tube the same way as was done in earlier RVs. Using a shorter flop tube and mounting it behind this mount structure might not leave a flop tube flexible enough to reach all the way to both top or bottom tank skins & affect fuel pick up potential. Additionally you would have a major challenge to route your fuel lines around the aileron control bell crank & linkages.

If you do figure out a successful 14 flop tube setup - Post Pictures!!
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Last edited by Ralph Inkster : 09-08-2023 at 03:22 PM.
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