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  #11  
Old 12-31-2018, 08:56 AM
Aircraft Specialty Aircraft Specialty is offline
 
Join Date: Jan 2012
Location: Oconomowoc, WI
Posts: 367
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Quote:
Originally Posted by mturnerb View Post
I'd think long and hard before making changes to Van's design in the fuel selector area, primarily because of the tight space - as Tom and Steve have mentioned. Once the fuel lines and fuel selector/filter/pump are installed, routing wires/tubing through the area is very "interesting". Getting the harness from this area to the control sticks is next to impossible (If I were building again I'd install these harnesses before installing any of the fuel system). I ended up cutting the harness and installing an extension so I could just route the bare wires - even this process required some creative "fishing" of wires through the structure. Adding more fuel lines, especially with bends, in this area would make the process even more challenging.

The current design is proven to work well with "stock" engine - my question would be what is the advantage of a duplex system? And I'm one of those who's made some changes - Beringer brakes/wheels, remote oil filter, single PMAG, etc. I'm using TS Flightlines/ Aircraft Speciality hoses/lines everywhere I can: we've done quite a bit of "back and forth" (Tom Swearingen and I are best buds these days).
This is the reason that we don't have the duplex tubes available for automatic ordering on the website. We like to have a conversation with customers about everything that the duplex tubes entail. It does add a lot of tubing/complexity.

The standard RV14 pre bent fuel lines have been a very popular item and make plumbing the fuel system easy.

There are situations where a duplex valve is necessary. For the majority of RV14 aircraft, the duplex valve is not the best solution.

The development we have been doing on the Andair Type 7 valve has been interesting. It is also a non duplex valve, but has a different Left/Right/Off configuration that is more appealing to some. But, fitting the tubes in the tunnel would be challenging endeavor without a special bender/die setup.

Our goal with these has always been to make plumbing the fuel system as easy as possible, for those who want the stock setup as well as those that want to make changes to it.

Steve
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  #12  
Old 12-31-2018, 09:30 AM
Kyle Boatright Kyle Boatright is online now
 
Join Date: Aug 2005
Location: Atlanta, GA
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Quote:
Originally Posted by Chedal View Post
I would like to install the fuel selector FS20 type7 instead of the type2 suplied by Van's. The type7 is much more ergonomic than the 2: left tank on the left, right tank on the right et OFF on the rear.
Before to order the fuse kit I would like to know if somebody has already made this installation.
Than'ks.
Grind off the pointer on the selector valve, route the incoming lines to the "opposite" side, and use the handle on the selector as the pointer. Now, when the handle points left, you're on the left tank and vice versa.
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  #13  
Old 12-31-2018, 10:32 AM
dmattmul dmattmul is offline
 
Join Date: Dec 2015
Location: Spring Hill, FL
Posts: 24
Default Duplex Valve for a 14 FI engine

Turner, thanks for the input. I am pretty sure I am going to need return lines for my EFI/EFII system and that will require a duplex fuel valve. I know it's going to tight but I wanted fuel injection and since this will probably be my last build (Unless an RV-18 comes along) wanted to have it. I know a duplex valve makes it even tighter but I am pretty sure I need it. Any comments would be more than welcome especially from a 14 builder who has FI.
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  #14  
Old 12-31-2018, 11:58 AM
mturnerb mturnerb is offline
 
Join Date: Apr 2015
Location: Ponte Vedra, FL
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Quote:
Originally Posted by dmattmul View Post
Turner, thanks for the input. I am pretty sure I am going to need return lines for my EFI/EFII system and that will require a duplex fuel valve. I know it's going to tight but I wanted fuel injection and since this will probably be my last build (Unless an RV-18 comes along) wanted to have it. I know a duplex valve makes it even tighter but I am pretty sure I need it. Any comments would be more than welcome especially from a 14 builder who has FI.
Help me understand how the "EFI"EFII" system is different/better than the Airflow or other fuel injection systems that don't require duplex valve? I'm aware that some systems have fuel return - like the Bonanza that I flew - so I understand how duplex valve works. In the Bonanza the main advantage of the return system was the ability to circulate fuel for hot starts.
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  #15  
Old 12-31-2018, 12:08 PM
Discus2b Discus2b is offline
 
Join Date: Mar 2016
Location: Willis Gliderport
Posts: 43
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Fuel Injection is standard on the 14. I find Vanís fuel selection valve simple and slick, hyper easy to operate. A snap to install. Locking pin. Looks good.
Whatís not to love.
I give it a 9.5 (10) on the perfect scale.

R
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  #16  
Old 12-31-2018, 12:24 PM
Mark33 Mark33 is offline
 
Join Date: May 2010
Location: Baton Rouge, La.
Posts: 472
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Quote:
Originally Posted by mturnerb View Post
Help me understand how the "EFI"EFII" system is different/better than the Airflow or other fuel injection systems that don't require duplex valve? I'm aware that some systems have fuel return - like the Bonanza that I flew - so I understand how duplex valve works. In the Bonanza the main advantage of the return system was the ability to circulate fuel for hot starts.
I guess this is another one of those never ending debates...like slider VS. tip-up. I think itís more of a ďpick your poisonĒ decision. Iím doing the EFI/EFII system in my -7 build. I think itís the simplest and most modern setup with the most adjustability of any other type of fuel injection and ignition system thatís available to us today....but Iím sure others will disagree. Thereís lots of threads/debates here on VAF regarding this.

Mark
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  #17  
Old 12-31-2018, 12:35 PM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Los Angeles
Posts: 588
Default Is this not the standard?

Quote:
Originally Posted by Kyle Boatright View Post
Grind off the pointer on the selector valve, route the incoming lines to the "opposite" side, and use the handle on the selector as the pointer. Now, when the handle points left, you're on the left tank and vice versa.
I thought the FAA has mandated that the biggest end of the fuel selector has to be the indicator after many accidents due to fuel selector on wrong tank. Are you implying the homebuilt community has not heeded this lesson?

I am about to start my fuel system and and really interested in this subject.
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WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.

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  #18  
Old 12-31-2018, 12:39 PM
rv7charlie rv7charlie is online now
 
Join Date: May 2006
Location: Pocahontas MS
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Quote:
Originally Posted by mturnerb View Post
Help me understand how the "EFI"EFII" system is different/better than the Airflow or other fuel injection systems that don't require duplex valve? I'm aware that some systems have fuel return - like the Bonanza that I flew - so I understand how duplex valve works. In the Bonanza the main advantage of the return system was the ability to circulate fuel for hot starts.
(Second edit: The Continental style system has the advantage of circulating fuel for hot starts, but that's not the *reason*. It's required for the system to work.)

The 'Bendix style' (mechanical) injection uses the engine driven diaphragm pump. That style pump uses a spring to push the fuel, so the pump itself sets pressure (via the strength of the spring). (edit: The engine's drive just 'cocks' the pump by compressing the spring, then the spring does the work of pushing the fuel.)

The auto-style electronic injection systems use electric, *positive displacement* (think about how the oil pump works) pumps, that pump a constant volume of fuel which is *much* higher than the engine consumes in normal operation. Because the pump is positive displacement, pressure must be set by an external regulator, which 'bleeds off' the extra fuel to maintain setpoint pressure. The extra fuel has to go somewhere, and because there's a risk of heated fuel causing vapor lock if plumbed back to the pump input, almost everyone runs this extra fuel back to the tank.

That help?

Charlie

Last edited by rv7charlie : 12-31-2018 at 12:46 PM.
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  #19  
Old 12-31-2018, 12:44 PM
mturnerb mturnerb is offline
 
Join Date: Apr 2015
Location: Ponte Vedra, FL
Posts: 832
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Quote:
Originally Posted by rv7charlie View Post
The 'Bendix style' (mechanical) injection uses the engine driven diaphragm pump. That style pump uses a spring to push the fuel, so the pump itself sets pressure (via the strength of the spring). (edit: The engine's drive just 'cocks' the pump by compressing the spring, then the spring does the work of pushing the fuel.)

The auto-style electronic injection systems use electric, *positive displacement* (think about how the oil pump works) pumps, that pump a constant volume of fuel which is *much* higher than the engine consumes in normal operation. Because the pump is positive displacement, pressure must be set by an external regulator, which 'bleeds off' the extra fuel to maintain setpoint pressure. The extra fuel has to go somewhere, and because there's a risk of heated fuel causing vapor lock if plumbed back to the pump input, almost everyone runs this extra fuel back to the tank.

That help?

Charlie
Yes it helps, but I'm not sure I understand the advantage over standard systems like Airflow etc. Fuel economy? Reliability? Serviceability? Not trying to be argumentative here, just want to learn from others.
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  #20  
Old 12-31-2018, 06:25 PM
Mark33 Mark33 is offline
 
Join Date: May 2010
Location: Baton Rouge, La.
Posts: 472
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Quote:
Originally Posted by mturnerb View Post
Yes it helps, but I'm not sure I understand the advantage over standard systems like Airflow etc. Fuel economy? Reliability? Serviceability? Not trying to be argumentative here, just want to learn from others.
For me, the answer to everything that you mentioned above...is yes! I think the ďadvantagesĒ are different for different reasons for each individual builder.

For me, it was the move away from old to new technology, almost no moving parts, adjustability/tune-ability, ease of installation, and almost no chance of vapor lock, which translates into easy engine starts.

One again, I think that every builders comfort level is different and what they feel the most comfortable with. I donít think thereís anything at all wrong with the Airflow Performance or Bendix style fuel systems...or even carburetors as far as thatís concerned. The mechanical systems have been around for a long time and have obviously proven themselves over the years, so like I said, I think for the most part, it just boils down to personal comfort level and preference.

Mark
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