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  #1  
Old 09-22-2017, 08:48 AM
jeterjim jeterjim is offline
 
Join Date: Dec 2009
Location: Orange Beach, AL
Posts: 21
Default Fuel Restrictor RV-12 Notice

I just received this form Rotax. Does this refer to the requirement to remove the Banjo bolt pilot jet? RV-12 Pg. 46-09.


The purpose of this Information Safety Notice is to inform ROTAX operators and owners about the mandatory fuel return line that is required to be incorporated into the aircraft's fuel system design.

As per the ROTAX installation manual, a Mandatory “restricted” fuel return line is to be incorporated within the aircraft's fuel system. The purpose of the fuel return line is to bleed off any vapors that may form within the fuel system that could cause vapor lock, resulting in a possible loss of engine power.

Please reference the latest ROTAX installation manual and check with the manufacturer of the aircraft to verify that a fuel return line has been incorporated within the design of the aircraft's fuel system.


The latest Rotax Installation Manual can be found at www.FlyRotax.com OR www.RotaxOwner.com

What is this Information Safety Notice about and how does it affect me?

Field reports have indicated a potential for fuel system vapor lock leading to loss of engine power or stoppage due to one or more of the following variables:

-Fuel system design
-Engine cowling design
-Fuel quality
-Seasonal adjustment on fuel
-High ambient temperatures

Owners and operators need to consider all of the above and understand how they may contribute to fuel system vapour formation.

Fuel System Design

Fuel system design is one factor in managing the formation of vapour in the fuel system due to heat soak. Fuel system components in close proximity to engine heat sources should be adequately protected from heat soak. Fuel line routing, heat shielding, fire sleeve etc. all influence fuel system temperatures.

Engine Cowling Design

Engine cowling design is another factor which can greatly influence heat soak on engine fuel system components. Tightly cowled engines can run much hotter under-cowl temps than more open cowl designs during certain conditions such as taxiing and climb.

Owners and operators need to understand their aircraft's temperature limitations and respect them. Rotax defines maximum engine component operational temperatures in the respective engine installation manual.

Fuel Quality

Fuel quality can have a large influence on the formation of vapour. Inadequate storage, handling and contamination can all affect fuel quality. Always respect the minimum fuel requirements as outlined by Rotax, maintain good storage practices and source the best quality fuel possible.

Seasonal Adjustments

Seasonal adjustment of fuel by manufacturers for high summer temperatures and low winter temperatures may affect the fuel vaporization rates. This can have consequences when using winter grade fuel in hot summer months. Always use seasonally correct fuel.

High Ambient Temperatures

High outside ambient temperatures may increase under-cowl operating temperatures and therefore increase the fuel system heat soak. Owners and operators may need to adjust performance expectations when operating in such conditions.

How Does This Affect Me?

In consideration of the above variables, Rotax has updated the engine installation manual to mandate the use of a fuel return line. Such a design helps to vent off the formation of fuel vapours, increasing the safety margin. Owners and operators are urged to consider all the aforementioned and review their fuel system design with their respective aircraft manufacturers.

NOTE: Although this video series is for the fuel injected engine, it is still relevant to the carbureted 912 series in regards to fuel vapor formation and cooling systems.
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  #2  
Old 09-22-2017, 09:24 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 7,060
Default

I just received this form Rotax. Does this refer to the requirement to remove the Banjo bolt pilot jet? RV-12 Pg. 46-09.

No

The just issued safety notice is to bring awareness to the requirement that a fuel return must be part of the fuel system for a 912ULS (when Van's first started on the RV-12 development program, there was no such requirement).

The RV-12 does have the fuel return incorporated into the fuel system design so as along as an RV-12 has been built per the KAI, this notification is complied with and can be ignored.
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RV-6A (aka "Junkyard Special ")
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  #3  
Old 09-22-2017, 09:32 AM
jeterjim jeterjim is offline
 
Join Date: Dec 2009
Location: Orange Beach, AL
Posts: 21
Default

Thanks Scott!
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  #4  
Old 09-23-2017, 07:52 AM
TS Flightlines TS Flightlines is offline
 
Join Date: Apr 2010
Location: Ridgeland, SC
Posts: 1,914
Default Jim--

yes the design of the RV12 fuel system does comply with the Rotax guidelines.
Our retrofit hose package does also, AND complies with Rotax SI-912-022, which (paraphrase) states that if teflon hoses are used, they do not fall under the 5 year replacement guidelines, other than obvious inspection.

In looking for this SB, I found an interesting one--SI-912-008r1, which (paraphrase) refers to fuel pressure indication problems. Check for the proper tolerances of the crush washers around the banjo bolts. It only affects the pressure INDICATION on the gauge, NOT the actual supply pressure.
(The TS Flightlines/Aircraft Specialty retrofit kit uses AN hardware and not banjo bolts and is not affected by this.)

For those of you that have experienced a low fuel pressure indication on your RV12's I wounder if it was AFTER some maintenance of the banjo connections and the crush washers were NOT replaced. The bulletin seems to indicate that the reduced thickness of a reused crush washer 'could' affect the fuel pressure indication.

The SI-912-008r1 is on the Rotax site.

Tom
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Tom Swearengen, TS Flightlines LLC
Teflon Hose Assemblies for Experimentals
Proud Vendor for RV1, Donator to VAF
RV7 Tail Kit Completed, Fuse started-Pay as I go Plan
Ridgeland, SC
www.tsflightlines.com
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  #5  
Old 09-23-2017, 03:40 PM
rjtjrt rjtjrt is offline
 
Join Date: Mar 2006
Location: Australia
Posts: 685
Default

Quote:
Originally Posted by TS Flightlines View Post
yes the design of the RV12 fuel system does comply with the Rotax guidelines.
Our retrofit hose package does also, AND complies with Rotax SI-912-022, which (paraphrase) states that if teflon hoses are used, they do not fall under the 5 year replacement guidelines, other than obvious inspection.
................
Tom
Tom
I just went to your web site to look for the Rotax hose retrofit/replacement package and could not find it.
I will be replacing Rotax hoses in a couple of years and will hopefully remember your kit, but it would help if there was some easy and prominent link to it on your web site (and indicating that your kit does not have a calendar life if that is the case).
John

Last edited by rjtjrt : 09-23-2017 at 03:46 PM.
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  #6  
Old 09-23-2017, 04:13 PM
Aircraft Specialty Aircraft Specialty is offline
 
Join Date: Jan 2012
Location: Oconomowoc, WI
Posts: 266
Default

Quote:
Originally Posted by rjtjrt View Post
Tom
I just went to your web site to look for the Rotax hose retrofit/replacement package and could not find it.
I will be replacing Rotax hoses in a couple of years and will hopefully remember your kit, but it would help if there was some easy and prominent link to it on your web site (and indicating that your kit does not have a calendar life if that is the case).
John
John,

Tom and I developed this kit together a few years back as a retrofit kit to improve on the standard package.

Here is a link to the kit

http://aircraftspecialty.com/rv-12.html

And here is a link to the install manual

http://aircraftspecialty.com/PDF&#37...l%20111013.pdf

If you have any questions at all please feel free to contact us. We will also be monitoring this thread.

Have a great weekend and happy building
Steve
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Please email us at aircraftspecialty@gmail.com with any questions.

Your Source for Custom CNC parts, CNC cut instrument panels and labeling, Teflon fuel/oil hoses, Headsets, and many other items for Experimental Aircraft.

Last edited by Aircraft Specialty : 09-23-2017 at 04:30 PM.
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  #7  
Old 09-23-2017, 09:54 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 2,132
Default

I installed the Aircraft Specialty fuel hoses at last annual. I have 6 months with them now (65 Hours) and I am very pleased with them.
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  #8  
Old 09-23-2017, 10:10 PM
John-G John-G is offline
 
Join Date: Jan 2012
Location: Northeast Ohio
Posts: 460
Default

Quote:
Originally Posted by RFSchaller View Post
I installed the Aircraft Specialty fuel hoses at last annual. I have 6 months with them now (65 Hours) and I am very pleased with them.
I agree, the Aircraft Specialty fuel hoses for the RV-12 are a top notch product ... I too am very pleased with them.
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www.dogaviation.com
RV-12 Wings, Empennage, Fuselage, Finishing, Avionics and Powerplant kits all completed
Now Flying!!

Dues paid until September 2018
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  #9  
Old 09-24-2017, 06:53 AM
TS Flightlines TS Flightlines is offline
 
Join Date: Apr 2010
Location: Ridgeland, SC
Posts: 1,914
Default

John in Australia,
the picture is in the gallery. Sorry! I'm not real computer/website functional, as alot of you know. Steve is MUCH better at this than I am. LOL----thats why we work so well together, and share stuff!
We've been trying to update our website, but frankly a bunch of other things have taken priority. But we'll get it done.

Tom
__________________
Tom Swearengen, TS Flightlines LLC
Teflon Hose Assemblies for Experimentals
Proud Vendor for RV1, Donator to VAF
RV7 Tail Kit Completed, Fuse started-Pay as I go Plan
Ridgeland, SC
www.tsflightlines.com
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  #10  
Old 09-24-2017, 10:40 AM
waterboy2110 waterboy2110 is offline
 
Join Date: Jul 2010
Location: SF Bay Area
Posts: 205
Default

Quote:
Originally Posted by TS Flightlines View Post
yes the design of the RV12 fuel system does comply with the Rotax guidelines.
Our retrofit hose package does also, AND complies with Rotax SI-912-022, which (paraphrase) states that if teflon hoses are used, they do not fall under the 5 year replacement guidelines, other than obvious inspection.

In looking for this SB, I found an interesting one--SI-912-008r1, which (paraphrase) refers to fuel pressure indication problems. Check for the proper tolerances of the crush washers around the banjo bolts. It only affects the pressure INDICATION on the gauge, NOT the actual supply pressure.
(The TS Flightlines/Aircraft Specialty retrofit kit uses AN hardware and not banjo bolts and is not affected by this.)

For those of you that have experienced a low fuel pressure indication on your RV12's I wounder if it was AFTER some maintenance of the banjo connections and the crush washers were NOT replaced. The bulletin seems to indicate that the reduced thickness of a reused crush washer 'could' affect the fuel pressure indication.

The SI-912-008r1 is on the Rotax site.

Tom

Tom - so the return line (I assume supplied by your group for the kit) does have some "restriction" included in the design? If so, how does it compare to the flow rate of the restrictor that is removed from the factory?

Thanks,
Jim
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Instrument Rating
A&P / Rotax iRMT 9 Series Maintenance
RV12 Flying.
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