Comment

Comment by Larry Zepp on September 16, 2012 at 8:25pm

For easy access to the fuel return fitting and hose, I added a second access cutout in the nose skin, just outboard of NR 4 and matching the cutout for fuel access. Because this cover is not in the prop blast, I made the cover out of .025 th. aluminum like the aileron bellcrank access cover instead of the .040 th. cover used for the fuel access. Except the for thickness, the covers are identical.

Comment by Larry Zepp on August 31, 2012 at 8:45pm

Hi Joe, I believe that everyone opting for a fuel injected engine in the Zodiac should add a second access plate to each lower nose skin just outboard of Nose rib 4. This will allow access to the fuel return fitting and hose. Just copy the one inboard of nose rib 3. This will allow inspection and service - even pulling a new return hose if needed. For inlet and return fuel line, I used the Parker Super-Flex FL fuel hose from Aircraft Spruce. This uses a thermoplastic inner liner that prevents fuel vapor from going througn the hose jacket. This limits fuel vapor inside your plane and it should last a longer time also.

The Viking engine locates the fuel pump and relief valve assy. between the wing and the firewall, so after that I am using the recommended 5/16" ID high pressure fuel injection rated hose only.
Best Regards, Larry Zepp

Comment by Joe Zinkel on August 31, 2012 at 5:42pm

Roger at Zenith just told me they will be going to a 5/16 return in the future(but there isn't any issues now???)

What type of fuel lines will you be using? I heard rubber should be replaced in 5 years, 10 tops, I don't want to tear the wings open if I don't need to. Looking at SS braided, PTFE lined, the conductive hoses are turning out to be expensive.

Comment by Larry Zepp on August 26, 2012 at 3:49pm

Hi Joe,
That is new information from UL. I asked Robert about inlet line size in Feb. He referred me to the factory in Belgium. The UL Power engineer said it must be 12 mm or 1/2" ID inlet line from tank to the engine at that time. He also said that they require a 12 mm or 1/2 " ID port on the selector valve for the inlet. Good information! LZ

Comment by Joe Zinkel on August 24, 2012 at 2:03pm

Hi Larry,

I talked to Robert Helms at UL and he said that the factory recommends 8-12mm ID for supply and that 3/8" ID would work fine. Robert also recommends 6mm return (not in manual) for which a 1/4' ID would work good. In the FAQ part on UL's web-site they talk about 10mm supply in one place and 8mm-12mm in another (8 being a minimum). There is also a mention of 8mm for return.

I talked to Roger at Zenith and they are using 3/8-supply and 1/4-return with no problems.

That's what I have gotten, Joe

Comment by Larry Zepp on July 13, 2012 at 10:19am

Hi Frank, I think the header tank is a good solution for the 701 or 750. For the Zodiac CH 650B I prefer to have the fuel outside the cockpit and just use the wing tanks into a six port selector valve. LZ

Comment by Frank A Pisz on July 12, 2012 at 10:53pm

Hi Larry!  Just want to offer this comment for what it's worth.  I'm a very inexperienced builder and currently building a CH750 as my first homebuilt project, so there may be no merit.  I put a deposit on a Viking HF-110 engine at Sun & Fun last April 2012 and Jan told me he is putting out a new header tank which only requires 1 fuel line per wing tank.....no return line, the returns go to the header tank and end there.  There is a single fuel ine from each wing tank to the header tank. I am at the stage where I need to run the fuel lines and then close up the wings.  While this is a 750, I don't think the 650 would be much different, despite the low wings. My concern with the return lines in the 750 was that you would have to drill the rear wing spar for the return fuel line, I was concerned about reducing the spar strength.  But Jan said no need to do so.  Thought I'd pass this on.

Comment by Tim Smart on July 12, 2012 at 4:42am

Thanks for the heads up, I'm building my skeleton(s) now and fuel tanks soon.