Author Topic: Replumbing fuel feed (Read 1568 times)

Bootlegger · « **on:** March 30, 2015, 11:13:32 AM »

Guy's I am in the progress of installing another engine in an early built model, and the tank feeds on the intake side of the engine, so that puts the needle on the exhaust side, so I am thinking about looping the fuel line over the front of the engine to be able to connect to the spray bar.

Has anyone else done this, and how well did it work?
Any suggestions will be appreciated...

Tim Wescott · « **Reply #1 on:** March 30, 2015, 11:27:02 AM »

I haven't done that particular thing, but I have had the occasional plane with exceedingly long fuel tubing runs. Contrary to popular opinion, if the tubing's big enough and you're diligent about not building in any leaks, it works fine.

bob whitney · « **Reply #2 on:** March 30, 2015, 03:35:44 PM »

most of the time it will work fairly well. what is keeping u from swapping the needle valve around??

Bootlegger · « **Reply #3 on:** March 31, 2015, 04:30:04 AM »

Bob, with the muffler on that side, it gets MIGHTY HOT and fingers get burned, I made a "Faux Pas" when I built the model, and it flies well, so I am gonna "retrain" it...

bob whitney · « **Reply #4 on:** March 31, 2015, 07:48:46 AM »

i would make a tool to adjust the needle valve and change it over to the other side

Perry Rose · « **Reply #5 on:** April 01, 2015, 04:29:27 AM »

Can the nva be removed and installed the other way?

john e. holliday · « **Reply #6 on:** April 01, 2015, 01:19:30 PM »

What engine are we talking about? Almost every engine the needle valve assembly can be reversed. Just make sure the hole in the spray bar is pointed into the intake.

Phil Krankowski · « **Reply #7 on:** April 01, 2015, 05:03:20 PM »

For "weird" plumbing runs using brass tubing can sometimes relieve problems of routing near moving parts. The tubing can be fastened down and has a slimmer profile.
Phil

Randy Cuberly · « **Reply #8 on:** April 01, 2015, 05:45:03 PM »

Is this an upright mounted engine? If so I can understand the problem with reversing the needle valve, however it still can be done by using a long needle extension to simply get the end of the needle out away from the muffler or exhaust.

We really need a little more information to suggest the best method. A picture is worth a thousand words!

Routing the fuel line around the engine is NOT the best method. It may work for a while but will be prone to leaks and poor fuel draw.

This is another good reason for inverted engine mounting!! The muffler is below the needle then and out of the way.

If upright the best solution is extension on the needle.

Randy Cuberly

Bootlegger · « **Reply #9 on:** April 02, 2015, 03:59:50 AM »

Thanks Guy's, the model is a "spin off" of John Simpson's Cavalier and it flies well enough to keep.
The engine is inverted, and I might make a needle adj tool like Bob W suggested in an earlier post.
Originally it had an OS 32 F and I am installing a T T 36 as they will inner change. I will try to keep everyone updated as I progress.
Again thanks for the help/advice...

john e. holliday · « **Reply #10 on:** April 02, 2015, 10:28:13 AM »

That should be a simple change even thou I don't have that engine in my stash.

Randy Cuberly · « **Reply #11 on:** April 02, 2015, 11:46:20 AM »

Given the situation you described, I fail to see a problem with the needle valve interferring with a muffler. In an inverted installation the muffler falls below the needle and it's usually very easy to access! This is a very common installation and typically presents no problem unless your fingers are two inches in diameter!

Randy Cuberly

Bootlegger · « **Reply #12 on:** April 02, 2015, 03:23:29 PM »

Mr Cuberly, I have been called a "Fat Fingered Friend" in the past so....2" Fat digits could be a problem...

Dennis Toth · « **Reply #13 on:** April 02, 2015, 04:24:14 PM »

Somehow I can't see the problem, the engine is inverted with the muffler on the inside of the fuse. Set up the tank to do an internal cross over so the pickup line exists the tank on the inside edge (same side as the muffler). The needle valve can then be positioned so it exits the fuse on the outside away from the muffler. This is done all the time, I'm sure if you call Eric at RSM he can build the replacement tank if you don't want to build it yourself.

Best, DennisT

Bootlegger · « **Reply #14 on:** April 03, 2015, 11:33:43 AM »

Dennis, after this mistake I have taken to running the feed from the wedge of the tank over to the vertical wall of the tank just like I understand from your post, don't know why I didn't do it this time.
I suppose that it was "brain fade"..

Bootlegger · « **Reply #15 on:** April 05, 2015, 02:04:19 PM »

Got a 3/8" dowel and cut a notch in it and made an "extended" needle valve adjustment tool.
Gotta say thanks to Bob W for the idea, and to all you other fellows I also say thanks...