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Engine basics => Engine set up tips => Topic started by: Lauri Malila on May 21, 2013, 10:22:19 AM
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Hi.
I am searching a needle valve with the fuel line nipple at 90 degrees to the valve body. I have some wonderful PA valves from Randy that are like that (picture), but the nipple is in wrong end of the body (needle side) for me.
So if anybody knows if they exist, all tips are welcome. The basic dimensions as in PA/ST valve are ideal but basically I can make whatever else work.
I remember that OS has had valves that I want but cannot find them anymore.
Lauri
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If it's just a matter of needing a valve with the nipple turned 90 degrees, why don't you find a valve that you like and rework it? Choose a nice valve, turn off the end of the nipple, make a cap with a nipple and a 90 degree hole, then silver solder the whole shebang together.
If you can't visualize what I'm babbling about then ask and I'll send a sketch -- but I think you see what I mean.
Or just cut the whole thing from solid -- you can build entire engines, for goodness sake, surely you can manage one measly little needle valve!
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If it's just a matter of needing a valve with the nipple turned 90 degrees, why don't you find a valve that you like and rework it? Choose a nice valve, turn off the end of the nipple, make a cap with a nipple and a 90 degree hole, then silver solder the whole shebang together.
If you can't visualize what I'm babbling about then ask and I'll send a sketch -- but I think you see what I mean.
Or just cut the whole thing from solid -- you can build entire engines, for goodness sake, surely you can manage one measly little needle valve!
You're right Tim, of course. Sometimes it's just not worth re-inventing the wheel :) You can call it laziness. L
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Hi.
I am searching a needle valve with the fuel line nipple at 90 degrees to the valve body. I have some wonderful PA valves from Randy that are like that (picture), but the nipple is in wrong end of the body (needle side) for me.
So if anybody knows if they exist, all tips are welcome. The basic dimensions as in PA/ST valve are ideal but basically I can make whatever else work.
I remember that OS has had valves that I want but cannot find them anymore.
Lauri
Hi Lauri
I have ones that are 90 degees, they are OS NVAs off LAs
Randy
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The Thunder Tiger GP 28 nva has the fuel feed on the same side as the needle. So do some of the older OS RC nva's. They make a spigot type fuel feed.
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The new Fox NVA's are similar. NV and fuel pick-up on the same side. Fuel pickup angled back towards the rear. You can see pictures of them installed on C/L engines on the Fox web site. I don't know if that is what you are looking for. I have bench run an engine with one installed. It works well although with the short NV engine adjustments may have to be made with a 4-40 allen wrench depending on the width of the engine compartment. 8)
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If you want the needle to be on the opposite side then maybe try Parra spray bars?
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If you want the needle to be on the opposite side then maybe try Parra spray bars?
Where can I buy them?
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Alberto Parra sells them. He also sells the Enya valve which seems to be allmost identical with PA (Randy's) valve. I really like the construction with plastic seal for the needle, but to have the fuel line nipple 90 degrees to the valve body is not so easy to do as there is the tightening nut in that end of valve. If I find the tools to duplicate the nut thread (What's the thread?), I might be able to modify the std. PA valve. The easies way would be to modify an ST type valve but as I said before, I'd prefer one with plastic seal. L
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The Thunder Tiger GP 28 nva has the fuel feed on the same side as the needle. So do some of the older OS RC nva's. They make a spigot type fuel feed.
If you mean that fuel spigot is on either left or right side of engine like in the "banjo" type in original Irvine .40RLS, it will not work well in side mounted engines. There is 2 issues:
-Fuel flow has to work against the G loads or in same direction, that causes asymmetry between inside- and outside maneuvres.
-It MAY be possibe to compensate it with tank height but usually at cost of lap time symmetry.
All kinds of stuntlores tell that what happens between fuel pickup point in fuel tank and the end of fuel spigot does not matter, but in real life G forces affect in differed way to the fuel masses fefore and after the point of regulation (inside needle valve). During static load they behave in same way but difference comes during dynamic load. L
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Hi.
I got tired in searching for one, so I modified Randy's PA valve like this:
Lauri
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Seems to work!
I couldn't find a tap to make thread, so I had to use the original nut. It's soldered with Staybrite, should stay together. L
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Well done Lauri, but I must say that the exhaust and the intake really fight for real estate at the back there!
Cheers.
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If you mean that fuel spigot is on either left or right side of engine like in the "banjo" type in original Irvine .40RLS, it will not work well in side mounted engines. There is 2 issues:
-Fuel flow has to work against the G loads or in same direction, that causes asymmetry between inside- and outside maneuvres.
-It MAY be possibe to compensate it with tank height but usually at cost of lap time symmetry.
All kinds of stuntlores tell that what happens between fuel pickup point in fuel tank and the end of fuel spigot does not matter, but in real life G forces affect in differed way to the fuel masses fefore and after the point of regulation (inside needle valve). During static load they behave in same way but difference comes during dynamic load. L
Hi Lauri
Interesting.. I have been flying those for over 3 decades now on side exhaust engines, both inverted and sidewinder mount, (It is nice to have the needle opposite the muffler..and needle on top with fuel line too away from muffler) I never had any of the problems that you describe here, maybe there is a difference in the rear exhaust setup??
I ran this same one side setup in one of my NATs planes in the APEX... zero problems, of course that motor had been in 2 other airplane also
Regards
Randy
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Hi.
I got tired in searching for one, so I modified Randy's PA valve like this:
Lauri
NICE workmanship !!
Randy