remote NVA

[Carl Cisneros]

for you engine guru's..................

Why aren't remote needle valve assemblies used?  Or, are they?

thanks much

[Tim Wescott]

They add a little bit of unreliability and variation, which is the last thing you need.

Actually, when you're crashing all the time it's the second-to-last thing you need: the last thing you need is to bend a needle valve with every inverted landing.

My personal recommendation is to use a remote needle if you still crash often, and to use a regular one if you don't.

[Paul Smith]

The remotes don't seem to perform so well with suction.  Too much plumbing.  With muffler pressure they work OK for me.  I have one on my Bi Slob.  If one comes on engine you might as well utilize it until it breaks.  The supply of remotes on LA engines is essentially free.

[Tim Wescott]

The remotes don't seem to perform so well with suction.

That could account for some of the variation in stories you hear -- I've always used muffler pressure, except on a few tanks that seem to generate excess bubbles on pressure compared to air-fed.

[Brett Buck]

Why aren't remote needle valve assemblies used?  Or, are they?

    My limited experience with remote needles has been excellent. I have used the OS 20FP RN setup, and stock, it's the best of the bunch. The 25LA integral mount works fine, too, but as expected, it broke off in the first crash. I think you can turn the backplate 90 degrees to get it in a better spot. I also adapted the OS remote needle kit (which is the "core" of an RC carburetor) to a Fox 35, again, with excellent results.

   I would have no hesitation using one on a big engine, but aside from the possibility of improved safety, I can't see a compelling reason to switch.

    Brett

[frank mccune]

     Hi Brett:

     Kindly post some pictures of how one may make a remote NVA and what parts are needed?

     Would it not be a better idea to mount the remote NVA on the airplane rather than the engine?  This may reduce damage and fuel problems due to engine vibrations.

    I like to get my digits farther from the prop if I have the chance!  Plastic props are not my friends! Lol

                                                                                                                         Stay well,

                                                                                                                         Frank

[Douglas Ames]

     Hi Brett:

     Kindly post some pictures of how one may make a remote NVA and what parts are needed?

     Would it not be a better idea to mount the remote NVA on the airplane rather than the engine?  This may reduce damage and fuel problems due to engine vibrations.

    I like to get my digits farther from the prop if I have the chance!  Plastic props are not my friends! Lol

                                                                                                                         Stay well,

                                                                                                                         Frank

If you do an eBay search for Remote Needle Valve, you'll come up with several to choose from. Fox, Perry and OS, plus others.

[Steve Helmick]

Perry? Could you provide a link to a picture of a Perry RNV? I don't do ebay...so far! I've seen the "new" Fox RNV and don't want any...big, heavy, and expensive.

The first RNV I tried was one from an OS Max III .29R. The response was slow and not linear...like the NV was bent or something. On down the road 40 years or so, I ran a .25LA on a Skyray, and didn't like it, either. I'd choke the venturi and draw fuel in, but then it'd run right back to the tank, apparently from air leakage in the RNV. If you used an electric finger like the R/C guys mostly do, you wouldn't notice, tho. So I converted it to front NV. Much easier to get to start and keep running, because the fuel hose didn't drain back to the tank.

The RNV units that come with some Magnum engines have very nice thread fits, and while I haven't run one of these, I think they're pretty good stuff.  I mounted them on other engines, specifically two MECOA .28's I gave to Glenn Reach for his youth program. Mounted the NVs so they were parallel to the cylinder, in order to protect them from breakage. Haven't heard a word from Glenn about how that worked out...but I'm hoping to see him in Edmonton in another few weeks. If you're interested in using a RNV setup, I'd suggest the ones from Magnum/ASP engines...maybe Evolution also...they look very similar, and they may come from the same factory in PRC.  Steve 

[RandySmith]

Remote needles  are not  good if you are cycling the motor, you get poor settings with them, and unless you are running in a wet 2  cycle they are inconsistent.

Randy

[FLOYD CARTER]

The OS46LA is generally run at a wet 2-cycle.  They come with remote NVA.  I've used them stock and with a front NVA.  The remotes seem to be OK, and I don't use pressure, just uni-flo.  I would agree that a 4-2-4 run is more critical, so a better NVA would be the best idea.

[Paul Smith]

I saw one of those OS Max III 29R's with the remote needle.  It was quite a concept at the time, although a bit mis-guided as it were.

The Max III had a gigantic air intake when you took out the venturi insert.  The remote was supposed to get the needle body out of the throat and make the air intake even bigger, thereby increasing performance.

The falacy was that the throat was already grossly oversize.  So letting in even more air just made it hard to needle. 

[Brett Buck]

Remote needles  are not  good if you are cycling the motor, you get poor settings with them, and unless you are running in a wet 2  cycle they are inconsistent.

    Using the OS Remote Needle valve kit worked perfectly even on a Fox 35.

     Brett

[RandySmith]

    Using the OS Remote Needle valve kit worked perfectly even on a Fox 35.

     Brett

If inconsistant is perfect  then yes, They don't work as well as a really good NVA in the venturie, not in a ST 46, a HP 40, a FOX 35 or any of the  OS  engines I have tried them on, unless  you are using a wet 2  run. The PA and other  NVAs  worked better than the  remote.  Your milage may vary. This comes not only from me  but from many dozens of pilots  that I have had call about this.  Pressure maybe better or worse, I rarely use it  so That i did not try

Randy

[PaulGibeault]

Carl,

For speed work using pressurized fuel systems, they work VERY WELL.

Cheers, Paul

p.s. the best remotes were available from Glen Dye. I don't know for sure if he still offers them for sale.

[Brett Buck]

If inconsistant is perfect  then yes,

   Mine was not inconsistent. It didn't fix any of the other issues I had but it worked perfectly, as well as any other.

     Brett

[Paul Smith]

I used to make remotes for Combat by soldering a little stub tube over the spray hole of an ST NVA.  This got my fingers away from the prop, made it much easier to connect the fuel line an a hurry, and drastically reduced crash damage.  With ST NVA's off the market crash losses needed to be minimized.  It worked great in fast, F2D, and even 1/2A.

This is not to say it's any good for stunt.

[Andrew Tinsley]

I have tried the OS remote NVAs on OS40s and 46s as well as the LA 25. I also run the conventional front mounted NVAs. I have a lot of hours on both types and have to agree with Randy. The rear mounted NVAs are not as good as the conventional front mounted versions. This applies even if you eliminate all the extra leakage points on the remotes.
They are not as consistent at holding a setting and they are a little more troublesome when starting. If you mainly run a wet two stroke, then it is difficult to see much difference between the two.
I note that Brett admits to "limited experience" with the remotes. Maybe he got lucky. If he were to put in a few more hours flying with the remotes, he would spot the difference.
I largely use the remotes on trainers that have a higher probability of crashing, they are certainly safer in use too. But if you want the best, then stick with the front mounted NVAs

[Brett Buck]

I note that Brett admits to "limited experience" with the remotes. Maybe he got lucky. If he were to put in a few more hours flying with the remotes, he would spot the difference.

  Oh, for Christ's sake.

    Brett

[Andrew Tinsley]

What's your problem Brett? I have a lot of experience with the OS remote NVAs and like Randy Smith, I find that the front mounted NVas are a more consistent solution. This is in direct contradiction to your findings.
So I am just trying to figure out how to explain this difference in results. You admit to having a limited experience of the remote OS NVAs , so maybe this is the difference? Maybe you have a better explanation?

Andrew.