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Engine basics => Engine set up tips => Topic started by: frank mccune on June 28, 2014, 06:04:10 PM
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Hi All:
What is the best method to protect the needle in the nva on a profile during an inverted landing?
Tia,
Frank
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Best is rear NV, mounted parallel with the engine's cylinder...IMO. The Magnum/ASP remotes are quite nice, but I haven't actually run one myself. I put two on MECOA .28's, but those went to Glenn Reach (and haven't heard a word about how they ran, OBTW!).
I've run the OS .25LA with the stock RNV and didn't like it at all, but the threads are loose, NV wobbles like Elvis, so they leak badly. H^^ Steve
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The OS FP 20 remote needle valve is very nice. The only complaint I have is that the fuel can pull back from the spray bar to the needle before you get the engine started -- this makes the prime more critical if you're hand-flipping, but if you get it right the fuel gets to the spray bar before the engine cuts out.
If you're still crashing often, I'd say the advantage of not bending needle valves all the time outweighs the disadvantages.
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bend a piece of 3/32 music wire into a U shape,, about an inch or so long,, stick it into the top of the fuse next to the needle valve so that the u is taller than the needle,, now when you flip over it will hit the U instead of the needle
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If your fingers still work ok (no carpal, no diabetic numbness or whatever) and you keep your wits about you when the engine lights up, cut the needle back to the clicker. Adjust needle by carefully spinning the disk. Saves the needle. Possibly shreds your fingers.
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http://lijnbesturing.nl/index.php/informatie/fotos?view=album&album=5699869323582862289&page=1
look at picture #19 and 20.
Put an aluminum elbow behind the needle and mount it at the engine.
We have "test" it many times :)
Greetings Robert-Jan
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Hello Robert-Jan et.al.
Thanks for the replies.
I have some aluminum angle stock that will work well for making a needle guard.
I mounted a wheel on the top of the nose just for laughs. Looks very crude but effective! Lol
Stay well,
Frank
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On Fox needles or any other ones that are solid, I just cut the end off and bend them over like a Super Tigre needle. I have never broken on by doing that and they are still easy to adjust.
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Back in the day we used to use a piece of plywood bolted on the outside using the engine bolts.. it sticks up but works like a charm... we used to also put a single wheel sticking up... mostly for touch and go's inverted..
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Hi All:
Thanks for the replies!
On one plane, I put a very thin, 1/8" wheel mounted via the top front engine mounting bolt that protects the needle valve well.
On another, I made a bracket from aluminum as pictured in one of the replies. It seemed to be too much labour for the task.
If I fabricate another "guard" it will be a very simple piece of plywood or aluminum attached by the engine mounting bolts on the outside of the fuselage.
Stay well my friends,
Frank
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I have always liked the coil spring Enya type needle valve posts - hard to seriously hurt something that will simply spring back in place after being knocked
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Try planting the plane hard inverted. Those spring NV's will break. I have done it.
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Try planting the plane hard inverted. Those spring NV's will break. I have done it.
Sounds like a face plant of the quality that you are describing would break off any protrusion Garf.
My point is the more flexible it is the less that it will need protection in the first place - kinda solves the problem before it starts.
Angling the needle valve back will also give some modicum of protection.
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Just before you land give it full down then full up and bonk it square on the nose.
MM