Re: fine thread needle on Norvel's and similar engines

[RknRusty]

First off, Thanks, Ken for showing me how to make this. I posted it on RCG too, and made sure I didn't take undue credit for this innovation.

Here's the finished product. The whole thing is JB Welded in place and clamped with a setscrew.

If you look closely you can see the index mark I scribed on the brass. There's also a mark on the venturi that the photo doesn't pick up. This is so I could keep it aligned while assembling it in case it turned

[Ken Cook]

Rusty, I think it's great your showing these pictures. I have a newcomer to 1/2A combat and I just got him setup with the plane. He now has the engine and this subject popped up recently. He's a member on the forum here and I can just point him in this direction so he can see your upclose progress. I found these to be a bit touchy but once you get the setting for the day it's good to go. Great stuff and your solution was quite innovative as well. Modelers helping modelers, great show. Ken

[RknRusty]

Now I need to re-attach the wing on the Refried Bean so I can use the engine. That might be tricky. The T-28 is going to get the MP Jet.

Did you see where I posted in Balough's thread that I'm having trouble with the allen screws in the cylinder? I don't have to take it apart, but still, I'd like to be able to.

What's this new member's name?

[Ken Cook]

I had a bear of a time removing the socket head screws from one of my Stels engines. Heat is the key to removing. This means a good glove and heat the you know what out of it. I like to put penetrating oil and trans fluid on the screws. Heating the case until the oil is smoking. Stinks real bad but the end result is the screw will remove. I had one round out so bad the allen key would no longer work. I had to use a very small diamond bit in the Dremel and come into and out the opposing side. I used a piece of music wire through the hole and this allowed me to break it free. Some of these can really be problematic. If it doesn't want to break free initially, don't force it. It took me hours to get the damaged one out. Keep soaking it. Ken

[pkrankow]

Professional looking. Nicely done.

Phil

[RknRusty]

Last night I put the new venturi on my best spare Big Mig to test run it. After I made a new bladder and plugged it in to the fuel nipple, it promptly fell off. The barb on the nipple isn't big enough to hold the line tightly. I didn't bury any of it, the whole thing is out in the open, but it wouldn't even reliably hold the small clear line like Bernie sells. I was, needless to say, aggravated.

So this morning I fiddled with a couple of fixes and came up with this aluminum tube to hold it in place. I'll just have to fasten it to the airplane, but it took care of the problem:

I think a metal clamp pinned under each mounting screw should be sufficient for flying.

It took a few tries to get the needle set, but it runs fine. The engine is a good one. It spins an MA 5x3 at about 24.3K with 3 shims in the head. So that should do the trick. Anyone that tries this, I hope you have a valve with a better barb on the nipple.

[fredvon4]

The soft wire inside of bread wrapper twist ties is what I use as a one turn and twist fuel line keeper

[RknRusty]

I tried one of the Sullivan wire ties. I'll try the soft wire from a bread bag before I put all this on the plane.

[fredvon4]

On the bigger engines I have success with the spring like sullivan or DuBro fuel line keepers but for the smaller .049 stuff the one, two, or three turn springs are too fat to seat right behind the barb. We also tend to have the newer very flexible fuel line as opposed to the older harder stuff that has to be forced over the barb. One wrap of any soft wire and a quick half twist is just right for the small nipple (barb)

When I was breaking in the BigMig (got one based on your experience) I tried folding the fuel line back on itself to make a tighter fit. Initially it worked until the slobbering castor greased it all up and then prop wash just blew off the line...and yest the first time I got it to fire I was in aw of the stinking fast RPM and scream.. Don't know how I would act with a 30K RPM Cyclon or Profi

[RknRusty]

Yeah, they're mean li'l suckers. I had to resist the urge to dive under the table the first time it spun up a small prop.

[Ken Cook]

Rusty, I use smaller tubing than you do, I use a product used in the medical field known as Theraband for my tubing. Works great for pinching but, It will melt if exposed to the exhaust. I reroute to the other side to avoid that. The wetter the tubing gets, the harder it is to come off. In the event you keep having that problem, wrap a bit of uncoated copper wire around it and solder it onto the nipple as this will make a excellent barb. Ken

[RknRusty]

I can see how soldering the copper wire around the nipple would work. I'll try that tomorrow. Although my fix works, it is sort of kludge-like. Failing that, I'll look up the Theraband. Thanks for the tip.

[fredvon4]

I pulled out a new Aero Norvel .049 this morning to modify for pressure.  Way back when Ken posted this thread and Rusty added in his "way" I decided to remove my NVA and sleeve up a Texas Timers sourced fine thread NVA only using JB weld and forgoing any soldering. Hardest part my way was keeping the center fuel hole in the spray bar and the sleeve hole lined up for the JB install. The modification worked and still holds. The engine is very happy on 35% and needles just fine.

As I was preparing to cut the 5/32 brass tube to sleeve UP the TT NVA to fit in the larger diameter Norvel venturi hole; I wondered if I just used the original Norvel NVA by removing the needle and plugging it's hole and using a small remote OS NVA would work. The OS part in the photo is much smaller than the 21181902 1A,15 versions I am using for the Fox and Nelson 36s

I have quite a few larger combat engines set up for pressure with remote NVAs but all my .049 1/2A stuff has the NVA on the engine and I don't recall if I ever saw a remote NVA on the 1/2A stuff

I am betting Ken has done it both ways and would like his opinion

[Sponsored content]