3rd channel mixture control.

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Jorgen Andersson

Well-Known Member
Joined
Aug 25, 2004
Messages
319
What are you experinces between the Violett mixture control compared to the CMDi current version?

Greatful to any input how they work.

Jorgen
 
Jorgen Andersson said:
What are you experinces between the Violett mixture control compared to the CMDi current version?
Greatful to any input how they work.

Jorgen

69204[/snapback]

No comparision for me. I've tried both, all my boats (except the twin) are outfitted with CMD needles. B)
 
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No real experiances with the Bob Violet but the CMD didn't work for me on .21's. Check them out on a flow meter. Set the meter to 40 and wiggle the outside of the needle around. I bet it will vary 1-1.5 on the gauge. Not good for little motors for sure. Maybe big stuff can vary that much.

Ron
 
The violet needle is very good it has a good range about two turns end to end.

Only thing you have to watch is the small orings will wear and shreds will go into the needle seat causing erratic lean mixture.

The company sells the replacements but you may find them at a industrial suppy co. that stocks o rings they are very small but are easily changed, the plastic body unscrews easily to flush out with out changeing the setting of the main needle.
 
Ron J said:
No real experiances with the Bob Violet but the CMD didn't work for me on .21's.  Check them out on a flow meter.  Set the meter to 40 and wiggle the outside of the needle around.  I bet it will vary 1-1.5 on the gauge.  Not good for little motors for sure.  Maybe big stuff can vary that much.
Ron

69215[/snapback]

Were you using the fine or coarse needle?? BIG difference............ :eek:

The fine CMD needle on my MAC 21 has performed flawlessly. :D
 
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Running with both needles and the Kalistratov(CMD) is more precise at least on my riggers.Also have experienced the o-ring problem mentioned on the BV but easily fixed as said.Besides that CMD is less expensive than the other!

Gill
 
I have also noticed the wiggle and that is the reason for my question. I did test it on a flow meter as Ron had done and I get about the same result, about 3-5% leaner mixture when you wiggle the needle, about the same both with the fine and the coarse.

It does not feel good, but maybe it does not matter when you run it in a boat.
 
Jorgen,

I have been using the CMD unit for a couple years now, with little or no troubles, until this year. I started noticing some irratic performance and when I got to looking into it, found what Ron J described. I am going to switch to the OS In-Flight needle ass'y for next year in all my boats. The only probelm is that you have to come up with the "other half" of the needle ass'y, meaning the part that the needle seats into. The unit is actually designed to be used directly mounted on some OS Max carburators. This is not a problem for guys like me (machine tradesmen) who can just make the mating parts, but not everyone has these capabilities at their disposal. Other than this, the OS usit is flawless.

Thanks. Brad.

Titan Racing Components
 
Brad

Thanks for your input. What did happen to your CMD units? Worn needles? Have you tried the BV unit?

Thanks

Jorgen
 
Jorgen,

Personally, I think it's the threads between the main body and the "actuator" sleeve. The needle itself is fine, and there are no O-rings to go bad (that is the one VERY cool thing about the CMD unit, they have a teflon sleeve with a snug fit on the needle). It's just the threads on the black plastic piece start to wear and the overall fit gets loose. I did see one CMD needle that had the side nipple come completely off and it appeared to have been GLUED IN!.

I have a BV needle in a 60 boat that I scratch-built, but it's not a very good design, and I haven't ran it much since it's maiden voyage, so I really can't give you any reliable input on the needle. I can tell you that with as well as the OS unit works, I probably won't be trying any BV or CMD needles until I have reason to.

Thanks. Brad.

Titan Racing Components
 
I believe Aeromarine sells the block that accepts the OS inflight needle. And, if Scott Vanslooten still makes them, his works fine as well. I got away from the OS because I got tired of spending 100plus dollars on a carb and needle valve. However, the OS needle is trouble free and a must on the little motors. Real precise...

Ron
 
Aeromarine sell the base for $18. I have used their base with the OS needle for the last three years and I won't use anythine else. I use them in every boat from the sport 20 to the twin. I tried the CMD in my scale and could never "find the needle" untill I put the OS combo in.

Buddy
 
"Other than this, the OS unit is flawless."

Hardly. The OS needles will need regular O ring changes to keep them dependable. I ran them for years & even with changing the O rings every season I still had, on two seperate occasions, a failed needle O ring cost me a win overall at races. The needle comes with one extra pair of O rings but after that it's a pain in the a$$ to get them.

As for the CMD needles & this "wiggle" test if you have the adjustment arm wound out too far I can see this on my flowmeter. BUT I found this condition also exists on the OS needle & it's worse on the BV needle. If you are running the "coarse" grade CMD needle you need to be easier on the TX adjusting. What would take 6-8 "clicks" on a OS only needs 2 or 3 on the CMD. We have started using the "fine" grade CMD needles on everything from the 21's to the 84's with good results. B)
 
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I use the o.s. in flight needle assy and it works great no completes here.
 
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I've used all 3. I have an O.S. with the fine needle built in on a D&J carb on one of my 20 Speedmasters and a fine CMD on the other 20 Speedmaster, 40 Speedmaster & Blackjack. My new Speedmaster & Lynx will have the O.S. They both are good needles, but I like the O.S. better becuase it's on the carb. Otherwise, I see no real advantage as far as quality goes.

As for O.S. O rings going bad, I've been running the O.S. for 4 years without needing to change them. It's not like CMD is using a special O ring. They are all the same. They go bad from taking them apart and putting them back together. The less you jack with them the longer they will last. And Don, McMaster Carr only has a few hundred at a time that will fit the O.S. needle. $.32 for a pack of 50.

BTW, changing the BVM O rings are a pain in the butt.
 
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Don,

My CMD needle was set as far in as I could get it. There are three leads on the thread to allow for set-up positioning. I had it set to where about 20 degrees past as far lean as my radio would travel would bottom out the threads and still had the wobble. The problem lies in that the threads are WAY too fine to be used in a thermoplastic like what is used for the CMD needle ass'y. The OS ass'y has one thread lead, and it's a square truncated thread that allows for absolutely no cross or end play. Set-up positioning is achieved by means of a splined arm that is held in place by a C-clip.

Joe, The CMD needle doesn't actually use O-rings. Like I said, this is the one thing that I really like about it. There is a teflon sleeve in the body of the ass'y that the needle snuggly fits in and this creates a good seal that never wears out.

Thanks. Brad.

Titan Racing Components
 
Terry Keeley said:
Is the OS set-up just the arm shown in this shot?  Gonna run a 9B on a Green Head next year, is this the way to go?
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCA22&P=0

69828[/snapback]

Terry-

If you decide to use the OS needle use it with a remote base like the previously mentioned Aeromarine. The drawback to being on a motor is the vibration can really accelerate the wear on the O rings. :eek:
 
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