[NSRCA-discussion] First day out with OS 140RX (somewhat long)

[Troy A. Newman]

David,

>From what you are saying and I have experience with both also I would say 
you need to work on the idle mixture like Hester says. You should be able to 
get a good idle lower. Remember when a new motor is breaking in all kinds of 
bits of ring...and sleeve flyin' through the motor. These little bits can 
hit the glow plug and create an instant hot spot then a dead spot on the 
plug.

This can cause it to not work properly. The old codger at the field takes 
his glow plug out and if it still glows its fine. Well this is the not the 
case. Look to change the plug in any performance motor like an OS 140 or DZ 
at some point during the break in period like around 2-20 runs. Its just a 
fact.

Also for 15% nitro,  I would say go to a slightly smaller prop and your 
power will be better on the OS as well. 7800 in my opinion is too low for 
that motor. try the 16-12 and your performance will increase. Remember I 
used to fly at 5000-6000ft in Denver. We learned about the power curve of 
the motors up there. There are lots of experts on this list that say they 
have unlimited power all they would ever need on 15% and a 17-12 prop on the 
OS 140. Been there and done that. I ran 25% nitro in mine with a 16-12 or 
16.5-12W!

Try a 16-12 and you should see good performance and about 8000-8100 on 15% 
nitro. This should give top end uphill close to the 140DZ. If it doesn't 
bump your nitro and it will.

Oh and by the way Greg  Frohreich is now running 160DZ's for the last year. 
I'll let him tell you how happy he is at the next contest. I'll sum it up 
this way, He just bought a second Pinnacle and is going with the 160DZ in it 
too.

The OS is a good motor but what you found with no mas' until it raps up 
above 1/3 power is a 2 stroke thing and why I choose the DZ motors. Many 
guys may remember back in 2002 I ran OS 140's and EFI's I switched back then 
to the 140DZ in 2003. Since then I have tried lots of options and they all 
were good but the DZ was the Gold Standard.

Oh and one more thing. I proudly represent YS Performance, because of their 
products and their service. I'm not paid and am free to choose the motor 
that works best for me. Since the DZ is what works best its an easy 
relationship.

Troy


----- Original Message ----- 
From: "Mike Hester" <kerlock at comcast.net>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, March 01, 2006 6:24 PM
Subject: Re: [NSRCA-discussion] First day out with OS 140RX (somewhat long)


> That's a good, honest comparison.
>
> One note: I'm betting that your bottom end is set rich, and that's why
> you're idling at 2000, and why it flamed in a high G. Probably when you 
> got
> back into the power, it drowned the plug. The OS likes a lean bottom end.
> Are you using an F plug? Turn the idle screw clockwise about 1/8 turn and
> your idle speed should actually increase. Then dial down your trim until 
> you
> hit about 1800 or so. It will go lower, but until you get used to it, 1850
> is good.
>
> -Mike
>
> ----- Original Message ----- 
> From: "David Flynt" <dflynt at verizon.net>
> To: <nsrca-discussion at lists.nsrca.org>
> Sent: Wednesday, March 01, 2006 7:40 PM
> Subject: [NSRCA-discussion] First day out with OS 140RX (somewhat long)
>
>
>> Today was one of those beautiful California days, in between the rain, 
>> and
>> I
>> have the week off, so I finally got my ZNline Supreme in the air for
>> several
>> trim flights.  Also, I switched from the Webra 160 with M/C to the OS
>> 140RX.
>> Below are my initial impression of OS, along with comparison to YS 140DZ:
>>
>> I was particularly careful while breaking in the OS.  I wanted to ensure
>> no
>> problems, and the engine was ready for fly time.  I broke in on the bench
>> with one gallon of fuel.  I saw 7800 rpm with a 16.5x12w prop mounted in
>> the
>> plane today, fairly rich.  I'm hoping I have it set way too rich, and 
>> that
>> it will gain more power as I get more fuel through it.  My setup is a 
>> Karl
>> Mueller header at 9 3/8 inches from from exhaust flange to the entrance 
>> of
>> the pipe, and an ES 2C140M80 muffler.  Cool Power 15%.  The Mueller 
>> header
>> has a sharper rise over the OS or Hatori header, and I needed that to
>> clear
>> my firewall.  Total length due to the sharper rise is near the same as 
>> the
>> stock OS header.  What a nice header BTW.  It has the right thrust built
>> in
>> so it is straight down the middle of the pipe tunnel.  It came with a
>> short
>> extension so that there is stress relief on the header to prevent it from
>> breaking.
>>
>> Big two strokes are new to me.  Before this engine, I was running a YS
>> 140DZ, and before that, YS 120 - 140.  Here are my initial observations
>> and
>> comparison between the 140DZ and 140RX:
>>
>> Ease of use:  Probably a toss up.  The OS is very user friendly, and is
>> simple, and runs on sport fuel.  It is not as easy as the YS in that you
>> need to tune header length and select optimal prop and muffler/pipe,
>> however
>> for the OS you can stand on somebody else's shoulders, and that is what I
>> did for the most part.  I don't know if I am done tuning it however. 
>> Both
>> engines are pretty much hands off once broken in and set (at least what I
>> hear for the OS).  I flew 300 times with the DZ, and never touched the
>> settings after break in.
>>
>> Ease of start:  Hands down, OS.  This engine starts with ease.  The DZ,
>> once
>> you learn it, will start easy so long as you have a strong starter and
>> strong glow source.  But it can lock up on you if you allow it to flood.
>>
>> Idle:  Definately the OS.  I had a good idle after one gallon, and I 
>> still
>> have not touched the low end from factory setting.  The YS will idle ok
>> for
>> a while once warmed up, but it won't idle forever.  It does not really
>> matter so long as you do not let it idle for long periods.
>>
>> Reliability:  No way to know since I don't have time on the OS, but one
>> strike against it today.  It flamed out at the bottom of the reverse
>> avalanche.  I just made it back, heart pounding all the way.  This is
>> probably an anomaly, and I only have 1 1/2 gallons through it (I should
>> not
>> have been practicing the reverse av with such little time on the engine,
>> but
>> oh well).  Idle speed was 2000 on the ground.  On the first flight
>> however,
>> I overshot the runway twice, and I had to go around.  So, it stayed lit
>> when
>> it counted.  The DZ never flamed out during flight.  I speculate that the
>> DZ
>> is more reliable, but I am splitting hairs.
>>
>> Quietness in the air:  OS is quieter, like a whisper compared to the DZ.
>> DZ
>> has a lower pitched noise.
>>
>> Vibration:  OS is much less vibration and very smooth at idle through 
>> full
>> thottle.  There is an area about 1/4 throttle where it shakes a little,
>> but
>> not bad compared to the DZ.  The 160DZ I hear is a lot smooother than the
>> 140DZ, which would be nice.
>>
>> Torque:  Hands down, the DZ.  The DZ has a smooth, linear throttle curve
>> and
>> usable torque at any throttle setting.  This is what is so great about 
>> the
>> DZ.  The OS is fairly limp and useless until you get past 1/3 throttle.
>> At
>> half throttle it comes alive, and at 5/8 throttle to full throttle, there
>> is
>> little difference in output.  I think this is one of the major 
>> differences
>> between two cycle and four.
>>
>> Power:  The OS does ok, but the DZ is far more powerful.  Maybe I need
>> more
>> time on the OS before a fair comparison.  I have a gut feeling however,
>> from
>> running this and watching other OS owners over the years, that the DZ
>> dominates in power.
>>
>> Weight:  OS with ES muffler is probably 3-4 ounces lighter than a DZ with
>> similar muffler.  But I think the DZ might be equivalent weight with a
>> Hatori short pipe.  Not sure.
>>
>> Fuel requirements:  DZ runs best on one type and brand of fuel:  Cool
>> power
>> 30% heli.  This is expensive stuff, and is my major gripe with the DZ.
>> The
>> OS ran outstanding with 15% sport fuel.  For economy, you cannot beat
>> this.
>>
>> Smoke trail:  DZ has a thick smoke trail with CP 30%.  This OS had fair
>> amount of smoke, but I expect it to decrease as I lean in.  None of OS'
>> that
>> I see at contests have a heavy smoke trail.
>>
>> Overall preference:  This is a little tough because the DZ performs 
>> better
>> for pattern, but the OS is probably good enough.  Greg Frohreich flies
>> very
>> well with his OS, and until I can fly better, I wonder if I need a better
>> engine.  Still, the DZ is a pleasure to run, with exception of the
>> expensive
>> fuel.  I choose the DZ as my preference, but I like the OS for the
>> positive
>> characteristics I mentioned.
>>
>>
>> David
>>
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