[NSRCA-discussion] First day out with OS 140RX (somewhat long)
David Flynt
dflynt at verizon.net
Fri Mar 3 08:48:23 AKST 2006
Just out of curiosity (I'm not trying to start a debate or anything like
that :-)), how did Christophe and the Japanese get around the DZ noise
problems at the World's?
I like very light planes and low vibration. So the OS 140 for me is great.
The 140DZ was pretty big on vibration amplitude initially, but it smoothed
out a bit over time. The Webra 160 was way worse than the 140DZ for
vibration, but I expect that that would decrease over time too, or I would
add a head shim. I hear the 160DZ is much smoother, and I will try it soon
(I picked up a brand new one up at RCU for $500). When I do rig the 160, I
will use a 16 ounce main tank, and a two ounce header tank. That is not bad
on weight. With the Hatori header and short pipe, I expect the takeoff
weight difference to be six to eight ounces difference than the 12 ounce
tank example. I am running a 16 ounce tank in my Supreme, so the weight
difference will be about two to four ounces greater for the DZ. Does
anybody know the weight comparison for the Hatori short pipe setup? I think
it will be considerably lighter, because you won't have a long segment of
teflon tubing connecting the header and muffler, and the short pipe is
probably as light or lighter than a long ES carbon fiber muffler.
All things considered, I am very happy with the OS and DZ. The cost of fuel
is not enough to stop me from running the DZ. Performance trumps the cost
of 30% heli fuel. For me, it comes down to performance of the DZ versus the
low vibration of the OS. If the 160DZ is smooth, then that tilts the scale
back to the DZ. If not, then the OS. I'm not finished tuning the OS, but I
doubt, in fact I know it will never perform like the DZ.
On a separate topic, you can build a very light plane if you select light
components such as PBG wing and stab tubes, carbon fiber mufflers, etc.
Most guys overlook the weight of covering and paint. Opaque monocote and
ultracote are pretty heavy. I have not been able to cover a set of wings
with monocote using less than 4 ounces. If you want to half that, then I
recommend a lightweight transparent film I used Ultracote lite. It is very
light, sticks well, and is as easy or easier than monocote to work with. I
have no wrinkles on my covering (yet anyway -- I'll have to wait until I go
to Vegas and Phoenix to see if that holds up), and it looks pretty. For
paint, you can cover a big 2m plane with three ounces. Sometimes less.
Craig Blodgett told me that he used just one ounce on his Smaragd!! In my
opinion and experience, all of the 2m planes that we fly can be built less
than 10 pounds with the glow engines we use, and they will hold up well too.
I would like to see somebody paint a set of wings using just 2 ounce of
total material, then I will start painting wings. Anybody (Matt?) have a
formula for that?
David
-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of David
Lockhart
Sent: Thursday, March 02, 2006 7:30 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] First day out with OS 140RX (somewhat
long)
I agree that a good running YS is a great glow powerplant for pattern, and
the folks at YS Performance provide great service to the YS faithful. And
to get solid performance, you need only to slap on any one of a number of
headers and mufflers at pretty much any length, dump lots of 30% nitro low
viz oil fuel, bolt on a prop that will hit sufficient RPM to bust the
noisemeter at 80% stick, and set the needle. Good power, good torque, and
nice throttle curve are the likely result - along with plenty of noise and
vibration (relative to a 2C).
Should you choose the 2C glow - the upfront is substantially lower, and
either the OS140RX, Mintor140, or Webra160 will save you 3-4 oz on the
engine alone (mounts, props, spinners, headers, muffler/pipes are pretty
much a wash), and another 1-2 can be pulled off the OS and Webra if you feel
the need. And they will run on cheap 15% nitro and make plenty of power.
And I've found 12 oz of fuel in a simple two line tank more than enough to
get through F3A flights in any condition (as a matter of fact, I have done
PO5 2x in calm air on 12 oz). So in comparison to the YS (which uses 20 or
more oz of high test in a double walled bladder tank for the same flight
time), my takeoff is about ONE POUND lighter. Why do we work so hard to
shave ounces and grams off the planes? ......And the down side of the 2C -
to get the lighter weight, lower vibration, cheaper purchase and operating
cost, you will need to learn how to tune the tuned pipe (it ain't called
"tuned" pipe for no reason) - or just copy anyone of the many setups around
that already have a nice fat torque curve and good throttle response.
Of course, that is just my experience of 20 years having bought every single
ST, Rossi, YS (2 and 4C), OS, and Webra I've ever competed with (and soon to
be ?? electric motor).
Regards,
Dave Lockhart
DaveL322 at comcast.net
----- Original Message -----
From: "Troy A. Newman" <troy_newman at msn.com>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, March 01, 2006 9:32 PM
Subject: Re: [NSRCA-discussion] First day out with OS 140RX (somewhat long)
> 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
> >>
> >> _______________________________________________
> >> NSRCA-discussion mailing list
> >> NSRCA-discussion at lists.nsrca.org
> >> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >
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> >
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