YS DZ160s... OS-160 EFI

[Dean Pappas]

Ah yes ... I love the smell of nitro in the morning: it smells like Pattern!
I also wax nostalgic about the banshee-like wail of a YS at close to 19,000 RPM.
Well, that's what the audio tachometer said.
What neighbors? Complaining, are they? Ahh, the heck with 'em!

There's actually more tinkering associated with a two-stroke, until you get a feel for how the variables like prop selection, pipe length, nitro, etc affect each other. Once you get it figured, its plug-and-play. Until then, you'll have plenty to play with!

Later,
	Dean

-----Original Message-----
From: Ed Miller [mailto:edbon85 at optonline.net]
Sent: Wednesday, January 21, 2004 4:50 PM
To: discussion at nsrca.org
Subject: Re: YS DZ160s... OS-160 EFI


Yes, I remember your Malibu, RIP, with an AC turning a huge prop at the time
in the mid to low 7K range, in fact I think I flew it too. I have to see if
the power delivery of the piped 2C will fit my tastes. I remember when I
sold my LA-1 with it's AR I swore I'd never go back to the 2C with a pipe,
how things change. Quieting the DZ's appears to be more involved than just
an effective exhaust, I noticed a pronounced amount of intake "honk" on
Landis's 140DZ in the Partner and Smaradz. The higher rpm it needs to spin
presents a challenge in noise reduction with the 2 blade props. My hope is
the 160DZ will have the muscle to spin effectively one of the APC 3 blades
twisted to between 10 and 12 pitch for both quietness and the constant speed
of the 3 blade.  As a lover of cams, gears, pushrods and "tinkering", I have
to be as a long time Harley owner, I sense 2004 may cause me withdrawal
symptoms running the relatively simple RX. I was and still am impressed with
the ST2300, mac header and Vtech muffler in my Hanson Dalotel, although that
setup is far from optimum. It's all a moot point, the electrons are here and
will win out. Sure glad I got to experience the internal combustion stage
though, there is nothing like the smell of nitro in the morning.......
Ed M.
----- Original Message -----
From: "Dean Pappas" <d.pappas at kodeos.com>
To: <discussion at nsrca.org>
Sent: Wednesday, January 21, 2004 12:08 PM
Subject: RE: YS DZ160s... OS-160 EFI


> That's an excellent observation, Ed.
> Since it seems to be impossible to add a voice to this (sometimes)
argument without declaring what side you are on: let me say that I was very
happy with my very reliable four-cycles, and after a fair amount of
experimentation, I am now happy with the two-cycles. I have always harbored
suspicions about the aerodynamic effects from the huge chins that are
required to package a four-cycle. I think that electrics may offer the
ideal, but for now ...
>
> I used to prop my reworked 120ACs down to 7,200 RPM, with a narrow-bladed
16-13.
> Of course, that RPM was with a rich setting, as required to prevent
pre-ignition with the necessary 30% nitro.
> The quiet was great! The flexibility to run large diameter and or very
high pitch props was welcome.
> When the two strokes became legal, I was pleased to find that I could
easily run in the mid-sevens.
> The FZ 140 (still a sweetly behaved engine) really needed to be propped
just under 8,000 RPM, provided the prop would allow the engine to unload to
about 8,500 or above. It wanted 12 pitches, not 13s: it needed to unload
with P/D ratios more like 77% (think 15.5 X 12) rather than the 85% (15 X 13
wide or 16 X 14) that was my typical with the AC. The quiet suffered, some.
Remember, my home field has a 92 dB limit on chicken wire topped table. It
appears to be equivalent to a 94 dB limit on pavement.
>
> When it comes right down to it though, there is no substitute for cubic
inches, and we are interested ion power-to-weight.
> Big engines can still be light, as proven by Yamada, Mintor, Webra, and
most dramatically Jett (with their built for CL Stunt RoJett 40 ... now that
little critter is practically weightless!)
> Regards to All,
> Dean P.
>
>
> -----Original Message-----
> From: Ed Miller [mailto:edbon85 at optonline.net]
> Sent: Wednesday, January 21, 2004 6:09 AM
> To: discussion at nsrca.org
> Subject: Re: YS DZ160s... OS-160 EFI
>
>
> What's interesting in the 4c vs. 2c comparison is the fact that as the 4C
YS
> has evolved, it needs to be propped to spin faster than the older
generation
> YS 4C's to stay on it's power curve. Although Yamada has increased the
> displacement to the practical limits of the existing case size, he still
> needed to compress and time the engine for a higher rpm range in order to
> increase power output at the expense of some low end grunt. By comparison,
> the newer 2C's seem to be very content to run at 8K to low 8K range which
is
> nearly silent with 15" 3 blade props. I can remember some older YS 120's
> being propped at a very quiet 7500rpm hauling around some very large ( mid
> 90's over 2meter Omen ) and over 10lb airframes. One would think the 4C
> would have the "torque" to spin a heavier load at a lower rpm than the 2C,
> but not so when you factor in the natural tuning affect of a pipe/muffler
on
> the current crop of  2C 's. There is no question in my mind that the 140DZ
> is not in the same league top end power wise as the OS140's, 160's, Webras
> and Mintor's provided they are on a PIPE and or a very large volume
muffler,
> in either case something that provides some tuning affect.  Blow a coupler
> on a piped 2C at the wrong part of the FAI schedule and watch all that
power
> disappear. Watching Danny Landis fly the 140 DZ in a 10 3/4 lb Partner in
> 2003 and a Smaragd in 2002, what disturbed me most about the 140DZ was
it's
> violent shaking and fuel appetite. What surprised me was Danny's 140DZ's
> could not spin the APC/Lockhart 15.75x11 3 blade that the OS and Webra 2C
> spin effortlessly.. Fuel consumption I can deal with but hopefully the
160DZ
> will be somewhat smoother and more powerful than the 140. It's amazing
that
> the YS has come from that small valve 120 version first seen here in the
> late '80's to the 140 and now 160 fuel injection version today and yet it
> still occupies the same footprint as the original 120. Quite an
engineering
> feat.
> Diehard YS fan going OS 2C in '04 but keeping a watchful eye on 160DZ's
for
> '05.
> Ed M.
>
> ----- Original Message -----
> From: "David Lockhart" <DaveL322 at comcast.net>
> To: <discussion at nsrca.org>
> Sent: Tuesday, January 20, 2004 11:17 PM
> Subject: Re: YS DZ160s... OS-160 EFI
>
>
> > And...as long as the 2C contingent is speaking up........
> >
> > The modified 3 blade that I run has been tried on a number of different
> > engines - OS140 EFI, OS 140 RX, OS 160 EFI (Jason's, along with some
other
> > props as he mentioned), Webra 145/160, and YS140DZ.  The 3 blade runs
> quite
> > nicely on the 2Cs w/ 15-20% nitro.  The 140DZ won't handle the prop even
> > with 30% nitro.
> >
> > Regards,
> >
> > Dave Lockhart (no engine sponsorship here!!)
> > DaveL322 at comcast.net
> >
> > PS - I've seen several 160 FX and EFIs run well - but none would keep up
> > with "THE ONE" Jason has - that particular sample must be the one were
all
> > the tolerances are just perfect.
> >
> >
> > ----- Original Message -----
> > From: "Jason" <jasonshulman at cox.net>
> > To: <discussion at nsrca.org>
> > Sent: Tuesday, January 20, 2004 10:55 PM
> > Subject: RE: YS DZ160s... OS-160 EFI
> >
> >
> > >
> > > Chips DZ 160 was close, but not as powerful as my OS-160 EFI. I don't
> have
> > > #s cause we never ran the same props, and I don't usually tach my
> motors,
> > > but it didn't seem to have the same pull. For fun at the TT I asked
Dave
> > > Lockhart to pitch UP a 15.75x13 3-blade and ended up with a 14.75
pitch.
> > It
> > > flew my 10 3/4 pound Shadow....and I was amazed. Although it was way
too
> > > fast, it still went through the sequence fine. I flew it again a
couple
> of
> > > weekends ago to learn the new patterns and it's just unbelievable the
> > power
> > > this thing has. It's more powerful than the 1.70 I had in it's twin,
and
> > > different power from the electric. If I get my pipe fixed and it
doesn't
> > > rain this weekend, I'll tach it this weekend.
> > >
> > > Jason, the lonely sponsored 2-stroke (& electric) pilot
> > >
> > >
> > > -----Original Message-----
> > > From: discussion-request at nsrca.org
> > > [mailto:discussion-request at nsrca.org]On Behalf Of Jerry Budd
> > > Sent: Tuesday, January 20, 2004 8:48 PM
> > > To: discussion at nsrca.org
> > > Subject: Re: New YS DZ160s
> > >
> > >
> > > Hi Troy!
> > >
> > > >We already know the 140DZ can keep up with any of the 2 strokes...
> > >
> > > Any?  Not exactly.  And certainly not mine (for that matter, neither
> > > of the two YS160's flown at last years Nats came anywhere close
> > > either).  Prop for prop I was turning 300-500 rpm more than ANY four
> > > stroke I came across.  How do I know?  I asked their owners.
> > >
> > > The simple reality is that most non-sponsored pilots are running 2
> > > strokes, and most (but not all) sponsored pilots are running four
> > > strokes.  I'll leave it to the audience to speculate as to why that
> > > is...
> > >
> > > Jerry
> > > --
> > > ___________
> > > Jerry Budd
> > > mailto:jbudd at qnet.com
> > > =====================================
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