YS 1.40DZ Questions

[Troy A. Newman]

Adam,

on first start up the motor will run a  little rich on idle. This has to do
with the fact that it is dumping raw fuel into the head of the motor. Once
its up to operating temps it should idle fine. Both 140 and 160 are this
way. I warm my motors up slowly when I first start them.  I throttle up slow
takes about maybe 5-10secs to go from idle to full power. I let it set at
full for a couple counts....You can hear the motor smooth out as the temps
come up....Then I set the idle ...1800rpm is a bit too low..2000-2200 is a
good number. At this RPM the motor is not pulling the model...This is as
slow as you need to go. Any slower and you really are not getting any more
braking anyway.

Then takeoff and as the motor settles into a temp...it will be fine. I see
lots of people..try to idle the engine from start up to takeoff roll and
never warm it up. I also see lots of people slam the throttle open and the
motor gets that hollow sound and barks a bit as it transitions. They then go
to tweaking the pump and can't get it set right. Glow engines of all kinds
are very dependant on operating temp. The mixture, chemical reaction, and
temperature all work together for the big bang. If your temps are too hot
the mixture ends up being too lean. If the mixture is too rich the temps
will be too cold.  So you need to get the motor up to operating temp for the
mixture to be right. Besides after a downwind pass and turnaround the motor
is up to operating temp. So just warm it up slow on the ground and then set
your idle rpm with your TX trim tab or what ever you choose to make throttle
trim adjustments.

Troy


----- Original Message ----- 
From: "Adam Glatt" <adam.g at sasktel.net>
To: <discussion at nsrca.org>
Sent: Tuesday, May 17, 2005 7:02 AM
Subject: Re: YS 1.40DZ Questions


> Larry, you have this mixed up.  The 17x12 is recommended for the 160DZ,
> not the 140DZ.  On the 140DZ I was running the 15.5x12w, spinning around
> 8600.  I started with the 16.5x12w, but later tried the smaller prop and
> found it worked a little better.
>
> And if anyone find outs the secret to idling a 140DZ slowly, let me
> know.  To get the idle lean enough to get down into the 1800RPM idle,
> the pump has to be too lean for full throttle.
>
> -Adam
>
> Larry Diamond wrote:
>
> >I refitted my Focus with a YS 140DZ. Don't know that I'm getting the
power I
> >should get. With that said, I now fly with less throttle than the YS
140L;
> >45 degree up lines are now at ½ throttle and vertical lines are about ¾
> >throttle.
> >
> >Here is my set up:
> >
> >1) Medium size fuel tubing, new (no air bubbles noted)
> >2) Power Master 30% DZ
> >3) APC 17x12
> >4) NMP Header from Central Hobbies (Having problems stopping the
> >exhaust leaks at the head, using Permatex -26B- Red RTV Silicone, rated
at
> >650F+).
> >5) 5/8" coupler
> >6) 698 Hatori pipe.
> >7) Check valve on the vent line.
> >8) 16oz Sullivan fuel tank w/ foam clunk (because that is what was in
> >it before. Any recommendation for a 20 oz tank?)
> >9) Pump is about ½ turn in from flush.
> >10) Needle is at about 2 turns out.
> >11) Max ground RPM - 7,900 / Air Temp - 60F
> >12) Idles -reliably- at 2,600 RPM
> >
> >Not necessarily considered broke in yet, 4 tanks ran on the ground
> >(following the steps by Don Szczur on Radio South's website) and two
flights
> >with the Intermediate sequence...
> >
> >What prop is being used and what RPM should be expected with PM 30% DZ?
> >
> >
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