YS dies at bottom of stall turn - Help!!

[Troy Newman]

How did you adjust the idle? using the air bleed screw? On this screw in is
rich and out is lean. Actually if you throttle up and it dies then its
probably lean. If it just loads up and dies it rich. Usually unlikely that a
too rich idle will allow the motor to die on throttle up. In most cases it
will just take a longer time to clear out and throttle. Think about
it.....Too much fuel is rich right. How to help too much fuel burn....give
it more air right? When you throttle up the barrel opens and does just that
takes in more air. Where as a too lean condition  means too much air...then
you throttle up and get even more air!

New plug? as the motor breaks in there are tiny pieces of metal that are
being floated through the motor as the ring seats in. If this stuff contacts
the element on the plug it will stick and cause a bad spot on the plug. You
really can see these things....I usually change plugs at about 15-20 flights
on a new motor.

Idle may be a little low at 1800...It should be right at 2000 for setting
and fly it about 2200 is best results especially when newer motor. What
happens is when they are new or new piston ring sleeve parts...the motor
will run hotter on break in for say the first 10 flights...Because of this
the idle is a little tougher to set and you will slowly chase it over time.
What happens is flt #1 it will need to be rich to accommodate the heat. Then
at say flt #20 this is too rich so it will need to be leaned out a little.
Its always better to be rich on the bottom end than lean. The reason is it
takes time for the fuel charge to hit the combustion chamber. If you are set
a little lean on the bottom end it will actually go lean for a second
waiting for fuel if you gun it open.  Richer will not do this. You are
getting this now by throwing the prop... I think you are on the lean side of
the curve on the bottom end air bleed screw...Dial it in....for rich.

Then the next question is the regulator...I assume its flush with the case.
If the motor throttles up to about mid rpm like 4000 rpm and it dies
there...then you could be need a reg adjustment.

The way to set the motors with a tach...

#1 HS needle with a tach go for peak then back it off 200-300rpm. Run the
motor in the 8500-9000 range on the 110 Which you are doing.

#2 Low end air bleed. Set the throttle trim for exactly 2000rpm not 1800 and
not 2200. Watch only the first 30 secs after you hit idle. This means clear
it out good going up to full and then drop right to 2000 rpm....Once the
motor will repeat this drop right back to 2000rpm you are ready to watch it
for lean or rich.

If the motor hits 2000 then climbs slowly and then slows it is lean. Air
bleed goes in to richen. If it sets at 2000 then slowly drops off to
1900-1800-1600 and dies its rich. Out is leaner on the air bleed screw.

You want the motor to set at the 2000 rpm for 30 secs. Then it should slowly
begin to load up. This is a rich idle condition but is just on the verge of
being rich. This is the way I run the motors. Once in the air the motor will
unload and heat up. You will rarely be at idle for 30 secs at a time and top
that off as the motor heats up it will lean this low end mixture out.

#3 Regulator adjustment same deal as the low end but the rpms should be
around 4000...Look for any slight surging or loading up here....This is a
rare adjustment needed.  but you can fine tune it. 1/8th to 1/4 turn
adjustments on the reg are OK. This can be a fair amount off and still
perform fine.

Good Luck with it

Troy Newman
----- Original Message ----- 
From: "Eddie Batchelor" <perkinsrx at centurytel.net>
To: <discussion at nsrca.org>
Sent: Monday, June 28, 2004 8:33 AM
Subject: YS dies at bottom of stall turn - Help!!


> Facts:  YS110 powermaster 30% Heli fuel Ys glowplug APC 15X10 turning 8800
> and idles between 1800-2000.
> Problem:
> My fairly new YS110 (about 2 gallons of fuel thru it) has started dieing
at
> the end of prolonged downlines -such as coming out of a stall turn or on
> final approach.
>
> I have done the following so far:
> 1. assumed the idle was rich - leaned it out until the motor started
> throwing the prop. Ok now it's too lean, so I richened it back up.
>
> 2. changed the tank and fuel lines.
>
> 3. discovered one of the in-line fuel filters partially unscrewed.
tightened
> this up
>
> 4. changed the throttle servo that appeared to have deadband around the
idle
> area(apparent bad pot)
>
> I've attempted to fly after each of these changes and the motor will die
> when I add throttle at the bottom of the stall turn. Now if I give a
little
> throttle during the downline & not let the motor slow down completely it
> appears to do fine.
>
> I want to be able to do a stall turn or a big loop and let the plane pull
> out at the bottom with the motor idling and continue flying (at idle)
until
> I wish to add power.
>
> Another example is on a landing approach when you realise you're a little
> short and try to add just a blip of power to reach the runway, it dies
about
> then. (has twice now)
>
> Does anyone see a "glaring" mistake I'm making, or have a suggestion of
what
> next to look at. I realise I'm at the bottom of the learning curve with YS
> 4-c motors and it ain't no fun  :-))
>
> Any help will be greatly appreciated.
>
> Eddie
>
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