[NSRCA-discussion] YS140DZ idle question-answer

John Ferrell johnferrell at earthlink.net
Tue Aug 1 07:33:21 AKDT 2006 

Impressive!
It costs less and weighs less than one LiPo.
It takes me a few days to make that decision but I am leaning that way...
It looks pretty cheap when compared to the KiloWatt Klub...

I am looking forward to the equipment report from the Nats. I know you and 
Michelle spent a lot of time gathering that info!

Another question: Does the 160DZ dropin replace the 140FZ?

John Ferrell    W8CCW
"My Competition is not my enemy"
http://DixieNC.US

----- Original Message ----- 
From: "Grow Pattern" <pattern4u at comcast.net>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Tuesday, August 01, 2006 9:51 AM
Subject: Re: [NSRCA-discussion] YS140DZ idle question-answer


> It has to be in the plane :-)
>
>
> The pumping action allows the tank to be on the CG just like the pressure
> systems.
>
>
> Regards,
>
> Eric.
> ----- Original Message ----- 
> From: "John Ferrell" <johnferrell at earthlink.net>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> Sent: Tuesday, August 01, 2006 9:49 AM
> Subject: Re: [NSRCA-discussion] YS140DZ idle question-answer
>
>
>> How critical is tank location?
>>
>> John Ferrell    W8CCW
>> "My Competition is not my enemy"
>> http://DixieNC.US
>>
>> ----- Original Message ----- 
>> From: "Earl Haury" <ehaury at houston.rr.com>
>> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
>> Sent: Tuesday, August 01, 2006 7:50 AM
>> Subject: Re: [NSRCA-discussion] YS140DZ idle question-answer
>>
>>
>>> Bob gets the award for proper description of the YS D engine series fuel
>>> system. Yamada san is a very innovative designer!
>>>
>>> As Bob states - fuel is "sucked" from the tank on the pump piston
>>> downstroke
>>> (low pressure in the pump results in atmospheric air pressure "pushing"
>>> fuel
>>> from the tank). Appropriate inlet / outlet check valves within the pump
>>> provide for incoming fuel draw or outgoing fuel injection.
>>>
>>> The pump is a positive displacement piston pump, ingeniously fitted into
>>> the
>>> intake valve pushrod which provides motion that is timed to the intake
>>> stroke of the engine. The output of the pump is determined by pump size 
>>> /
>>> stroke and pump rate (engine rpm) - this output is controlled by the
>>> needle
>>> valve (high end) and the throttle barrel slot. As with all positive
>>> displacement pumps transferring fluids (non-compressible), there must be
>>> some way to accommodate excess volume (i.e. closing the throttle at high
>>> rpm) or parts will break! A spring vs. fuel pressure against a diaphragm
>>> regulator provides an internal return path from the pump outlet to the
>>> pump
>>> inlet - recirculating excess fuel. Another ingenious YS design
>>> application
>>> is that the regulator spring pressure is modulated by crankcase pressure
>>> (against the spring side of the diaphragm) - increasing pressure at high
>>> rpm. Because of this - idle mixture can be changed by adjusting the idle
>>> fuel pressure with the tension of the regulator spring. Of course -
>>> changing
>>> the spring tension also affects the high end pressure (CC + spring) and
>>> must
>>> be accommodated with appropriate needle valve changes.
>>>
>>> For those still convinced that the regulator on the front of the pump is
>>> actually "the pump" - I suggest that you remove the crankcase pressure
>>> line
>>> between the regulator and the engine and run the engine (it'll lean out
>>> at
>>> WOT but can be richened with the needle) - fuel will still be pumped 
>>> just
>>> fine!
>>>
>>> Earl
>>>
>>>
>>>
>>>
>>> ----- Original Message ----- 
>>> From: "Bob Kane" <getterflash at yahoo.com>
>>> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
>>> Sent: Monday, July 31, 2006 10:14 PM
>>> Subject: Re: [NSRCA-discussion] YS140DZ idle question-answer
>>>
>>>
>>>> No. The DZ series does not use a pressurized fuel
>>>> system. The fuel is "sucked" from the tank by the fuel
>>>> pump on the down stroke of the intake pushrod (valve
>>>> closing), and "squirted" out to the injector as the
>>>> intake valve pushrod opens the valve. The regulator on
>>>> the front of the fuel pump limits the fuel pressure by
>>>> opening when the fuel pressure is sufficient to
>>>> overcome the spring tension in the regulator. The
>>>> spring is much stiffer than the spring in the FZ/L
>>>> series motors. There is no low end adjustment on the
>>>> carb in the DZ series, so the regulator is used to set
>>>> the idle mixture. Start the engine, set the high end
>>>> needle as you would on any other YS, pull the throttle
>>>> back to idle. If the engine slows down and dies, it is
>>>> rich, turn the regulator out to lean it. If it speeds
>>>> up and dies, it is lean, turn it in to richen it.
>>>> Recheck the high speed needle.
>>>>
>>>> These engines will not tolerate restrictive fuel
>>>> filters. I am currently using a Sullivan Crap Trap to
>>>> keep the big boulders out of the fuel system and it is
>>>> working well. I'm still playing with using a check
>>>> valve on the vent side of the tank. It works well
>>>> without it but I get some leakage out of the vent.
>>>>
>>>> I have recently been through an extensive learning
>>>> experience with the pump system on these engines. If
>>>> the fuel lines past the pump blow off the fittings,
>>>> the pump regulator is set too rich or is sticking
>>>> closed. If you are having trouble with the adjustments
>>>> it might be time to have the pump/engine serviced.
>>>>
>>>> I will say the power of the 160DZ is incredible, way
>>>> more than what is needed to pull my Temptation through
>>>> the Masters sequence. I'm running an APC 18.1X10 prop,
>>>> the thing pulls like a locomotive and slows down as if
>>>> you threw the anchor out. Vertical uplines, even with
>>>> rolls are just over half throttle. The only possible
>>>> disadvantage is the prop is heavy and will probably
>>>> cause more rapid conrod wear.
>>>>
>>>>
>>>> --- vicenterc at comcast.net wrote:
>>>>
>>>>> Eric,
>>>>>
>>>>> I got a new YS 160 DZ.  Is this procedure equivalent
>>>>> for both engines?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Vicente "Vince" Bortone
>>>>>
>>>>> -------------- Original message -------------- 
>>>>> From: "Grow Pattern" <pattern4u at comcast.net>
>>>>>
>>>>> Michael,
>>>>>              The big and first thing to remember is
>>>>> that the DZ uses a pump. If you keep thinking about
>>>>> the pump as a regulator it may not help you set your
>>>>> engine. Unfortunately the instructions call it a
>>>>> regulator. The fuel is metered out to the carb by
>>>>> the pushrod action and the "pulsating" crankcase
>>>>> pressure operates the pump side.
>>>>>
>>>>> The next thing is that the carb does two things. It
>>>>> controls the air flow to the inlet valve and the
>>>>> fuel supply to the injector. Even though the needle
>>>>> effects all of the fuel flow it is not the right
>>>>> thing to use to get a good idle. Many people
>>>>> accidentally/unintentionally override the pump
>>>>> settings with the main needle to get a good low-end
>>>>> rpm.
>>>>>
>>>>> The "regulator" screw restricts the primary fuel
>>>>> flow and is the one that you must use to set an idle
>>>>> and transition. If you get the big brass screw set a
>>>>> bit too rich it will keep dousing the plug,
>>>>> especially at low rpm.
>>>>>
>>>>> The trick to a good setting is to keep closing the
>>>>> pumped fuel supply until the engine will not run any
>>>>> more.
>>>>>
>>>>> You do this by turning the big brass screw clockwise
>>>>> about 1/8 of a turn and then start and warm up  the
>>>>> engine. Keep the main needle at about 1.5 turns or
>>>>> more and don't worry if it runs a bit rich as you
>>>>> open the throttle about half way, in short bursts.
>>>>> Do this again and again until the engine will not
>>>>> start or keep running at idle or open up.
>>>>>
>>>>> You are now very close. Turn the brass screw back
>>>>> anti-clockwise about 1/8 of turn. and see if the
>>>>> engine will start and idle. It should be able to go
>>>>> as low as, and hold about, 1.500 rpm.for about a
>>>>> minute. If the throttle smoothly increases the rpm
>>>>> you have a good low-end setting. (Go more "open" on
>>>>> the brass screw if it is needed to keep it running).
>>>>>
>>>>> Now is the time set your top-end needle. It may need
>>>>> more or less fuel so please open up carefully and
>>>>> listen for the warning "bark". Richen the main
>>>>> needle if it barks. If all goes well, set the
>>>>> high-end needle for max rpm and then richen it back
>>>>> about 500 rpm.
>>>>>
>>>>> After that it should run like a Swiss-watch, start
>>>>> better, and last a good while. It should not quit in
>>>>> the air or on the ground.
>>>>>
>>>>> Please let me know if this worked for you.
>>>>>
>>>>> Regards,
>>>>>
>>>>> Eric.
>>>>> ----- Original Message ----- 
>>>>> From: Michael Cohen
>>>>> To: NSRCA Mailing List
>>>>> Sent: Sunday, July 30, 2006 2:31 PM
>>>>> Subject: [NSRCA-discussion] YS140DZ idle question
>>>>>
>>>>>
>>>>> OK list, I have a question for you.  I have a 140DZ
>>>>> that will not idle below 2300ish RPM.  Richard
>>>>> Lindberg and I have adjusted the regulator, but it
>>>>> appears to have little or no effect.  I might be
>>>>> able to get one flight in, but eventually, on a down
>>>>> line, it will die and 7 dead sticks are not that fun
>>>>> to try.   Full power seems to hold just fine.  We
>>>>> figured there might be an air leak, and that is why
>>>>> it seemed to idle worse after a warm up flight, so I
>>>>> replaced the valve cover gasket and the other
>>>>> gaskets at the backplate, but that did not seam to
>>>>> make a difference.  Anybody got any ideas besides
>>>>> the usual OS/Webra/Mintor/E-power/power slope
>>>>> soaring comments?
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> NSRCA-discussion mailing list
>>>>> NSRCA-discussion at lists.nsrca.org
>>>>>
>>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion>
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>>>>> NSRCA-discussion mailing list
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>>>>>
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>>>>
>>>>
>>>> Bob Kane
>>>> getterflash at yahoo.com
>>>>
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