YS 140 DZ going lean in -ve g maneuvers

[Lees,John W]

Dean: 
 
Good point.
Filling is somewhat cumbersome. 
There is a weight penalty w/bladder.
I prefer simple, the addition of another tank and associated pluming is more
complicated to me. Once I switched to bladder and it ran flawlessly, I
accepted the additional work of filling tank. --john
-----Original Message-----
From: Dean Pappas [mailto:d.pappas at kodeos.com]
Sent: Thursday, May 13, 2004 9:45 AM
To: discussion at nsrca.org
Subject: RE: YS 140 DZ going lean in -ve g maneuvers


Hello John,
That's interesting ... have you also tried a hopper tank? I had great
success with one in preventing air-gulp hiccups with other engine setups.
The hopper is a small (2 ounce) tank plumbed in series between the main tank
and engine. Its clunk only runs to the middle of the tank, so that it can
never uncover, until more than half emptied. The Hopper starts life
completey full as its overflow is connected to the main tank pickup, and
stays that way almost until the end of the main tank. Air gulps take a bit
out of the hopper, but as long as they don't make it more than half empty
things are good. Its cheaper, and does not require fancy tank filling
procedures. Given the weight of the bladder it might even be lighter.
Dean
-----Original Message-----
From: Lees,John W [mailto:jlees at mwdh2o.com]
Sent: Thursday, May 13, 2004 12:33 PM
To: 'discussion at nsrca.org'
Subject: RE: YS 140 DZ going lean in -ve g maneuvers


 I thought DZ's were crap, had several different tanks, clunk's, ect. Not
until I went to a Bladder tank{no air in media} did the engine run flawless.
Since then it has never even hick-upped. 
It is of my opinion that the DZ will not tolerate any air in the fuel
delivery system. --john
-----Original Message-----
From: PENNISI Peter [mailto:Peter.Pennisi at publicworks.qld.gov.au]
Sent: Wednesday, May 12, 2004 5:29 PM
To: discussion at nsrca.org
Subject: YS 140 DZ going lean in -ve g manoeuvres


Hi all,
 
 
My DZ has only returned from holidays in Japan were it was repaired by YS
from another cam failure.
 
 
The engine is running absolutely superb except when you pull high negative g
manoeuvres like the reverse humpty bump it gets a little lean for a few
seconds put it does come good.
 
I have re-plumbed the model put the problem is still there. 
 
Running
 
APC 16 x 12
OS F plug
Tetra 20 oz tank with OS sintered(Spelling) bubble less pickup.(Yes the
expensive one)
Hatori exhaust (698 pipe)
Coolpower 30% heli blend
Model is ZN-LINE Alliance.
 
Any suggestions
 
 
Peter
 
 
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