YS 140 DZ going lean in -ve g maneuvers

[Dean Pappas]

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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