YS 110S

[Trevor Plumbe]

I am running a 110s and until lately has been fine on 20% Technics fuel,15x8 APC peaking at 9,600 rpm

However,it is now "leaking" fuel from either or both the carb and silencer even when the tank pressure has been released,fuel in the tank and needle valve open 1 1/4 turns

Changed the check valve and diaphragm but no difference,would appreciate any suggestions on the problem

Trevor 

[Adrian Mansell]

Well, it can only leak fuel if the regulator is open I think so did you inspect the little silicone valve plunger and its seat for damage or debris? Is the regulator spring OK?  Is the little plunger/rod thingy (how technical am I?) moving easily in the assembly?

Something has changed I guess.  I presume if you screw the adjuster in 1/2 turn it stops the flow?

[A Brightman]

If you have a flexible H.pipe have you checked for a small fracture. It can be difficult to detect and will spray burnt fuel from the fracture. I find the best way to test is to immerse the pipe in water and blow into the pipe with your finger over the other end and look for bubbles.
Arthur Brightman.

[Pittsartist]

I've got a bag of diapghrams, plungers, springs etc trev - I'll put them in my 'van for next time I'm up there

Cheers,

Richard

[Trevor Plumbe]

Thanks guys for your ideas
Adrian.....regulator adjustment screw is flush with top of casting,is there a starting point for setting the pressure?
Arthur..... standard silencer
Richard.... thanks very much for the offer
It doesn't just drip it trickles from the silencer after a flight,also, it smokes like a steam train and uses 16 oz of fuel in 8 minutes


Any more ideas please?


Trevor 

[Adrian Mansell]

Hmmm...I'm sure lots of people have their pet way of setting the regulator, and I have no knowledge of what the official way to get a starting point is, but here are two ways I've tried before:

:  Fill the tank, flip it a handful of times to get a bit of pressure up.  Have the model inverted and throttle open.  Open the regulator until fuel starts dripping/running from the carb.  Close it again until it stops, then a further 1/4 turn.  Start the engine and go through the needle/regulator juggling game to get it right (http://www.patternflyer.com/troy/?page_id=13)

:  This one got me out of a right mess whilst I was trying to find a fault on 110S.  Set the slow running needle to 3 turns out from fully in.  Set the reg one turn in from flush.  Set the throttle roughly to a hi idle position.  Crank the engine and open the reg till it starts!  Then open it 1/4 turn and get juggling again.

They are very heavy on fuel (but what power!!!).  No matter how many times I go back and try to lean it out a bit on the reg it always ends in tears.  I turn an APC 15x10 on 30% Optifuel (can't recall the rpm, but it's >9k I think) and get through a 14oz tettra tank (normal clunk) in 8 to 9 minutes flying schedules.  So, only marginally better than you.  It really does sound like yours might just have the regulator a bit too far open, but that doesn't explain what has changed in your set-up seeing as it was running good.

A

[Adrian Mansell]

Hi Trevor, did you get any joy in the end?

[Trevor Plumbe]

Hi Adrian
Since your last posting I've been concentrating on my winter project...a Rapture 110

Thanks for the info, it does appear to be the regulator and hopefully after changing the spring,plunger and diaphragm "just" needs adjusting

The engine is now on the test stand waiting for this white stuff to disappear so I can run it down at the field

Need to test soon  as the Rapture is almost ready for painting
Regards
Trevor   

[Adrian Mansell]

Cool.  Steve mentioned you had had a Rapture from him.  Not really the weather for painting unless you have somewhere toasty you can do it!  I look forward to seeing it fly, I know I'm going to end up with one eventually; but for this year I'm going to treat Steve Haywood's old Leo to a fresh skin of profilm.  I've nearly finished the Zephyr, everything has been in it once, so just fuel proofing and final assembly to do.  Exciting.

This is probably teaching granny to suck eggs, but I tend to do my bench running without a spinner these days, and definitely without a nice aluminium tru-turn spinner.  Saves a lot of money when a YS decides to detonate :-)

Good luck :-)

[Trevor Plumbe]

Ran engine this afternoon,superb
Started easily,idled at 1500,1 1/2 turns main needle,3 1/2 turns, small amount of smoke,no fuel running from carb/exhaust,screw flush with top of regulator body but peaking at 10k on a 15x8 apc (20% technics)
I think a 15x10 may be in order
Thanks for all suggestions just need to finish the Rapture
Trevor

[tom bootyman (aeropaint)]

it smokes like a steam train and uses 16 oz of fuel in 8 minutes

are you sure Stuart hasnt popped his prototype steam engine in the front again!! the one with carbon fibre fire box!!