Not PFA -approved but a standard feature of the 912S on a certain Section S
UK microlights (Pegasus Quik).
That one works by tapping-off a low pressure area in the side of the carb
(i.e. a tapping into the venturi placed through one of the four blind
drillings on the opposite side to the "choke" mechanism). This partial
vacuum is then applied to the vents to the float chambers (i.e. the vents
that are usually connected into the airbox (if the airbox mod. is present)).
The partial vacuum is regulated crudely on the Quik by means of a 1/4-turn
fuel tap (the cheap version supplied by ASS and used on things like
Kitfoxes), which is mounted on the panel. The downstream part of the circuit
has a bleed orifice (a 210 carb jet, which looked to be about 2.1mm bore) to
prevent over application of the vacuum and (probably) to allow the crude
fuel tap to work .
Sort of "playing with fire" if the operator gets it wrong. The advantage
must be quite minimal.
Duncan Mcf.
----- Original Message -----
From: "Carl Pattinson" <carl@flyers.freeserve.co.uk>
Subject: Re: Europa-List: Bing Carbs
> <carl@flyers.freeserve.co.uk>
>
> It is a very easy to modify the 912 carb installation to lean out the
> mixture.
>
> You just need a means of bleeding air into the balancer pipe between the
> carbs
>
> Run a T piece to a pipe into the cockpit. Terminate with a screw operated
> valve - just remember to close on descent.
> I guess if you have alarms on your EGT guages this would warn you if the
> mixture became too lean.
>
> It is not an approved mod (the PFA would certainly not approve it) and
> has
> the potential to burn the valves out if used incorrectly.
>
> Use at your own risk.
>
>
> ----- Original Message -----
> From: "Kingsley Hurst" <hurstkr@growzone.com.au>
> To: <europa-list@matronics.com>
> Subject: Re: Europa-List: Bing Carbs
>
>
>> <hurstkr@growzone.com.au>
>>
>>> I don't think it does, the UK agent did some experimentation, a very
>>> simple
>>> mod but dependant on the pilot remembering to richen on descent.
>>> It certainly does lean but as you suggest probably not enough.
>>> Ivan noticed in the early days, (G-YURO) that going high wasn't
>>> particularly economical.
>>
>> Thanks Graham,
>>
>> So the plot thickens !
>>
>> Are you able to share what the simple mod was please ole mate ? Don't
>> see
>> the manual enrichment on descent being a problem - have to do it in all
>> the
>> spam cams !
>>
>> Best Regards
>> Kingsley
>>
>>
>>
>
>
>
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