Don't think it matters Ram or not Ram, what's important is that the float c
hamber sees the same pressure as the inlet throat. It is important the the
airflow is same velocity across the diameter. Variation will upset the mixt
ure and smooth elbows into the carb will give varying velocity. Best if the
air goes in straight from the plenum not elbowed.=0AGraham=0A=0A=0A=0A=0A_
_______________________________=0AFrom: Gary Leinberger <Gary.Leinberger@mi
llersville.edu>=0ATo: "europa-list@matronics.com" <europa-list@matronics.co
m>=0ASent: Monday, 7 June, 2010 19:56:00=0ASubject: RE: Europa-List: Combus
ry.Leinberger@millersville.edu>=0A=0AMy understanding is that the Bing carb
s on the 912S are not designed for ram air - on my Europa I am using the 91
4 FWD kit on a 912S (I originally planned on a 914 but the price differenc
es of recent years seems excessive). This has the advantage of not taking i
n water during rain or when on the tarmac. The air box around the NACA inle
t is sealed mainly so that only cool air enters the carbs - but the air fil
ter box is vented to the carbs so that there is no excess pressure in the a
ir going to the carbs. The 914 is boosted, but requires numerous other gadg
ets to allow the Bing carbs to function properly with the excessive pressur
e.=0A=0AGary Leinberger=0AA237=0ALancaster, Pa.=0A=0A95% done, 95% to go.
=0A=0A________________________________________=0AFrom: owner-europa-list-se
rver@matronics.com [owner-europa-list-server@matronics.com] On Behalf Of Fr
ed Klein [fklein@orcasonline.com]=0ASent: Sunday, June 06, 2010 7:41 PM=0AT
o: europa-list@matronics.com=0ASubject: Europa-List: Combustion air inlets
=0A=0AOn Jun 6, 2010, at 12:38 PM, Frans Veldman wrote:=0A=0AWhile solving
my cooling problems, I learned a few things:=0A1) Naca ducts provide no ram
air, but merely "allow air to get in".=0A=0ATo all you 912S powered flyers
,=0A=0APage 8-1 of the Europa "912 Rotax installation manual" states:=0A=0A
The engine inlet air is fed through a NACA duct situated in the top cowling
. It passes into a plenum=0Achamber which feeds the air directly to the car
burettors. This ensures that the coolest air available is=0Aused at all tim
es, thus ensuring no reduction of engine performance.=0A=0AIf Frans is corr
ect, it would appear to follow that the 912S plenum does not offer inlet ai
r to the carbs under ram air pressure.=0A=0AAnd since the 914 engine inlet
is a NACA vent also, the same would apply.=0A=0AI'm surprised...having thou
ght that engine performance benefits when the carb gulps air which is above
ambient pressure.=0A=0AAny wisdom to pass on to a heretic?=0A=0AFred=0AA19
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