Hi,
As I understand it, at full throttle, the TCU will control the wastegate
to
give 39.9in HG.
Rotax say that at 5800rpm and 39.9inHG the engine will burn 8.7us gph.
To burn more than 8.7gph the MP or the rpm must be higher or there is an
error in Rotax figures.
If the MP gauge is suspect, then for a gauge reading of 39.9inHG the
actual
MP must be higher (to give a higher FF) but this is unlikely if the
wastegate is being correctly controlled hence my comment thta the airbox
sensor/TCU must also be in error.
Of course, as others have pointed out, Rotax rpm gauges are notoriously
inaccurate so could this be the culprit?
Simon
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Erich
Trombley
Sent: 07 June 2006 16:52
Subject: Europa-List: 914 Fuel Flows
Simon,
Can't say I agree with your assessment. The MP gage in the panel is
independent of the airbox pressure/TCU. As part of the installation of
a MP
(electronic not analog) you are required to calibrate the sensor. If
the
sensor is off by any amount from the true MP that the engine is really
producing then you will be incorrect in you assumption of H.P. For
example
if the pilot has not correctly calibrated the MP gage and it is reading
31"
of MP, however, in reality the engine is producing 34" then that would
explain the excessive fuel flow for a given MP reading. Make sense.
Off
course too rich of a mixture could also be the cause, however, with the
Bing
carbs this is unlikely. My fuel flows per indicated MP are very close
to
the published figures in the Rotax manual. Just my two cents.
Erich Trombley
N28ET Classic Mono 914
From: "Simon Smith" <
<http://webmaila.juno.com/webmail/8?folder=Inbox&msgNum=00000O00&bloc
k=1&msg
Nature=all&msgStatus=all&count=1149694132#> jodel@nildram.co.uk>
Subject: RE: Europa-List: 914 fuel flows
Surely, if the MP gauge is suspect the Airbox sensor/TCU would also have
to
be in error by the same amount? I initially queried the figures because
I
assumed (and we all know how dangerous that can be!) that the Rotax book
fuel flows ought to be accurate.
Simon
-----Original Message-----
From:
<http://webmaila.juno.com/webmail/8?folder=Inbox&msgNum=00000O00&bloc
k=1&msg
Nature=all&msgStatus=all&count=1149694132#>
owner-europa-list-server@matronics.com
[mailto:
<http://webmaila.juno.com/webmail/8?folder=Inbox&msgNum=00000O00&bloc
k=1&msg
Nature=all&msgStatus=all&count=1149694132#>
owner-europa-list-server@matronics.com] On Behalf Of Erich
Trombley
Sent: 06 June 2006 18:07
Cc:
<http://webmaila.juno.com/webmail/8?folder=Inbox&msgNum=00000O00&bloc
k=1&msg
Nature=all&msgStatus=all&count=1149694132#>
kandshill2@sbcglobal.net
Subject: [Norton AntiSpam] Europa-List: 914 fuel flows
Ken,
Knowing your fuel system as I do, I concur the problem is not with the
fuel
flow sensor.
I would verify that your manifold pressure gage is properly calibrated.
This would explain the excessive fuel flow per inches of mercury.
I believe for each fuel flow you have listed the actual H.P. you are
producing is actually greater than that corresponding to the M.P.
listed.
Erich Trombley
N28ET Classic Mono 914
________________________________________________________________________
|