I saved a message by Jim Butcher on a blue-mountain-avionics forum where
he reported measuring a flow of 41 gph into a bucket. The Rotax 914
installation manual gives 30 gph as the rated flow for 1 pump at 300 hPa
(airbox at sea level pressure) to 25 gph at 1000 hPa (airbox at 16000'
with full boost). The second pump would increase this by a small amount.
Floscan 201A-6 seems marginal, 201B-6 seems better.
I bought from Floscan 2 of type 231 ("marine use only"), similar to
201B-6 but heavier (steel). And less expensive. And no fretting with
aluminium adapters...
Alan, if you have a 914 I believe you might get the 914 installation
manual - it has a flow graph for the pump (Pierburg E1F no. 7.21440.78.0).
And you might check out the Floscan website. There are 2 aviation pages.
Regards, Jan de Jong.
On 9/11/2013 7:45 PM, Dean Seitz wrote:
>
> The 914 does not have a low flow rate. It pumps around 20 gal per hour from
> the
tank and returns all of that minus what the engine used back to the tank. Feed
is around 20 gal/hr and return is about 15 gal/hr at cruise. At idle it's
almost 20 gal/hr return.
>
>
> ---- David Joyce <davidjoyce@doctors.org.uk> wrote:
>>
>> Alan, I go along with that. My 914/twin Floscan set up has
>> worked nicely without any sort of jet. The only relevant
>> stipulation I can remember is that there should be a
>> reasonable length of fairly straight hose leading into
>> each Floscan as sharp corners will produce turbulence and
>> false readings. One of the key points with the Floscan I
>> believe is that even if its spinner jams it will not
>> significantly impede flow. It seems a bad idea to put
>> anything in the flow if you don't have to.
>> Regards, David Joyce, G-XSDJ
>>
>>
>> "rampil" <ira.rampil@gmail.com> wrote:
>>> <ira.rampil@gmail.com>
>>>
>>> Alan,
>>>
>>> Floscan makes 3 models of the 201 sender for varying
>>> expected mean
>>> flow rates of gasoline. The appropriate unit for the
>>> 914 is the 201A
>>> model which handles 0.3 - 30 gal per hour.
>>>
>>> If a jet is added, at least in my imagination of what a
>>> "jet" or orifice might
>>> be, it will add turbulence and reduce accuracy of the
>>> flow turbine. I could
>>> not find a reference to such an addition in the FloScan
>>> site. Further, in a
>>> 914 application, the meaningful flow regime is roughly 3
>>> - 7 gal/hour, well
>>> within the linear range of system. Does it really matter
>>> if the measured
>>> flow rate at idle power (less than 2 gal/hr) is slightly
>>> off?
>>>
>>> The only place where the flow rates are less than that
>>> is in the return line
>>> to the tank. In my 912s application, the return flow is
>>> unmeasured, but
>>> very small, since my measured forward flow rate are
>>> right at what Rotax
>>> predicts in the manual. It is much less than the LAA
>>> posited rate of 0.8
>>> gal/hr through the 0.35mm orifice.This was after I
>>> independently
>>> calibrated my Floscan at three different flow rates.
>>> Perhaps the LAA
>>> used a higher than Rotax max pressure head of 5 psi
>>> through the orifice?
>>> The slight apparent increase in fuel flow rate (by not
>>> measuring the return
>>> flow and subtracting it in the totalizer) seems to me a
>>> a safety feature.
>>>
>>> BTW, any additional "jet" in the return line, if that is
>>> what you were
>>> contemplating is a direct violation of the engine
>>> install instructions for the
>>> 914 which requires a low resistance path bach to the
>>> tank after the
>>> pressure regulator.
>>>
>>> The return flow rate situation with the 914 may be a bit
>>> different than
>>> with the 912s, though the pressures and the return
>>> orifice are the same.
>>>
>>> I recognize that if the LAA tells you that you must have
>>> return flow measured, if measuring flow at all, you must
>>> comply.
>>>
>>> It is just my opinion that trying to measure flow rates
>>> under 0.5 gal/hr will
>>> be inherently inaccurate with the Floscan 201A in an
>>> aircraft environment
>>> and isnot worth the trouble and expense. On the other
>>> hand, many
>>> builders have this feature installed.
>>>
>>> Best of luck!
>>>
>>> --------
>>> Ira N224XS
>>>
>>>
>>>
>>>
>>> Read this topic online here:
>>>
>>> http://forums.matronics.com/viewtopic.php?p=408424#408424
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> Un/Subscription,
>>> Forums!
>>> Admin.
>>>
>>>
>>>
>>
>>
>>
>
>
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