Will, I missed the earlier stages of this thread, but an alternative
approach to the problem is to fit a propeller with a high degree of
twist. I had always had cooling issues (like having to shut down & wait
for things to cool down if delayed in a queue to take off at a rally)
with my low twist Woodcomp SR 2000 prop which were
transformed/eliminated on changing to a high twist Woodcomp Sr3000W,
quite apart from going faster and more economically. Warp drive blades
and most other blades seen on Rotax powered planes have twist (that is
difference in incidence between 1/3 radius & tip) of around12 degrees.
Simple analysis shows this is about right for sitting still at half
throttle. At air speeds of 100kts the central portion of such propellers
is working in beta mode effectively diverting air away from the cooling
inlets. Look at any WW2 warbird, racer or modern turbo prop and you will
find they all have twists of the order of 28 degrees so that at normal
operating speeds, the blade is producing effective thrust along its
whole length. I will send you, off network,the text of the
analysis/comparitive trials published in the Europa mag some years back.
Regards, David Joyce, GXSDJ
On 2015-08-11 23:47, William Daniell wrote:
> Thanks again Bud,
> The thing is that I have the engine installed and the firewall done per the
> manual.
Id be loath to undo it all however if thats what it takes.....
> Do you have an instruction of how to put the firewall behind the nose gear
> frame?
Or a picture at least. I can imagine roughly how it might be done...im thinking
putting in a bulkhead and lining it and the tunnel with firewall blanket.
I assume the bottom is not covered allowing the air to exhaust.
> Thanks
> Will
> On Aug 11, 2015 4:33 PM, "Bud Yerly" <budyerly@msn.com> wrote:
>
>> Will,
>> Only the sealing of the radiators and the opening up of the exit area by
>> moving
the firewall are necessary, provided you increase climb speed on long duration
climbs. 12AY and most others still cool quite well with just sealing the
radiator gaps, leaving the cowl stock, and moving the firewall to behind the
nose
wheel.
>>
>> Mono's can use our flat firewall to increase cooling exit air.
>>
>> If you have long ground taxi, must do max performance angles of climb in 30C
or hotter weather, is engine plenum ducting necessary.
>>
>> Regards,
>> Bud Yerly
>>
>> _Sent from my Verizon Wireless 4G LTE DROID_
>> On Aug 11, 2015 9:17 AM, William Daniell <wdaniell.longport@gmail.com> wrote:
>>
>> Buds instructions are pretty comprehensive as usual
>>
>> I shall move the round intake holes up to level with the spinner as
>> suggested.
>>
>> I would very much like to see any pics of cooling shrouds/ducts. the
>> aluminium
shrouds on Bud's website look like a lot of work.
>>
>> thanks
>> Will
>>
>> William Daniell LONGPORT
>>
>> +57 310 295 0744
>>
>>> http://www.matronics.com/Navigator?Europa-List [1]
>> onics.com [2]
>> ww.matronics.com/contribution [3]
>>
>> arget="_blank">http://www.matronics.com/Navigator?Europa-List
>> tp://forums.matronics.com
>> _blank">http://www.matronics.com/contribution
>
Links:
------
[1] http://www.matronics.com/Navigator?Europa-List
[2] http://onics.com
[3] http://ww.matronics.com/contribution
[4] http://forums.matronics.com
[5] http://www.matronics.com/contribution
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