Roland, I had endless problems with overheating with my 914/XS. Going to
LAA Rally was a nightmare, because sitting in a queue to take off always
led to overheating, needing me to pull out of the queue and shut down. I
then had a Woodcomp SR2000 which is a low twist prop, very much like a
Warp Drive one or pretty much any prop you see on a Rotax 91X. The
problem is that at idling speeds the central part of the prop is in Beta
mode, effectively diverting air from the cooling inlets. When I switched
to a Woodcomp SR3000W the problem was abolished completely, quite apart
---From gaining an appreciable amount of performance (equivalent to an
extra 7 horse power). I can now sit in a queue all day if needs be!
I tried to attach the paper documenting a detailed comparison of
performance with the two props, which appeared in the Europa mag some
years back, but the list rejected it. However if you google, 'Does
Propeller Twist matter' it comes up top of the options
Regards, David Joyce, G-XSDJ
On 2016-07-28 11:22, Roland wrote:
>
> Hello,
>
> I have the conventional XS cowling with the 914 and overheating might occur on
the ground in high OAT's (25-30C). I've shut down the engine once when reaching
118C and then I could hear the 50/50 antifreeze boiling lightly. Does anyone
know roughly the temperature gap between the CHT/CT (I only have a CHT gauge)?
>
> I've read on another forum, that increasing to 2700RPM (and switch to a
> courser
pitch?) brings down the temperature. I also have a water Thermostate installed,
which I'll remove in a first step to lower the CHT-temperatures on the ground
and increase the time until I have to shut down the engine (when reaching
115C CHT). With this measure I (hopefully) increase the oil temperature at the
same time (oil cooler partly covered by Radiator) so that I can taxi and take
off earlier, since I don't have to wait for the oil to warm. Same goes after
landing regarding the cooling run for the Turbo, when the CHT is creeping up
quickly.
>
> What are your experiences especially without water Thermostate on the ground
in high temperatures / measures to avoid overheating?
>
> I want to start with simple things before modifying the cooling tunnel,
> because
I "only" have issues on the ground and quite satisfying setup for flying. Also
modifications often end in a never ending story and often the only practical
solution might be the best compromise...
>
> The cooling of the XS is only sufficient for English summers I'm afraid :-)
>
> Roland
> PH-ZTI
> XS TG 914
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=458822#458822 [1]
>
Links:
------
[1] http://forums.matronics.com/viewtopic.php?p=458822#458822
[2] http://www.matronics.com/Navigator?Europa-List
[3] http://forums.matronics.com
[4] http://wiki.matronics.com
[5] http://www.matronics.com/contribution
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