I have done without a coolant temp for years so I'm inclined to agree. I'm also
tired of looking at at a row of blanks for coolant temp on my EIS. Just looking
to get a reading on the display.
Martin
Sent from my iPad
> On Mar 21, 2015, at 6:38 PM, Timward <ward.t@xtra.co.nz> wrote:
>
>
> Absolutely agree with you Remi.
> Tim
>
> Tim Ward
> 12 Waiwetu Street
> Fendalton,
> Christchurch, 8052
> New Zealand.
>
> ward.t@xtra.co.nz
>
> Ph 64 3 3515166
> Mob 0210640221
>
>
>> On 21/03/2015, at 10:31 pm, Remi Guerner <air.guerner@orange.fr> wrote:
>>
>>
>> In spite of what Rotax say in their Manuals, I do not think that monitoring
coolant temperature is necessary. This is why:
>> 1. The coolant is heated by the cylinder heads. So obviously coolant
>> temperature
is always below cylinder head temperature.
>> 2. Conventional water based coolant boils at 120C at the 1.2 bar pressure, at
sea level.
>> 3. Anytime the hottest cylinder CHT exceeds 120C, there will be at least some
local boiling.
>> 3.1. Then, if the engine is running at cruise RPM or more, the water pump
>> insures
a good flow through the cylinder heads, the bubbles are pushed downstream
to the cooler and condense, so there is no boiling over.
>> 3.2. If the engine is at idle on the ground, while you are waiting for your
take off clearance, then it will boil over. Moreover, as soon as CHT reaches
110C,
you must either shut down the engine or take off quickly. If you wait a few
more minutes and let the CHT reach 115C, then the only choice is to take off
immediately. Then the CHT will decrease instantly. If you shut down at this
point, then the heat transferred from the hot engine to the coolant will make
it to exceed its boiling point and you are facing a big mess.
>> So the only advantage of monitoring the coolant temperature would be to allow
the CHT to slightly exceed 120C, for example during a full power climb in very
hot conditions, while the coolant temp would stay slightly below 120C. It seems
to me this is a very marginal and risky advantage.
>> So in my opinion, monitoring the CHT of the hottest cylinder and considering
the redline is 110C on the ground and 120C in flight is good enough. This is
especially true on the Europa where cooling is very good in flight but very
marginal
on the ground.
>> Remi Guerner
>> F-PGKL, XS Monowheel, 912ULS, 1195 hours
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=439699#439699
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