Would just like to add that I know of two cases here in Austria where the
plastic expansion bottle ruptured due to extensive heat and/or pressure and due
to the fact that the very small vent hole incorporated in the screw cap was
obstructed and possibly even totaly blocked!
Both instances happened on ground during engine test runs on experimental built
aircraft equiped with Rotax 912 and 912S (not Europas).
I would strongly recommend to check the vent hole in the red screw cap of the
expansion bottle!
In my opinion the vent hole - at least on my cap - was hardly visible and seemed
too small; therefore I increased the size of the vent hole to 1,5 mm and also
drilled a second vent hole with a diameter of 1,5 mm.
Klaus
Graham Singleton wrote:
>
> >A note of caution on that! I recently read teh UK accident report
> >(http://www.aaib.detr.gov.uk/bulletin/apr01/gkwip.htm) on an accident where
> >coolant, having been intentionally diluted with water (but possibly to a
> >greater extent thatn the owner realised?) started to boil at what would
> >otherwise have been a "safe" engine tempurature.
>
> The coolant was measured at 50/50 after the accident. Boils at 130 C at
> operating pressure.
>
> >but at a *serious* penalty in terms of coolant
> >boiling point), it would appear that teh engine could boil while other temp
> >readings were in teh acceptable range.
>
> It did.
>
> >I have no idea whether (in consequence of this accident or otherwise) there
> >is any directive prohibiting or limiting coolant dilution, but the accident
> >cited should be taken as a serious warning.
>
> Which is why I posted my assessment a couple of weeks ago. PFA will
> recommend but not insist on 80/20. So do I with the benefit of painful
> 20/10 hindsight.
>
> Graham
>
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