Rotax 912ULS too cool

[WestCoast]

Iam not sure if anyone else has had the "too cool" problem with their Rotax 912S temps however this has been a problem with mine as you willsee from the engine log figures below.(where there have been two pick ups for a parameter, I have averaged the reading)<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

 

Alt 5500 ft

 

RPM 4600 MP 810 FF 19.5 LPH OAT 8C TAS 115 EGT 770C CHT 75C OIL T 76C

 

Alt 4500 ft

 

RPM 4800 MP 860 FF 22LPH OAT 11C TAS 117 EGT 776C CHT 80C OIL T 81C

 

RPM 4670 MP 830 FF 19.5LPH OAT 11C TAS 115 EGT 790C CHT 80C OIL T 77C

 

RPM 4590 MP 830 FF 20LPH OAT 10C TAS 115 EGT 786C CHT 78C OIL T 75C

 

Alt 2500ft

 

RPM 4710 MP 910 FF 21LPH OAT 8C TAS 115 EGT 809 CHT 74C OIL T 70C

 

My CTsw came from the factory in May 06 with 50% BASF Glysantin Protect Plus coolant & 50% water.

 

I have just replaced the coolant at the first 25 hour service with Evans NPG+ (as recommended by Rotax in the 912S manual) and what a difference it has made! I flushed the system twice using the Evans prep fluid (4 litres in all) and then added the Evans NPG+ at 100% as recommended.

 

CHT's are now sitting around 107C and OIL temp at 90C during cruise...when you compare that to what I was getting previously....the change of coolant appears to have solved the problem.

 

Figures after Evans NPG+ added:-

 

Alt 5500 ft

 

RPM 4540 MP 824 FF 19.5 Lph OAT 15C TAS 115 EGT 746C CHT 107C OIL T 90C

 

Alt 4500 ft

 

RPM 4500 MP 850 FF 20 LPH OAT 17C TAS 115 EGT 765C CHT 108C OIL T 85C

 

Regards Dave.

 

 

[Paul Willett]

I had about a 15 degree rise in CHT when changing to the Evans. On a Tecnam Airframe.

 

 

[WestCoast]

Thanks Paul.....have you only recentlychanged over to Evans NPG or have you been using it for quite a while? I would be interested to know how the CHT behaved over the hottest months during summer.

 

Thanks

 

Dave

 

 

[Paul Willett]

Dave,

 

I changed to Evans in February and have always remained in the green arc - although I tend not to fly on really hot days through choice (turbulence / comfort etc.)