zkvii
Well Known Member
Hi,
I'm still in the early stages of flight testing and fighting high oil temps. I've had a couple of good runs but the good seems more linked to outside air temp rather than anything else - ie. 15C day / 5C @ 4000' everything is within green - but warmer, 26C day / 15C @ 4000' oil temps are red lining after about 20 mins (takeoff -> 4000' S&L @ 150+ kts). CHTs are all sensible, 400-420. Oil pressure is always good, > 70 psi @ the high temps (eg. upto 115C)
Just for the record / background, this is a brand new engine (TMX OF-360) so I expect some heat for a few hours, I've checked the verntatherm, oil temp probe accuracy and changed from NDM to SW 8604R cooler. Leg and main fairings are installed too. Some improvments but all pretty small amounts.
We do have a custom cowl inlet / plenum which may be the source of my grief but changing the cowl is big work and I want to confirm before hacking it around.
So questions:
We are currently working on the inlet shapes a bit and also setting up instrumentation across the cooler so at least we can measure what we are getting right / wrong.
All rather frustrating...... but it seems to fly well![Big grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Carl
I'm still in the early stages of flight testing and fighting high oil temps. I've had a couple of good runs but the good seems more linked to outside air temp rather than anything else - ie. 15C day / 5C @ 4000' everything is within green - but warmer, 26C day / 15C @ 4000' oil temps are red lining after about 20 mins (takeoff -> 4000' S&L @ 150+ kts). CHTs are all sensible, 400-420. Oil pressure is always good, > 70 psi @ the high temps (eg. upto 115C)
Just for the record / background, this is a brand new engine (TMX OF-360) so I expect some heat for a few hours, I've checked the verntatherm, oil temp probe accuracy and changed from NDM to SW 8604R cooler. Leg and main fairings are installed too. Some improvments but all pretty small amounts.
We do have a custom cowl inlet / plenum which may be the source of my grief but changing the cowl is big work and I want to confirm before hacking it around.
So questions:
- Plenum 101 - can someone confirm I'm not actually that interested in 'air flow' into the plenum, what I want is a good pressure delta between upper and lower segments?
- What pressure delta should I be aiming for across the oil cooler?
- Intake / Outlet ratios - I know this has been debated / covered before, can some with the SJ cowl give me some details - ie. inlet diameter and outlet shape for side/side RVs.
- We are a nose dragger and currently I don't have an upper intersection fairing on the cowl - could this be seriously hurting our cooling flow?
We are currently working on the inlet shapes a bit and also setting up instrumentation across the cooler so at least we can measure what we are getting right / wrong.
All rather frustrating...... but it seems to fly well
Carl