Mounting oil cooler

by Eugene Klimenko in General Tech Discussion 6 years ago

Moving oil cooler up front. Have 2 questions:

- Fittings/elbows for supply and return lines have more then 90° bend. More like 135° or so. It was installed like this by manufacturer in Europe. Can I reuse them like that? Or I need to change them to 90° fittings?

- Do I really need bottom bracket in this situation? Feels very solid with only top bracket.

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Re: Mounting oil cooler

by Roger Lee » 6 years ago

Roger Lee

127 5.21k 4.79k

Two things I see. First the oil cooler fittings (your 135 degree). I have seen these used and swapped some out because where they are bent they have a reduced radius. It slows oil flow and causes higher oil temps. You want no restrictions in fluid or air flow.
Second the parachute is in front of the radiator and oil cooler. The radiator may not be affected at all. The oil cooler will be affected more because it is lower. This is just like us putting tape over the oil cooler in the winter months to restrict air flow that causes oil temps to stay up where we want them. Most likely not an issue in cold months, but you may have hot oil temps in the summer especially on takeoff. These two items coupled together could easily cause a 20-30F temp increase on takeoff and higher temps in cruise. I live in sunny hot Arizona. I had good air flow and good fluid flow. My oil temps even on a hot day (100F-110F)was 217F in cruise and 230-235F on a good takeoff climb out. I see some with poor flows easily hit 250F+ on takeoff and 225-230F in cruise.
Even the parachute motor will have some affect.
Unrestricted flow is everything.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Thank you said by: Eugene Klimenko

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Re: Mounting oil cooler

by Bill Hertzel » 6 years ago

Bill Hertzel

13 1.95k 7.97k

These all look like cosmetic issues to me.
Unless there is a specific reason you do not want the bottom bracket, I would leave it in place for no other reason than redundancy.
If the Oil tubes are helping to point the hoses in the correct general direction (Downward) they need to go, so much the better.
The additional length of exposed metal tubing will dissipate more heat than the equivalent length of rubber hose.
It might not be significant, but at least it is a positive value.

Bill Hertzel
Rotax 912is
North Ridgeville, OH, USA
Clicking the "Thank You" is Always Appreciated by Everyone.

Thank you said by: Eugene Klimenko

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Re: Mounting oil cooler

by Eugene Klimenko » 6 years ago

Eugene Klimenko

12 74 1

Thank you! My hope is that airflow to water and oil coolers will be OK for Wisconsin. I will be monitoring temperatures during my test flights during summer time.

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Re: Mounting oil cooler

by Roger Lee » 6 years ago

Roger Lee

127 5.21k 4.79k

Hi Bill,
Look at his second picture. The reduction in tubing ID. I've had 4 planes I had to remove these because of the slowing of the oil flow causing higher temps.This isn't any different than a hose with too tight a bend and the radius gets squeezed down to flattening of the hose causing the oil to slow down and causing higher oil temps. In hoses we either re-route or put a spring in it to help keep the radius wide open. Bending these tubes does the same thing.
Heat may not be a big issue if it's an open air engine, but it still slows oil flow and volume is our friend. More so than just pressure alone.

Hi Eugene,
Is this going to be an open air engine or a cowled one? Open air engine's tend to always run cooler.
p.s.... You can put the bend or sweep in the hoses. Those ID's are usually bigger than the metal fitting. Less chance for flow reduction.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Thank you said by: oeyvind kvig

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Re: Mounting oil cooler

by Eugene Klimenko » 6 years ago

Eugene Klimenko

12 74 1

Yes, when I am all done this hopefully will be cowled and beautiful engine, just like on this pictures. Peter Garrison was telling me that I need 75 sq. in. opening up front for 100 HP engine.

Someone send me massage today, that I can use larger oil cooler from 914 engine, if needed. I didn't know that we have this option.

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Mounting oil cooler

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