Liquid Cooling Part 1: Radiator Theory

[@foesfly3047]

Excellent material.

[@daveberenholtz335]

What a great video. I was riveted! Thanks so much for making it and sharing the data.

[@vat_1989]

Brilliant 👏👏

[@willhibbardii2450]

Thank you for sharing. I enjoyed your presentation.

[@bettyromberg8544]

Great info

[@alessdre]

Great to see the numbers, but I think the great advantage of use 100 EG or Evans is the fact of you have 0 pressure in your system, this can avoid explosion and leaks at high pressure altitudes increasing reliability. Viking engines recommends only Evans. What fluid you use?

[@rv6ejguy]

70% water, 30% EG and dash of Water Wetter. Evans means a bigger rad and more drag since the C of heat transfer as far less. I used Evans for a few years and didn't like the cooling margin it offered.

[@alessdre]

@@rv6ejguy make total sense, what do you think about the way that Viking install their radiator lying under the belly with the air doing 90 curve? I watch some videos and he keeps the temperature under 180, but I can understand how it can work in that configuration.

[@rv6ejguy]

@@alessdre I'm no fan of rads placed parallel to the the airstream. It results in high momentum loss and drag. Viking doesn't care about drag, it's just easy to do it this way.

[@johndavidwolf4239]

On the thermal conductivity of the liquid coolant, have you heard of the product "Water Wetter" by "Red Line" oil company, they claim it improves the conductivity of heat from the liquid coolant to the metal of both the radiator and the engine? It was designed for drag racing where glycols are prohibited as if they gets on the track, it makes it slippery.

[@rv6ejguy]

I use this in my plane. It reduces surface tension so should improve thermal conductivity. I have never tested back to back to measure the difference however.

[@johndavidwolf4239]

@@rv6ejguy : Thanks for the reply, I too use it and have only seen anecdotal reports on it and not quantitative

[@tiitsaul9036]

Very interesting. I don't understand why it's commonly accepted, in early last century the shift from air cooled to watercooled airplane engines were made practical thanks to glycol. Why is that? I don't get it.

[@superspectacularday]

Excellent. Looking forward to Part 2.

[@highpointview256]

superb info.

[@patrikj]

For that radiator comparison, are those pressure drops for equal mass flow through the radiator? I'm not following how pressure drop by itself is the relevant quantity, won't the drag scale as pressure drop * mass flow, and for a given radiator the pressure drop depends on the mass flow through it.

[@rv6ejguy]

The test rig blower put out the same volume of air over the same area in all cases, again apples to apples, changing only one variable at a time and observing results. As you increase mass flow though a given core, pressure drop will increase. Higher pressure drop equates to higher momentum loss and thus higher drag. The purpose was to quantify pressure drop for several different rad cores.

[@Dr_Reason]

You never want to have coolant above your ideal oil temperature. If you did the oil cooler would have to be made bigger and this offsets the gain of the high temp coolant using a smaller radiator. The USAAC wanted high temp coolant in their 'hyper' engines before WW2 but most agree on anything past 250, the ideal oil temp, is a mistake.