It’s not clear to me why you think it is OK to spray water around the engine and it’s radiators, without knowing exactly what you are doing, and at the same time you see the true and trusted method of injecting water/methanol into the manifold is somewhat more “experimental” and “complicated”. Just saying 
Maybe it will do the job just fine though, only one way to find out
@Ultranomad: there are 3 radiators being discussed. Oil and Coolant will be at 100C ir more – which is 10 or more C above ambient at FL100 – thank you @Airborne_Again.
@Antonio: thanks for the advice about FF. Actually, what you say may well be already in use!
I was present when “they” adjusted fuel flow. I insisted on a setting that is substantially higher than the upper limit per AMM.
The result is additional margin to enrich the mixture beyond the upper limit. Boost pump is always on in the climb.
This said, I typically lean in the climb ( to about 125 liters) for fear of losing power due to overrich mixture.
I did not notice a change in temps but will look more closely and report back.
@tmo – thank you I did. Interesting Mogas STC for normally aspirated engines, but unfortunately beyond my scope… I am looking for a solution that can be field approved.
T28 wrote:
What in your youtube-educated guess makes said particles move “very quickly” and where does it come from?
I only got I PhD in mechanical engineering. What do I know about basic ABC thermodynamics shit? Seriously, I have since long forgotten most of it, but it doesn’t take much to bring it back Anyway, heard about the Maxwell-Boltzmann distribution of molecular velocities?
Absolute zero K does not exist anywhere in the universe AFAIK. But if there were, there would be no evaporation, except some weird quantum effects perhaps.
T28 wrote:
What in your youtube-educated guess makes said particles move “very quickly” and where does it come from?
LeSving is correct. The YouTube video is, too. I know you can’t expect that, but occasionally it happens.
The random movement of molecules in water causes collisions which mean that they will transfer kinetic energy between each other, so there will be a random variation in kinetic energy.
Read all about it in Wikipedia.
Thank you for making my point LeSving. Minute 1:23. “Some particles will be moving very quickly”. What in your youtube-educated guess makes said particles move “very quickly” and where does it come from?
@Airborne_again I agree with you but in the absence of an outside source of heat (i.e. absolute zero temperature) I believe there wouldn’t be any significant kE delta between the particles.
Evaporation vs boiling explain once and for all
Flyingfish wrote:
- I routinely fly in heavy rain. This is a lot more water throughput then I could possibly spray on the radiators, and none of this causes any icing issues.
Well you surely do not routinely fly in rain in sub-zero temps. I believe even if vaporized at the radiator, most of this water will freeze when in contact with sub-zero surfaces. That may or may not be a problem depending on where on t he airframe, but you will likely carry that ice for the rest of the flight through to your descent below freezing levels.
If I understand correctly, the issue is you would like to have more cooling power so you can perform longer and higher climbs at low IAS and high VS, right? This is common to all TN and TC piston aircraft.
Maybe there is a more straightforward way to partially address it. Unlike RSA-5 systems and the like ,our TSIO 520 /550 simple Bendix fuel injections systems are fuel-pressure sensitive, so if you increase fuel pressure you will get more fuel flow. When flying ROP, this is similar if perhaps a bit less effective and more expensive than water-methanol injection. I just use the electric fuel boost pump on low or high and then adjust with mixture to get the required cooling effect, at the expense of increased fuel flow. Could this work for you? At least the system is already installed on the aircraft!
Flyingfish wrote:
Can anyone point me to the boiling temperature of water at FL100 ISA?
FL100 is approximately the 700 hPa level. The boiling point of water at 700 hPa is 90°C.
T28 wrote:
Physics 101 suggests water molecules won’t “jump out of the surface” if their kinetic energy isn’t sufficient to go through the phase change. Molecular kinetic energy is proportional to heat. Heat has to come from somewhere.
Water molecules don’t all have the same kinetic energy even if the temperature is constant throughout a volume of water. The molecules that “jump out” will have higher kinetic energy. The result, as we all know, is that the volume of water loses energy, i.e. it gets colder.
