Factors that affect
Hi
Each manufacturer develops their own brand of fluid.
While glycol is the main constituent in the fluids the glycol ratio may vary by small amounts from brand to brand.
This ratio has no relationship to the 100% 75% or 50% mix ratio this is based on the total makeup of the fluid; ie wetting agents, corrosion inhibitors, vulgo rubber material in long chain polymers and glycol and if done so water.
The fluids manufacturers are naturally commercially sensitive to revealing their fluids make up.
Thus some fluids are better at managing snow over freezing drizzle or other forms of ice contamination.
What is important to remember that fluid integrity is governed by freezing, dilution and fluid layer thickness.
The glycol as a freezing point depressant converts ice to melt water. This melt water dilutes the fluid making it more runny /lowers viscosity. Lower viscosity fluids flow more readily thus on an uncontained surface like a wing the fluid drips/ flows off at an increasing rate over time of exposure. Over time the fluid layer will thin, as well as start to freeze as the freezing point depression diminishes towards ambient freezing temperature or aircraft skin temperature.
As many of you know water can be added to provide a level of economy. Additionally a battery of tests are required to qualify the fluid. One of these tests is on wing viscosity, ensuring that the fluid behaves in such a manner that it will stay on the wing long enough to protect but will eliminate during the latter stages of the take off roll to avoid it becoming a contaminant itself.
Type IV fluids are Non Newtonian fluids and behave in a somewhat counter intuitive fashion. While these fluids have pouring/spraying properties they can semi solidify if a force is applied to them like airflow giving them good staying ability on the aircraft structure. Occasionally some of this fluids are too resistant to elimination or their behavior does not conform to the strict testing criteria of fluids.
To redress these some fluid manufacturers may tweak their fluids constituents or declare that the fluid cannot be used at 100% concentration or in fact they might declare that 100% concentration contains water as part of the makeup of the fluid and sell it that way. Additionally LOUT or lowest operation use temperature may limit a fluids ability at lower ambient temperatures close to fluid safety buffers. As you can imagine when you’ve poured a lot of money into research, development and testing of fluids and they show promise the last thing you want is to fail.
So to that end I’m not sure you can compare like with like when comparing Type IV fluids. Some are better than others at certain jobs in certain weather conditions but may be less optimal in other weather phenomena. Most engineering departments will do an analysis on fluids based on the requirements for the weather conditions normally encountered for their airline operation, aircraft code, fluid type availability for the region and the old chestnut; cost.
I hope this helps.