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It can't be both.
In this thread, there is no surface cooling on the He 100.
We can ask him when he stops by on this forum
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It can't be both.Both
Looking at the surface-evaporative cooling system: It's cooling system takes up nearly the whole aircraft.
When he said "high temperature cooling", I assume this didn't mean just temperature, but pressure as well?
The Rolls Royce Merlin pressurised its coolant so that it could run at 130C. The DB601 lacked this capability or at least, not to 130C. This was a sore point for Willy Messerschmitt, who wanted smaller radiators on his aircraft.I could be wrong but "high temperature cooling" means that the cooing system is going be operating at a higher temperature than the boiling point of water. Wither that is 15% or 20% or more is subject to question. Turns out you can't go too high or some of the load gets transferred to the oil system.
Good call for people to be vary with what Wikipedia says.From what I read on Wikipedia about the development of the Jumo 211/213 (Wikipedia, so take it as you will), the DB 601 did have a pressurized cooling system--a sore point with Junkers over the original 211 design. However, if the Merlin was capable of running up to 130C without issues, I'd have to say that it was likely that the 601 might not have been able to do 130C, at least without difficulty or engine/cooling problems.
Agreed. While it did yield planes like the He 178, it also yielded the He 100 and He 177.Ernest may have been a bit too obsessed with speed.
Indeed, he basically focused on drag to the exclusion of everything else.Ernest bet on the wrong horse with cooling system.
It is kind of ridiculous that this managed to slip past me...I could be wrong but "high temperature cooling" means that the cooing system is going be operating at a higher temperature than the boiling point of water.
It's surprising that they didn't consider that. It seemed that some manufacturers such as Focke-Wulf did factor in ruggedness moreso than others.The cooling system/cooling drag issues are quite involved. The concept of high temperature cooling seems to have been in the background for quite a few years before WW2 but, the resolution was slow to resolve. This stems back to air racing, where the simple lowest drag was very important and surface cooling of water coolant was possibly king. However, the simple unworkability of that in a fighter was unaccountably ignored.
Wait, I thought the whole point of a coolant is to absorb heat? Wouldn't that be kind of self-defeating?So, Glycol based high temp cooling came along. Engine companies seem to have ignored the fire risk, even though Rolls-Royce record the "spectacular" fires caused by glycol leaks in engine testing in the mid '30's. Additionally, the heat capacity of the Glycol was lower than water.
I thought the tendency for bubbles to form was specific to the He 177?Unless DB figures out that their lubrication system is wrong
Actually it did predominantly use surface-cooling; it just had a radiator to deal with low-speed flight.In this thread, there is no surface cooling on the He 100.
Jumo 211 was with pressurized cooling system from day one - the 'closed, pressurized cooling system'* that allowed for sea-level max of 95°C was on the 211s before the F (includes the G and H that actually pre-dated the F).
From what it would appear the Merlin was designed for 120-130˚C and the V-1710 was built for 125˚C so that still is a bit on the low side, but a considerable improvement from 95˚C. (I have no idea what temperatures were used for the DB601).The 211F introduced the 'over-pressure cooling system'*, that upped the max temp at sea level to 115°C, and at 10000 m up to 85°C.
And that would have been an issue of cost, war economy, and a bit of a learning curve?Very high pressures on the radiator require strong construction, without skimping on quality of material for the radiator itself and of the adjoining pieces.
So they used one cooler to cover both oil and engine cooling?Junkers circumvented the issue by the time Ju 213 arrived via 'low-pressure' radiator cooling both oil and high-pressure coolant circuits
I didn't factor in the outside air-pressure, but it definitely makes sense.Big advantage in aircraft is that pressurized cooling keep the pressure and boiling point of water constant, especially at high altitudes (less dense air, less cooling effect, lower the coolant's boiling point).
So the engine's basic design dictates what the manufacturer can do? Is there normally collaboration between both?Each engine manufacturer will have their own specific design in regards to how the engine's cooling system will operate.
The design of the coolant flow through the heads, the placement of the water pump(s), inlets, outlets, and so on is unique to each manufacturer and even then, to each engine series.
I thought the tendency for bubbles to form was specific to the He 177?
Also why did the RLM impose restrictions on cobalt, nickle, and chromium?
So they used one cooler to cover both oil and engine cooling?
No, you're entitled to your own opinions, not your own facts. So it formed in all installations, but was worse on others?That is indeed your prerogative.
Was this an issue early on (1936-1942)?Supply of that (and a lot of other things) was low and was getting lower as the war progressed.
So, the learning curve for high pressure radiators was that steep?Yes.
Yes and yes - the aircraft engineer decides that a certain engine will be incorporated into their design and the engine manufacturer provides data to the aircraft manufacturer so that the aircraft will be able to function properly.So the engine's basic design dictates what the manufacturer can do? Is there normally collaboration between both?
Surprising that Daimler didn't look into ways to jack up the pressure on their cooling systems.Yes and yes
I thought the tendency for bubbles to form was specific to the He 177?
Think about your cars cooling system.Surprising that Daimler didn't look into ways to jack up the pressure on their cooling systems.
The only aircraft that reached combat status that is closest to the He100, would be the KI-61 - so how did the Japanese solve the cooling system needs with the Ha40 (license built DB601A)?
From what I read on Wikipedia about the development of the Jumo 211/213 (Wikipedia, so take it as you will), the DB 601 did have a pressurized cooling system--a sore point with Junkers over the original 211 design. However, if the Merlin was capable of running up to 130C without issues, I'd have to say that it was likely that the 601 might not have been able to do 130C, at least without difficulty or engine/cooling problems.
Big advantage in aircraft is that pressurized cooling keep the pressure and boiling point of water constant, especially at high altitudes (less dense air, less cooling effect, lower the coolant's boiling point).
Only a couple.