DonL
Banned
I think part of the problem is bad translation of the cooling system and how it works, many people using the term "evaporative" when they shouldn't. The plane did not use conventional radiators and did use panels in the wings. I think ( and could be wrong here) that it rather depends on what proportion of the coolant was allowed to turn to steam/vapor. I believe the Merlin at times had some of the coolant vaporize and had a "separator" that sent a line of liquid and vapor to the header tank where the vapor condensed back to a liquid. The total amount of vapor was very small. RR had had their fill of steam cooling with the Goshawk engine. RR and Curtiss and a few others had used "surface radiators" on race planes to reduce drag. This was successful but expensive in initial construction and in maintenance.
The German system ( to me anyway) seems to be a combination. A bit more liquid is allowed to vaporize (but nowhere near all), the vapor is separated out and sent to the surface radiators/condensers ( or what ever you want to call them) where it condenses back to a liquid. It is collected and sent back to the header tank where it is mixed with the liquid coolant returned from the engine. (clarification wanted?)
In some race planes a true "evaporative" system was used. The plane was fitted with a large coolant tank and after the liquid reached the boiling point the "vapor" was allowed to escape to the air. With enough coolant the plane can fly long enough for record runs.
The Fw 187 and He 100 did not vent the vapor ( at least not on purpose) and flight times were not restricted by the coolant supply as in a "true" evaporative system.
I would note that the presence of surface cooling panels is NOT a sure indicator of what kind of cooling system a plane has. I would also note that some low performance ( and a few high performance planes) of the 1920s and 30s did not have oil coolers. they simply mounted the oil tank with one or more surfaces exposed to the air stream.
As long as I have understand you correct I would agree.
Some comments from me.
From all research I have done and through Dietmar Hermans Book about the FW 187 (also the pictures in it) the coolimg system of the He 100 (Oberflächenverdampfungskühlung) and the experimental system at the FW 187 V5 (Dampfheißkühlung) were fundamental different.
The He 100 has a true evaporative cooling were the steam/water was running through the wings at water lines in the wings and the wing was the surface of cooling!
As I understand the FW 187 V5 had a high pressure water cooling very simular as you have described from RR and Curtiss with the goal to have very low drag conventional cooler/radiator. Also as I have understand it was to optimistic but from the system it was nothing else as Junkers and DB introduced with the DB 605, 603, Jumo 213 and partly with the DB 601E and Jumo 211F a high pressure water cooling to reduce drag of the cooler.
To me that has nothing to do with an evaporative cooling through surfaces.
Anyway this has nothing to do with our discussion here in this thread and it is totaly unimportant.
All datas and estimations of the FW 187, that were published from Focker Wulf are basing on the FW 187 V4 which flew with a conventional cooling system and Jumo 210G. Also the V4 was at Rechlin and had testflights against the Bf 110 and Bf 109 and it was a full armed version .
Most to all datas and later estimations from Focker Wulf were from the datas of this Prototype (FW 187 V4).
This includes speed-, climb- and range- performances.
I've consulted several different sites, all agree there was a Fw 187 V6, not one makes the remark it never flew, ( which I find strange for a aircraft you say never flew) 3 agree it had the DB 601, and 2 note that that the V6 had the evaporative cooling system.
Many sites out there were just copies of the Wiki site, these were not.
But I have a feeling no matter what I come up with online, i'm never going to meet you requirement of "primary sources".
You can ask Shortround6, as I have understand from an early thread, he has also the book from Dietmar Herman which is basing on primary sources. So he can confirm that the FW 187 V6 never flew and in reality it was the V5 of which all internet sites are talking!
Also I don't understand why do you put primary sources to quotes?
Mr. Hermans book base on original documents from Focker Wulf which are to me primary sources, do you can confirm this of your citated internet sites?