Why Was The Fw-190A So Fast?
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4 سال پیش
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How did the Fw-190 manage
How did the Fw-190 manage so much speed with a blunt nosed airframe and an aircooled radial engine? This is episode three in a series, I'll get into the power and aerodynamics of this amazing plane.
This is part 3 in my Fw 190 series. I didn't put that in the title because youtube hates series and doesn't seem to recommend anything much past an episode 1.
I referenced David Lednicer, creator of "The Incomplete Guide to Airfoil Usage" and much more. Here is one of his videos on Korean war jets:
• Korean War Fighter Tactics presented ...
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Note: the pictures in this video don't exactly match what's I'm talking about, for example when talking about an A5, not every 190 picture is of an A5, it could be an A8 or whatever.
Some people are having a hard time understanding how ethylene glycol allows for a more compact cooling system, so I'll post a section from "Aircraft Propulsion" the source document from THE SMITHSONIAN. This is copyright free.
"The use of high-boiling liquids (mixtures of water and ethylene
glycol) for engines formerly water-cooled was an important forward step
in reducing the heat-transfer area, and thereby the drag, of radiators for
liquid-cooled engines. At the suggestion of S. D. Heron, a 1-cylinder engine
was tested at McCook Field in 1923 with a mixture of water and ethylene
glycol at a high coolant temperature, probably near 300° F During 1928-
1929 further tests were made at McCook Field with a Curtiss D-12 engine.
After considerable development work to avoid leaks and to overcome other
troubles encountered, the use of this method of cooling was adopted for
Curtiss liquid-cooled engines by 1932, and used soon afterward by Allison
and Rolls-Royce. This change, which allowed operation of the coolant
at 250° F, reduced the radiator area required by about 50 percent (fig.55).
This improvement, together with better radiator design and radiator
cowling (fig. 56) brought the drag of liquid-cooled engines well below that
of air-cooled radials of equal power. "
Now if all that doesn't do it for you, here are some fun facts to help out. The maximum allowable coolant temp in a Curtis P-40 is 125C/257F. Cooling system pressures in WW2 aircraft were between about 10psi and 30psi, with 30 being the highest I have ever seen in documentation. Even at 30PSI water will boil at 257F. As steam won't circulate properly and cool the engine, something with a higher boiling point must be used. That something was ethylene glycol. Thus by using ethylene glycol they were able to run at higher coolant temps for a given pressure and still cool the engine, thus were able to use smaller coolers.
I hope that helps.
4 سال پیش
در تاریخ 1399/09/28 منتشر شده
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