Spitfire Documentary 1976

[jedi25]

I found this spitfire documentary on another forum....enjoy.

http://www.youtube.com/watch?v=vDzZnCkbxgs

[smoe]

I always wondering about water cooled engines and why high drag, honey combed radiators were used and why WWII fighters didn't make use of a plane's skin to reduce drag, explained at time: 5:10. I always pictured using something like an low drag aluminum heat sink similar to that used on electronic components.

I remember reading a article about a modified F8 Bearcat (probably was Rare Bear) that was trying out for a speed record. The F8 resorted to using a zero drag water boil-off cooling technique to cool the engine oil and not the standard oil coolers.

[pipz]

Fantastic! Those old documentaries are great stuff! 

[Charge]

"I always wondering about water cooled engines and why high drag, honey combed radiators were used and why WWII fighters didn't make use of a plane's skin to reduce drag, explained at time: 5:10. I always pictured using something like an low drag aluminum heat sink similar to that used on electronic components."

Such radiators were used already before WW2 e.g. in Supermarine race planes, take S.5 and S.6B for example. Such arrangement makes a huge target of the radiator and as it is built in it is very difficult to repair compared to a modular radiator which can simply be replaced if there's a bullet hole.

There are actually a few Hurricane warbirds which can use evaporation cooling if need be. That is established by spraying water into the radiator to enhance the surface heat dissipation for a short while.

-C+

[GScholz]

Heinkel unsuccessfully experimented with surface evaporation cooling in both the He 100 and He 177.

[nrshida]

There are actually a few Hurricane warbirds which can use evaporation cooling if need be. That is established by spraying water into the radiator to enhance the surface heat dissipation for a short while.

Evaporative cooling in aircraft doesn't work by spraying water into a conventional radiator. If that's what you meant?

[Charge]

"If that's what you meant?"

No. E.g. Reno racer P-51 Galloping Ghost had a true evaporative cooling system.

-C+

[GScholz]

Galloping Ghost has a boil-off cooling system. Different thing altogether. It's a lossy system where liquid is boiled and jettisoned. A surface evaporation cooling system is closed and does not lose coolant, it's a big heat pump.

[Hap]

 

[Charge]

http://en.wikipedia.org/wiki/Evaporation
http://en.wikipedia.org/wiki/Dissipation

Take a pick and tell me which depicts "boil-off" and which is "heat sinking".

-C+

[GScholz]

It's called a boil-off cooling system to distinguish it from closed evaporative systems like those used on the Supermarine trophy racers you mentioned in your earlier post. It wasn't just a big radiator like you seem to think, but a high-pressure water/low-pressure steam evaporative heat pump.

The boil-off system works on the principle of ablation: Transferring the heat to a separate medium trough vaporization and dumping it overboard.

http://en.wikipedia.org/wiki/Ablation

[nrshida]

Yes and the really interesting part is how in a closed system you can exploit what pressure does to boiling points. Also this is incidentally why the Spitfire has very strong wings given their thin section. That box-section formed by the spar and leading edge was originally intended to house the steam condensers. Imagine how slick the Spitfire would have looked with no radiators.

[GScholz]

Interesting fact Nrshida.

[Gman]

Great video, worth it for Bader's hilarious interview comments alone.

I literally laughed out loud when the gent described "Ms Shilling's orifice", the penny with the hole in it to solve the carb/inverted issue.  They way he laughed as he said it...

Also, Bader saying he felt back at home when he sat in that Spitfire, and saying if you open that hangar, I'll fly this thing right out of here - easy to believe in his case.  Also, him stating that he felt it was such a shame that Mitchell didn't survive to see what he had created - very kind and correct statement IMO.

[Rob52240]