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What Are Cowl Flaps?  
User currently offlineFaroeFlyer From Faroe Islands, joined Aug 2005, 87 posts, RR: 0
Posted (9 years 1 month 22 hours ago) and read 12874 times:

Can anyone give me an explaination, please?


Cast your dancing spell my way...
12 replies: All unread, jump to last
 
User currently offlineHAWK21M From India, joined Jan 2001, 31684 posts, RR: 56
Reply 1, posted (9 years 1 month 22 hours ago) and read 12867 times:


Usually Cowl flaps are doors that are located on the bottom of the cowling, located either inside or outside. They are in this location because that is usually the end of the path for the cooling air flow. These doors are opened and closed by the pilot from the cockpit.
Usually they are manual and are operated by a lever or a knob. In some cases they are electric and are opened and closed by a switch.

LINK

regds
MEL



Think of the brighter side!
User currently offlineLeanOfPeak From United States of America, joined Oct 2004, 509 posts, RR: 1
Reply 2, posted (9 years 1 month 21 hours ago) and read 12860 times:

Most reciprocating aircraft engines are air-cooled. At low speed, there's not as much airflow as there is at cruise (As should be obvious). As such, when operating at low speed and/or an extremely high power setting, opening the cowl flaps allows additional cooling for the engine. But in an established cruise with a higher volume of air available, the cowl flaps can be closed to eliminate excess cooling (And the drag associated with it).

User currently offlineFaroeFlyer From Faroe Islands, joined Aug 2005, 87 posts, RR: 0
Reply 3, posted (9 years 1 month 19 hours ago) and read 12835 times:

Very good explaination. Thank you both very much


Cast your dancing spell my way...
User currently offlinePilawt From United States of America, joined Dec 2003, 101 posts, RR: 0
Reply 4, posted (9 years 4 weeks 1 day 3 hours ago) and read 12629 times:

On large radial engines the cowl flaps often completely encircle the engine nacelle, as shown below:

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Click here for bigger photo!

Photo © Lawrence Feir
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Click here for bigger photo!

Photo © Jeffrey P. Jacobs



-- Pilawt


User currently offlineSWISSER From , joined Dec 1969, posts, RR:
Reply 5, posted (9 years 2 weeks 3 days 7 hours ago) and read 12431 times:

Even Concorde had such a system, but they where called rampers!
they provided more air for the engine at high speeds and altitude!


User currently offlineHAWK21M From India, joined Jan 2001, 31684 posts, RR: 56
Reply 6, posted (9 years 2 weeks 3 days 7 hours ago) and read 12429 times:

Quoting SWISSER (Reply 5):
rampers

Why the Name.
Any Pics.
regds
MEL



Think of the brighter side!
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 7, posted (9 years 2 weeks 3 days 6 hours ago) and read 12424 times:

There was another cooling system for big recips, called augmentor tubes. The Convair 440 and the Martin 404 were rather similar airplanes as seen below:

View Large View Medium
Click here for bigger photo!

Photo © Art Brett
View Large View Medium
Click here for bigger photo!

Photo © Jeffrey S. DeVore


The Martin on the right has cowl flaps running almost the full perimeter of the cowling and you can see the big exhaust stacks on the lower outboard side.

The Convair on the left had augmentor tubes which ran the length of the engine nacelle, all the way to the trailing edge. The intake for these tubes was at the firewall just behind the engine and the exhaust stacks ended at the mouth of these tubes. At high power settings the increased exhaust pressure would draw the air out of the inside of the cowling by venturi effect. The more power you pulled the better the system worked. I have to believe it was lower drag than the big old barndoor cowl flaps.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineVc10 From United Kingdom, joined Nov 2001, 1411 posts, RR: 16
Reply 8, posted (9 years 2 weeks 3 days 3 hours ago) and read 12385 times:

Swisser,
Sorry no such thing as rampers on Concorde

Intake Ramps --Yes-- these reduced intake air speed when aircraft speed above Mach 1.3

Secondary Air doors --yes-- these introduced powerplant cooling air when aircraft speed above 220 kts [closed for take off ]

But there was nothing on the aircraft like adjustable cowl flaps

little vc10


User currently offlineSWISSER From , joined Dec 1969, posts, RR:
Reply 9, posted (9 years 2 weeks 2 days 1 hour ago) and read 12302 times:

Quoting Vc10 (Reply 8):
Swisser,
Sorry no such thing as rampers on Concorde

Intake Ramps --Yes-- these reduced intake air speed when aircraft speed above Mach 1.3

Secondary Air doors --yes-- these introduced powerplant cooling air when aircraft speed above 220 kts [closed for take off ]

But there was nothing on the aircraft like adjustable cowl flaps

little vc10

Yes off course Peter,
if you go more technical on the complete Concorde system it is indeed different on the fuction of the prop cowl flap, just as you said!

But basically it has quite the same function like a cowl flap on a prop aircraft, it reduces the airflow and produces more air density for the engine.

I cannot say it is the same system, better said the same science family, to correct my previous post!

I think that was really a marvelous piece of engineering and what really made Concorde "the" Concorde!


User currently offlineJetlagged From United Kingdom, joined Jan 2005, 2556 posts, RR: 24
Reply 10, posted (9 years 2 weeks 1 day 21 hours ago) and read 12284 times:

Quoting SWISSER (Reply 9):
But basically it has quite the same function like a cowl flap on a prop aircraft, it reduces the airflow and produces more air density for the engine.

Supersonic intake ramps and radial engine cowl flaps are totally unrelated. Intake ramps don't reduce airflow. They reduce air intake velocity by changing intake area and directing shock waves. Air mass flow remains the same.

Cowl flaps control the airflow past the engine cylinders for cooling purposes.



The glass isn't half empty, or half full, it's twice as big as it needs to be.
User currently offlineSWISSER From , joined Dec 1969, posts, RR:
Reply 11, posted (9 years 2 weeks 1 day 5 hours ago) and read 12236 times:

Quoting Jetlagged (Reply 10):
Supersonic intake ramps and radial engine cowl flaps are totally unrelated. Intake ramps don't reduce airflow. They reduce air intake velocity by changing intake area and directing shock waves. Air mass flow remains the same.

Cowl flaps control the airflow past the engine cylinders for cooling purposes.



Quoting SWISSER (Reply 9):
I cannot say it is the same system, better said the same science family, to correct my previous post!


User currently offlineJetlagged From United Kingdom, joined Jan 2005, 2556 posts, RR: 24
Reply 12, posted (9 years 2 weeks 1 day 3 hours ago) and read 12221 times:

Quoting SWISSER (Reply 9):
I cannot say it is the same system, better said the same science family, to correct my previous post!

Depends how widely you define "science family" I suppose.



The glass isn't half empty, or half full, it's twice as big as it needs to be.
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