What are these air-break looking things on World war 2 aircraft engines?
Posted by aviationstudy@reddit | aviation | View on Reddit | 92 comments
Posted by aviationstudy@reddit | aviation | View on Reddit | 92 comments
taint_tattoo@reddit
Is that Howard in the driver seat?
REDDITCEOSUXDICK@reddit
what are these air vents.. on the engine... holy shiiit 🤡
sgtg45@reddit
Cowl Flaps for engine cooling
Enough-Meaning1514@reddit
Indeed. They are there to suck more air through the air cooling fins of a radial engine.
Agreeable_Garlic_912@reddit
Do they suck or expel air? Because to me that looks like it is there to expel the air after it passed over the cylinder heads
CrappyTan69@reddit
They create a low pressure behind them due to the air flowing over them. This low pressure then "encourages" more air to be pulled through.Â
Der-Lex@reddit
The low pressure is „asking the air nicely“ to hurry up flowing through the cooling fins.
Tough_Bee_1638@reddit
It’s politely gesturing the air to move in an afterly direction.
Oinkster_1271@reddit
'Afterly' my new favourite word đź‘Ť
Bigredmachine878@reddit
So venturi-esque principal?
Dewey081@reddit
Bernoulli has entered the chat...
bazbloom@reddit
"Please proceed in an orderly fashion to the rear of the engine. Your cooperation is appreciated."
CrappyTan69@reddit
That's laminar. This is chaos.Â
Throwaway1303033042@reddit
“But you see how the camera is moving somewhere and you’re being attracted TOWARDS the camera?”
Ambiorix33@reddit
Low pressure air is the guy yelling at parachutes to fucking move or else he'll pull them in and throw them out himself
girl_incognito@reddit
Everybody seems to be stuck on this explanation but im not buying it. Cowl flaps work by varying the size of the exit for the cooling air from the cowl. This lowers the pressure inside the cowl and ultimately allows more cooling air to enter the cowl rather than bypass it.
Agreeable_Garlic_912@reddit
I'm with you. But I have zero interest in arguing on Reddit.
deleted_by_reddit@reddit
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BoneSetterDC@reddit
If you're into physics, see Bernoulli's principle.
wunderkit@reddit
Yes. They taught us in flight school, Venturi sucks and Bernoulli blows.
hatlad43@reddit
Sucked as sucked out.
By expelling the hot air quite near the prop wash that has a high air velocity (therefore low pressure), the hot air inside the cowling is also sucked out instead of only being pushed from the intake port.
SnooMaps7370@reddit
well, if we want to be extra pedantic, it's still only pushed out from the intake port, but it's a lot easier to push because the resistance is lower, so the same amount of push at the intake moves more air.
Raguleader@reddit
Fun fact! Both are technically the same thing as far as the air is concerned because it is the pressure differential that causes the movement of the air.
Agreeable_Garlic_912@reddit
well not in a plane that actively moves through the air.
Raguleader@reddit
How do you figure?
Coomb@reddit
Total pressure gradient (static pressure plus dynamic pressure) is what drives flow, not just static pressure, is probably his point.
Vaideplm84@reddit
Both.
Cezetus@reddit
Extending the flaps creates low pressure zones behind them, which suck more air through the outlets than just ambient pressure. You're trading drag for extra cooling.
TigerIll6480@reddit
It switches the air from “blow” to “suck.”
xdr567@reddit
What is their overall effect on lift ?
ScroungingMonkey@reddit
No effect on lift as far as I know, but an increase in drag.
Molecular_Pudding@reddit
Cowl flaps. It helps the engine cool down when operated at higher power at lower altitudes.
DashTrash21@reddit
higher power at ~~lower altitudes~~ low airspeeds. There is a lot less air flowing around the engine at low speeds and high power settings (takeoff, climb) compared to once you're in the air and level.
Sufficient_Ad_5395@reddit
The fun way to fly!
_INNUEND0@reddit
Lmao
InstructionWise5757@reddit
They are cooling fins, when the outside air goes over them it creates a low pressure are at the opening, therefore the hot air gets forced out,
Superb_Health9413@reddit
My grandfather and his crew invented and developed these cooling fans while stationed in the South Pacific during WWII.
They gave the b-24 an additional 400 miles of flight.
freddie54@reddit
The cowl flaps are cool but they’ll never be as cool as counter rotating props :)
Logical-Let-2386@reddit
By the way that's not any old WWII aircraft, that's the XF-11 prototype with Howard Huges at the controls.Â
crystaloftruth@reddit
I gotta watch The Aviator again now <3
Aggravating_Speed665@reddit
Desperate for it to be released in 4K.....like, cmon already
rubbercat@reddit
4K really is the way of the future.
-praughna-@reddit
Why? So he can show you the blueprints?
yermawn@reddit
which crashed about an hour later
rickythepilot@reddit
The Aviator - Crash Scene
Logical-Let-2386@reddit
Hit a house in Beverly Hills, and accelerated Hughes personal downward spiral.Â
ScarHand69@reddit
But hey while he was recovering laying in a hospital bed…he was so fed-up with the bed and how uncomfortable it was he designed a new bed. That bed design is basically the forerunner to all modern hospital beds.
a_scientific_force@reddit
The way of the future.
GrethaThugberg@reddit
The way of the future
a_scientific_force@reddit
The way of the future
rickythepilot@reddit
The Aviator - Crash Scene
dingman58@reddit
I was wondering why there was a hillbilly sitting at the controls
SippsMccree@reddit
At what point does trying to properly air cool so many cylinders become harder than just going with water cooling lol
Logical-Let-2386@reddit
Easy. 28 cylinders, Pratt and Whitney stoped there.Â
maniBchef@reddit
Thank you. Came to say this. The hat gave it away.....
Bu1Seabee@reddit
That's Howard Hughes in the pilot seat. He almost died when it crashed.
Cold_Flow4340@reddit
Thats Howard Hughes! Almost got killed flying this monster plane.
Malrdux@reddit
Cowl flaps used to help control engine temperature.
iGrok_n_Foolness@reddit
Cool pic, counter rotating props and HH in the drivers seat.
esloquehay@reddit
That’s Howard Hughes at the controls
Certain-Tennis8555@reddit
As a couple have said, they are for cooling the engine. The aircraft you are referring to with this question use air-cooled engines (think lawnmower or weedeater). Air enters the front of the engine between the prop spinner and the cowling and is directed around the outside of all the engine cylinders and is exhausted through those cowl flaps.
The pilot controls the cowl flap positions to regulate the airflow around the engine cylinders to keep the engine within operating temperatures. In this photo, the cowl flaps are wide open to help cool the engines while taxiing on the ground, the cowl flaps would be closed once cruising at speed since more air is rammed around the engine by the velocity of the aircraft.
Prof01Santa@reddit
Indeed. Good answer.
In the 1930s, aircraft engines started to be limited by engine cooling. The straightforward way to solve the problem was liquid cooling. The RR Merlin and its cousins, the US Allison V1710, and the Daimler-Benz DB600 series all did this. It was an expensive & fragile solution.
Another way was to find a way to cool the common radial engines. NACA came up with cowl contours & adjustable cowl flap designs that gave the maximum cooling with the minimum drag. Combined with advanced cylinder heat transfer designs, this allowed practical radial engines to produce as much as 4000 shp.
Post WW II, gas turbines, which are self cooling, replaced most engines below 2000 shp, but the radial engine & the NACA cowling still rules in the 500-1500 shp range.
Cloud_Garrett@reddit
Thank you for a detailed and complete response!
MarvinPA83@reddit
They had a series of engines being returned to the manufacturer because metal was found in the oil filters. It turned out to be caused by one instructor pilot taking off with the flaps closed. An INSTRUCTOR at the RAF flying college, Manby, early 60s (yes, I'm that old).
mkosmo@reddit
To add to the rest of the answers: We still use cowl flaps today in modern piston aircraft. Some are fixed, some are pilot adjustable, and some are more NACA ducts than flaps... but the concept remains the same.
Notreallyme0000@reddit
Is the pilot Howard Hughes? With that hat it looks like him.
cyanide_sunrise2002@reddit
Learn the difference between brake and break
Ok_Concentrate9822@reddit
Do they open and close depending on airspeed or something? Or they're fixed in position?
mechENGRMuddy@reddit
What plane is this?
Mauled_@reddit
Looks to be the Hughes XF-11
Decent_Ad_9615@reddit
brake*
OkSatisfaction9850@reddit
The pilot? Looks so cool in that hat!
Pat0san@reddit
Looks like Howard himself!
RevengeOfPolloDiablo@reddit
It's for cooling the engines, by making them look cool
hifumiyo1@reddit
Cowl flaps
eatsmandms@reddit
I assume you were hit by autocorrect, but it is air brake. Break is when someting breaks in half.
hypercomms2001@reddit
Technically the Hughes "Hughes XF-11" was not a World War II aircraft as it first flight was 7 July 1946, after the end of the second war war.........
dendronee@reddit
On the airplane I flew that had them like this, they were either OPEN, CLOSED or In-TRAIL
willits1725@reddit
Of note, the picture is of Howard Hughes at the controls of an experimental fighter, that nearly killed him on a test flight!
pornborn@reddit
Hughes XF-11. Later redesigned to the D-2.
JuanTamadKa@reddit
Is this the one that crashed?
Howard Hughes at the controls, isn't it?
pornborn@reddit
Yes. That is him in the cockpit.
joesnopes@reddit
They're gills. They're on most radial engined aircraft. They control the cooling airflow past the air-cooled engine by being closed and opened.
Festivefire@reddit
Cowl dlaps over the oil coolers. If your engine is too hot, you open them up for more cooling stuff the expense of drag.
blurrrsky@reddit
Cowl Flaps. Aircraft in this era were mostly air-cooled, but some were liquid-cooled and had radiators like most cars today. The plane that is pictured was never manufactured, unfortunately. I’ve ever seen one if these. Thank u for posting.
deleted_by_reddit@reddit
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PamuamuP@reddit
That is the man himself, Howard Hughes at the controls!! Absolute legend
iepure77@reddit
Please don't break the air
Available-Run-2144@reddit
Cowl flaps. They help regulate air flow through the cylinders for cooling purposes
Awkward_Narwhal_4547@reddit
Venturi opening to improve refrigeration