A quick question about radiators.

[69th_Mobile_BBQ]

On plane models with underbelly/hanging box radiators, does opening the radiator covers beyond neutral/flush settings add anything to cooling, or does it just increase drag for no added benefit?

[Hayduke]

From my experience, opening beyond neutral cools the engine more quickly (varies by aircraft), but with a significant drag penalty that varies by airframe.

[RedKestrel]

What are the neutral settings for most radiators? I Know its often mentioned that fully closed on some radiators causes more drag than partially open, but how do we find this out?

[69th_Mobile_BBQ]

Well, on the P47, there's indicators just under the left side canopy rail and the cowl flaps are easy to see so, that's an easy one.  On other planes, like the Il2 '43 100% is the flush setting for both oil and water rads.  The only time you'll need to close those up is to prevent overcooling or to use the radiator covers for added armor when taking fire.  (Watch the heat but protect the underbelly box at all cost).   P-40 is full closed once above (IIRC) 225 mph.   

 

Other planes - I've been going to single player QMB and using external views to see what settings match up to the radiator assembly without poking out into the airstream and making notes.  

[unlikely_spider]

1 minute ago, =AVG77=Mobile_BBQ said:

Well, on the P47, there's indicators just under the left side canopy rail and the cowl flaps are easy to see so, that's an easy one.  On other planes, like the Il2 '43 100% is the flush setting for both oil and water rads.  The only time you'll need to close those up is to prevent overcooling or to use the radiator covers for added armor when taking fire.  (Watch the heat but protect the underbelly box at all cost).   P-40 is full closed once above (IIRC) 225 mph.   

 

Other planes - I've been going to single player QMB and using external views to see what settings match up to the radiator assembly without poking out into the airstream and making notes.  

Does this mean that on the il2, there is no performance penalty for having them 100% open?

[69th_Mobile_BBQ]

From what I can see the box underneath has a "window blind" style slat that covers the oil rad.  There is a cover on the front and one on the back of the hanging 'fridge' box.   100% is the flush/least-or-no drag setting. From the looks of it less than 100% is actually more drag-inducing.  The water radiator cover on the 'fridge' is pretty much the same design and also 100% is best.

 

These slats were also meant as armor from small arms and ground fire when closed, so unless it's a really cold map (overcooling) or you're entering combat, or you're being shot at by any enemy - including planes - run them 100% wide open.  

Edited April 30, 2019 by =AVG77=Mobile_BBQ

[unlikely_spider]

I understand now. So this is different than some fighters where the radiator cover actually protrudes outward when opened. This complexity - of the differences in how the covers interact with the slip stream - is actually modeled?

[69th_Mobile_BBQ]

I do believe so.  If you have a plane designed with covers that can protrude from the radiator assembly into the slipstream, then yes, it will induce drag and shave off some speed.  

[Velxra]

On German planes with their box style water cooling units. Typically anything over 20-30% will begin to induce drag. 

[CountZero]

On most fighters in game 0% will give you best top speed, only yak7b has lovest drag at 47% both rads position, and P-39 at 40% oil and 60%watter.

You can start free flight in QM and turn on aiutopilot and test things there by looking at gui speed that is more accurate and see differances in speed after 5-10min of flying, you can speed up time, also you can go with outside vie and see on P-39 or yak7b where its osition of its radiator flap and will see why its like that best.

 

On lagg3 for example differance in speed when oil is 0 or 100% is 5kmh, and for watter its 16kmh 0-100%, but most of time because it has bad radaiator you fly all 100%, even in winter maps you cant close it below 50-60% or youll brake negine in 2-3min if your low or try to climb or df.

[69TD_Hajo_Garlic]

3 hours ago, 77.CountZero said:

On most fighters in game 0% will give you best top speed, only yak7b has lovest drag at 47% both rads position, and P-39 at 40% oil and 60%watter.

You can start free flight in QM and turn on aiutopilot and test things there by looking at gui speed that is more accurate and see differances in speed after 5-10min of flying, you can speed up time, also you can go with outside vie and see on P-39 or yak7b where its osition of its radiator flap and will see why its like that best.

 

On lagg3 for example differance in speed when oil is 0 or 100% is 5kmh, and for watter its 16kmh 0-100%, but most of time because it has bad radaiator you fly all 100%, even in winter maps you cant close it below 50-60% or youll brake negine in 2-3min if your low or try to climb or df.

The yak1b has weird flush settings too irc, 35 on water and 50 on oil? I'm so poor in yaks I dont like to waste them

[CountZero]

49 minutes ago, Joeasyrida said:

The yak1b has weird flush settings too irc, 35 on water and 50 on oil? I'm so poor in yaks I dont like to waste them

0% rads on oil and watter will still give you best speed even on yak1b, i noticed only on yak7b out of all yaks in game 0% position will not give you best speed

[FeuerFliegen]

Some radiators, such as on a Yak, LaGG, Spitfire, Bf110, Bf109 E-7, and maybe a few others, when open, are angled diagonally in the same way a control tab would be, or flaps.  I've always wondered.... not considering the negative aspects of drag, would there be any benefits as far as extra lift?  in a place such as the Bf110 it looks as if it would give similar effect to flaps, although obviously not to the same degree.

[69th_Mobile_BBQ]

On 8/29/2019 at 11:20 PM, FeuerFliegen said:

Some radiators, such as on a Yak, LaGG, Spitfire, Bf110, Bf109 E-7, and maybe a few others, when open, are angled diagonally in the same way a control tab would be, or flaps.  I've always wondered.... not considering the negative aspects of drag, would there be any benefits as far as extra lift?  in a place such as the Bf110 it looks as if it would give similar effect to flaps, although obviously not to the same degree.

 

I'm not sure about it, but if you take a Yak into a windless environment, set the radiators to "flush" settings and trim it to be (mostly) hands-free at ~450kph, then open the rads all the way, the plane will slightly change how it behaves.