Aircraft icing

[Snuff_Pidgeon]

I found this vid on ice forming on aircraft, it may not be so important for sow, but in future where high alt bombing is taking place or even the eastern front.http://www.youtube.com/watch?v=9I40DQcK_6Ung will be taking place.

[TheGrunch]

it may not be so important for sow.
Well, the top cover of Lufwaffe formations often operated at 30,000 feet toward the end of the Battle of Britain, so it's a good idea for SoW even. Probably very hard to simulate, though.

[Snuff_Pidgeon]

Well, the top cover of Lufwaffe formations often operated at 30,000 feet toward the end of the Battle of Britain, so it's a good idea for SoW even. Probably very hard to simulate, though.

Yes Grunch you are right,and it would be difficult to simulate but Oleg is doing amazing things at the momemt.

[TheGrunch]

Yes Grunch you are right,and it would be difficult to simulate but Oleg is doing amazing things at the momemt.
Actually, I imagine it could just be a timer that started at a certain altitude that increased the weight of your aircraft up to a certain point, and then gradually decreased back to your normal weight once you went below that altitude. No need to make it more complicated than that at first. Visual effects optional, I guess. :) Good suggestion, definitely.

[JVM]

Considering the flight mechanics of each aircraft are mostly simulated via a number of equations (and not tables) it would not be very difficult to integrate a modification of the proper lift/drag coefficients as well as weight to simulate very well icing effects.
The visual aspect would be taken care of via texture evolutions which are already anticipated in the game.

But...and this is a big but!

- this has to happen in real time (so does this change of coefficients and weight I have mentioned)
- icing happens only in visible humidity, i.e. clouds...but this was depending on temperature (itself depending on altitude, air mass and air layers = time of the year) and several other factors, the biggest one for clear icing (the most dangerous) being water in surfusion: this becomes quite complicated in reality but could possibly be simplified sufficiently for the purpose of the game...
- icing simulation must take in account initial conditions: say you enter an icing zone and a good accumulation occurs, sufficient enough to severely affect your ability to stay airborne...your only hope is to get out of the clouds which may not too safe depending where you are (due a little to enemy, a lot to potential high ground), but you are out of choices; if you succeed, the ice is not going to disappear instantly, far from it! at worst, it will just not increase and will beging to decrease very slowly (sublimation in the airflow). this may be slow enough to let you harmonize your altitude with the ground around you!
Obviously if you go low enough without hitting anything and the temperature goes above zero, it will go much faster...
However, simulating this whole increase/decrease aspect will be difficult unless it is much simplified.

This being said, there were no big issue with icing during the hot summer of BoB (maybe one or two poor souls lost into a thunderstorm), so OM has still some time to think about it!

Besides, the flight planning of bombing missions did take this aspect in account in order to avoid these situations: in most cases the bombers were fully loaded and forcing them to go willingly in known icing conditions would have been...difficult...and stupid risk taking.

On the other hand, transport aircraft like the C-47, 46 or 54 were fully equipped to deal with icing....bombers and fighters were not. Many losses of the JG3xx Geschwadern during the Reich Defence nights were due to flying in icing conditions with fighters not equipped for it.

JVM

[TheGrunch]

This being said, there were no big issue with icing during the hot summer of BoB (maybe one or two poor souls lost into a thunderstorm), so OM has still some time to think about it!
That's true, although apparently there was some pretty terrible weather shortly after the battle. Thanks for the explanation about icing, not something I've ever really known about. :)

[philip.ed]

This being said, there were no big issue with icing during the hot summer of BoB (maybe one or two poor souls lost into a thunderstorm), so OM has still some time to think about it!

I beg to differ. From reading various accounts by pilots, ice was a regular problem when on long patrols (particularly in the early stages of battle). Trust me, no matter about the summer time it was bloody cold at over 20000 feet! :-P :grin:

[JVM]

I may have been a tad exaggerating but icing was not a generalized issue during BoB like it would have been during fall or winter time (lack of cold clouds, maybe?).

Aren't you referring more to issues about effect of cold and frozen preexisting water drops/depots on weapons proper functioning, various fluids not behaving etc?
If not then I apologize and I would like you to elaborate a bit, as icing as mentioned in the beginning of the thread is really related to visible humidity, surfusion and sub-zero temperatures and nothing else...

JVM

[Panzergranate]

There are quite a few accounts, from fighter pilots, of guns failing to fire due to icing of the mechanisms.

Leading edge flaps icing up would be only of concern to a player when attempting to land,

Most Allied late war aircraft, mainly the bombers, had anti-icing heaters and vibrating rubber leading edges to counter wing icing.

Icing will also occur in summer and the tropics, despite the ground temperature, if an aircraft is flying high enough.

Through in flying high with a tropical storm and icing can happen.

[JVM]

Most Allied late war aircraft, mainly the bombers, had anti-icing heaters and vibrating rubber leading edges to counter wing icing.

Icing will also occur in summer and the tropics, despite the ground temperature, if an aircraft is flying high enough.

Through in flying high with a tropical storm and icing can happen.

You are right, but it was really concerning the bombers; they were called de-icing boots.
By the way the boots were made pulsating (manually or in sequence) but there was a real knack to be had in using them...it was really easy to exercise them too much (ice forming over the boots and boots not touching ice any more or too late (too much ice already and boots not powerful enough to break it); in both cases the result was the same: you were going down.

There was also the very serious issue of minute flak splinters making holes all over the boots and making them totally unusable...

Here is an extract from "rec.aviation.military", by Erik Shilling:

>>>>

Yes transports as well the bomber had pneumatic boot.
Incidently they were inflated from the pressure side of the
instrument vacuum pump, needing only a few pounds. Depending upon
the wing span and number of engines, depended upon the number of
sets of boots that were installed. In a twin engine plane such as
C-47 and C-46, there was an inboard section and an outboard
section. Each section of boot, normally had three cells, and
inflation took place sequentially. They were inflated in pairs,
first the inboard sets and then the outboard sets. Each boot was
made up of three cells. First the center cell was inflated, then
the two joining outer cells inflated.

Pilots had to deal with three types of ice formation. Carburetor
ice, wing ice and windshield ice. Ice could be in the form of rime
ice or clear ice. Rime ice was not as difficult to remove since
its build up was normal on the leading edge of the wing, and could
be deiced by the pulsing of the boots. Clear ice could occurred at
or slightly below freezing, It could form either on the leading
edge or worse, form behind the boot, run back onto the wing.

There were two ways of dealing with ice, one was to deicing such as
removing it after it built up. This deicing was accomplished as a
result of the boot pulsating. The other was anti-icing such as
pumping anti-icing fluid on the windshield, prop and carburetor.
Anti-icing fluid for the propeller was normally made up a mixture
of alcohol and glycerine. Straight alcohol was used to deice the
windshield.

Propellers didn't have boots. They had a slinger ring that
direction anti-icing fluid along the leading edge of each
propleller blade. Some, not all of the propellers had a rubber
strip with molded groves to direct the anti-icing fluid down the
leading edge.

There was a knack of using the wing deicer boot. They had to be
used intermittently. If they were left on continuously Ice could
build up in front of the boot and its pulsing would be working
inside a pocket, not touching the ice. The secret was to allow
just the right amount of ice to build up and then turn the boots
on. Then turn then off until a sufficient amount had build up
again. If one waited too long the boot didn't have enough force to
break the ice away and you were in deep do do.

Slightly more than six hundred airplane were lost flying the
"Hump," from India to China during the war. It is estimated that
at least 300 of those that were lost, went down in the mountain due
to sever icing conditions. In other words the ice build up became
so sever, and rapid, the deicer boots weren't able to hand the
build up.

Regards,
Erik Shilling
Author, Destiny;
A Flying Tiger's
Rendezvous With Fate.

<<<<

[Panzergranate]

I can remember a James Cagney Film where he was a pilot testing these de-icing boots out.

I kind of forgotten what the film was called.

The thing is that a surface only has to be warmed to 1 Celsius to stop ice forming.

Wind chill is scientifically regarded as being -1 Celsius per 12 MPH of airspeed. So at 120 MPH, the wind chill factor will be an additional -10 Celsius below the noraml air temperature.

Therefore, as bombers became faster and could fly higher, icing became growing problem.

The PC based "Red Baron" simulator series, by Sierra, had icing effects including carb icing as there was an option to turn icing effects off.

[AndyJWest]

'Wind Chill' is completely irrelevant. It is only meaningful when discussing an object (usually the human body) which is significantly warmer than the air temperature. Apart from any engine heat, and anything done to deliberately heat the wings, their temperature will be pretty much the same as the outside air temperature. The only way airspeed can make a difference is when there are friction effects in the transonic/supersonic range: not really significant in IL-2.

If the film mentioned 'wind chill' as affecting ice formation, it is just plain wrong.

[SlipBall]

Carburetor icing was always a concern in my flying history, no matter the time of year. RPM's drop had to be watched closely, and heat supplied via a switch when needed for icing...Would be cool to have the possibility of icing problems in SOW.:cool:

[AndyJWest]

Carburetor icing would be relatively easy to simulate - it is done in FS 2004 and FSX for instance. This needs no visual model, but ice on wings etc would be more difficult to model accurately I'd have thought. Something for the future maybe, but I'd be surprised if it is included from the start. Still, you never know...

[Azimech]

This is a great vid about horizontal stabilizer stall and loss of control due to icing on the horizontal stabilizer, just to keep you guys entertained.

http://www.youtube.com/watch?v=w1c4-aDB4k8&feature=related

[RAF74_Winger]

S!

Airframe icing isn't really a concern at very high altitudes as most of the moisture in the air is already frozen.. Though equipment icing (i.e. guns) can be a problem, hence the practice of taping up gun ports prior to take-off to prevent water ingress and subsequent freezing at altitude.

Airframe icing is more likely to accumulate at lower altitudes when taking a cold-soaked airframe through cloud or climbing through a warm front.

W.

[AndyJWest]

That video is seriously scary stuff. Line up on finals, select full flaps, and the control column is yanked forwards out of your hands. All you have to do to recover is pull hard back (if you can pull that hard), raise the flaps a bit and reduce power!

Maybe the Wright brothers got it right after all: at least with a canard, you can see the control surfaces. But then you can't see the ice build up on the wing...

[Crumpp]

As has already been pointed out, you need moisture to form ice. Stay out of the clouds and you are fine.

Icing is more of a low level to mid-level issue unless we have significant vertical development in our cloud structure.

The most dangerous is freezing rain as an aircraft will accumulate ice very quickly.

http://www.aopa.org/asf/publications/sa11.pdf

Flying your airplane through hail is a great way to not have an airplane anymore.

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=586

http://img693.imageshack.us/img693/9159/haildamage.jpg (http://img693.imageshack.us/i/haildamage.jpg/)

Carburetor icing is very common in aircraft and can occur even in much warmer weather.

The pilot should be aware that carburetor icing
can occur at temperatures between -7°C (20°F) and +21
°C (70°F) when there is visible moisture or high
humidity.

Although the German direct injection engines are are much more robust in resisting icing, this was a very real issue with the GM-1 system.

Even without injecting an oxidizer or ADI into the intake, even direct injection can experience induction icing.

Fuel injection systems are less susceptible to
icing than the carburetor system. Ice, which can partially
or totally block the air from entering the engine, forms
on the air intake of the engine. The usual indication of
icing in a fuel injection system is the same as in a
carburetor system. An alternate air source located inside
the engine cowling is used to provide air to the engine to
continue combustion.

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/list/AC%2091-51A/$FILE/AC91-51A.pdf