Jump to content
Sign in to follow this  
Guest DreamFleet

FSX and Aircraft ICE SYSTEM

Recommended Posts

This question is more related to the ability of modelling a certain function of an aircraft's anti-ice system. Currently in FS9 if the aircraft you want to model has an anti-ice "AUTO" position there is no way for the aircraft to "know" if it is actually in icing conditions to "activate". Is there a way for this to be addressed?...............Randy J. Smith................A PROUD MEMBER OF THE PMDG BETA TEAM[h4]Evolution is a process that results in heritable changes in a population spread over many generations[/h4]

Share this post


Link to post
Share on other sites
Guest tdragger

What is the definition of icing conditions? You should have access to weather variables already. Seems like this could be done now unless there's some special sauce I'm missing.

Share this post


Link to post
Share on other sites
Guest BlueRidgeDx

>What is the definition of icing conditions? Hi Mike,I'm not sure if you're asking rhetorically or not, but if you're really wondering, icing conditions exist in flight at a TAT of 10

Share this post


Link to post
Share on other sites

Nick, you do sound as if you were quoting a mathematical formula. All the conditions you are mentioning could be present yet there could be no ice. Mother Nature is far more complicated than this, tdragger perhaps realizes this.Michael J.http://www.precisionmanuals.com/images/forum/pmdg_744F.jpghttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

Share this post


Link to post
Share on other sites
Guest Peter Sidoli

I agree with Michael as icing is a very hard thing to predict. Other than for carb icing in a basic single I have never seen visible icing in plus anything.Most icing lies in the band of 0 to -10 deg C. Rain Ice has its own rules.I never liked the fact that aircraft used to break at VNE in MSFS as this appeared as Gimmicky.We all know in reality that an aircraft can dive way beyond VNE with no ill effect yet can break up way before VNE.If MS want to truly model the effects of icing and systems to remove or prevent it then that is fantastic. Icing is one of the major and most unpredictable threats to flight.If its a case of pick a number. Now you have it, now you dont then thats a poor gimmick. In my opinion if icing isnt realistically modelled then forget it altogether.That includes its effect on Lift, Drag and weight as well as effect on thrust. Other areas to consider are air friction.It would also be nice to see it visually modelled building up on the airframe and blowing off with boots :-) They can do effects with smoke why not ice.Peter

Share this post


Link to post
Share on other sites
Guest BlueRidgeDx

Okay, well, Bombardier defines icing conditions for the CRJ-200 and CRJ-700 exactly as I stated above...verbatim. It is easily referenced in both the AFM and the POH.I dispatch these airplanes everyday, and if its less than 10c with visible moisture present, I plan takeoff with the nacelle anti-ice on. If its less than 5c with visible moisture, I use both wing and nacelle anti-ice.I have dispatched the J-41, Do-328JET, CRJ-200, CRJ-700, A319, and DC-10. All have had the same icing limitations: less than 10c and visible moisture.You guys are looking at it the wrong way. Meeting the above criteria does not guarantee ice formation, but it is the envelope outside of which, structural icing will not form.Further, I thought we were talking about structural icing. If we're talking about carb icing, then thats a whole separate issue. Carb ice can form even in significantly warmer temperatures provided there is a high relative humidity. The carb's venturi lowers intake pressure and temperature, and given sufficiently low RPM and sufficiently high humidity, can cause ice formation well outside the envelope I mentioned above.Regards,Nick

Share this post


Link to post
Share on other sites

>Okay, well, Bombardier defines icing conditions for the>CRJ-200 and CRJ-700 exactly as I stated above...verbatim. It>is easily referenced in both the AFM and the POH.Nick,You are confusing two completely different things: recommended use of anti-ice systems on an aircraft and actual ice formation in flight. Bombardier may have you (wisely) turn on anti-ice systems in certain situations but it does not automatically mean that you would fall out of the sky had you had them off. Michael J.http://www.precisionmanuals.com/images/forum/pmdg_744F.jpghttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

Share this post


Link to post
Share on other sites
Guest BlueRidgeDx

Hi Michael,I'm not cunfused. As I stated, the envelope for structural icing - as defined not only by Bombardier, but also BAe, Dornier/Fairchild, Airbus, and McDonnell Douglas - includes a temperature range from -10C to -40C when visible moisture is present. Barring a cold-soaked wing situation, structural icing will not form outside of this range. Being within that envelope, however, does NOT guarantee icing. Do you see the difference?Also, I never said anything about falling out of the sky just because you're in the icing envelope. I'm not sure where you got that from. Regards,Nick

Share this post


Link to post
Share on other sites

>What is the definition of icing conditions? You should have>access to weather variables already. Seems like this could be>done now unless there's some special sauce I'm missing. When one sets anti-ice to "ON" it is on because of pilot input but how does an anti-ice system know to activate from 'auto' to ON when the aircraft 'enters' icing conditions? In other words, the sim does not give any parameters to be read from to activate/de-activate the anti-ice system on it's own because there is nothing to tell it when it's in these conditions. Make sense? ...............Randy J. Smith................A PROUD MEMBER OF THE PMDG BETA TEAM[h4]Evolution is a process that results in heritable changes in a population spread over many generations[/h4]

Share this post


Link to post
Share on other sites
Guest BlueRidgeDx

Everyone,I guess I should also point out, that my answer to tdragger is rooted in the real world, and not meant to construe that structural icing, in its infinite complexity, should or could be modeled in FS.Nick

Share this post


Link to post
Share on other sites
Guest Peter Sidoli

NickI think you will have to be more specific for the reasoning on +10 to -40.By that I mean by what methods those figures are come by.Example a jet is on the ground about to takeoff into a 300 foot overcast the temp on the ground is +10.We know that this jet will climb at maybe 3000 fpm ie it wont take long before it is in a temperature where ice will form.Hence in such a situation it would be prudent to turn on ice protection.I can only talk from my own experience, I have never seen ice form at above +3 or below -15.That doesnt mean that there are not rare situations where ice will form. An aircraft structure supercooled in an inversions layer could for a brief time pick up ice while climbing into +10 air mass.An aircraft could pick up rain ice in plus conditions as supercooled particles of water hit the airframe.It is normal to have a higher temp out side cloud only for the temp to drop entering cloud. Usually 3 degrees by experience but maybe more in certain situations.I would like to know the basis of those quoted temp bands which seem more precautionary figures rather than actual ice formation figures.Peter

Share this post


Link to post
Share on other sites

Depends on the aircraft and the system it uses. Same with the present autopilot-they all work differently depending on the autopilot model-FS has a "generic" one....I don't fly jets-I fly Ga and my real Baron has deice boots and the system on the Baron works this way:I have a 3 position switch with OFF,MAN, and AUTO. When in AUTO position the deice boots inflate for a period of 5-6 seconds, then deflate automatically and return to vacuum hold down position. The switch must be tripped for each complete cycle. When in the MAN position the deice boots inflate as long as the switch is held in the position-when released the boots deflate. I would love to see this modelled-and see the boots inflate/deflate, and various types of ice (rime, clear etc. ) break off. Pretty complicated to do though-and that is just to model a GA aircraft deicing system. My system also has alcohol for the props and windshield-other models of my aircraft have electrical systems for both.I assume you are talking about a jet aircraft and I have no knowledge of their systems.Shows how complicated it is to model-do they make a "generic" icing system which no one is completely happy about and doesn't duplicate complete reality-kinda like the "generic" autopilot that exists now?http://mywebpages.comcast.net/geofa/pages/rxp-pilot.jpg

Share this post


Link to post
Share on other sites
Guest DreamFleet

Remember, Goef, what the jet has is essentially ice "prevention" (anti ice) via heated wings. What you have is ice "removal" via boots. You cannot prevent ice from forming. The jet can prevent it from forming, as they can keep the wing heated continuously.BTW, take good care of those boots, 'cause you will not like to see the bill for replacing them!As to simulating it in FS, we could do that right now, and we thought about doing it with our Baron. Problem was, many folks expectations that it must be "100% realistic", often without knowing just what "100% realistic" means. Ice comes in different forms, and can accrete at different rates. Affects on flight dynamics can also differ, and we are then faced with dynamically changing the flight dynamics as the plane is flown, not to mention creating different forms of ice, changing accretion rates, and making it look realistic when the boots break it off.Ultimately, we decided that the end result of the level of realism that we could accomplish would not be worth the price of doing so which, of course, would be passed on to the customer.With most, if not all piston-driven GA aircraft with boots, even those that are certified for FIKI, it is still known that once ice is encountered that you should look to leave the area of icing as soon as possible, not stay in it.The fact is, unless your aircraft is certified for Flight Into Known Icing, you cannot legally enter conditions where it could exist, that's the regs. Of course, we all know this is impossible at times to accomplish, thus we have aircraft equipped with boots even though they may not be certified for FIKI. I'm pretty sure that your Baron is not certified for FIKI.In FS, we would have folks staying in icing conditions, watching the ice, then posting "bug" reports in the support forum telling us how this and that does not appear to be "realistic". You'd have people going into spot view and looking at different parts of the aircraft to see if we have ice forming on it, such as antennas, etc.Imagine if we had to simulate clear ice, rime ice, a mix of both, etc. Along with accretion rates ranging from an inch an hour to an inch a minute, then make it look "realistic" as the boots break it off, then having to simulate varying affects on flight dynamics. Afterwards, we would have to provide support for all this, some of which would concern "frame rates".My philosophy is: If you cannot make it close to 100% realistic (I'd settle for 50% realism for icing), then it is not worth doing. The costs of doing it followed by the costs of support later make it impractical.Unfortunately, many folks expect that if you do it, it must be close to if not 100% realistic. When expectations are such, it is best to stay away from it unless you are certain that you can accomplish it.Regards,http://www.dreamfleet2000.com/gfx/images/F...R_FORUM_LOU.jpg

Share this post


Link to post
Share on other sites
Guest Peter Sidoli

Lou I know your post was directed at Geof but here is my take anyway ;-)Icing in my book comes very much under the heading of "weather".Take a world devoid of weather and flying would be a very easy occupation.We all know those rare days( In Northern Europe even rarer :-) when you get a clear blue Sky, 50 miles vis and no wind.Weather creates the biggest problem for a mechanical flying machine not only by the fact that the seeing pilot can no longer see but because it challenges the aircrafts ability to fly.As a realism nut for me there are two important parts of a simulation .The first is modelling the aircraft in a way that it reacts and behaves as closely to its real counterpart as possible.The second is that it reacts and behaves in its invironment as close to reality as possible.That means that it should operate in a moving living airmass with winds, air currents, temperatures, density, etc "as close as possible".The sim should then have to deal with the challenges that faced aircraft designers, ie that the pilot enters clouds or poor vis and has to keep the sunny side up while navigating to another strip of tarmac.He has to land on that strip of tarmac without hitting cumulus granitus enroute.The aircraft has to deal with weather and a major part of that weather is aspects of the weather which will destroy the aircraft or stop it flying.Icing is one MAJOR aspect of weather which effects all flying objects which require lifting devices to fly.Manufacturers go to great lengths to keep an aircraft flying when ice is present.Some do better than others. The worst off is the unpressurised GA aircraft which tends to operate in the worst weather, has the poorest performance and the cheapest deicing ability.Reading weather and making descisions becomes all important and one of the biggest challenges of flight. Icing is an integral part of WEATHER.What I am getting at as a realism NUT is that I want realistic flight dynamics and a realistic, living, breathing, moving weather system that challenges me and my aircraft in the sim as it does real world.Visually we are a very demanding lot. If a rivet is out of place or a shape not quite right the forums shout and scream.Why should we be any less demanding on the way an aircraft behaves or the invironment it behaves in?I would pay twice what you charge for an addon aircraft if it oozed realism in every way.;-)Peter

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
×
×
  • Create New...