ryanbatc 4 Posted April 30, 2011 Share Posted April 30, 2011 I don't understand this phenomenon. I was flying west from my home airport at 2500 msl, prop pulled back to 2200rpms, throttle still maxed. Flying for about 15 min, started to encounter rain, and slowly my MP decreased and engine died (within about 3 minutes). Did an emergency landing on a road. Why is this doing this? I'm set to realistic mode and for the quick start beta patch I was set to pre takeoff config. I'm not out of gas either hehe. Link to comment Share on other sites More sharing options...
Snave 466 Posted April 30, 2011 Share Posted April 30, 2011 CLASSIC case of carb icing... Link to comment Share on other sites More sharing options...
ryanbatc 4 Posted April 30, 2011 Author Share Posted April 30, 2011 CLASSIC case of carb icing... CLASSIC noob error Man this thing get's me every flight. OAT was +6 - is that carb icing time? nm, I found this neat little chart: http://ibis.experime...romcaassl14.gif Yep conditions were perfect for the carb icing So with that said, do I want it on during takeoff in these weather conditions? Or on the entire flight? I thought carb heat decreases engine power after some time? Also, I tried starting it again and it the engine wouldn't provide adequate power to takeoff from the road. Do I need to wait to let the ice melt away? 1 Link to comment Share on other sites More sharing options...
tup61 185 Posted April 30, 2011 Share Posted April 30, 2011 Also, I tried starting it again and it the engine wouldn't provide adequate power to takeoff from the road. Do I need to wait to let the ice melt away? I guess so. But as Snave said elsewhere: the Carb heat PREVENTS icing, it won't MELT the ice just like that. (Not his exact words, mind you...) So you might have to wait a while... Link to comment Share on other sites More sharing options...
Damocles 24 Posted April 30, 2011 Share Posted April 30, 2011 Also, if you use real weather add-ons and see a towering cloud......go the other way quickly Link to comment Share on other sites More sharing options...
Mr.Düssel 44 Posted April 30, 2011 Share Posted April 30, 2011 Also, if you use real weather add-ons and see a towering cloud......go the other way quickly I have still both problems. The one thing are the CTDs...but they are discused in another thread. The second is the CHT/Carb Heat. I have read everything, which has something to do with, but it seems, that I am too stupid to understand it or.... I don´t know :-(( I have spend now 23hours with Katy (i guess it has been more, but this is what hobbs clock says). And I am not able to fly longer than 20minutes. Too high CHT or CTD..... Everytime the same situation (to be able to compare), WA38 - 7S3 (both PNW) Temperarture mostly between -1 and 6°C, cloudy... best conditions for icing. I tried to start the flight without using Carbheat and used it later = mistake. Take carb heat with beginnig of the flight = mistake In both cases the CHT rises up to the end = stopping engine... (Marcel, the propeller shows with broken ends... but not as a result of a wrong start on grass) It must have broken in the air, because when the engine stopped, the prop was ok, two minutes later it shows broken endings.) The last time, I let the engine runnig before start ( I had to make food, so I took it as a test ;-) ). 30minutes the engine was running on the ground - everything OK - CHT about 200°F.. Together with the start I pulled Carb Heat ( because misty weather, 3°C) 25nm everything was OK and then suddenly the CHT began to climbed till the point I knew now very good: stopping engine with broken propeller. RPM I take everytime back to 2200 and manifold pressure I always set to 22-23. Level is between 2500 and 4500 f. KIAS then is appr. 95kn. If I don´t use Carb Heat, I get carb icing and the engine slows down... So, with every possible combination, its not possible (for me) to fly more than a little round. And this has nothing to do with the beta patch - these behavoir has the katy from beginning. I have no further Idea. Perhaps to fly the Katy just in Summer tempertures? If there are more tipps - please post.... Cheers, Stephan Link to comment Share on other sites More sharing options...
Snave 466 Posted April 30, 2011 Share Posted April 30, 2011 CLASSIC noob error Man this thing get's me every flight. OAT was +6 - is that carb icing time? nm, I found this neat little chart: http://ibis.experime...romcaassl14.gif Yep conditions were perfect for the carb icing So with that said, do I want it on during takeoff in these weather conditions? Or on the entire flight? I thought carb heat decreases engine power after some time? Also, I tried starting it again and it the engine wouldn't provide adequate power to takeoff from the road. Do I need to wait to let the ice melt away? No, it sounds like you've damaged the engine. Carb heat is never used on take-off and normally only when decreasing power, say for descent or very low-power cruise. At high power settings their should be sufficient heat to avoid carb icing. If you're also experiencing power loss on the ground then you've probably got a wear and tear issue and need to put the bird in the shop. Link to comment Share on other sites More sharing options...
Snave 466 Posted April 30, 2011 Share Posted April 30, 2011 I have still both problems. The one thing are the CTDs...but they are discused in another thread. The second is the CHT/Carb Heat. I have read everything, which has something to do with, but it seems, that I am too stupid to understand it or.... I don´t know :-(( I have spend now 23hours with Katy (i guess it has been more, but this is what hobbs clock says). And I am not able to fly longer than 20minutes. Too high CHT or CTD..... Everytime the same situation (to be able to compare), WA38 - 7S3 (both PNW) Temperarture mostly between -1 and 6°C, cloudy... best conditions for icing. I tried to start the flight without using Carbheat and used it later = mistake. Take carb heat with beginnig of the flight = mistake In both cases the CHT rises up to the end = stopping engine... (Marcel, the propeller shows with broken ends... but not as a result of a wrong start on grass) It must have broken in the air, because when the engine stopped, the prop was ok, two minutes later it shows broken endings.) The last time, I let the engine runnig before start ( I had to make food, so I took it as a test ;-) ). 30minutes the engine was running on the ground - everything OK - CHT about 200°F.. Together with the start I pulled Carb Heat ( because misty weather, 3°C) 25nm everything was OK and then suddenly the CHT began to climbed till the point I knew now very good: stopping engine with broken propeller. RPM I take everytime back to 2200 and manifold pressure I always set to 22-23. Level is between 2500 and 4500 f. KIAS then is appr. 95kn. If I don´t use Carb Heat, I get carb icing and the engine slows down... So, with every possible combination, its not possible (for me) to fly more than a little round. And this has nothing to do with the beta patch - these behavoir has the katy from beginning. I have no further Idea. Perhaps to fly the Katy just in Summer tempertures? If there are more tipps - please post.... Cheers, Stephan Sounds like your engine now has some persistent damage in the oil system. Either put the engine in for a change, or use the reset option. Also check the winter baffle has not been installed by installing it then de-installing it. Link to comment Share on other sites More sharing options...
Mr.Düssel 44 Posted May 1, 2011 Share Posted May 1, 2011 Hi Simon, thank you again, that you aren't tyred to answer to this issues.... I had a long night with Katy ;-), and it seems that I have it now.... !! The initial hint was - oerhaps I didn't get it in another post - that the carb heat is NEVER used during take off. Because I've had some carb icing before during my flights and had read, that pulling carbheat can prevent icing but has a slow indication, I meant I should use it earlier! I further didn't realize, that everything about a 20 Mp protect icing. So I went out this night for four flights - each more than one hour and? NO HIGH CHT!!! I didn't get icing, although the weather conditions were good for that (misty, fog, -1C at start, up to -6C during flight) With beginning of decend and taking down Mp to less than 20, I pulled the carbheat and let it pulled until I have landed. CHT rises just a bit and was a bit more than 200F. And this was the same with the other three flights!! Thanks again, Simon!! I think, the "carbheat-issue" should be solved for me now....! Btw, I did it, concerning the Ctds, what you said about tweaked cfgs.... I'm running a fresh cfg, but I had CTDs in the same situations... the message is a fault with a g3d.dll (not sure but similar). I've read, that this happens with some sceneries (ORBX) and its recommended to turn down Autogen to normal. I did it, made the same flight again and? No CTD! More tests will follow... Today I have "family-day" ;-).... So thanx a lot again! Cheers, Stephan Link to comment Share on other sites More sharing options...
Snave 466 Posted May 1, 2011 Share Posted May 1, 2011 Try this Looking after your Rotax Carb heat is a tool for when the engine inside the cowling is not providing enough latent heat to keep the carb body from dropping its' temperature below the condensation point. If you don't need it, you don't use it. That's what the Katana 4X manual is referring to when it invites you to check for rpm and MP drop. Although we've mentioned several factors already these are NOT the only criterion that apply - there are even some esoteric factors that combine to increase or decrease the likelihood of carb icing. In some Rotax 912 engines there is even a `permanent ON` carb heat system, so there's not even a consensus for the engine type - it varies wildly, as do the possibilities of it occurring in the first place. Don't get hung up on carb heat. As long as you can recognise the situations under which icing is likely to occur (power reduction, descent in `wet` or cool air), know how to recognise the symptoms and what action to take, you've got it covered... In simple terms, apply carb heat as a precautionary measure when the temperature and dew point are either close together or the temperature is in single digits, when you are pulling back the power prior to a descent, or when flying in wet conditions when the ambient temperature is low. Don't have carb heat applied when the manifold pressure is above 20" UNLESS MP shows a drop with no change in throttle setting or altitude. Those are the situations when you should need it. 3 Link to comment Share on other sites More sharing options...
bliksimpie 14 Posted May 1, 2011 Share Posted May 1, 2011 Thanks for the document. I also read the Pilot handbook from diamond company that I downloaded but still I do not have some solid info on this subject. I fly a lot in PNW area where temps are very low with a lot of rain/snow. Ok to summarise then in cold/icy conditions (less then 10 degrees with moist/rain about) Start engine. let it run up to engine warm before taxi commence - NO Carb heat Takeoff normally - NO carb heat Fly normally with MP above 20 - NO Carb heat When start descent and you pull back throttle to be under 20 - Apply Carb heat till after landing After landing - Carb heat switch off as soon as you can after landing. If you do fly into ice conditions and MP decrease by itself below 20, then switch on carb heat and find a landing strip as quick as possible. Link to comment Share on other sites More sharing options...
Snave 466 Posted May 1, 2011 Share Posted May 1, 2011 You've got it. Also one extra point. For go around also switch carb heat off before applying full power. Link to comment Share on other sites More sharing options...
Mr.Düssel 44 Posted May 1, 2011 Share Posted May 1, 2011 Hi Simon, thanks again! I think even me have got it now ;-) Thanks for the pdf! No CHT problems since your explanations! Cheers, Stephan Link to comment Share on other sites More sharing options...
CoolP 24 Posted May 1, 2011 Share Posted May 1, 2011 Thanks for you guys posting those docs here (Ryan and Snave). I've "thumbed up" those posts of yours up as they enlightened my view on some aspects of this great addon. I hope that this green +1 thing was meant for this purpose. 1 Link to comment Share on other sites More sharing options...
Snave 466 Posted May 1, 2011 Share Posted May 1, 2011 I believe it sends money... your money. Use it with care! Your're welcome. I think it great we can have this level of sophistication in a sim forum when covering the features of a simulated product. It really is something else, this Katana. And hopefully by putting the flying into context with the maintaining and preparing, it might give some insight into the real ownership and use of a real aircraft. 1 Link to comment Share on other sites More sharing options...
bliksimpie 14 Posted May 2, 2011 Share Posted May 2, 2011 Hi Simon, thanks again! I think even me have got it now ;-) Thanks for the pdf! No CHT problems since your explanations! Cheers, Stephan +1 much appreciated your help. Link to comment Share on other sites More sharing options...
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