ryanbatc 4 Posted May 2, 2011 Share Posted May 2, 2011 I'm having an issue with high CHT. Temp at sea level around +16, temp in cruise about +4, so I've been flying with carb heat on as a preventative mesaure (thanks simon lol) But now my CHT is in the red. What gives...? My prop is below 2236m throttle is fully forward, and ive been doing touch and goes, so alternating the use of carb heat (0ff for landing with +16 temps) I tried lowering the throttle, then descending (to increase airflow over engine), but that didn't help. I'm feeling like the engine's going to die again, oh well, it's only money EDIT: And the engine died while the game was paused... nice... good thing I could land on a road. That's starting to be a common practice with how I fly this bird "make sure I'm flying near a road" LOL Link to comment Share on other sites More sharing options...
bliksimpie 14 Posted May 2, 2011 Share Posted May 2, 2011 you not suppose to use carb heat as preventative measure. it will kill your engine very quick. See my post here Losing MP then engine quits entry 11 From I dont touch carb heat my engine last now longer then hour.. touch carb heat, you ruin your engine Link to comment Share on other sites More sharing options...
ryanbatc 4 Posted May 2, 2011 Author Share Posted May 2, 2011 you not suppose to use carb heat as preventative measure. it will kill your engine very quick. But documents I've read online say it is for prevention, and not so much for a quick fix... but I will read your post! Link to comment Share on other sites More sharing options...
trisager 16 Posted May 2, 2011 Share Posted May 2, 2011 You should use carb heat whenever you significantly reduce power and there is humidity in the air. Pull it out during descent and landing. It is used as a preventive measure - once ice has formed, it will take a while to melt it and you may well be in trouble. Leaving carb heat on should not ruin your engine - if indeed this is what is causing the high CHT, that is an issue with the simulation. Carb heat will rob you of a little power, so if you have to go around, make sure to push it in as you add power. The simulation of carb heat in FSX is not particularly accurate, and you may find you have to use carb heat in circumstances when you would not expect to need it. Just one of those things ... Link to comment Share on other sites More sharing options...
bliksimpie 14 Posted May 2, 2011 Share Posted May 2, 2011 You should use carb heat whenever you significantly reduce power and there is humidity in the air. Pull it out during descent and landing. It is used as a preventive measure - once ice has formed, it will take a while to melt it and you may well be in trouble. Leaving carb heat on should not ruin your engine - if indeed this is what is causing the high CHT, that is an issue with the simulation. Carb heat will rob you of a little power, so if you have to go around, make sure to push it in as you add power. The simulation of carb heat in FSX is not particularly accurate, and you may find you have to use carb heat in circumstances when you would not expect to need it. Just one of those things ... Absolute agree with you on what you say about Carb heat in real life. In this simulation however when you use carb heat unnecessary it will ruin your engine very quickly. I have flown this as I was tought and engine life in this sim only give max engine life of 1.5 hours then you will have CHT in the red and you will need to overhaul/replace engine. So yes I am sure there seem to be a little bug maybe in the sim. However I am no expert, but it sure do not work like in RL. My remark not to use carb heat is solely based on this simulation and to extend this simulation engine life. For RL scenario my comments will not hold water at all..! but then that is totally different subject. Link to comment Share on other sites More sharing options...
Snave 466 Posted May 2, 2011 Share Posted May 2, 2011 Quite right. Not only do Rotax engines sometimes have continuous carb heat applied (i.e. no `off` switch) the problem we are dealing with here is the poor representation of the onset and prevalence of carb icing as presented by FS, not 4X. When even fuel injectde engines can suiffer from carb ice, you know MS did a BS job on CH... There are NO changes to the Carb Heat environment made by this addon as it does not modify core files, so basically it's doing the best it can within it. So `sim rules` and real life rules will be slightly different. Link to comment Share on other sites More sharing options...
Damocles 24 Posted May 2, 2011 Share Posted May 2, 2011 So, knowing the issue is with fsx, can anything be done as a workaround for the x4? I hope so Link to comment Share on other sites More sharing options...
Snave 466 Posted May 2, 2011 Share Posted May 2, 2011 A workround? Surely we should just fly it right..? When ice is suspected, the aircraft should be removed from the icing environment as soon as possible - seek warmer air, or land at the first opportunity. The aircraft is not certified for flight into known icing. Carburettor icing is an early indicator of the potential for icing of other types. Which is also modelled in the Katana, so I suppose there'll be a demand for de-icing boots next... Carb heat is NOT a de-icing measure, it's an ANTI-icing measure. So in addition to applying carb heat you should also seek to address the cause of the icing. No doubt Marcel will look at this issue when he returns, but frankly the majority of the bugs reported on this subject appear to be poor understanding, not poor coding - unless you count Microsoft's interpretation of icing! There is more than enough information floating about in these forums to enable correct pilotage. Then and only then, allied with proper reporting, can we even establish that there is a `problem` that needs looking at. A good example would be uploading the saved flight and weather files so that the aircraft can be tested in other computers to see whether the symptoms are repeatable, or merely lamentable. Also supplying system specs and scenarios would be extremely helpful as there is no doubt in my mind that without knowing who, what and how the weather is being generated it is utterly futile to pursue this. Not one single poster has reported their weather engine - FS, REX, Active Sky or whatever. Not a single one has provided a screenshot as a snapshot of the cockpit environment so we can check switch positions and correct operation. Not a single one has provided a sample .flt which could be used as a repeatable benchmark to test whether the issue exists. And some have, via the information they HAVE provided, revealed that they are simply doing it wrong. We are able to correct those. Without proper reporting it is only the simplest measures can be recommended. Like reading the manuals or flying it right. 1 Link to comment Share on other sites More sharing options...
Damocles 24 Posted May 2, 2011 Share Posted May 2, 2011 Agreed, personally, I have not had a problem with CHT after my first encounter with it rising. Pilot error, my bad I use REX and keep an eye on potential icing conditions and definitely stay away or move out of danger ,pronto. The problem with fsx is that sometimes you don't know when you are in trouble until it bites you in the bum Link to comment Share on other sites More sharing options...
Ron Attwood 33 Posted May 2, 2011 Share Posted May 2, 2011 Simon, I love it when you talk dirty. Link to comment Share on other sites More sharing options...
Ron Attwood 33 Posted May 2, 2011 Share Posted May 2, 2011 And I love it when forums mess ya about! Link to comment Share on other sites More sharing options...
BenJohara 2 Posted May 3, 2011 Share Posted May 3, 2011 I had the same thing happen on a flight so I landed asap and did a walk around and found that the tank cover was still on (or off not sure) which seemed to be causing CHT to go up. After that was corrected CHT went back to normal as I resumed my flight. Just wanted to add that! Link to comment Share on other sites More sharing options...
tup61 185 Posted May 3, 2011 Share Posted May 3, 2011 Simon, I love it when you talk dirty. Amen! Link to comment Share on other sites More sharing options...
dwhite601 0 Posted May 3, 2011 Share Posted May 3, 2011 I'm not sure if this is modeled in the sim version, but I've heard that in real life, if the Rotax loses coolant, it can run at 50% power. That works out to about 72 knots which is also the best glide speed. Last summer, on the one hot weekend we had in San Diego, my oil temp approached red line during a climb. I hoped it would cool as I got higher, but we had a temperature inversion that day and climbing only made it worse so I cut power and flew home. Overheating is an issue Katana pilots know too well. Link to comment Share on other sites More sharing options...
bliksimpie 14 Posted May 3, 2011 Share Posted May 3, 2011 .. Overheating is an issue Katana pilots know too well. yes but in RL they dont have to replace engines every 1.5 hour after temps reach red line... The damage in RL is not that bad as in the simulation. In the Sim it is way excesssive.... Link to comment Share on other sites More sharing options...
MathijsTest 1 Posted May 3, 2011 Share Posted May 3, 2011 yes but in RL they dont have to replace engines every 1.5 hour after temps reach red line... The damage in RL is not that bad as in the simulation. In the Sim it is way excesssive.... Understood. We'll discuss this item with Marcel. Link to comment Share on other sites More sharing options...
dwhite601 0 Posted May 3, 2011 Share Posted May 3, 2011 If you are going to tweek the engine simulation, you should also look into max RPM during the runup. It should go all the way to max even when the airplane isn't moving. On my first simulated Katana 4x flight, I couldn't get the RPM above 1700. On my real Katana, I have to set 2000 RPM in order to cycle my prop. I thought there was a problem with my throttle hardware. I eventually tried a takeoff, and as I started moving, the simulation increased the RPM to full value. Link to comment Share on other sites More sharing options...
trisager 16 Posted May 13, 2011 Share Posted May 13, 2011 I've avoided the use of carb heat on my last several flights, and I've had no further problems wiht high CHT. Use of carb heat does seem to affect the simulation in some way that wasn't intended. (I've been getting away with not using carb heat until today, when my engine quit on me on downwind. Good thing I had plenty of altitude ) Link to comment Share on other sites More sharing options...
bliksimpie 14 Posted May 13, 2011 Share Posted May 13, 2011 I've avoided the use of carb heat on my last several flights, and I've had no further problems wiht high CHT. Use of carb heat does seem to affect the simulation in some way that wasn't intended. (I've been getting away with not using carb heat until today, when my engine quit on me on downwind. Good thing I had plenty of altitude ) Carb heat knob on katana = engine self destruct start knob but I am sure marcel is working on it. Link to comment Share on other sites More sharing options...
AaronMyers 23 Posted May 13, 2011 Share Posted May 13, 2011 Yeah, I use it sparingly, but it is necessary if you want to keep the engine running at cooler temps. I too have had the engine lose MP and ultimately die complete if I didn't use it in appropriate places. The sensitivity of those operations is perhaps mildly too touchy. I do like real consequences for real actions, but some play room there might be good too. Link to comment Share on other sites More sharing options...
Snave 466 Posted May 13, 2011 Share Posted May 13, 2011 Yeah, I use it sparingly, but it is necessary if you want to keep the engine running at cooler temps. I too have had the engine lose MP and ultimately die complete if I didn't use it in appropriate places. The sensitivity of those operations is perhaps mildly too touchy. I do like real consequences for real actions, but some play room there might be good too. The problem is that MS uses a simplistic model for the potential and then presence of carb icing. The only solution is to use carb heat only when carb icing is presented by the signs and cues in the sim, or when its appearance is likely. Basically, don't use it on the ground. Don't use it for taxi or runup. Don't use it for take-off or climb. Use in cruise when potential for carb ice is recognised. ALWAYS use it when pulling throttle back for descent. That seems to solve the problem. And coincidentally happens to be pretty close to the real world, too. While I agree the sensitivity is a little to much, the best lesson to learn is how to anticipate carb icing, and take the appropriate steps before it becomes an issue. That means understanding ambient temperature, pressure and - most importantly - their relationship to dewpoint. And actually taking notice of the weather before leaving the clubhouse! Then the other lesson of recognising the onset of carb ice from the cockpit and quickly applying carb heat to prevent blockage becoming an issue in the first place. All good lessons for the sim pilot that directly translate to the real world experience. Or as my old instructor succinctly put it (nearly): "Proper pilotage prevents pass-poor performance!" Link to comment Share on other sites More sharing options...
trisager 16 Posted May 13, 2011 Share Posted May 13, 2011 Just to clarify, the problems I've had with high CHT occurred with correct use of carb heat. After I've stopped using carb heat (in situations where it is required) I've had no further CHT problems. Link to comment Share on other sites More sharing options...
bliksimpie 14 Posted May 13, 2011 Share Posted May 13, 2011 Just to clarify, the problems I've had with high CHT occurred with correct use of carb heat. After I've stopped using carb heat (in situations where it is required) I've had no further CHT problems. +1, most of us know how to use carb heat in RL.. and we try to replicate that in sim. BUT.. Just this simulation of carb heat/excessive CHT and engine wear is not correct.. Link to comment Share on other sites More sharing options...
Snave 466 Posted May 14, 2011 Share Posted May 14, 2011 +1, most of us know how to use carb heat in RL.. and we try to replicate that in sim. BUT.. Just this simulation of carb heat/excessive CHT and engine wear is not correct.. That is correct. But have we established that the cause is the excessive use of carb heat leads to excessive engine wear? I think we've established only that improper use of the carb heat can cause problems, but that those problems may be symptomatic of other issues compounded by the persistent use of CH in situations which do not call for it. But persistent use of CH in situations which do not call for it is ALSO a symptom of improper pilotaqe. So what ELSE might be going on that they are not reporting, which is also contributing..? As has been stated, use CH `correctly` according to the MS model, and the `problem` no longer exists. That would seem to indicate that once proper pilotage is instigated, CH is a non-issue. Link to comment Share on other sites More sharing options...
trisager 16 Posted May 14, 2011 Share Posted May 14, 2011 Simon, I'm not sure what you have established, but this is what I am seeing: After a few flights with correct use of carb heat, the CHT temperature will climb above redline in cruise. A maintenance inspection post flight does not reveal any problems. Using the Katana reset tool fixes it. After a few more flights, conducted with absolutely no use of carb heat (because someone pointed to that as the possible culprit) CHT temperatures remain low. I'm not a beta tester, so I haven't flown the exact same flight over and over again with the same date/time settings etc. Obviously something else could be causing this, but I don't think so. I understand that not everyone is having this problem. I'm posting about my experience mainly to give Marcel another data point. If it helps him fix it, fine - if not, I'll just have to stay alert so I know where to put down in case the engine quits. Link to comment Share on other sites More sharing options...
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