---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Wed 02/11/09: 24 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:19 AM - Re: Re: Carb ice on a 912 (Craig Payne) 2. 01:07 AM - Re: Carb ice on a 912 (Robert C Harrison) 3. 04:46 AM - Re: Re: Carb ice on a 912 (Graham Singleton) 4. 05:02 AM - Re: Carb ice on a 912 (Thom Riddle) 5. 05:45 AM - Re: Re: Carb ice on a 912 (Graham Singleton) 6. 06:15 AM - Re: Re: Carb ice on a 912 (Noel Loveys) 7. 07:04 AM - Re: Carb ice on a 912 (Noel Loveys) 8. 07:50 AM - Re: Carb ice on a 912 (rampil) 9. 08:00 AM - Re: Carb ice on a 912 (Roger Lee) 10. 08:30 AM - Re: Carb ice on a 912 (Thom Riddle) 11. 09:17 AM - Re: Re: Carb ice on a 912 (Gilles Thesee) 12. 09:55 AM - Re: Re: Carb ice on a 912 (Peter Jeffers) 13. 10:14 AM - Re: Re: Carb ice on a 912 (Craig Payne) 14. 10:15 AM - Re: Re: Carb ice on a 912 (Graham Singleton) 15. 10:21 AM - Re: Re: Carb ice on a 912 (Gilles Thesee) 16. 11:05 AM - Re: Re: Carb ice on a 912 (Craig Payne) 17. 12:03 PM - Re: Re: Carb ice on a 912 (Noel Loveys) 18. 12:19 PM - Re: Re: Carb ice on a 912 (Robert C Harrison) 19. 01:39 PM - Re: Carb ice on a 912 (rampil) 20. 02:12 PM - Re: Re: Carb ice on a 912 (Dave G) 21. 05:41 PM - Re: Re: Carb ice on a 912 (Robert C Harrison) 22. 06:09 PM - Re: Carb ice on a 912 (Roger Lee) 23. 06:42 PM - Re: Carb ice on a 912 (Roger Lee) 24. 07:31 PM - Re: Re: Carb ice on a 912 (Noel Loveys) ________________________________ Message 1 _____________________________________ Time: 12:19:45 AM PST US From: "Craig Payne" Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 But feeding cool air from outside the cowl gives you more power than the usual set-up of a filter on each carb drawing warm air from inside the cowl. How much I can't say. But I'm glad my Skyshop FWF kit for my Zenith 701 came with the Rotax air box because with my home field at 6300 feet I can use all the power I can get. -- Craig -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Les Goldner Sent: Tuesday, February 10, 2009 11:33 PM Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 Thanks Roger, Les Do not archive -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: Tuesday, February 10, 2009 6:33 PM Subject: RotaxEngines-List: Re: Carb ice on a 912 The majority of 912ULS's in the world or USA don't have carb heat. Because of the variable throat slide the Bing 64's are not prone to carb ice. Some say they have had it, but there are several well authored articles looking for anyone to actually prove they really had carb ice. I have posted these articles from the aviation world and well known authors on other sites before. There will be people who say they had it and pulled carb heat on and the roughness went away, but other situations can cause engine roughness. The aviation people are still looking for someone to prove carb ice in the 912ULS. Carb heat in in many planes using the 912 is more of a recent development over the last several years. The 912 has been around since late 1989. They haven't been falling out of the air from carb ice and they fly in every environment in the world. There are after market carb heating units for the carbs. One is electric and another hot coolant. Is it impossible well: "Never say Never" -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229658#229658 ________________________________ Message 2 _____________________________________ Time: 01:07:57 AM PST US From: "Robert C Harrison" Subject: RE: RotaxEngines-List: Carb ice on a 912 Hi! Les. I can't help with the situation on the 912ULS but you say that you usually fly high and over mountains presumably you will at some time of the trips be descending?. If you get a problem it would be descending on a low power setting into humidity at low altitude. You really need to seek out a graph which has been circulating which helps identify the flight envelopes where icing is most likely. It is humidity which is the ogre in this problem . Unfortunately I can't point you where to find the graph. I have a 914 Turbo which heats the intake charge much more than is healthy for the engine but also have an intercooler which drops the intake temp by 25 deg in the winter and 20 deg in the summer, however I have never seen the throat temp less than 6 deg. Regards Bob Harrison G-PTAG Europa -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Les Goldner Sent: 11 February 2009 01:48 Subject: RotaxEngines-List: Carb ice on a 912 I had to fly the other day in my Zenith 701 when OAT and dew point were both Zero-degrees. Erring toward caution, I flew high and over landable places since I don't have carb heat. This flight got gray matter going. I have heard that the 912ULS isn't very prone to icing but would like a more definitive answer to the carb icing prospects in a 912ULS that is inside a cowling. How important is it to have carb heat if you only fly high mountains in summer months? Les ________________________________ Message 3 _____________________________________ Time: 04:46:55 AM PST US From: Graham Singleton Subject: Re: RotaxEngines-List: Re: Carb ice on a 912 Roger Lee wrote: > > Carb heat in in many planes using the 912 is more of a recent development over the last several years. The 912 has been around since late 1989. They haven't been falling out of the air from carb ice and they fly in every environment in the world. There are after market carb heating units for the carbs. One is electric and another hot coolant. > > Is it impossible well: > "Never say Never" > -------- > Roger Lee Roger Agree, never say never! The UK Rotax agent has photographs of ice in a Bing carb on a 912, (Nigel Beale) He developed the hot coolant carb heat which I think makes the engine run better anyway, helps to evaporate the fuel drops and give better distribution. Check your EGTs, they swap around with different throttle settings due to the bends in the inlet manifold Graham ________________________________ Message 4 _____________________________________ Time: 05:02:25 AM PST US Subject: RotaxEngines-List: Re: Carb ice on a 912 From: "Thom Riddle" Les, I'm one who knows without a doubt that I've had carb ice in more than one of my 912UL engines. It can't be proven without equipping the engine with a "carb ice detector" because once you've landed and removed the air cleaner and disassembled the carb while the hot engine was melting the ice that was there, it is gone. I've been flying since 1966 long before Rotax was making aircraft engines and have had carb ice on many different aircraft over the years and know how the engine behaves when it has carb ice. I live in a somewhat humid area and have experienced definite carb ice on a cowled 912UL without airbox twice. Catching it early, I've been able to clear the ice by cycling the throttle from full to idle and back a few times. Apparently raising and lowering the slide while opening and closing the throttle valve is sufficient to break it up when caught early enough. The Bing 64 carbs are less likely to encounter carb ice than many other types of carbs but they are not immune to it. It is infrequent enough that I do not consider carb heat a requirement for me. Infrequent is not that same as non-existent. Following is a link to a probability chart for atmospheric conditions that are conducive to carb ice. http://www.ez.org/carb_ice.htm If you live in Arizona or other part of the SW or other arid desert areas, you will probably never encounter carb ice because the atmospheric conditions that are conducive to carb ice are unusual events, compared to other areas. In the eastern part of the US and other humid areas of the world a 912 engine can have carb ice. Notice on the chart that really cold temps are less prone to carb ice than moderate temps. -------- Thom Riddle Buffalo, NY http://riddletr.googlepages.com/sportpilot-cfi http://riddletr.googlepages.com/a%26pmechanix Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229710#229710 ________________________________ Message 5 _____________________________________ Time: 05:45:14 AM PST US From: Graham Singleton Subject: Re: RotaxEngines-List: Re: Carb ice on a 912 Thom Riddle wrote: > > Les, > > I'm one who knows without a doubt that I've had carb ice in more than one of my 912UL engines. I > If you live in Arizona or other part of the SW or other arid desert areas, you will probably never encounter carb ice because the atmospheric conditions that are conducive to carb ice are unusual events, compared to other areas. In the eastern part of the US and other humid areas of the world a 912 engine can have carb ice. > > Notice on the chart that really cold temps are less prone to carb ice than moderate temps. > > -------- > Thom Riddle > > Les Spot on! You won't get ice with dry air. Humidity is the problem. Nigel's hot water heater works well Graham ________________________________ Message 6 _____________________________________ Time: 06:15:17 AM PST US From: "Noel Loveys" Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 >From what I've read about the Bing carbs, the possibility of carb icing increases with the use of an airbox. Fortunately most of the engines with the airbox also have carb heat. Past posts have described icing but always with the airbox... Go figure! Noel -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Les Goldner Sent: Wednesday, February 11, 2009 3:03 AM Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 Thanks Roger, Les Do not archive -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: Tuesday, February 10, 2009 6:33 PM Subject: RotaxEngines-List: Re: Carb ice on a 912 The majority of 912ULS's in the world or USA don't have carb heat. Because of the variable throat slide the Bing 64's are not prone to carb ice. Some say they have had it, but there are several well authored articles looking for anyone to actually prove they really had carb ice. I have posted these articles from the aviation world and well known authors on other sites before. There will be people who say they had it and pulled carb heat on and the roughness went away, but other situations can cause engine roughness. The aviation people are still looking for someone to prove carb ice in the 912ULS. Carb heat in in many planes using the 912 is more of a recent development over the last several years. The 912 has been around since late 1989. They haven't been falling out of the air from carb ice and they fly in every environment in the world. There are after market carb heating units for the carbs. One is electric and another hot coolant. Is it impossible well: "Never say Never" -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229658#229658 ________________________________ Message 7 _____________________________________ Time: 07:04:03 AM PST US From: "Noel Loveys" Subject: RE: RotaxEngines-List: Carb ice on a 912 I think there is one of those graphs in the Cessna 172 POH. Noel From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Robert C Harrison Sent: Wednesday, February 11, 2009 5:36 AM Subject: RE: RotaxEngines-List: Carb ice on a 912 Hi! Les. I can't help with the situation on the 912ULS but you say that you usually fly high and over mountains presumably you will at some time of the trips be descending?. If you get a problem it would be descending on a low power setting into humidity at low altitude. You really need to seek out a graph which has been circulating which helps identify the flight envelopes where icing is most likely. It is humidity which is the ogre in this problem . Unfortunately I can't point you where to find the graph. I have a 914 Turbo which heats the intake charge much more than is healthy for the engine but also have an intercooler which drops the intake temp by 25 deg in the winter and 20 deg in the summer, however I have never seen the throat temp less than 6 deg. Regards Bob Harrison G-PTAG Europa -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Les Goldner Sent: 11 February 2009 01:48 Subject: RotaxEngines-List: Carb ice on a 912 I had to fly the other day in my Zenith 701 when OAT and dew point were both Zero-degrees. Erring toward caution, I flew high and over landable places since I don't have carb heat. This flight got gray matter going. I have heard that the 912ULS isn't very prone to icing but would like a more definitive answer to the carb icing prospects in a 912ULS that is inside a cowling. How important is it to have carb heat if you only fly high mountains in summer months? Les - The RotaxEngines-List Email Forum - --> http://www.matronics.com/Navigator?RotaxEngines-List - MATRONICS WEB FORUMS - --> http://forums.matronics.com - List Contribution Web Site - Thank you for your generous support! -Matt Dralle, List Admin. --> http://www.matronics.com/contribution ________________________________ Message 8 _____________________________________ Time: 07:50:46 AM PST US Subject: RotaxEngines-List: Re: Carb ice on a 912 From: "rampil" I have Nigel's carb heater system instead in my humid area of the NE USA. Unlike Cessna carb heat, it does not heat the inlet air, only the metal carb body, so there is little to no performance hit. It also weighs very little. I would certainly install it again if I were starting over. >From my week in Kingman, Az last summer, I can see how it would be hard to find icing condx in the summer (9) months of the year in Az. -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229751#229751 ________________________________ Message 9 _____________________________________ Time: 08:00:52 AM PST US Subject: RotaxEngines-List: Re: Carb ice on a 912 From: "Roger Lee" You can't apply standard icing issues to a 912ULS with the [b]variable throat[/b] carb because those studies are done with a fixed throat carb. If any of you have a picture or any proof please post it. There are several aviation authorities that would like to see this. I will try to dig back up those articles. I know what the conditions are that cause the problem, but we still don't see any 912ULS engines quitting because of carb ice. I haven't read any FAA investigations laying the blame on carb ice. These engines have been flying in all parts of the humid world (hot and cold) for decades with no carb ice heater. The variable throat is still the key help. If you have some proof please post it so I can send it on to the aviation authorities. I don't believe it is impossible, just so highly unlikely no to ever worry about. If you are flying I wouldn't lose any sleep over it. I have flown all over the country with a 912 ULS from sea level to 16K, from 0F-115F and 7%-95% humidity, rain and snow and have never had a problem.If you really think about so do all of you fly in these conditions because you live all over the world and we fly and don't have any issues. You shouldn't always think because your engine had a rough moment that it was carb ice. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229756#229756 ________________________________ Message 10 ____________________________________ Time: 08:30:00 AM PST US Subject: RotaxEngines-List: Re: Carb ice on a 912 From: "Thom Riddle" Roger, No one is arguing that carb ice is unlikely with the variable venturi type carbs. I stated that myself in my posts on this subject both today and in previous posts. I've also stated that without a carb ice detector installed in the carb there can be no scientific proof that ice actually formed in the carb. This statement applies to all carburetors, not just Bing 64. The closest thing to proof one can get without an ice detector is with a manually controllable carb heat device, like those on virtually all GA aircraft engines. When the engine behaves as if the carb is icing, apply this manual carb heat and see the results which are described in virtually every GA aircraft POH built in the last 40 years or so. To my knowledge, no one has "proven" that carb ice existed in these GA aircraft engines without a carb ice detector but by the same token nobody disputes it is happening without said proof. Absence of proof (carb ice detector) is not absence of evidence, regardless of whether you are talking about a conventional GA aircraft engine carburetor or a variable venturi carburetor. Your travels all over the country including humid conditions without experiencing carb ice is not proof that sometimes some Bing 64s do ice up. As I've stated multiple times. I rarely (not the same as never) get carb ice in my Bing 64 carbs but it does happen occasionally; in my case twice in the last eight years of flying 912 engines. This is based on the distinctive symptoms that accompany carb ice and the elimination of those symptoms by the method I already described. BTW, are you aware that the Diamond Katana, type certificated airplane with Rotax 912 certificated engine is equipped with manual carb heat? If you insist on proof that a Bing 64 carb has actually iced up, I must ask for similar proof from you that it CANNOT ice up. Works both ways. -------- Thom Riddle Buffalo, NY http://riddletr.googlepages.com/sportpilot-cfi http://riddletr.googlepages.com/a%26pmechanix Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229764#229764 ________________________________ Message 11 ____________________________________ Time: 09:17:30 AM PST US From: Gilles Thesee Subject: Re: RotaxEngines-List: Re: Carb ice on a 912 Thom Riddle a crit : > BTW, are you aware that the Diamond Katana, type certificated airplane with Rotax 912 certificated engine is equipped with manual carb heat? Thom and all, Diamond and some others have chosen the easiest way : implement the carb heat systems specified in the FAR/JAR 23. No problem with red tape, no problem with the majority of pilots who have only heard of Lyco/Conti engines. Now the question might be, is this carb heat efficient or not, do others way to prevent carb ice exist ? To my knowledge, no one has a clear idea as to when, how, under what conditions the Bing carburetors do ice up and deice. The only thing I know for sure, is that ice cannot possibly build up in a warm carb body, and our own carbs do run warm. Are our carb throats, needles, jets etc. warm enough, I don't know. Are the off-the-shelf electric or water heating devices efficient, I don't know either. Bottom line, if one builds with the inspector's approval on mind, do put a carb heat devised for a Marvel carb, he'll be happy. If one builds for maximum safety, the question is still open. Best regards, -- Gilles http://contrails.free.fr ________________________________ Message 12 ____________________________________ Time: 09:55:19 AM PST US From: "Peter Jeffers" Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 In the UK we probably fly in more potentially icing conditions than in most other locations. I fly my Europa with a 912ul engine with plenum chamber fitted and no carb heater of any kind. I now have some 1200 hours on the aircraft and can definitely affirm that we do experience what we take to be carb icing. Yes probably carb icing because it always and only occurs in high humidity conditions. I have found it to be fairly predictable, to the extent that I can warn my passengers in advance when I expect it to occur and it usually does. The symptoms are not the same as those experienced on Continentals/Lycomings where a slow almost imperceptible loss of power with constant throttle is observed. On the 912 the clue is a short period (1 or 2 seconds) of rough running which then clears to normal running followed a few moments later by the same symptoms presumably the other carb. The whole sequence will then be repeated several minutes later (assuming you do nothing about it). I find that warming the engine by making it work ie climbing or accelerating for a few minutes will delay a further event by some considerable length of time if not the rest of the flight. The other solution is a carb heater. The best is that which uses engine coolant to warm the carb body. Pete Jeffers --Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Thom Riddle Sent: 11 February 2009 16:29 Subject: RotaxEngines-List: Re: Carb ice on a 912 Roger, No one is arguing that carb ice is unlikely with the variable venturi type carbs. I stated that myself in my posts on this subject both today and in previous posts. I've also stated that without a carb ice detector installed in the carb there can be no scientific proof that ice actually formed in the carb. This statement applies to all carburetors, not just Bing 64. The closest thing to proof one can get without an ice detector is with a manually controllable carb heat device, like those on virtually all GA aircraft engines. When the engine behaves as if the carb is icing, apply this manual carb heat and see the results which are described in virtually every GA aircraft POH built in the last 40 years or so. To my knowledge, no one has "proven" that carb ice existed in these GA aircraft engines without a carb ice detector but by the same token nobody disputes it is happening without said proof. Absence of proof (carb ice detector) is not absence of evidence, regardless of whether you are talking about a conventional GA aircraft engine carburetor or a variable venturi carburetor. Your travels all over the country including humid conditions without experiencing carb ice is not proof that sometimes some Bing 64s do ice up. As I've stated multiple times. I rarely (not the same as never) get carb ice in my Bing 64 carbs but it does happen occasionally; in my case twice in the last eight years of flying 912 engines. This is based on the distinctive symptoms that accompany carb ice and the elimination of those symptoms by the method I already described. BTW, are you aware that the Diamond Katana, type certificated airplane with Rotax 912 certificated engine is equipped with manual carb heat? If you insist on proof that a Bing 64 carb has actually iced up, I must ask for similar proof from you that it CANNOT ice up. Works both ways. -------- Thom Riddle Buffalo, NY http://riddletr.googlepages.com/sportpilot-cfi http://riddletr.googlepages.com/a%26pmechanix Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229764#229764 Checked by AVG - www.avg.com 17:44:00 ________________________________ Message 13 ____________________________________ Time: 10:14:20 AM PST US From: "Craig Payne" Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 But the same Bing carb (at least style) is fitted on Jabirus and their FWF kits routinely include carb heat. -- Craig -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: Wednesday, February 11, 2009 9:00 AM Subject: RotaxEngines-List: Re: Carb ice on a 912 You can't apply standard icing issues to a 912ULS with the [b]variable throat[/b] carb because those studies are done with a fixed throat carb. If any of you have a picture or any proof please post it. There are several aviation authorities that would like to see this. I will try to dig back up those articles. I know what the conditions are that cause the problem, but we still don't see any 912ULS engines quitting because of carb ice. I haven't read any FAA investigations laying the blame on carb ice. These engines have been flying in all parts of the humid world (hot and cold) for decades with no carb ice heater. The variable throat is still the key help. If you have some proof please post it so I can send it on to the aviation authorities. I don't believe it is impossible, just so highly unlikely no to ever worry about. If you are flying I wouldn't lose any sleep over it. I have flown all over the country with a 912 ULS from sea level to 16K, from 0F-115F and 7%-95% humidity, rain and snow and have never had a problem.If you really think about so do all of you fly in these conditions because you live all over the world and we fly and don't have any issues. You shouldn't always think because your engine had a rough moment that it was carb ice. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229756#229756 ________________________________ Message 14 ____________________________________ Time: 10:15:07 AM PST US From: Graham Singleton Subject: Re: RotaxEngines-List: Re: Carb ice on a 912 Thom Riddle wrote: > > Roger, > No one is arguing that carb ice is unlikely with the variable venturi type carbs. This is based on the distinctive symptoms that accompany carb ice and the elimination of those symptoms by the method I already described. BTW, are you aware that the Diamond Katana, type certificated airplane with Rotax 912 certificated engine is equipped with manual carb heat? > > If you insist on proof that a Bing 64 carb has actually iced up, I must ask for similar proof from you that it CANNOT ice up. Works both ways. > > -------- > Thom Riddle > Thom You are right. I have seen photographs showing carb ice, taken by Nigel Beale, at least ten years ago. It does happen. He used them to help market his carb heater. What more proof do you want Roger? Graham ________________________________ Message 15 ____________________________________ Time: 10:21:23 AM PST US From: Gilles Thesee Subject: Re: RotaxEngines-List: Re: Carb ice on a 912 Craig Payne a crit : > But the same Bing carb (at least style) is fitted on Jabirus and their FWF > kits routinely include carb heat. > What is not sure is, did they do their homework and conducted a thorough icing study, or did they do like others and install a Lyco carb heat ? Now a Jabiru quitting in flight due to carb ice is something unheard of ;-) Best regards, -- Gilles http://contrails.free.fr ________________________________ Message 16 ____________________________________ Time: 11:05:08 AM PST US From: "Craig Payne" Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 Doesn't that make sense? Engines with air boxes are drawing cool air from outside the cowl. Engines without are drawing warm air from under the cowl. Without an air box carb heat is essentially always on. -- Craig -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Noel Loveys Sent: Wednesday, February 11, 2009 7:14 AM Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 >From what I've read about the Bing carbs, the possibility of carb icing increases with the use of an airbox. Fortunately most of the engines with the airbox also have carb heat. Past posts have described icing but always with the airbox... Go figure! Noel -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Les Goldner Sent: Wednesday, February 11, 2009 3:03 AM Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 Thanks Roger, Les Do not archive -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: Tuesday, February 10, 2009 6:33 PM Subject: RotaxEngines-List: Re: Carb ice on a 912 The majority of 912ULS's in the world or USA don't have carb heat. Because of the variable throat slide the Bing 64's are not prone to carb ice. Some say they have had it, but there are several well authored articles looking for anyone to actually prove they really had carb ice. I have posted these articles from the aviation world and well known authors on other sites before. There will be people who say they had it and pulled carb heat on and the roughness went away, but other situations can cause engine roughness. The aviation people are still looking for someone to prove carb ice in the 912ULS. Carb heat in in many planes using the 912 is more of a recent development over the last several years. The 912 has been around since late 1989. They haven't been falling out of the air from carb ice and they fly in every environment in the world. There are after market carb heating units for the carbs. One is electric and another hot coolant. Is it impossible well: "Never say Never" -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229658#229658 ________________________________ Message 17 ____________________________________ Time: 12:03:27 PM PST US From: "Noel Loveys" Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 As I have been reading the mail on this thread something came to mind... As a Kid I owned a 69 Rover SC 2000 car complete with the side draft SU carb... I eventually swapped out a few parts and turned it into a TC ( Twin carb ) Today I can't remember ever seeing a heat stove hooked up to that carb. I also don't remember a heat stove on any of the Jags, minis or even the couple of RR that I had the chance to peek under the bonnet. If those cars can work for decades without carb heat I guess the 912 will too with the similar bing carb.. Later I had a Pontiac Safari Station wagon with a 305 (terrible engine) for some reason the scat tube form the heat stove to the air cleaner had been removed. Almost every time it rained I would have carb ice but at that time I didn't know what it was... until the day the throttle froze open. As was mentioned about taking apart the air cleaner and having a look down the throat of the carb by that time a lot of the ice had melted. I wasn't long hooking up the heat stove again. Noel -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: Wednesday, February 11, 2009 12:30 PM Subject: RotaxEngines-List: Re: Carb ice on a 912 You can't apply standard icing issues to a 912ULS with the [b]variable throat[/b] carb because those studies are done with a fixed throat carb. If any of you have a picture or any proof please post it. There are several aviation authorities that would like to see this. I will try to dig back up those articles. I know what the conditions are that cause the problem, but we still don't see any 912ULS engines quitting because of carb ice. I haven't read any FAA investigations laying the blame on carb ice. These engines have been flying in all parts of the humid world (hot and cold) for decades with no carb ice heater. The variable throat is still the key help. If you have some proof please post it so I can send it on to the aviation authorities. I don't believe it is impossible, just so highly unlikely no to ever worry about. If you are flying I wouldn't lose any sleep over it. I have flown all over the country with a 912 ULS from sea level to 16K, from 0F-115F and 7%-95% humidity, rain and snow and have never had a problem.If you really think about so do all of you fly in these conditions because you live all over the world and we fly and don't have any issues. You shouldn't always think because your engine had a rough moment that it was carb ice. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229756#229756 ________________________________ Message 18 ____________________________________ Time: 12:19:41 PM PST US From: "Robert C Harrison" Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 Hi! Gilles I can vouch for my ex-jabiru 3300 getting ice three or four times once in the UK on very hot and humid flight in the midlands, second time departing from Southend direct to Denmark about 20 miles out about 2,000 ft level, third time crossing Sweden same height (with nothing but rocks lakes and damn trees as far as one could see!) all in June. Fourth time going straight out five miles from LeTouque at about 1000ft probably in August. ALL VIVIDLY MARKED ON MY BRAIN! In all cases engaging carb heat caused a further little engine cough with no further problem. The carb heat was a simple flap valve enabling warm air from round the muffler to be fed to the air box. I'm convinced that the engine knows when you are in the most critical part of your journey to give a cough ! Regards Bob Harrison G-PTAG(now with 914 and Bell Intercooler and no carb heat YET!) -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Gilles Thesee Sent: 11 February 2009 18:21 Subject: Re: RotaxEngines-List: Re: Carb ice on a 912 Craig Payne a crit : > But the same Bing carb (at least style) is fitted on Jabirus and their FWF > kits routinely include carb heat. > What is not sure is, did they do their homework and conducted a thorough icing study, or did they do like others and install a Lyco carb heat ? Now a Jabiru quitting in flight due to carb ice is something unheard of ;-) Best regards, -- Gilles http://contrails.free.fr ________________________________ Message 19 ____________________________________ Time: 01:39:01 PM PST US Subject: RotaxEngines-List: Re: Carb ice on a 912 From: "rampil" Drawing air from the engine compartment may prevent many cases of carb ice but at a tremendous performance hit of using only heated air, and with no ram pressure effect. No one flys a cessna with carb heat on, full time, and carb heating has been cited by the NTSB as responsible for crashes in attempted go-arounds. -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229841#229841 ________________________________ Message 20 ____________________________________ Time: 02:12:30 PM PST US From: "Dave G" Subject: Re: RotaxEngines-List: Re: Carb ice on a 912 I don't know how this carb was iced, but it claims this is an example of carb icing. It's from an ad for carb body heater. Thery fact that they had a camera and an icy carb together at the same place makes me think it was staged, but still; here is an icy Bing ________________________________ Message 21 ____________________________________ Time: 05:41:09 PM PST US From: "Robert C Harrison" Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 Hi! Noel I had an early Austin A 40 my first car it was fitted with a zenith down draught carb gave me lots of problems and many journeys had to be run at very low RPM until I got pissed off with it pressed it hard for a few miles stopped and jumped out to look under the bonnet to find enough ice to operate a bloody oxygen plant ! Can't remember what I did to it other than sell it !(happy days) Regards Bob Harrison -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Noel Loveys Sent: 11 February 2009 20:00 Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 As I have been reading the mail on this thread something came to mind... As a Kid I owned a 69 Rover SC 2000 car complete with the side draft SU carb... I eventually swapped out a few parts and turned it into a TC ( Twin carb ) Today I can't remember ever seeing a heat stove hooked up to that carb. I also don't remember a heat stove on any of the Jags, minis or even the couple of RR that I had the chance to peek under the bonnet. If those cars can work for decades without carb heat I guess the 912 will too with the similar bing carb.. Later I had a Pontiac Safari Station wagon with a 305 (terrible engine) for some reason the scat tube form the heat stove to the air cleaner had been removed. Almost every time it rained I would have carb ice but at that time I didn't know what it was... until the day the throttle froze open. As was mentioned about taking apart the air cleaner and having a look down the throat of the carb by that time a lot of the ice had melted. I wasn't long hooking up the heat stove again. Noel -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: Wednesday, February 11, 2009 12:30 PM Subject: RotaxEngines-List: Re: Carb ice on a 912 You can't apply standard icing issues to a 912ULS with the [b]variable throat[/b] carb because those studies are done with a fixed throat carb. If any of you have a picture or any proof please post it. There are several aviation authorities that would like to see this. I will try to dig back up those articles. I know what the conditions are that cause the problem, but we still don't see any 912ULS engines quitting because of carb ice. I haven't read any FAA investigations laying the blame on carb ice. These engines have been flying in all parts of the humid world (hot and cold) for decades with no carb ice heater. The variable throat is still the key help. If you have some proof please post it so I can send it on to the aviation authorities. I don't believe it is impossible, just so highly unlikely no to ever worry about. If you are flying I wouldn't lose any sleep over it. I have flown all over the country with a 912 ULS from sea level to 16K, from 0F-115F and 7%-95% humidity, rain and snow and have never had a problem.If you really think about so do all of you fly in these conditions because you live all over the world and we fly and don't have any issues. You shouldn't always think because your engine had a rough moment that it was carb ice. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229756#229756 ________________________________ Message 22 ____________________________________ Time: 06:09:28 PM PST US Subject: RotaxEngines-List: Re: Carb ice on a 912 From: "Roger Lee" I think I'm with OCCOM on this picture of Bing carb ice. I blew this pic up to 500% and took a good look. I don't think this carb would even work with this much ice. How did it fly? How did they set up just the right atmospheric and pressure situations and how did they get it back on the ground pull a cowl in a hot compartment, pull the air cleaner and have this much ice? What about the other carb. I will forward this picture to Eric Tucker at Rotax and see what his take on it is. When I see an Mfg. with a hard to believe pic or claim to fit their product I tend to take a step back and look again. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229894#229894 ________________________________ Message 23 ____________________________________ Time: 06:42:01 PM PST US Subject: RotaxEngines-List: Re: Carb ice on a 912 From: "Roger Lee" Ok here is a more official word even if I have to eat my own. I will always seek out a good answer and I admit I need to adjust my thinking some. Here is an answer from Eric Tucker from Rotax. I sent the picture to Eric and ask his opinion. Hello Roger Do I believe it, yes...in England they have high humidity and the temperatures that make any engine with a carburetor prone to icing. (Due point and temperature match) Any venturi that moves air will experience a temperature drop, if that drop occurs and brings saturated air into the engine venture at the freezing point of moisture, bingo carb ice. While it may be unlikely that a Rotax will ice, it can and has happened in my experience. In most cases the engine bay is so hot, due to the fact that most installations do not have baffles and very few OEM do any airflow testing, the engines are sucking hot air from inside the cowlings. Hot air robs a bit of power, but protects against ice. In the case of exposed engines, as in most UL applications, the operations are normally not in these conditions, its just too cold to fly in saturated air even at mild temperatures up to 70 degrees. I personally like the hot water systems that they have developed, they do not cause a loss of power because they do not heat the air, they heat the carb body were the ice forms. In addition it should be noted that the guys in the UK who developed this are long time aircraft supply people and both of the principals happen to be engineers. They also developed the soft start module for the ignition. Rotax liked the idea so much that it will be built into the ignitions starting mid 2009. Regards, Eric P.S. I hope this helps all of us. Roger Lee -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=229902#229902 ________________________________ Message 24 ____________________________________ Time: 07:31:00 PM PST US From: "Noel Loveys" Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 When I was a little kid my father had an A-40 in Glasgow. His friends used to joke it was the only "loy" car in the UK. Loy is what they called body filler. It never ran when it was needed and there was only one window crank. When he bought it the left indicator was shot. He had that car for the full four years we lived in Scotland. I never asked what happened to that car when he finally left Scotland. I expect it may be an anchor at the bottom of Loc Dhoon. I remember visiting one of his friends once and going for a drive in his Rolls Royce. Want to talk about culture shock! Go from the remains of a well abused A40 hanging on by a roll of cotton thread and a wad of chewing gum to a brand new Rolls Royce! Being a kid I liked the tables in the back seat. Noel -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Robert C Harrison Sent: Wednesday, February 11, 2009 10:10 PM Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 Hi! Noel I had an early Austin A 40 my first car it was fitted with a zenith down draught carb gave me lots of problems and many journeys had to be run at very low RPM until I got pissed off with it pressed it hard for a few miles stopped and jumped out to look under the bonnet to find enough ice to operate a bloody oxygen plant ! Can't remember what I did to it other than sell it !(happy days) Regards Bob Harrison -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Noel Loveys Sent: 11 February 2009 20:00 Subject: RE: RotaxEngines-List: Re: Carb ice on a 912 As I have been reading the mail on this thread something came to mind... As a Kid I owned a 69 Rover SC 2000 car complete with the side draft SU carb... I eventually swapped out a few parts and turned it into a TC ( Twin carb ) Today I can't remember ever seeing a heat stove hooked up to that carb. I also don't remember a heat stove on any of the Jags, minis or even the couple of RR that I had the chance to peek under the bonnet. If those cars can work for decades without carb heat I guess the 912 will too with the similar bing carb.. Later I had a Pontiac Safari Station wagon with a 305 (terrible engine) for some reason the scat tube form the heat stove to the air cleaner had been removed. Almost every time it rained I would have carb ice but at that time I didn't know what it was... until the day the throttle froze open. As was mentioned about taking apart the air cleaner and having a look down the throat of the carb by that time a lot of the ice had melted. I wasn't long hooking up the heat stove again. Noel -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: Wednesday, February 11, 2009 12:30 PM Subject: RotaxEngines-List: Re: Carb ice on a 912 You can't apply standard icing issues to a 912ULS with the [b]variable throat[/b] carb because those studies are done with a fixed throat carb. If any of you have a picture or any proof please post it. There are several aviation authorities that would like to see this. I will try to dig back up those articles. I know what the conditions are that cause the problem, but we still don't see any 912ULS engines quitting because of carb ice. I haven't read any FAA investigations laying the blame on carb ice. These engines have been flying in all parts of the humid world (hot and cold) for decades with no carb ice heater. The variable throat is still the key help. If you have some proof please post it so I can send it on to the aviation authorities. I don't believe it is impossible, just so highly unlikely no to ever worry about. If you are flying I wouldn't lose any sleep over it. I have flown all over the country with a 912 ULS from sea level to 16K, from 0F-115F and 7%-95% humidity, rain and snow and have never had a problem.If you really think about so do all of you fly in these conditions because you live all over the world and we fly and don't have any issues. You shouldn't always think because your engine had a rough moment that it was carb ice. -------- Roger Lee Tucson, Az. 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