bmar Posted April 7, 2017 Report Share Posted April 7, 2017 Does anyone have a stock muffler for the CTLS. Doing a pre-buy and the muffler is cracked. Thanks! Link to comment Share on other sites More sharing options...
FlyingMonkey Posted April 7, 2017 Report Share Posted April 7, 2017 It can be welded. Mine had extensive cracking and a good stainless welder made it better than new. Link to comment Share on other sites More sharing options...
Roger Lee Posted April 7, 2017 Report Share Posted April 7, 2017 Just weld it. Cheaper, easier and quicker. It won't cause any problems and if welded right will last forever. This is not uncommon. Link to comment Share on other sites More sharing options...
bmar Posted April 7, 2017 Author Report Share Posted April 7, 2017 Here is the crack. Is this the same area your muffflers have cracked? What's the cause? Link to comment Share on other sites More sharing options...
FlyingMonkey Posted April 7, 2017 Report Share Posted April 7, 2017 That's a totally different crack than mine. If you pop the muffler off and pinch that joint back together, bead weld it, and then put a doubler around it and weld that, it should be better than new. Here's the cracks I had, spider-webbed out from the exhaust stack: And the repair: Link to comment Share on other sites More sharing options...
Roger Lee Posted April 7, 2017 Report Share Posted April 7, 2017 Nice talking to you this morning. Easy. Weak spot at the base of the welded knuckle. It can be welded to get you home. You can buy this female knuckle through a Rotax service center IF it needs replacement after you get home or you think the weld isn't that great. Link to comment Share on other sites More sharing options...
N456TS Posted April 7, 2017 Report Share Posted April 7, 2017 I am curious.... Those making these exhaust repairs on an S-LSA, are these repair procedures approved by FD via an LOA, or by the maintenance manual, or is this repair claimed to be covered under AC 43.13? Link to comment Share on other sites More sharing options...
Roger Lee Posted April 7, 2017 Report Share Posted April 7, 2017 Yes, maybe or possibly not. I will say that this is how 95% of the people deal with a crack in the muffler system. Rotax only supplies an engine with the exhaust pipe as a stub out on a new engine and the rest of the pipe gets welded because there are some many variations in the flying world. Link to comment Share on other sites More sharing options...
Anticept Posted April 7, 2017 Report Share Posted April 7, 2017 Rotax provides the info on repairing exhausts in their manuals, such as the stainless steel spec. They leave it really open ended because generally, exhaust repairs are recommended to be handled by specialists (who know how to handle the carbon residue issues), but there's nothing prohibiting it anywhere. If you put two lawyers in a room to argue it out, the LOA part would probably win out by strict interpretation. If you asked flight design though, they will say "do what rotax recommends" as they wash their hands of it. Link to comment Share on other sites More sharing options...
N456TS Posted April 7, 2017 Report Share Posted April 7, 2017 Hmm... I like that you're trying to argue that there is nothing wrong, and I personally believe this is a safe repair. However, it is pretty clear, unless there is step-by-step directions in the manuals (per ASTM spec), or in via an LOA (per ASTM spec), or something approved by the FAA, it's an illegal repair rendering the airworthiness invalid. As I said, I don't believe there is anything unsafe at all, but I don't think it's wise to suggest welding unless the person receiving the advise understands the full situation. If FD is asked, they shouldn't be saying "do what Rotax recommends". Rotax didn't make that exhaust. They have an obligation to stay within those specs. I suspect they will say "replace it" and give us lots of money for the part. Link to comment Share on other sites More sharing options...
Anticept Posted April 8, 2017 Report Share Posted April 8, 2017 Yes, rotax made that exhaust. The parts that are not rotax made are the pipes coming off the engine to the manifold, but they are made to rotax spec using rotax parts. You will find these parts in the rotax parts catalog. Link to comment Share on other sites More sharing options...
N456TS Posted April 10, 2017 Report Share Posted April 10, 2017 Yes, rotax made that exhaust. The parts that are not rotax made are the pipes coming off the engine to the manifold, but they are made to rotax spec using rotax parts. You will find these parts in the rotax parts catalog. So, there is a Rotax part number(s) for a complete bolt-on exhaust system for a CT? Not components of a part? What P/N? Link to comment Share on other sites More sharing options...
Roger Lee Posted April 10, 2017 Report Share Posted April 10, 2017 There is no complete exhaust system for any plane. Rotax only supplies the stub out of the engine (about 2") and it supplies the muffler with the female knuckle welded on. Anything in between you must weld. You can buy the parts from Rotax though. Link to comment Share on other sites More sharing options...
Anticept Posted April 10, 2017 Report Share Posted April 10, 2017 So, there is a Rotax part number(s) for a complete bolt-on exhaust system for a CT? Not components of a part? What P/N? Exhausts are made by the manufacturers to rotax's recommendations, consisting of said components for a part. Much the same way the fuel system is unique to each aircraft model, yet follows specific recommendations. The info on the exhaust recommendations, as well as specifications regarding the materials in which it is made, is found in the respective engine installation manual. Part numbers are found in the parts manual. Simply put: I would love to have LOAs or step by step repair information to be 100% kosher. It's an exercise in futility getting them. The common response has been pointing the fingers elsewhere (rotax doesn't want to say anything that puts them on the hook that isn't already in their manuals regardless of aircraft certification, and flight design just points to rotax and says 'ask them'). There is, however, quite detailed specifications contained in the install manual. Spec numbers. Steel thickness recommendations. Radii. Diameters. Dimensions. It's all there, everything one needs that would be found in repair instructions. Link to comment Share on other sites More sharing options...
Runtoeat Posted April 10, 2017 Report Share Posted April 10, 2017 Corey, good info. IMHO, a repair of the exhaust that is done by a repair person who is knowledgeable of metallurgy and who uses this published info to support the proper welding technique, would result in a airworthy repair. If there is no published repair procedure forthcoming from either FD or Rotax after this has been requested, IMHO the only option would be for the repair person to research the published part and material information and then use "best practices" to make the repair. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted April 10, 2017 Report Share Posted April 10, 2017 The exhaust system is probably the simplest part of the airplane. It's just stainless tubing. Any welder competent in stainless can make repairs to it. When I had my repairs done, I was 1400nm from home, and used a certified welder at the local airport do the repairs with the advice of some very experienced CT folks. Frankly the practicality of getting the airplane repaired and ready to return home outweighed considerations of the possible need for an LOA/MRA, especially since, as the discussion here shows, it falls in a somewhat gray area. Since then I have taken the airplane E-LSA, and the inspection for that change was done by a DAR with plenty of LSA / Rotax / CT experience. He looked my airplane over with a fine-toothed comb, and any change made that didn't conform to the original S-LSA condition would have had to be corrected before he issued a new E-LSA AW certificate. He didn't say boo about my quite obvious exhaust repairs, even after he ran his hand over the patch on my muffler. Based on my experience, I think quality repairs on this system made by qualified individuals are among the least likely to be questioned by anybody either at FD or the FAA. And that opinion is worth exactly what ya'll paid for it. Link to comment Share on other sites More sharing options...
Anticept Posted April 10, 2017 Report Share Posted April 10, 2017 The ones that are least likely to be questioned are those that are professional and don't result in accidents Link to comment Share on other sites More sharing options...
FlyingMonkey Posted April 10, 2017 Report Share Posted April 10, 2017 The ones that are least likely to be questioned are those that are professional and don't result in accidents I agree, but the chances of an exhaust problem causing an accident seem unlikely. I flew my broken exhaust without knowing it for probably 2-3 hours before catching it (from Page to Sedona to Tucon!), and that failure included a complete break in one of the pipes just a few inches past the cylinder, close to the battery and the carb drip tray: That is about a worst case scenario for exhaust issues, and the only issues noted was that my airplane was louder than usual and there was gray exhaust dust all over that side of the engine compartment. My CO monitor never showed any problems, and there was no heat damage to anything in front of the firewall. Notice in the picture even the zip ties are not melted or otherwise damaged. Link to comment Share on other sites More sharing options...
Anticept Posted April 10, 2017 Report Share Posted April 10, 2017 To be a bit pedantic in the interest of safety, there's still quite a difference between unlikely and impossible. That said, I would agree. Link to comment Share on other sites More sharing options...
Roger Lee Posted April 10, 2017 Report Share Posted April 10, 2017 The CO monitor most likely would not have shown anything because that air gets flushed out the bottom of the plane and the CO in the cockpit would have to reach a certain level. Publish a pick of your weld job. Link to comment Share on other sites More sharing options...
N456TS Posted April 12, 2017 Report Share Posted April 12, 2017 It's nice to see my point confirmed above. Once again, I consider it a safe repair, but not legal. The regulations are pretty clear cut. The specs in the Rotax manual is perfect for home builders and manufacturers, but is nowhere close to meeting the instructional requirements with regard to using that data along to justify the repair. So, this goes back to do this correctly, you need to buy an exhaust assembly from FD (unless they authorize an alternative method via an LOA). If we all recall, the OP is buying a used aircraft and this problem was found during a pre-buy inspection. They should be trying to work down the price based off of the cost of a proper legal repair and not a weld job. This is the point. But as I said, I would consider it a safe repair. I have the background to make those calls, but this is about what's correct for the OP. I have concerns about why they're failing, but I'm not on their payroll! Link to comment Share on other sites More sharing options...
Wadeflyguy Posted April 17, 2017 Report Share Posted April 17, 2017 Hello, If you are still thinking about replacing the muffler I have a used one off a 2007 CTSW. It is in great shape with 300 hours but has very small dent in it. I am asking half price of new. Thanks! Wade Nelson 763-464-2566 Link to comment Share on other sites More sharing options...
FlyingMonkey Posted April 18, 2017 Report Share Posted April 18, 2017 Publish a pick of your weld job. Sorry, meant to do this days ago. Amazing work, with stress relief patches on both sides of the bend. Link to comment Share on other sites More sharing options...
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