Gary Manuel Posted April 11, 2014 Share Posted April 11, 2014 I'm just building a model with a DLE55RA petrol engine, which is the first petrol model I've ever built. I already own a model with a Zenoah G62 so I know about running petrol engines. I'm a little confused about how to deal with fuel foaming / air bubbles, which I'm told are our worst enemy. I believe that there are two options - Felt Clunks or Sintered Bronze clunks. I've never seen this explained so these are my thoughts and I may be wrong, so please feel free to correct me. Both work by creating a small filtered "resevoir" of fuel which soaks up fuel from the tank and maintains the fuel flow if the clunk is starved of fuel. They both also act as fine filters, preventing air bubbles from entering the reservoir. So here's the questions: 1. Which is best - Sintered Bronze or Felt , and why? 2. Any recommendations on particular brands / suppliers? 3. Am I talking rubbish about how they work? Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted April 11, 2014 Share Posted April 11, 2014 I cant give you the science Gary all mine have felt ones All my work tools, chainsaws, petrol shears etc have felt ones If its good enough for Stihl its good enough for me Never have problems by the way Quote Link to comment Share on other sites More sharing options...
Levanter Posted April 11, 2014 Share Posted April 11, 2014 I read somewhere that felt was widely used for petrol engines and sintered bronze for nitro. I don't know why though. Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted April 11, 2014 Author Share Posted April 11, 2014 John, People used to put hay into the power plant of their transport - now they use petrol Times they are a changin' PS - I do plan on using a felt one myself unless someone convinces me that Sintered Bronze ones are better. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted April 11, 2014 Share Posted April 11, 2014 You would know more about farmyards than myself Gary I have seen your build blog Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted April 12, 2014 Author Share Posted April 12, 2014 Posted by Levanter3 on 11/04/2014 15:31:40: I read somewhere that felt was widely used for petrol engines and sintered bronze for nitro. I don't know why though. That's interesting. Can anyone confirm this and ideally explain why? Quote Link to comment Share on other sites More sharing options...
Lindsay Todd Posted April 12, 2014 Share Posted April 12, 2014 Always used felt, never had any issues. Linds Quote Link to comment Share on other sites More sharing options...
iqon Posted April 12, 2014 Share Posted April 12, 2014 Only use felt onesfor petrol..... Quote Link to comment Share on other sites More sharing options...
reg shaw Posted April 12, 2014 Share Posted April 12, 2014 Only issue with felt clunks is that they can give off fluff if they've been left empty for a while. Simple solution is to leave some petrol in the tank. Best option though is to fly regularly!! All mine have felt clunks but it's an issue to be aware of. Ian. Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted April 13, 2014 Author Share Posted April 13, 2014 Ian, That makes sense. One distributor is saying that the Sintered Bronze is the ultimate filter and as it can be left for long periods in an empty fuel tank. Anyway, I will use felt but am still intrigued by the Sintered Bronze ones, so if anyone can throw any light, please do. Quote Link to comment Share on other sites More sharing options...
Ultymate Posted April 13, 2014 Share Posted April 13, 2014 Felt all the way sintered bronze good for fish tanks Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted April 13, 2014 Author Share Posted April 13, 2014 Hi Ultimate, You are saying the same as everyone else, but is this from experience? Quote Link to comment Share on other sites More sharing options...
Charles Lee Posted April 13, 2014 Share Posted April 13, 2014 I've used the JP felt clunk with no problems except the weight of the clunk + a heavy arrival caused it to turn back on itself, now cured by a piece of brass tubing midway. I was told to wash the new clunk in water a couple of times to remove excess fibres. Quote Link to comment Share on other sites More sharing options...
Ultymate Posted April 13, 2014 Share Posted April 13, 2014 Posted by Gary Manuel on 13/04/2014 09:36:35: Hi Ultimate, You are saying the same as everyone else, but is this from experience? Yes been flying petrol for years now always use felt clunks (have tried sintered once) Felt are easy to clean by back flushing if necessary. They never seem to clog, I've seen them in my chainsaws when I pull them for servicing looking like a solid mass of sawdust but still allow the fuel through. I do always keep fuel in my tanks be it chainsaw or model Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted April 13, 2014 Author Share Posted April 13, 2014 Thanks for your feedback fellas Quote Link to comment Share on other sites More sharing options...
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