Manish Chandrayan Posted November 20, 2021 Share Posted November 20, 2021 Danny, can't you use the flexible conduit to do the same instead of the 90 degree knuckles or may be one knuckle and then the flexible extension on to the cylindrical chamber? 1 Quote Link to comment Share on other sites More sharing options...
David Davis Posted November 20, 2021 Share Posted November 20, 2021 It will work, I have a piece of silicone connecting the exhaust of my OS70FL to the silencer supplied with my BE2e kit, but be prepared replace the silicone every season. According to Jonathan Harper of Laser Engines, it's the temperature of a four-stroke exhaust which will destroy a silicone pipe. 1 Quote Link to comment Share on other sites More sharing options...
cymaz Posted November 20, 2021 Share Posted November 20, 2021 Try theses people for some silicone hose, they do high temp stuff somewhere https://www.ebay.co.uk/str/autosiliconehosesoutlet?_trkparms=folent%3Aautosiliconehosesoutlet|folenttp%3A1&_trksid=p3542580.m47492.l74602 1 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 20, 2021 Author Share Posted November 20, 2021 Thanks guys. The flex wont bend enough to be used directly into the engine exhaust port. The 90 bend with flex attached won't clear the bulkhead, but may if I hack some wood away. I am wondering if I can make an exhaust from aluminium tube and canisters on my lathe and join the parts, never soldered alloy but have heard it can be done? Anybody have experience? Cheers Danny Quote Link to comment Share on other sites More sharing options...
cymaz Posted November 20, 2021 Share Posted November 20, 2021 (edited) Copper tube might be easier to work with than aluminum. At least you’ll be able to silver solder copper without difficulties. It will be heavier though Edited November 20, 2021 by cymaz Quote Link to comment Share on other sites More sharing options...
alan p Posted November 21, 2021 Share Posted November 21, 2021 I think you can use Durafix alum solder, you will need a good heat source to maintain temperature. Quote Link to comment Share on other sites More sharing options...
Nick Somerville Posted November 21, 2021 Share Posted November 21, 2021 (edited) Saw this today on FB. Edited November 21, 2021 by Nick Somerville 1 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 21, 2021 Author Share Posted November 21, 2021 Yes I did too..... thx Nick Cheers Danny Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 22, 2021 Share Posted November 22, 2021 (edited) the double knuckle solution will work but you will need to support the back end to prevent it thrashing around and coming loose. I would make some sort of bracket that will grab the thing towards the back and then tie it to either one of the engine mounting bolts or some other solid thing. What ever you tie it to needs to be on the same rotational axis as the engine when it vibrates so that the engine, exhaust and its tie rod all move as one. If you tie the support rod to the bulkhead for example it would continually load/unload the rod as the engine vibrates and it would break very quickly. My high quality engineering drawing below shows the general idea Silicone tube is a non starter if you dont want maintenance every 5 minutes. Given the engine is pretty small you might even be able to run it without a muffler at all Edited November 22, 2021 by Jon - Laser Engines Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 22, 2021 Author Share Posted November 22, 2021 Thanks guys, food for thought indeed. Cheers Danny Quote Link to comment Share on other sites More sharing options...
RottenRow Posted November 22, 2021 Share Posted November 22, 2021 Hi Danny, This is how I did it on my DB 58" Tiger Moth. Originally for an OS FS48 but since replaced by an SC FS52 which was a direct replacement dimensionally. The header (fitted to the engine) was the original OS item with the thread removed from one end. A double flanged joint was made and silver-soldered on to attach the rest of the system to this. Everything was made from brass and silver soldered. The weight isn't really an issue as noseweight is definitely required on the DB Tiger anyway. May as well make it useful. The brass was from the offcuts bin at work at the time. The flanged joint is necessary as the header has to be screwed into the head before the rest of the system is fitted. The section on the header has a small sleeve that fits inside the other part and it is secured using three small screws (probably 8BA). The outlet pipe was shaped such that it exited in roughly the scale position. I had to put a restrictor inside the end of the outlet to improve running. I can't remember all of the details now as it was done a long time ago. The other end is just closed off. I still have the model though it hasn't flown for a few years. The expansion box has a couple of brackets and is supported on the firewall using a couple of screws with silicon tube shock absorbing washers. Ignore the extra screw in the box, that was the first position of the pressure take off but it needed moving as it was too close to the engine. Brian. 1 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 22, 2021 Author Share Posted November 22, 2021 Brian that is a big help thanks for posting. Not got a pile of brass but plenty of alloy, hence my earlier comments. Might have a browse around Wickes see what pipes etc they have, as you say silver solder is a very easy way to go. As an aside I had always wanted to master welding aluminium and was looking at small gas sets as well as TiG set up's not an outlandish price. But maybe one for another day. Was you cannister a commercial unit or did you make that as well? Cheers Danny Quote Link to comment Share on other sites More sharing options...
RottenRow Posted November 22, 2021 Share Posted November 22, 2021 Hi Danny, The canister is a length of thin walled brass tube, about 1” diameter. I made brass disks to be a good fit in either end and silver soldered them in. The tube would have probably come from a model engineering company. At that time our company had a model making department and the guy there made live steam locos so I got it from him. The rest of the tubing was probably the K&S stuff or from B&Q or similar. The contents of the factory’s scrap bin back then would have kept us modellers going for years… Brian. 1 Quote Link to comment Share on other sites More sharing options...
Richard Mallam. Posted November 25, 2021 Share Posted November 25, 2021 Hi Danny, I was on the Hawker Fury build with you some while back and have been following this Auster build as well. I am some way behind you, but have a question. In the last part of the fuselage instructions - it says 'Servo Bearers (112) can now be fitted to suit your servos'. While I am happy to source my own bearers, I am unable to find part number 112 and furthermore, cannot see it (unless my eyes deceive) on the plan. Did you suffer same?? Richard Quote Link to comment Share on other sites More sharing options...
Maurice Dyer Posted November 25, 2021 Share Posted November 25, 2021 My answer. Saito 100F. 1 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 25, 2021 Author Share Posted November 25, 2021 (edited) 50 minutes ago, Maurice Dyer said: My answer. Saito 100F. Hello Maurice, lovely to hear from you, that exhaust is EXACTLY what i had in mind, i have spent the last few days gathering the materials. So more details would be appreciated ? Hi Richard, I cannot see 112 on the plan either, however they are mentioned in the text. I used two hardwood rails and it is possible they were supplied with a number in the kit. Cheers Danny Edited November 25, 2021 by Danny Fenton Quote Link to comment Share on other sites More sharing options...
Maurice Dyer Posted November 25, 2021 Share Posted November 25, 2021 Danny Hi The exhaust is soldered up copper pipe sourced, if I remember from Screwfix, after a balsa mock up was made to make sure it fitted in the cowl. The manifold came from Just Engines, all connected up with Mick Reeves flexible pipe. 1 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 25, 2021 Author Share Posted November 25, 2021 Thanks, i have only ever silver soldered bits of undercarriage, never several joints on the same part ie thos 4 stub pipes. Looks like i just need to get on with it. Thanks again, those colours make me suspect yours is Echo Echo? Cheers Danny Quote Link to comment Share on other sites More sharing options...
Maurice Dyer Posted November 26, 2021 Share Posted November 26, 2021 13 hours ago, Danny Fenton said: Thanks, i have only ever silver soldered bits of undercarriage, never several joints on the same part ie thos 4 stub pipes. Looks like i just need to get on with it. Thanks again, those colours make me suspect yours is Echo Echo? Cheers Danny Danny Silver solder would be better. It is indeed, Echo Echo. 2 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 10, 2021 Author Share Posted December 10, 2021 Okay team I need some advice, I have silver soldered piano wire and steel before but never this thin walls K&S brass. Any hints and tips? I might do a test, it would be a shame to wreck the work so far, this is just pushed together, but the parts are a snug fit and do not move. Cheers Danny 1 Quote Link to comment Share on other sites More sharing options...
RottenRow Posted December 10, 2021 Share Posted December 10, 2021 Hi Danny, That looks great. I think I would definitely practice on a few off-cuts first to get a feel of things. Then perhaps treat the main tube and 4 pipes as one assembly. After a final cleaning and application of flux, support the tube with the outlets facing upwards. Then four rings of silver solder can be placed around the joints and the heat applied at one end, playing the flame around the joint. When the melting point of the solder is reached it should wick into the joint by capillary action. Then move to the next one which will already have been warmed. I guess you have blanks in the ends of that tube, do those individually. Then the inlet tube and flex pipe, again probably both at the same time due to the closeness of the joints. Brian. 1 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 10, 2021 Author Share Posted December 10, 2021 Thanks Brian, had never thought of a ring of solder around the joint, i have always fed it in, no wonder i have had trouble Cheers Danny Quote Link to comment Share on other sites More sharing options...
RottenRow Posted December 10, 2021 Share Posted December 10, 2021 Hi Danny, There’s nothing wrong with feeding in the solder, it’s just if the parts are loose the solder can move them a little. Also you need to coordinate both hands a bit more. We used the ring method in the factory that I used to work, in fact the rings were issued with the other parts from the stores when parts were being compiled for production. Brian. 1 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 10, 2021 Author Share Posted December 10, 2021 5 hours ago, RottenRow said: Hi Danny, There’s nothing wrong with feeding in the solder, it’s just if the parts are loose the solder can move them a little. Also you need to coordinate both hands a bit more. We used the ring method in the factory that I used to work, in fact the rings were issued with the other parts from the stores when parts were being compiled for production. Brian. Thanks Brian, as the solder rings melt whats to stop gravity sending the solder to the floor? Probably overthinking this, should just get on with the test piece..... Cheers Danny Quote Link to comment Share on other sites More sharing options...
RottenRow Posted December 11, 2021 Share Posted December 11, 2021 Hi Danny, Yes I suppose that could happen as your ‘main tube’ is not that much larger in diameter than your outlet, so it would appear to be ‘downhill’ to the s. solder. On my Tiger Moth silencer the tube was larger so gave a bigger area around the joint that was a bit more level. I suppose it is relying on the surface tension of the molten solder to be sufficient to draw it into the joint and overcome gravity. If need be you could always feed some extra in if you didn’t get a continuous line of s. solder around the finished joint. Hope the test piece works. Brian. 1 Quote Link to comment Share on other sites More sharing options...
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