wonwinglo
SMF Supporter
- Joined
- Apr 18, 2004
- Messages
- 6,754
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- 113
- First Name
- Barry
Issue 73 Carburettor Support backet (Modified assembly)
For those struggling with the carburettor support assembly aft of the engine bulkhead the following independant modifications have been made,this also addresses the issue associated with the hang of the heavy rotary engine and gives it more support at the rear,the support brackets have been used but reworked to fit the correct central bearing tube.
After giving this item a lot of thought the following method was devised,the idea was to use as much as possible of the existing assemblies,and with the addition of a few pieces of scrap tube and a standard threaded spiked anchor nut,whilst the mods were taking place the aft bearing assembly has also been improved upon so that it does not rely solely acting on the floating front bearing,this is how I set about getting this job done-
#1 First obtain a large spiked blind anchor nut,these can be obtained from model shops specialising in radio control aeroplanes and used to fix the wings in place on radio models,the nut forms the basis of a solid sturdy mount about which we can build on and improve the whole integrity of the engine itself.
You need to reverse the spikes so they bed into the built up circular ply pieces,use slow drying araldite for extra security and make sure that it lies central and in line with the bearing,allow to dry overnight,once fully cured it forms the basis of a central bearing.
#2 The next important job is to make a bearing extension for the rotary engine shaft,to do this get hold of a piece of suitable brass tube ( all tube was purchased from a model shop ) cut it to the respective length which is achieved by trial and error dry fitting,this should be a force tight fit into the blind mounting nut,run a little thin cyno down the seam being careful not to get any in the main bearing,dont worry you will not shift this assembly believe me !
#3 Make the outer spacer main bush,once again a piece of tube,we have reversed the existing carb fitting because there is a flange on the end we want,on the other end simply file off the rivets so that it will seat firmly against the carb itself,see I told you we were going to use as much as possible of existing bits ! put a bead of cyno on the lip and hey presto job done,you dont need to mount the carb assembly yet.
#4
Here is another picture showing the existing part sitting inside the tube spacer.
#5 Mount the assembly over the inner bearing,but before you do this flood the void between the two brass tube walls with epoxy resin,this is not essential but will keep everything in line.
#6 Here we are performing a trial fit with the carburettor assembly,no need to fix this yet but offer it up and make sure everything is in line.
#7 Make use of the support frames provided,one fits fine,the other needs to be shortened a bit to keep it in line,here also I am holding the tubes to get the final picture,these should now line up perfectly with the exit holes in the side of the fuselage,the assembly is solid,its a belt and braces approach but it works fine.
#8 This is how everything looks when assembled,the rotary now sits properly into a decent bearing with better support and the extension brings everything into line as it should be.
For those struggling with the carburettor support assembly aft of the engine bulkhead the following independant modifications have been made,this also addresses the issue associated with the hang of the heavy rotary engine and gives it more support at the rear,the support brackets have been used but reworked to fit the correct central bearing tube.
After giving this item a lot of thought the following method was devised,the idea was to use as much as possible of the existing assemblies,and with the addition of a few pieces of scrap tube and a standard threaded spiked anchor nut,whilst the mods were taking place the aft bearing assembly has also been improved upon so that it does not rely solely acting on the floating front bearing,this is how I set about getting this job done-
#1 First obtain a large spiked blind anchor nut,these can be obtained from model shops specialising in radio control aeroplanes and used to fix the wings in place on radio models,the nut forms the basis of a solid sturdy mount about which we can build on and improve the whole integrity of the engine itself.
You need to reverse the spikes so they bed into the built up circular ply pieces,use slow drying araldite for extra security and make sure that it lies central and in line with the bearing,allow to dry overnight,once fully cured it forms the basis of a central bearing.
#2 The next important job is to make a bearing extension for the rotary engine shaft,to do this get hold of a piece of suitable brass tube ( all tube was purchased from a model shop ) cut it to the respective length which is achieved by trial and error dry fitting,this should be a force tight fit into the blind mounting nut,run a little thin cyno down the seam being careful not to get any in the main bearing,dont worry you will not shift this assembly believe me !
#3 Make the outer spacer main bush,once again a piece of tube,we have reversed the existing carb fitting because there is a flange on the end we want,on the other end simply file off the rivets so that it will seat firmly against the carb itself,see I told you we were going to use as much as possible of existing bits ! put a bead of cyno on the lip and hey presto job done,you dont need to mount the carb assembly yet.
#4
Here is another picture showing the existing part sitting inside the tube spacer.
#5 Mount the assembly over the inner bearing,but before you do this flood the void between the two brass tube walls with epoxy resin,this is not essential but will keep everything in line.
#6 Here we are performing a trial fit with the carburettor assembly,no need to fix this yet but offer it up and make sure everything is in line.
#7 Make use of the support frames provided,one fits fine,the other needs to be shortened a bit to keep it in line,here also I am holding the tubes to get the final picture,these should now line up perfectly with the exit holes in the side of the fuselage,the assembly is solid,its a belt and braces approach but it works fine.
#8 This is how everything looks when assembled,the rotary now sits properly into a decent bearing with better support and the extension brings everything into line as it should be.