Sizing wing tubes and fabrication.
04-21-2003, 11:55 AM
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Sizing wing tubes and fabrication.
Hi,
Browsing the archives I found a lot of information on how to use wing tubes but not much on how big to make them. I also have looked at the Gator RC site and while they seem to sell a lot of wing tubes I can't find any info on application!
I am desigining a .50 sized pattern stick type model with a mid wing (in line with thrust and tail stab). Wing span will be about 1490mm since I have ripped off the dimensions (fuse and wing span) of MK's .50 sized Synergy CPLR as a guide. The wing will be a scaled down version of that found on the anonymous AG120 design floating around the internet. (e.g. http://www.aerotech-rc.com/plans/ search for "pattern"). The fuselage is a scaled down and stretched version of the AG120 fuselage with slightly smaller control surfaces taking into consideration the greater moment of the longer fuselage.
So, given that this will be a very aerobatic model, how big should I make my tube? Practivally, if I am going to have the tube aligned between the upper and lower spars I am limited to about 19mm (3/4"). My thought is to make a glass/epoxy or paper/epoxy tube over my aluminium tube with a few layers of mylar to stop it from sticking. I am hoping that if lubricated I will be able to slip this off the tube. I will then clean up and use kevlar thread and epoxy to fit the tube between the spars up to the third rib then carry the kevlar on past the tube to the end of the wing. The spars will also be webbed of course. I am also considering using plywood doughnuts on the spars to further provide strength. Wing location on the fuselage will be via pegs and there will be the traditional hook and rubber band setup to hold the wing in place.
Am I over or under engineering this? Any advice to make things work out better? I fully expect this the plane to be a work in progress. I am not just out to build a beautifully flying plane or I would fork out the A$500 odd to build a Synergy CPLR or similar from a kit... Actually I may do this anyway since I am sure that I will learn a lot from the design and construction techniques.
Thanks in advance,
Richard.
Browsing the archives I found a lot of information on how to use wing tubes but not much on how big to make them. I also have looked at the Gator RC site and while they seem to sell a lot of wing tubes I can't find any info on application!
I am desigining a .50 sized pattern stick type model with a mid wing (in line with thrust and tail stab). Wing span will be about 1490mm since I have ripped off the dimensions (fuse and wing span) of MK's .50 sized Synergy CPLR as a guide. The wing will be a scaled down version of that found on the anonymous AG120 design floating around the internet. (e.g. http://www.aerotech-rc.com/plans/ search for "pattern"). The fuselage is a scaled down and stretched version of the AG120 fuselage with slightly smaller control surfaces taking into consideration the greater moment of the longer fuselage.
So, given that this will be a very aerobatic model, how big should I make my tube? Practivally, if I am going to have the tube aligned between the upper and lower spars I am limited to about 19mm (3/4"). My thought is to make a glass/epoxy or paper/epoxy tube over my aluminium tube with a few layers of mylar to stop it from sticking. I am hoping that if lubricated I will be able to slip this off the tube. I will then clean up and use kevlar thread and epoxy to fit the tube between the spars up to the third rib then carry the kevlar on past the tube to the end of the wing. The spars will also be webbed of course. I am also considering using plywood doughnuts on the spars to further provide strength. Wing location on the fuselage will be via pegs and there will be the traditional hook and rubber band setup to hold the wing in place.
Am I over or under engineering this? Any advice to make things work out better? I fully expect this the plane to be a work in progress. I am not just out to build a beautifully flying plane or I would fork out the A$500 odd to build a Synergy CPLR or similar from a kit... Actually I may do this anyway since I am sure that I will learn a lot from the design and construction techniques.
Thanks in advance,
Richard.
04-23-2003, 01:10 AM
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Sizing wing tubes and fabrication.
just buy a 3/4" tube and socket set. No need to re-engineer the thing.
If you just want to build it to say you built it, thats fine too. But the sockets and tubes only cost about $20.
24" tube will be fine, with supports on the ends of the sockets just like you spoke of, and a ply support on the root ribs to maintain the tubes location during flight loads.
If you just want to build it to say you built it, thats fine too. But the sockets and tubes only cost about $20.
24" tube will be fine, with supports on the ends of the sockets just like you spoke of, and a ply support on the root ribs to maintain the tubes location during flight loads.
04-23-2003, 02:34 AM
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Sizing wing tubes and fabrication.
G'day,
Thanks for the sizing info I will look around for 0.75" hard aluminium alloy tube.
There is certainly an aspect of "make it so that I can say that I made it" going on here. This is my first fully scratch built aircraft and I am trying to use as many different techniques as I can. The goal is education rather than a brilliant plane at the end. I am pretty sure that the result will fly well though!
Richard.
Thanks for the sizing info I will look around for 0.75" hard aluminium alloy tube.
There is certainly an aspect of "make it so that I can say that I made it" going on here. This is my first fully scratch built aircraft and I am trying to use as many different techniques as I can. The goal is education rather than a brilliant plane at the end. I am pretty sure that the result will fly well though!
Richard.
