In one of the other threads the conversation turned to (touched on) fully 3D printed rockets. I have always avoided printing body tubes whenever possible and instead prefer to print parts that fit on standard Estes cardboard body tubes. Someone posted that they have 3D printed lots of complete rockets and that "I do not think that they are that much heavier" so I was curious about what the difference in weight is.
Quick table below -- for the purpose of this quick analysis I basically selected the stock Estes body tube and trusted the thickness and weight that was presented in OpenRocket for the stock Estes cardboard tube (with the exception of the BT-80 which is obviously incorrect so I weighed a couple of those). Then I switched the material to "Printed PLA" and changed the Wall Thickness to either .8mm or 1.2mm (representing 2x or 3x .4mm layers). Obviously weighing everything would be more accurate but I was just trying to get a rough approximation for the increased weight. These are all 18" long tubes except the BT-80 which is the stock 14.25". The weights listed are in grams with the multiplier indicating the ratio of the 3D printed weight to the cardboard tube weight.
So the printed body tubes range from 2.4x to 7.1x as heavy as the cardboard tubes with total weight increases of a range of 20g to 80g. Obviously, whether the 3D printed body tube is "too heavy" is going to depend on your design, purpose, how large an engine you want to use, etc... I would also point out (for anyone that happens to come across this that is new to rockets) that often increasing weight in the rear of the rocket forces us to offset that with more weight in the nose to create similar stability. Generally speaking a fully 3D printed rocket shifts weight backward as compared to a rocket with a plastic nose cone, cardboard body tube, balsa fins, and cardboard engine mount. Given this, some designs will see the increased weight being further compounded if nose weight is needed to stabilize the rocket.
What the heck I will look at the weight of fins also... This analysis is simply looking at 4x flat fins that are 5cmx5cm in size (obviously the real benefit in 3D printed fins is in the cool shapes you can print but I was just curious about weight). This also assumes a solid print which would be the case if you just printed a flat fin that is not too thick.
Not as much of an increase as I would have guessed (at least not over plywood that I usually use). Balsa is still the king when it comes to light fins but I still think that 1.5-2mm plywood is a good balance of strength, finishing, weight, etc...
Quick table below -- for the purpose of this quick analysis I basically selected the stock Estes body tube and trusted the thickness and weight that was presented in OpenRocket for the stock Estes cardboard tube (with the exception of the BT-80 which is obviously incorrect so I weighed a couple of those). Then I switched the material to "Printed PLA" and changed the Wall Thickness to either .8mm or 1.2mm (representing 2x or 3x .4mm layers). Obviously weighing everything would be more accurate but I was just trying to get a rough approximation for the increased weight. These are all 18" long tubes except the BT-80 which is the stock 14.25". The weights listed are in grams with the multiplier indicating the ratio of the 3D printed weight to the cardboard tube weight.
So the printed body tubes range from 2.4x to 7.1x as heavy as the cardboard tubes with total weight increases of a range of 20g to 80g. Obviously, whether the 3D printed body tube is "too heavy" is going to depend on your design, purpose, how large an engine you want to use, etc... I would also point out (for anyone that happens to come across this that is new to rockets) that often increasing weight in the rear of the rocket forces us to offset that with more weight in the nose to create similar stability. Generally speaking a fully 3D printed rocket shifts weight backward as compared to a rocket with a plastic nose cone, cardboard body tube, balsa fins, and cardboard engine mount. Given this, some designs will see the increased weight being further compounded if nose weight is needed to stabilize the rocket.
What the heck I will look at the weight of fins also... This analysis is simply looking at 4x flat fins that are 5cmx5cm in size (obviously the real benefit in 3D printed fins is in the cool shapes you can print but I was just curious about weight). This also assumes a solid print which would be the case if you just printed a flat fin that is not too thick.
Not as much of an increase as I would have guessed (at least not over plywood that I usually use). Balsa is still the king when it comes to light fins but I still think that 1.5-2mm plywood is a good balance of strength, finishing, weight, etc...
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