Some folks may have seen this over on Facebook but for those who do not waste time on that social platform... Over the last two weeks I designed, printed, revised, built, and launched a TB-3 model.
I asked on FB about what models people would like to see and the TB-3 came up a few times. I had looked at the model before and thought it was too much 3D printing. I looked back at it and rethought how I could break it down into components. Wound up with a BT-60 front tube, BT-80 rear tube portion, and BT-50 side pods.
My built version came out at 23.5" (60cm) which is as tall as a Big Bertha and way more impressive. This weighs in at around 175g w/o motor and has a 24mm motor mount. Simulations show it flying to 110m on D12-3 and 170m on E12-4. I have shifted to using internal BT-50 / 24mm motor mount / stuffer tubes to make it easier for folks to use composite engines.
I launched this last week on a D12-3 and it was really stable. Here is the video (filmed by my 7 year old):
https://youtu.be/H8gYl8Pzvbs?t=6
I went through a number of evolutions in this design. I originally made the side pods with BT-20 tubes but they seemed too small. I originally planned to use 1.5mm plywood for the cooling fins in the middle of the model. However, I wound up printing the entire central core with cooling fins. I did split off the front cone since the circle details were printing upside down originally and needed supports. They print better as a separate part. I also modified the original engine retainer cap -- the first version was a bit too inset so motor was hard to remove.
Here is the OpenRocket simulation:
I asked on FB about what models people would like to see and the TB-3 came up a few times. I had looked at the model before and thought it was too much 3D printing. I looked back at it and rethought how I could break it down into components. Wound up with a BT-60 front tube, BT-80 rear tube portion, and BT-50 side pods.
My built version came out at 23.5" (60cm) which is as tall as a Big Bertha and way more impressive. This weighs in at around 175g w/o motor and has a 24mm motor mount. Simulations show it flying to 110m on D12-3 and 170m on E12-4. I have shifted to using internal BT-50 / 24mm motor mount / stuffer tubes to make it easier for folks to use composite engines.
I launched this last week on a D12-3 and it was really stable. Here is the video (filmed by my 7 year old):
https://youtu.be/H8gYl8Pzvbs?t=6
I went through a number of evolutions in this design. I originally made the side pods with BT-20 tubes but they seemed too small. I originally planned to use 1.5mm plywood for the cooling fins in the middle of the model. However, I wound up printing the entire central core with cooling fins. I did split off the front cone since the circle details were printing upside down originally and needed supports. They print better as a separate part. I also modified the original engine retainer cap -- the first version was a bit too inset so motor was hard to remove.
Here is the OpenRocket simulation: