32% Sport-Scale Black Brant Vc

[JMZawodny]

I've always been a fan of rocket models that are modeled after actual rockets, although I'm not a stickler for precision scale - I simply do not have the disposition for that. I'm particularly fond of the Black Brant Vc and have designed versions in several scales all the way up to 2/3rds scale. Before I go to that extreme I wanted to build something smaller. One of the challenges in this rocket is the step down in tube diameter midway along the length of the fin root. A scale-like fin would also be a challenge. I selected the Vc version because it has 4 rather than 3 fins and offered an opportunity to experiment with control finlets just behind the nose cone. What is presented here is the current status of the design I am likely to begin building this winter. I will take advantage of the fact that filament wound fiberglass tubing from Performance Rocketry (Rocketry Warehouse) in sizes of 5" and 5.5", along with their respective couplers, nest within each other nicely. Additionally, the ratio of 5" to 5.5" diameters closely matches the required dimensions for a 32% (sport) scale model. Here is a simulation of the assembly along with a OpenRocket file for this design. I wanted to attach my RockSim file, but it exceeded the site file size limits by a factor of 2.

 

[dixontj93060]

That is funny. Rocksim files are usually tiny.

 

[JMZawodny]

I can try to reduce the file size by deleting some/most of the 45 motors I have simulated, or I could just compress it with zip. Wait, there is a simpler solution to this problem. Here is a link to the RockSim file.

 

[dixontj93060]

I can try to reduce the file size by deleting some/most of the 45 motors I have simulated, or I could just compress it with zip.

Oh, maybe that is it. Typically I only keep 5 or six sims around.

 

[JMZawodny]

Here are the parts I am starting with: a 3:1 FWFG nose cone from Mad Cow, a 75mm motor mount, a 48" section of 5.5" G12, a longer-than-required section of 5" G12 (inside the previously mentioned tube), a 24" section of 5.5" G12, and a 5.5" coupler. 1" long rings from the coupler and nose cone shoulder will be cut off and used to attach the 5" and 5.5" diameter airframe parts as per drawings. Everything else will be cut from sheet stock, either G10 or plywood.