Estes Black Brant XII

[billeblurzz]

I’m finally starting the Black Brant and run into this issue with the first stage lower fins. Although I have the Vanderburn? upgrade the problem exists even with stock fins. As you see there is an open space above the lower fins and body tube? Is this supposed to be filled in or does the real rocket have this feature? I’ve seen a detail photo on the Apogee rocket site and it looks like they built their example model this way too? Anyone dealt with this or know if this is the way it’s supposed to be built?

 

[NOLA_BAR]

The gap appears to be true to scale.

http://modelrocketbuilding.blogspot.com/2023/10/estes-black-brant-xii-kit-9723-build_5.html

 

[billeblurzz]

Excellent! Thanks for the reply and link! I’ll proceed that way knowing that’s to scale!

 

[billeblurzz]

Finished…lots of work!

 

[cls]

Looks great!!

Following this thread with interest. Opened the box to read the instructions today.

Now I have paralysis from analysis!

What paints did you use?

Also I'm wondering about how to double diamond bevel the built up fins. I remember TVM showed a jig in his model rocket construction book... my copy is in storage, ugh.

 

[billeblurzz]

Thank you! I used the masking tape across the centerline of each bevel and sanded down to the center thickness of the 3 layers of each fin…4 times for each fin. The resulting thickness may have been more than desired but I figured would be less nick prone upon landing. The paint is Krylon Acryli-Quik.

 

[billeblurzz]

Hey guys, my all up weight with chute, F15 motor, and required CG according to instructions is 496 grams. The max liftoff weight of an F15-6 is 482 grams. An F15-4 liftoff weight is 595 grams. Would either of these 2 motors be too risky? All opinions welcomed!