Delta IV Heavy

[gladiator1332]

I have been working on a Delta IV Heavy scartch built on and off for the past year. Just wondering, will I need to add clear plastic fins to this rocket, or will the two CBCs act as fins to keep it stable. I am using 3 B engines to launch this rocket. I was told this would add a lot of weight to the back, which would cause it to be unstable.

I am thinking about the following configuration for the flight:

CBC2 CBC1 CBC3
B-6-0 B-6-4 B-6-0

Sound good?

This is going to be one hell of a launch if I can pull it off. My electrical class is building rocket launchers and rocket kits, and I figured a 3 engine parallel cluster would be a great way to test out the launcher. I'll also bring a long my Duece for it maiden voyage.

 

[gladiator1332]

And I know you guys would love to see pictures, but unfourtanatley at the moment I am digital cameraless.

 

[stl1951]

A two tube fin rocket can be stable in zero wind conditions, try it sometime. The Delta 4 Heavy
model with engines in each tube IMHO will not be stable without fins.

 

[JRThro]

Do you have any idea where the CP will be, either for the entire rocket, or for each of the common booster core sections?

It probably will be unstable w/o fins, but I only have the demo version of RockSim, and I can't get it to put nosecones on the two side boosters.

If someone could sim the central booster with payload fairing and everything, and then sim one of the side boosters, that should tell us something. Or there probably is a way to simulate the full-up Delta 4 Heavy configuration, but I can't do it.

Actually, simulating them separately probably won't do all that much good, since the airflow will be different with them adjacent to each other.

 

[gladiator1332]

I guess removable clear plastic fins wouldn't be so bad. I'll just pop the fins on when I am setting it up on the pad.

 

[JRThro]

But here's what I got when I simulated the central core. The length and diameter are to scale. I added 0.4 oz of weight 1/2" from the front of the nose cone, and I added 4 small trapezoidal balsa fins.

Launching this model on a C6-5 took it to 646 feet, according to the demo version of RockSim 5.

 

[JRThro]

Now, what that configuration has to do with a simulation of a full-blown Delta 4 Heavy, I'm not sure. But I would guess, and it IS a guess, that you'd still need fins.

 

[gladiator1332]

Thanks