Super Big Bertha - fin question

[vincarroll]

So I just started construction, and when they glue dried on one of the fins I assembled, the 3 pieces are not aligned. so I’m wondering if this rocket could be modified to fly on 3 fins? Also wondering if I could get a replacement. Estes website doesn’t sell them. I’ve seen upgrade kits with plywood fins, which are pricey but are an option. Thanks in advance for any advice!

 

[mh9162013]

It probably could be modified, but you'd have to add a bunch of weight to the nose to compensate for ther higher CP (CP that's closer to the nose).

Try simming your design in OpenRocket and see what happens.

 

[SolarYellow]

Unlikely to need nose weight. It's a long rocket and the Bertha is known for being very (over) stable. It's how it survives being so big and having slow liftoffs. Unless someone launches in a breeze, then it can weather cock.

But yes, it would be a good exercise to model it in OR and see what three fins would do.

Or you could just go to a hobby shop/Hobby Lobby, buy some wood, and remake the fin.

 

[BEC]

How far misaligned? Depending on the severity you could likely just sand the edges enough to even things out and just use it. Big Bertha (in whatever size) is a very forgiving design.

I agree with @SolarYellow that added noseweight, should you opt to go with there fins, would be unnecessary. You'd just be making a Super Big Betty. The Quest Big Betty is, for all intents and purposes, just a three-finned Big Bertha.