Fin Structure on Aela's Sythe

[TangoAlphaZulu]

This thread concerns Aeva's pretty cool rocket design in this thread: Fins or no fins

I have a question about the design, so I am starting a thread here to avoid hi-jacking original thread.

I am going to be letting my nOOb show a bit here. I've done LPR and MPR so far. Level 1 is in the not to distant future.

I couldn't find any specifics on dimensions, motors, etc. in the original thread, but since it is on the HPR section, I will assume for the moment we are talking HPR rocket here. Looking at the picture above, it pretty much looks like a minimum diameter body tube at the aft end of the rocket. It certainly does not look like enough room for "fins through the body tube and glue the fins to the motor mount". From what I have learned this tends to be the rule for HPR. Is this a case where it is OK to glue the fins to the body tube?

To me, the structure of the 4 rings and six fins looks to be crazy stiff. The only in-flight forces trying to remove the fins would be linear shear due to drag.

I think it would work, but I would love to hear comments from the more experienced.

Thanks,
Jeff

 

[Aeva]

It's not actually min diameter; the design is a 38mm MMT inside a 5cm body tube at the moment. I'm not settled on those dimensions, and I personally want to see this on some bigger long burn motors. It's pretty draggy, and will likely have a short coasting phase after burnout. The design completely considers aesthetics over performance lol

There are plenty of minimum diameter not-through-wall examples though. It's about getting a good bond between the body tube and fins, as well as using the correct tools to keep them aligned.

 

[TangoAlphaZulu]

It's not actually min diameter; the design is a 38mm MMT inside a 5cm body tube at the moment. I'm not settled on those dimensions, and I personally want to see this on some bigger long burn motors. It's pretty draggy, and will likely have a short coasting phase after burnout. The design completely considers aesthetics over performance lol

There are plenty of minimum diameter not-through-wall examples though. It's about getting a good bond between the body tube and fins, as well as using the correct tools to keep them aligned.

It's not actually min diameter; the design is a 38mm MMT inside a 5cm body tube at the moment. I'm not settled on those dimensions, and I personally want to see this on some bigger long burn motors. It's pretty draggy, and will likely have a short coasting phase after burnout. The design completely considers aesthetics over performance lol

There are plenty of minimum diameter not-through-wall examples though. It's about getting a good bond between the body tube and fins, as well as using the correct tools to keep them aligned.

Thank you fro the explanation!

TAZ