Aluminum fin cans

[SDramstad]

At what point is an aluminum fin can considered necessary or preferred on a rocket? Thinking 98mm minimum diameter for next years Airfest. See how high I can get it. I know with proper techniques carbon fiber fins could be made to work but seems to me an aluminum fin can would take the guess work out of it.

 

[JackC]

At what point is an aluminum fin can considered necessary or preferred on a rocket? Thinking 98mm minimum diameter for next years Airfest. See how high I can get it. I know with proper techniques carbon fiber fins could be made to work but seems to me an aluminum fin can would take the guess work out of it.

I have the Max-Q aluminum fin cans on both fiberglass and carbon fiber rockets. I would say if you are going to fly something like the AT N5800 or a 3 inch minimum diameter on a CSR M2245, I would recommend an aluminum fin can. It is much heavier than tip to tip fins but it won’t shred. Many flyers at the Spaceport America Cup and at BALLS use the aluminum fin can.

 

[plugger]

at the performance envelope of the vast majority of our reloads (including N5800s and O3400s) I would say they're entirely unnecessary. I also think they're substantially draggier (specifically the bolt on ones) when compared to composites with clean fillets. This doesn't show up in sims though as people don't model the bolts in simulation, at least from what I've seen.
A properly designed and appropriate thickness CF fin will survive a Mach 3 boost without even requiring t2t, only fillets. Basically you're worried about two things at those speeds; flutter and damage to the leading edges. Flutter is mitigated by appropriate thickness, leading edges can be 'hardened' without requiring the whole fin to be aluminum.

 

[Hobie1dog]

they are sexy looking, TIG welded fins

 

[MClark]

If at Airfest contact them first about aluminum fin cans.
They do not like metal parts.

 

[Titan II]

If at Airfest contact them first about aluminum fin cans.
They do not like metal parts.

They are fine and it is addressed on their website.

 

[MClark]

I would still contact the Prefect before starting construction with metal parts. It’s his opinion that matters on if metal is required not the flyer’s.

 

[SDramstad]

What if you want to do a test flight with a motor that wouldnt require the aluminum fin can but you do intend to eventually fly it with something that does require it?

 

[MClark]

Goes back to contact Prefect

 

[G_T]

Beyond a certain point aluminum is not a good material choice for fins. It softens at too low a temperature. Conventional composites with high temperature epoxy (Cotronics, etc) can go higher, and other materials take over after that

Most hobby rockets don't have an issue with aluminum. If you are going for speed though, it is worth investigating the stagnation temperature at Max-

Gerald