Will these fins hold?

The Rocketry Forum

Help Support The Rocketry Forum:

Schuyler

Well-Known Member
Joined
Apr 8, 2009
Messages
79
Reaction score
0
I'm currently building my first minimum diameter rocket. It's a 54mm Madcow Tomach. I didn't fiberglass the fins because I've never done that and I was afraid I would end up making a big mess of it. I used Rocket-Poxy for the fillets. Will this be able to handle speeds approaching Mach 1? Does anyone have any experience with fins separating at high speeds?

tomach.jpg
 

patelldp

Well-Known Member
Joined
Jan 23, 2009
Messages
5,647
Reaction score
88
I'm currently building my first minimum diameter rocket. It's a 54mm Madcow Tomach. I didn't fiberglass the fins because I've never done that and I was afraid I would end up making a big mess of it. I used Rocket-Poxy for the fillets. Will this be able to handle speeds approaching Mach 1? Does anyone have any experience with fins separating at high speeds?
Yes.
 

Buckeye

Well-Known Member
TRF Supporter
Joined
Sep 6, 2009
Messages
2,827
Reaction score
600
I'm currently building my first minimum diameter rocket. It's a 54mm Madcow Tomach. I didn't fiberglass the fins because I've never done that and I was afraid I would end up making a big mess of it. I used Rocket-Poxy for the fillets. Will this be able to handle speeds approaching Mach 1? Does anyone have any experience with fins separating at high speeds?
Most likely. What is the radius of fillet or diameter of the smoothing tool?
 

OverTheTop

Well-Known Member
TRF Supporter
Joined
Jul 10, 2007
Messages
5,915
Reaction score
3,449
Location
Melbourne Australia
If you are keeping subsonic you should be ok. Once you get above about 0.7 Mach, possibly scratching on transonic, risks go up a bit.

FYI, "transonic" means that part of the airflow around the vehicle is supersonic. That could be in some turbulent flow in one part around the fin at a particular angle of attack. As soon as any part of the flow is supersonic the speed is called transonic.

Nice rocket. Enjoy :)

I had a Tomach 54 that went to Mach 1.8 on an L640DT. I had slotted the tube so the fins had some extra strength, and reinforced the fillets.
 

cbrarick

Wildman CT
Joined
Jan 23, 2009
Messages
2,631
Reaction score
345
strength depends on how you prepped things. Hopefully you did your sanding because epoxy is a mechanical bond not a chemical one. Those little scratch marks make a big difference - ask me how I know.......
transonic, no problems...supersonic, depends....worth a try to see how good your gluing is.
 

Latest posts

Top