Quantcast

sweep angle for a rocket fin?

The Rocketry Forum

Help Support The Rocketry Forum:

mccordmw

Well-Known Member
Joined
Jan 18, 2016
Messages
1,020
Reaction score
49
Location
St. Louis, MO
Fin sweep angle is the angle between a perpendicular line and a line drawn from 25% of the fin root length to 25% of the tip length. I found a decent image on Google.



Or do you mean you want to calculate the best sweep for a model you're designing from scratch?
 

KarimMurad

Member
Joined
Nov 25, 2016
Messages
8
Reaction score
0
Fin sweep angle is the angle between a perpendicular line and a line drawn from 25% of the fin root length to 25% of the tip length. I found a decent image on Google.



Or do you mean you want to calculate the best sweep for a model you're designing from scratch?
Yes I want to calculate the best sweep for a model that I design.
 

FredA

Well-Known Member
Joined
Jan 19, 2009
Messages
2,170
Reaction score
347
Target 70-degrees.
Seems to be the accepted best angle for all flight profiles.
 

mccordmw

Well-Known Member
Joined
Jan 18, 2016
Messages
1,020
Reaction score
49
Location
St. Louis, MO
OpenRocket is your friend.

http://openrocket.sourceforge.net/

You'll be able to play with it to get what's best for your model. You want to get a stability margin of >1 (usually 1.5-2.0 range). There are several threads here on how to use OpenRocket. Plus, it's fun to play with and dream up designs. I prefer building from scratch myself vs kits. It's neat to launch something and think, "I dreamed that up!", when it flies beautifully.

The clipped delta is generally considered a great all-around shape. Here's a rule of thumb for dimensions:



But that's a rule of thumb. Always calculate and sim yours to be sure.

That reference is from: G. H. Stine & G.W. Stine, Handbook of Model Rocketry (7th Ed.), John Wiley & Sons, Inc., Hoboken, NJ, 2004
 
Last edited:

mccordmw

Well-Known Member
Joined
Jan 18, 2016
Messages
1,020
Reaction score
49
Location
St. Louis, MO
That rule of thumb actually seems to give some really large fins, IMO. I'd go with 1 diameter for semispan (S).
 
Top