Shift in CP

[tony]

I am building a kit and modifying it be to be a 3 cluster. As a result of design I plan to change the rocket from a 4 fin design to a 3 fin. Is there any easy way or rule of thumb for estimating a shift in CP?

 

[PGerringer]

Doesn't Rocksim give you an estimate of CP? Don't know how accurate it is but you may want to check it out.

 

[Oliver Arend]

Which kit is it?

If it is very stable anyway, 3 fins will do. It does happen too, that the decrease in mass (3 instead of 4 fins) evens with the shift in CP. But I would double check.

Oliver

 

[Electrode]

Tony.. let me know what kit it is.. and I can run it in Rock-Sim for ya... and let you know where the CP will be with 3 or 4 fins... can even do an estamint on the weight with the cluster for CG if you'd like.. if it's not a know'n kit.. Give me dia., lenght, basic dimentions of the fins and that should work for CP.

Clusters are awsome.

 

[tony]

Thanks for offering assistance. I am modifying an Estes Beta Launch Vehicle. It has a BT-60. The nose cone for the rocket is not typical and has a transition. I entered the data into VCP but because of the odd nose cone shape I am not sure if it is accurate. I have attached a picture from an 1993 Estes catalog. Thanks for the help.

 

[Electrode]

I can't seem to find any info on the rocket... if you give me some dimentions to work with.. that would help a lot. just do a really bad drawing in paint or something to the basic shape of the rocket and add the dimentions.