Calculating Fluttering Speed with a Two Stage Rocket

[Alan Offer]

Goodevening,

I'm currently designing a two stage rocket that will go to 30km and I was wondering how could I calculate the fluttering speed when the two stage are together. Should I add the root length of the two set of fins to make "a bigger one " or is there any other method to calculate it?

Thank you for your help,

Alan Offer from IMF.Rockets

 

[RocketPro]

You calculate them independently using the normal methods. Without knowing your familiarity with this, I can recommend this article for starters…
https://www.apogeerockets.com/Peak-of-Flight/Newsletter615

 

[kjhambrick]

If you want to get into the background of the Apogee Article that @RocketPro linked, attached is NACA TN 4197.

Read and understand the Intro in TN 4197. It is important before applying Eq 18 to real rockets.

And this is the old InfoCentral article referenced in the Apogee Article: WayBack Machine > Info Central > What is Fin Flutter ?

It helps one understand the important relationships in NACA TN 4197 Eq 18.

HTH and good luck with your flight !

-- kjh

 

[Alan Offer]

You calculate them independently using the normal methods. Without knowing your familiarity with this, I can recommend this article for starters…
https://www.apogeerockets.com/Peak-of-Flight/Newsletter615

Thank for the advices !

 

[Alan Offer]

If you want to get into the background of the Apogee Article that @RocketPro linked, attached is NACA TN 4197.

Read and understand the Intro in TN 4197. It is important before applying Eq 18 to real rockets.

And this is the old InfoCentral article referenced in the Apogee Article: WayBack Machine > Info Central > What is Fin Flutter ?

It helps one understand the important relationships in NACA TN 4197 Eq 18.

HTH and good luck with your flight !

-- kjh

I will definitely look into that and thank you for you reply

 

[Alan Offer]

I will definitely look into that and thank you for you reply

If you want to get into the background of the Apogee Article that @RocketPro linked, attached is NACA TN 4197.

Read and understand the Intro in TN 4197. It is important before applying Eq 18 to real rockets.

And this is the old InfoCentral article referenced in the Apogee Article: WayBack Machine > Info Central > What is Fin Flutter ?

It helps one understand the important relationships in NACA TN 4197 Eq 18.

HTH and good luck with your flight !

-- kjh

I have to be aware of coning also, I've seen that the fins should not pass their natural frequency in order to be stable, do you guys know how to calculate it ?