Early Start Design Review

I hope you can help me out with another design. I want to order the parts for both rockets at the same time so that is why I am working out two.

This rocket is intended to be my 29mm G64 Flyer. I would like it to split down the middle with each half comming down on it's own chute if possible. I saw Bob do this I think with his G-Force and it was great. I guess you pack the chute for the booster section on top of the one for the nosecone side.

Nose cone BMS Balsa Nose shape: BNC80KH (fits T80H)

Fins TTW Plywood

Body tube BMS - T80H-34 - 2.640x2.558x.041x34in long (white Heavy wall),
OD: 2.6400 In. , ID: 2.5580 In. , Len: 34.0000 In.

Tube coupler BMS - C80-6 - 2.554x2.474x6in T80 or T80H coupler stock,

MMT BMS - T52H-34 - 1.210x1.140x.035x34 29mm

Centering ring BMS - CR52H80-W - 2.558x1.215x.125thk lite-ply

Questions I have:

1 - How thick aircraft birch plywood for the fins. 3/32? 1/8?
2 - I have it planned so there is a CR at the very aft end to help support that area from getting banged around plus one on each side of the TTW fins and a fourth at the end of the 16" stuffer. Need all of these?
3 - I have read that I need to take care with long skinny rocket stability. How overstable should I be?
4 - Will my dual chutes work with this design ok?
5 - Any other comments or suggestions?

Thanks for your help!!

View attachment Early Start Design.rkt

1/8" is plenty strong for G64
(and most 29mm high power loads)
if you use good quality birch ply and
30 min epoxy. I've flown them on H165's,
H180's and even on twin H238's with no problems...

Four c-rings is a strong design, but will be somewhat
pain in the neck to glue on the two innermost ones...

Didya plan on any kinda positive motor retention, many
clubs prefer having it with 29mm motors, like Kaplow clips,
T-nuts or ye... You might have to move that aft c-ring a bit
for those, then maybe not depending what you're gonna use.

Move your launch lugs so they are on the same piece of body tube,
else your rocket might twist and get hung on the rod....

Happy building and post pix !

I would rethink the dual chute/2 pieces thought. Just remember you now have to track 2 pieces instead of one. I like having everything together, easier to track and find.

Launch Lugs. Thanks. I shortened them and put them both on the booster section.

I plan to use t-nuts with a screw and washer for motor retention.

If 1/8 plywood is plenty strong, what about 3/32?

Rodkill, I should have mentioned that I am planning all wood glue construction.

Thanks!

I would also plan to make it modular so here is the short version.

View attachment Early Start Design Short.rkt

For stability, you should go to about 10-15% of the rocket length in CG-CP distance (this applies a lot better to most rockets than the 1 caliber rule). The CG in your first RS screenshot should move a bit aft anyway once you put a motor in.

And yes, you can't put too much effort into positive retention. Losing a rocket due to altitude, trees or corn fields is painful, but losing a casing due to inadequate retention is painfully stupid (had that happen to me twice now...).

Oliver