A section out of the ARA's "Blue Book" caught my attention and has sparked the interest of at least one of my students: the Super Roc challenge.

The idea of making the longest rocket possible that will still achieve a high altitude is both interesting and highly amusing to me.

Has anyone had experience making these kinds of rockets? I'm interested to know what basic dimensions we should be using to achieve safe flights.

This is tempting.
I'm thinking several meters of 29mm motor mount tube with a H-128 or something in it.

Quoted from George

This is tempting.
I'm thinking several meters of 29mm motor mount tube with a H-128 or something in it.

H128  

How'd that dash get in there? Hmm.

Anyway, what is the most I can fit into a 29mm? I'm not going to try it anyway, I think I would need carbon or glass fiber to make that actually survive a flight.

Quoted from George

This is tempting.
I'm thinking several meters of 29mm motor mount tube with a H-128 or something in it.

lol... but doesn't that break the "length to diameter" rule of thumb that a rocket's dimensions should be somewhere within 10:1 and 20:1?

Using that as a guide, a rocket with a 29mm body tube should only be 600mm(ish) long, at most.

you are right mr f

They're really only guidelines.
The Estes "Mean Machine" is around 47:1
The Fliskits "Richter Recker" is around 41:1
and my scratch-built "Placebo" is 29:1 (used to be 30:1 )

Quoted from kryten

my scratch-built "Placebo" is 29:1 (used to be 30:1 )

lol Kryten... that's very funny

Cheers for the info. I had looked at the Mean Machine and wondered just that. So is the idea just to put larger fins on the thing or doesn't that matter too much either? How big are the fins on your Placebo compared to the tube diameter and length?

you will need to follow the table as per blue book

sorry George only goes up to G in the sporting code  

33.1 Scope
Super-Roc Duration Competition comprises nine events open to single-staged model rockets
whose body length is no less than the minimum allowed for the classes of the event. The purpose
of this competition is to achieve the greatest duration possible with the longest rocket possible
without impairing the structural integrity of the rocket.

Quoted from Mr F

How big are the fins on your Placebo compared to the tube diameter and length?

Length 1440mm
Diameter 50mm
Fins:
Root chord 100mm
Tip chord  45mm
Span  50mm
Photos here (Images 16 & 17):
http://www.nswrocketry.org.au/gallery/Doonside_2008_11/03_photos_nov.html

cheers Kryten... that's very helpful

nice looking rocket, too!

When are we goin 2 hav our super roc comp???

Quoted from Fuzball

When are we goin 2 hav our super roc comp???

The proposed date is Friday of week 2, term 4. Pencil in October 23.

It depends a lot on what happens with fire danger season. They're talking about starting it early this year. Normally it starts in November, I think. I think we can still launch during this time but there's probably a few more hoops to jump through. Rocketball is going to give us an update on this when the time nears.

Apart from that, it also depends on the weather! If it's too windy then we'll reschedule for the following Friday (and so on) until we get these things off the ground

ps. I'm making tubes for them right now.
pps. don't tell anyone because I'm actually meant to be writing reports