12 replies to this topic

[Amleth]

There's always dirt cheap bamboo skewers for small rockets (I even found some jumbo ones that work well for 3/8" rockets), but it's hard to find sticks for 1/2" and above that are equally as negligibly expensive. None of the garden stakes I can find in my local area are long enough to balance my 1/2" rockets even without a header (and they don't work out all that cheaply, anyway). I've heard suggestions to use rods from bamboo blinds, but ideally I'd like something straight (could definitely be an option, though). Hardware store dowels and mouldings are right out for cost ($1AU per metre and up depending on size)...

Before I crack and try and find somewhere to saw up a load of planking into square rods for me, does anyone have any magic ideas for affordable stabilising nirvana? All suggestions and ideas appreciated. I'm sure someone out there has a simple, elegant, and (most importantly) dirt cheap solution to the problem...


So, what do you use to balance your larger rockets?

[RegimentalPyro]

Bamboo blinds/matting

Lots of straight long sticks for NotMuchCashAtAll[tm]

Edited by RegimentalPyro, 19 January 2006 - 12:07 PM.

[Pretty green flames]

I recycle, most sticks are usable for about 5 launches. Buy it ---> Launch it ---> find it ---> Reuse it

[Rip Rap]

There's always dirt cheap bamboo skewers for small rockets (I even found some jumbo ones that work well for 3/8" rockets), but it's hard to find sticks for 1/2" and above that are equally as negligibly expensive. None of the garden stakes I can find in my local area are long enough to balance my 1/2" rockets even without a header (and they don't work out all that cheaply, anyway). I've heard suggestions to use rods from bamboo blinds, but ideally I'd like something straight (could definitely be an option, though). Hardware store dowels and mouldings are right out for cost ($1AU per metre and up depending on size)...

Before I crack and try and find somewhere to saw up a load of planking into square rods for me, does anyone have any magic ideas for affordable stabilising nirvana? All suggestions and ideas appreciated. I'm sure someone out there has a simple, elegant, and (most importantly) dirt cheap solution to the problem...
So, what do you use to balance your larger rockets?

I get these - http://www.lbsgarden...=R-F12G&recno=1 - 250 of the 36". Good for all but really big rockets. Do a search for similar near you.

[newtoolsmith]

One of my friends is a carpenter and has a big stationara circular saw in his cellar at home (I dont know the correct english name for these Saws, used to get wooden plates to a defined length and width).

With this saw its quite easy to cut a 10*10cm beam into sticks of 5*5mm or 8*8mm (my favorite dinemsions).

Only need is such a saw and a beam of the needed length !!without brenches!!(often found somewhere for free).

MfG
newtoolsmith

[alany]

I use bamboo blinds and table mats for smaller rockets as well as kebab sticks which tend to be cheaper but shorter. The blind ones are long enough for 8 oz rockets, but are generally too thin, even for 4 oz rockets. They are perfect for 2 oz though, and you can cut them into two or three pieces depending on the length.

I've launched 4 oz motors with such thin sticks. They worked but where erratic and too fragile before launch for my taste. You couldn't lift them by their stick without fear of breaking them.

http://nexus.cable.n...90/p0004665.jpg

If you can borrow or otherwise get access to a bench saw you can rip up those 40x10x1500 pine scraps bunnings sell for around $1 into many ~ 5 mm square sticks or a few larger ones for bigger rockets

Bunnings also sell stakes similar to those garden direct ones. Target used to sell tomato stakes that were perfect for 1 lb rockets, but I haven't seem them there in years.

[juggalo_pyro]

why don't you just go to a hardware store and buy some wooden dowels there cheap and come in different diameters and come at about 3-4 foot long just use a small hand saw to cut then to the length you want and that?s it

[alany]

Dowels are very expensive for the timber you actually get, same with moldings of other cross section like beading for window and picture frames. Round dowels are harder to work with for larger rockets too. It is far easier to attach a square or rectangular stick to a rocker than a round one.

Some also argue that square sticks offer more drag and hence can produce the required CP/CM stability with shorter lengths than round ones. I don't know that the effect is really that large of a difference, in my mind the mechanical properties are more important. It is definately significant with wide rectangular cross-section sticks, but square vrs circular is less noticeable and square sticks mass more for the same "size" anyway so the improvement may be completely pointless.

[EnigmaticBiker]

Before I crack and try and find somewhere to saw up a load of planking into square rods for me, does anyone have any magic ideas for affordable stabilising nirvana? All suggestions and ideas appreciated. I'm sure someone out there has a simple, elegant, and (most importantly) dirt cheap solution to the problem...
So, what do you use to balance your larger rockets?

Time for a strange idea (NOT TESTED)

Why not find a small rod and make paper tubes, then balance using putty, clay, mud, whatever as a counterweight?

A crazy idea (DEFINITELY NOT TESTED)

I wonder if a suitable string with some weighting on the end might work, supporting the rocket on a ramp for launch?

I'd be fascinated if this pendulum idea works, not thought of it before.
If not, why not?

Simon

[fishy1]

the string idea won't work, but the paper tube sounds interesting.

[EnigmaticBiker]

the string idea won't work, but the paper tube sounds interesting.

I might try the string idea just to see what happens; Reasoning that, if the main function of a stick is to force the rocket to point upwards, a pendulum should basically do the same. Stability would be poor initially but improve with acceleration. Think I'll wear the bike helmet though

I have another reason for suggesting a tube, if the tube were left open (weighting being provided by the thickness, rather than attached) the minumum air resistance would be straight down the tube, any deviation in flight being resisted by the side of the tube acting like a sail.

(elliptical sails were once used on a transatlantic ship, if my addled memory serves me).

Simon

[Frozentech]

I might try the string idea just to see what happens; Reasoning that, if the main function of a stick is to force the rocket to point upwards, a pendulum should basically do the same. Stability would be poor initially but improve with acceleration. Think I'll wear the bike helmet though

I have another reason for suggesting a tube, if the tube were left open (weighting being provided by the thickness, rather than attached) the minumum air resistance would be straight down the tube, any deviation in flight being resisted by the side of the tube acting like a sail.

(elliptical sails were once used on a transatlantic ship, if my addled memory serves me).

Simon

Yes a helmet would be a good idea with a pendulum 'stabilizer'. I predict a tumbling trajectory in a random direction. The main function of the stick is not to force the rocket to point upwards, but to impart drag behind the center of mass, which you are not going to get from a string and a weight. You might just pull the center of mass to the rear, greatly *decreasing* stability ? I assume you plan to use a flame proof string ( kevlar?).

[EnigmaticBiker]

Yes a helmet would be a good idea with a pendulum 'stabilizer'. I predict a tumbling trajectory in a random direction. The main function of the stick is not to force the rocket to point upwards, but to impart drag behind the center of mass, which you are not going to get from a string and a weight. You might just pull the center of mass to the rear, greatly *decreasing* stability ? I assume you plan to use a flame proof string ( kevlar?).

Yes, I can visualise a very shaky start and a spectacularly spinning end as the weight overtakes the motor!

I like coming up with wacky ideas, at least I get to learn from why they don't work plus the initial excitement of uncertainty. (Admin/Mods - On a small enough scale not to be seriously dangerous <=25g motors, total weight)

The tube idea is serious, I'd be interested in the results if someone with more experience tried this. My motors are on such a small scale and too inconsistent.

Maybe I should be in the rocket forum with this.