Nose weight ???

Hey all,

I am helping my daughter with her scratch built staged rocket and we are using a balsa nose cone from Semroc for the project. According to Open Rocket, we need about an ounce worth of weight in the nose. Embarrassingly, this is my first time using a balsa nose cone and I do not know how to add weight.....any help would be MUCH appreciated!

how big of a nose cone? you can drill a hole in the base, add lead sinkers or shot and then glue a dowel in the hole to attach eye, or you can add washers to the base with glue or held in place with the eye or a screw

What SteveF said...Estes would use lead washers held with a screweye for their smaller balsa nosecones.

On the SRAM (BT-60 sized nose cone), I drilled a half inch hole about 4 inches in depth. What I did to make sure I didn't drill out the side (I don't have a good workshop) was start with smaller, thinner drillbits and switch out to a larger bit after each drill. Worked fine but made sure I gave myself plenty of balsa left around the deepest part of the hole. I also used sinkers with modeling clay around them to use up all the space I had.

FC

paul.nortness said:

Embarrassingly, this is my first time using a balsa nose cone and I do not know how to add weight.....any help would be MUCH appreciated!

Click to expand...

Here's a page I put together on adding noseweight. Lots of pics there which should be helpful.
https://www.doug79.com/noseweight/

Doug

.

SteveF said:

you can drill a hole in the base, add lead sinkers or shot and then glue a dowel in the hole ....

Click to expand...

That's one good way. Another: cut off the tip (carefully and neatly), drill a hole from the front end toward the middle of the NC, fill with ballast, and glue the tip back on. Continue with sealing the balsa and adding a normal outer finish.

The reason you want the ballast as far forward as possible is because that location requires less ballast. The rocket will be lighter overall, and will fly better.

The reason you would add washers at the base of the NC is because that approach is more flexible. You have 'access' to the washers and can add or remove as needed, if you want to use different motors later.

They're all good ways to do it, just depends on what you like to do-

paul.nortness said:

Hey all,

I am helping my daughter with her scratch built staged rocket and we are using a balsa nose cone from Semroc for the project. According to Open Rocket, we need about an ounce worth of weight in the nose. Embarrassingly, this is my first time using a balsa nose cone and I do not know how to add weight.....any help would be MUCH appreciated!

Click to expand...

Aside from all the advice on how to add the weight, how about correcting the design flaw and making the upper stage body longer (add a tube) or make the fins larger or add another set of fins (if currently 3, make it 6 or if currently 4 make it 8).

Adding an ounce of nose weight will cause 2 or 3 massive problems:
1) At staging, the nose cone will tend to fly off the top as the rocket momentarily decelerates. This will be a disaster. The fix is to make sure the shoulder is snug enough to not fly off yet loose enough to eject properly.
2) A massive nose cone will strain or break the shock cord at ejection.
3) A massive nose cone will make the rocket drop like a rock unless you have a large parachute (sized to handle the weight).

shreadvector said:

Aside from all the advice on how to add the weight, how about correcting the design flaw and making the upper stage body longer (add a tube) or make the fins larger or add another set of fins (if currently 3, make it 6 or if currently 4 make it 8).

Adding an ounce of nose weight will cause 2 or 3 massive problems:
1) At staging, the nose cone will tend to fly off the top as the rocket momentarily decelerates. This will be a disaster. The fix is to make sure the shoulder is snug enough to not fly off yet loose enough to eject properly.
2) A massive nose cone will strain or break the shock cord at ejection.
3) A massive nose cone will make the rocket drop like a rock unless you have a large parachute (sized to handle the weight).

Click to expand...

Yeah... Is this a matter of:

1) Not enough nose weight?

2) Not enough fin at the rear?

3) Forward fins doing some destabilizing - maybe in an upper stage?

How big is this rocket?

Regards,
-LarryC

and
4) how much nose weight (if any) is needed for the upper stage to be sufficiently stable by itself?

Perhaps you can post the .ork file and the assembled brain trust can suggest specific alternatives to a bunch of dead weight at the top....

Shread,

An ounce of noseweight in an Estes-sized rocket is a complete non-issue. Yes, you need to make sure the fit is correct (snug, but not too tight), but I don't really see an issue with the shock cord breaking. Similarly, the parachute shouldn't be a problem if sized appropriately (and since chutes are sized based on complete rocket weight, it doesn't matter where the weight is in the rocket, just how much the total is).

cjl said:

Shread,

An ounce of noseweight in an Estes-sized rocket is a complete non-issue. Yes, you need to make sure the fit is correct (snug, but not too tight), but I don't really see an issue with the shock cord breaking. Similarly, the parachute shouldn't be a problem if sized appropriately (and since chutes are sized based on complete rocket weight, it doesn't matter where the weight is in the rocket, just how much the total is).

Click to expand...

The OP said he was helping His daughter with Her rocket. I did not assume that all components were sized and designed by an expert rocketeer. I simply provided clear and sound advice. If he and his daughter have considered all of those points, then no problem. If not, then they have discussed them and learned something new.

My desire is to provide information to help them succeed and have fun.

An ounce of nose weight in a low power rocket is not an insignificant amount of weight. The NAR payload competition mass is about one ounce (actually 28 grams) and it is used in even A class events. But something's off if the rocket needs that much just to be stable. I'm with Fred on this - fix the design if you can so that no weight, or much less weight, in the nose will be necessary for stability. Even when it is not needed for stability, though, adding a small amount of weight up at the top can make a lightweight rocket go higher because the mass will give the rocket more inertia during the coast phase after motor burnout.