Nose weight Question?

I just wanted to get some feed back from you guys.

I have a PML Spitfire that I'm building and it calls for some nose weight.

According to RS with a J350 and 4oz of nose weight I get a GG of 1.42 margin.

My question is this. Is it necessary to use a wood dowel to secure the nose weight or can I get by with just epoxy and maybe add some expanding foam? I'm figuring maybe 2 oz of weight and the rest foam? Not sure exactly what the foam comes in at, but couldn't be more than a a few ounces to fill it to the shoulder?

Past build such as the Madcow Jayhawk and 4"Patriot I always used this method with the wood dowel as an anchor. My friend has a drill press which makes drilling the holes easier, but I don't feel like bothering him.

Maybe later I'll invest in a table top drill press.

Rather than dowel, have you considered John Coker's method using thin brass rod as an anchor? His technique doesn't need a drill press:
https://www.jcrocket.com/plastic-nose-mods.shtml

Hi Afterburners, I don't like things flopping around inside, I would just make sure all is secure. The foam comes in various weights. Do you have any now? Probably won't need much. I would not trust epoxy to hold weight on the inside of a plastic NC. Just think at 10 G's that 4 oz now weighs 40 ozs. I know you said you do not have a press, but a lot can still be done with just a hand drill. I like to make my NC bulkheads removable with a weight system inside that I can adjust depending on the motor I am flying. Bigger motor, bigger weight. Glued in bulkhead is in the first pic, second is the removable weight tube, third is tube in place, fourth is the bulkhead that will hold the eye bolt and secure everything in place.

I've done two rockets with only epoxy holding the weight and the weight came loose both times.

Another trick I've done is use rods of some sort: all thread, brass, aluminum, or wood dowels. I've done it with two and three. Use them to make a frame of sorts inside the nose cone, with one end of each rod in the tip and the other ends wedged/braced up against the shoulder. Then pour in the ballast. Works much better with a centering ring above the shoulder, or a plate to spread the rods and keep them spread.

John Coker has a good video how to add nose weight.

https://jcrocket.com/plastic-nose-mods.shtml

Tim51 said:

Rather than dowel, have you considered John Coker's method using thin brass rod as an anchor? His technique doesn't need a drill press:
https://www.jcrocket.com/plastic-nose-mods.shtml

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I like this method. Definitely going to do it this way! Thanks for sharing.

AfterBurners said:

I like this method. Definitely going to do it this way! Thanks for sharing.

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Its my favorite method as well.

4 ounces ain't nothing. Just a few bbs' and some epoxy.

Now, I have 40 pounds in my bullpuppy nose cone. Different story.....

David Schwantz said:

second is the removable weight tube

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Nice, what do you do for weight and how do you mount it?

I have done similar to Coker's method but with screws instead of rod. Just cut the heads off with a Dremel.

cbrarick said:

4 ounces ain't nothing. Just a few bbs' and some epoxy.

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I did this up to a pound. It’s worked for ten flights. I just didn’t wanna start sh*t and turn the thread into a frenzy.

These other methods others posted I’d Argue are better.

to make my jart fly straight I put in about 2.2ounces of bb's (half a 375 count container from walmart) chased with a syringe of 1 minute epoxy (supposedly 2.4 ounces). Got dozens of flights on it (all g's and h's) and about 6 years banging around my trailer. Still rock solid.
We tend to vastly overbuild everything as rocketeers..... JMHO. Overbuilding isn't necessarily better though. do what ever makes you feel good....

Micro, I use duck decoy weights, they are solid lead, usually have a hole in them to bolt through, come in either 6oz or 8oz sizes. They are long and skinny. Are flexible if you need to mold them. In the tube I just put in the correct amount of weight and use either foam or paper towels to keep them from shaking around. The screw on bulk head keeps them in the tube.

lead no bueno.

What happens if you bring one in ballistic?

A couple of notes on the 'Coker' method. I've been doing it that way for a long time but I had never seen his video. I would add several points:

• if you are using a lot of epoxy based on the amount of lead, keep the nose cone in a container of cold water to prevent the epoxy from melting the plastic due to the exothermic reaction
• use enough epoxy to create at least a thin layer that completely covers all the shot - that prevents any bbs from coming loose since they are covered in dust and oxide that does not bond to the epoxy very well
• use a good dust mask/respirator to avoid breathing lead dust when working with shot
• you can use brass rod for retention as well which is softer and easier to cut/file, but increase the diameter a bit for strength

If you have a nosecone with an aluminum tip, it's super easy to just use a longer 1/4" scew or all thread to add varying amounts of weight. That's what I've gone to on most of the rockets that I have that need nose weight. I can now very easily set the correct weight using heavy steel fender washers that slide over the rod. If I need a lot of weight, I have some old lead bullets that I add to the tip of the nose cone and then retain those with the fender washers. Works very well.


Tony

Don't know if you are asking me, but if I hit the dirt at 500 mph, I don't think no matter how weight is mounted, that it is going to save the rocket

cbrarick said:

lead no bueno.

What happens if you bring one in ballistic?

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5 lbs of lead, tungsten, sand or whatever is still 5 lbs (plus whatever kinetic energy it has due to velocity. As for the lead its easy to recover and re-use as it melts easily and can be separated from the epoxy the others are much harder to re-use.

Andrew_ASC said:

I did this up to a pound. It’s worked for ten flights. I just didn’t wanna start sh*t and turn the thread into a frenzy.

These other methods others posted I’d Argue are better.

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In a plastic or composite nose cone? Because when it comes to bonding a chunk of weight those are two massively different things.

All methods are good as mentioned above. I like to cap it with a thin layer of epoxy followed by expanding foam epoxy.

plastic.

I'm concerned with lead because ballistic recoveries aren't always things you get back. I got a big one in the METRA peat moss, the nose cone is at least 12 feet in. We were able to pull the motor and fill the hole. Nose cone (bb weight) is now part of the environment. Glad it's not lead. It would have taken a backhoe to get it out.

Where does lead come from??

David Schwantz said:

Where does lead come from??

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umm, the ground originally.....

The only time I am concerned about lead is working with it (melting or cutting), in a form wildlife can consume or a form that can contaminate water. Locked in epoxy buried 10' deep in the ground isn't one of them.

Yup. we went to non lead shot many, many years ago.

Same here, was an avid waterfowler until 5 years ago (20 hunts per season for Duck and Goose). My daughter wants to start this next year.

Got a couple of rockets I am going to use the Coker method to install noseweight in this weekend.

David Schwantz said:

Yup. we went to non lead shot many, many years ago.

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Good luck to your daughter. My youngest son had his first shotgun at 6 yo. Single shot .410. He is now 30, and damn him if he don't shoot better than me now.

I looked around for some brass rods and I found them on Micro Marks website.

https://www.micromark.com/Round-Brass-Rod-Assortment-18-Pieces-12-Inches-Long_2

I also found these. You can select the size you want. Do you think 1/32 is small enough in diameter to cut with wire cutters? Should I go smaller??

https://www.micromark.com/Brass-Rod-12-long_2

1/32" brass rods you could cut with a pair of kindergartner's scissors. I'd recommend 1/8" brass - it's big enough to be easy to work with, it's easy to cut with wire cutters (even fingernail clippers), and every set of drill bits comes with a 1/8" bit. Not true for 1/32". You should be able to find the brass rods at any hobby store - even Hobby Lobby will have them.

If you have a pair of wire cutters, then you could just as easily use a wire clothes hanger. It's mild steel, stronger than the brass, a bit harder to cut (but the wire cutters won't have any issues).

Lead shot and polyurethane glue( Gorilla Glue), ain't going anywhere!!

I agree with rcktnut on the polyurethane glue, it does stick to most plastics better than epoxy, though the rod reinforcement becomes important with larger weights.

I have a bag of old nuts/bolts/screws (mostly small stuff) from building computers that will never get used which I sometimes use as weight with the polyurethane. That's mostly steel bits, not as dense as lead, but good enough if you've got plenty of room in the nose. That way if I lose the rocket (we all have at some point), I'm not worried about leaving lead behind in the environment. It's also a way of recycling some of that old metal, as well as being easy on the wallet.

I've also used sand and epoxy. Once in the field I had to come up with a quick and dirty nose weight, and found an aluminum cola can, half filled it with sand, added some 5 min epoxy, and wedged it up into the nose cone, the aluminum deforming to wedge it in. Added a few drops of CA and some 5 min epoxy, and it was good enough for that flight, and I was able to remove the nose weight later (it was a fiberglass nose cone, with removable bulk plate for electronics).

I use the lead "shot" out of a weight bag for scuba divers. Easy to buy on amazon. Epoxy in. Works great.

rcktnut said:

Lead shot and polyurethane glue( Gorilla Glue), ain't going anywhere!!

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I tried that, and it did eventually come loose! even scuffed up the inside of the NC.. (And this wa sonly about 4-6oz weight..)

All my NC weight is now secured, and with chopsticks, not metal rods. Easier to come by, cheaper, easier to sand smooth & blend, glue tends to 'soak in' more, etc.. 2 pieces of stick, 90°from each other