Removable nose weight in a plastic NC

This is something I have never had to do before. I bought a squat and noticed that it is margionally stable on 54mm 1G motors, but I want to be able to add/subtract nose weight. My idea was to mount a single bulkplate in the tip of the nose and support it with two parallel dowels, run all thread through that to another removable bulkplate, and add washers as needed.

How do others do this? Give me some ideas. View attachment mad_cow_squat.rkt

That's kind of the way I have it in my Little John. I cut an opening in the side of the shoulder. I installed an eye bolt through the bottom of the shoulder. This allows me to add or remove weight as required. The down side is that in my case the weight is not at the tip of the nose, but at the base. Not efficient, but it works for me. Unfortunately my camera has disappeared so I cannot send a photo....

The other problem I see with that is that in the Squat, space is key, so I plan to cut off the base of the nose cone.

What about securing some bb/epoxy mix in the cone with a dowel and place a bulkhead with an eyebolt directly over that, and secure THAT with another dowel?

Seems like I have seen build threads here that are similar to that. I have a couple in OR that I was going to try that with. Mount a 'base' weight in the tip, then have adjustable weight for different motors. No reason why one couldn't embed a threaded rod in the nose slurry, then use that for attaching a bulkhead, adjustable weights and an eye-nut. You would have to consider the rod during placement of the retaining dowels, and maybe swap them for short wood screws for added strength.

Terry

See post 52 here.
https://www.rocketryforum.com/showthread.php?39611-Family-Drag-Race-Build/page2

I usually drill a half dozen small holes 1/8" - 1/4" or so near the tip of the nosecone, tape the outside to prevent leaks and pour my epoxy slurry into the nose cone. You can pour in lead shot for weight, or add a threaded rod. The epoxy hardens after it fills the holes drilled in the tip. It won't come loose under normal use (lawn darts, lake stakes, etc, not normal use).

A technique that has worked well for me with larger nosecones is to:
1) Cut the bottom of the NC off
2) Make a bulkplate that fits above the shoulder inside the NC - add a ubolt to the plate for retention, and a central hole for either a 54 or 38mm body tube. Add tee nuts to the back side to attach a smaller plate to cover the central hole. Glue bulkplate in.
3) Insert a body tube as far as it will go, and cut flush with the bulkplate. Epoxy in. Usually fill NC around the tube with foam, leaving center clear.
4) Glue another bulkplate into the top of a coupler tube that is the same length as the body tube in the NC. Bolt a short threaded rod into the coupler bulk plate. Variable weights as needed are attached to the top of the coupler tube on the threaded rod with a locknut.
5) Insert coupler tube into NC body tube, with weights at top. Empty coupler tube usually holds trackers. Use thumbscrews to attach cover to NC bulkplate to hold everything in.

Works great! A bit more complicated, but very flexible.

I find steel washers to be pretty inefficient (weight vs space). For 3" or larger rockets I will typically make provision for using lead "muffin weights" also. Here is a picture of a 4" nosecone for a ShadowAero Ultra Fatboy that has provision for 45 ounces of noseweight (five lead weights). They are variable from zero to five (three are shown installed in the first picture) and are held in via a 1/4-20 rod that is epoxied in (nuts, fender washer, and cross pins drilled/epoxied through fore end of nosecone). The lead weights are drilled through the middle (second picture shows a weight pre-drilling) and I just use a fender washer and wing nut to old them in and they are very secure.

May I ask where you get muffin weights?

From the picture it looks like the "muffin weight" is a casting made in the workshop?

Did anyone else cast lead soldiers as a kid? It's a miracle we survived.

T-Rex said:

May I ask where you get muffin weights?

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On eBay. Many different sellers.

dixontj93060 said:

On eBay. Many different sellers.

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Thank you, I'll look into them. I was concerned that you were going to say you made them. I don't want to invest in a lead pot just for nose weights....

T-Rex said:

Thank you, I'll look into them. I was concerned that you were going to say you made them. I don't want to invest in a lead pot just for nose weights....

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Since lead is so heavy look for those eBay sellers that strategically make their weights a size that evenly fits into USPS Priority boxes. It is interesting to get a small USPS Priority box in the mail ($5.95 or so in shipping) and you go to pick it up and it weighs like 30 lbs!!!

I know nose weight will vary depending on motor size but any idea how much to add for a 3 grain CTI?

Cheers

dixontj93060 said:

I find steel washers to be pretty inefficient (weight vs space). For 3" or larger rockets I will typically make provision for using lead "muffin weights" also. Here is a picture of a 4" nosecone for a ShadowAero Ultra Fatboy that has provision for 45 ounces of noseweight (five lead weights). They are variable from zero to five (three are shown installed in the first picture) and are held in via a 1/4-20 rod that is epoxied in (nuts, fender washer, and cross pins drilled/epoxied through fore end of nosecone). The lead weights are drilled through the middle (second picture shows a weight pre-drilling) and I just use a fender washer and wing nut to old them in and they are very secure.

View attachment 105494 View attachment 105495

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powderskierman said:

I know nose weight will vary depending on motor size but any idea how much to add for a 3 grain CTI?

Cheers

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Obviously that would totally depend on the rocket you are flying it in--so you will have to do your own sims. As stated before, the weights are 9 oz.

BTW, if you are asking about the Ultra Fatboy, which from your signature it looks you are building, I would post my Rocksim file, but the file it comes with the kit, so instead of messing with Dave T.'s business model, I would just use his Rocksim (but be careful, I found errors in my Rocksim file; and also made a number of changes--mostly related to fin and MMT position).

My RNWS is similar: I start with a coupler (e.g. 1/4", 5/16", 3/8") and weld a washer on one end--will serve to anchor the coupler in epoxy. I spray a small amount of WD40 on a piece of all-thread, and screw it into the coupler. Set the coupler down inside NC, use all-thread to center it, then pour epoxy in NC (of course, rough up inside of NC or drill holes first). Takes about 2oz of epoxy most of the time. Let epoxy harden, then back out all-thread. Now I have a coupler that I can add anything I want into NC. I have a Garmin tracker in an AVbay with a bolt on top that screws in, for example.

Another option to consider for weight: I have a local machine shop with a CNC plasma cutter--lots of commercial shops have them now. They can cut 1/4 or 3/8" thick steel in any diameter you want, and can cut the center hole as well.

Here was my solution. https://www.rocketryforum.com/threads/v2-for-my-l3.129292/page-6#post-1661839

Post 170.