Nose cone weight HPR

[Adam3836]

Ok I know this subject has been beat down before so forgive me for starting it up again but here’s my question.
Iam not really interested in drilling my freshly painted nose cone and inserting wood dowel’s to then have to shave and sand and paint the NC again just to hold the lead shot and epoxy in place .
So what’s next best way to add weight to a high power rocket nose cone
Iam mainly flying H/I/ and a J motor here and there

Thanks in advance
Thanks for your time

 

[dhbarr]

Lots of folks just do weight and epoxy, maybe a ring or plate and some foam.

 

[Adam3836]

Lots of folks just do weight and epoxy, maybe a ring or plate and some foam.

makes sense so the foam is just to hold the whole set up in place especially if the epoxy gives way ?

 

[heada]

I cut the aft end of the cone off and sand down a bulkhead so it'll fit in the shoulder area. I add an eyebolt to it and use that as my recovery attachment point. You could add fender washers to that to add secured nose weight as well as getting a better attachment point than the weak plastic loop that snaps on an overly energetic ejection.

 

[dhbarr]

makes sense so the foam is just to hold the whole set up in place especially if the epoxy gives way ?

The one I'm thinking of goes bb's + epoxy, a plate with the eyebolt, some more epoxy, then foam. Essentially the foam just filled the cone up to the shoulder.

 

[Cameron Anderson]

How much weight do you need?

 

[Adam3836]

How much weight do you need?

I don’t think very much iam trying to confirm that now it’s for madcow 4inch diameter patriot 38mm

 

[noffie79]

Are you less than 1 caliber stable without adding nose weight?

 

[Adam3836]

Are you less than 1 caliber stable without adding nose weight?

Without adding the motor and casing weight and nothing for nose cone weight I am less than 1 caliber

 

[Nytrunner]

The 4" Patriot needs a few oz for general flying, and some more for bigger motors. I have a few oz epoxied into the tip (scratched up the inside like crazy) and a couple leadshot/epoxy donuts that I put in for bigfee motors

 

[Cameron Anderson]

Throw a few extra large quick links near the nose for extra weight. They're removable and you can customize the weight you want easily.

 

[dr wogz]

I have a fair amount of nose weight in my 4" Madcow patriot. Them small fins!!

 

[Flyfalcons]

This is why you figure out nose weight requirements before you paint.

 

[Adam3836]

This is why you figure out nose weight requirements before you paint.

Yea I agree
My patriot isn’t painted yet but my loc mini mag is that’s the one I don’t feel like messing the paint up on so lesson learned with painting before figuring nose weight out but still have options for the patriot that’s not painted yet

 

[Joe Bruce]

I built a Madcow 4" Patriot for my L1 cert. Added 16 oz modeling clay to NC (cut off base, used plastic rivets to attach to payload tube). Flew on H115 and H182 with 8 sec delays. Would need another 16 oz. to balance an I280.

 

[zeotherm]

I came to ask a similar question. I am on my second attempt with a Devastator (1st one flew great, but was eaten by a rocket hungry tree on it's maiden flight ). How much nose cone weight should be added when you might fly motors of different impulse levels and widely different weights? I would like to fly this on something between a I212 (475g + 212g for 38mm casing) to J430 (1104g + 405g 54mm casing).

Last go around I loaded it with an I motor + hardware and added lead shot until I got my margin right. Should I use the heaviest possible motor I might fly with to balance this out, or would that be overkill for all smaller motor flights possible making it overstable?

 

[Cameron Anderson]

I came to ask a similar question. I am on my second attempt with a Devastator (1st one flew great, but was eaten by a rocket hungry tree on it's maiden flight ). How much nose cone weight should be added when you might fly motors of different impulse levels and widely different weights? I would like to fly this on something between a I212 (475g + 212g for 38mm casing) to J430 (1104g + 405g 54mm casing).

Last go around I loaded it with an I motor + hardware and added lead shot until I got my margin right. Should I use the heaviest possible motor I might fly with to balance this out, or would that be overkill for all smaller motor flights possible making it overstable?

Adjustable weight systems are one option.
Another is to use enough weight for the heaviest motor you will use and just accept the altitude penalty when you fly smaller motors.
Or a third option is to balance toe rocket for your most used motor and accept slight instability with your heaviest motor.

 

[Nytrunner]

Adjustable weight is the most versayile option. It requires a compartment in the nose/payload bay, but allows you to fly most any motor you want with optimal weight

 

[David Schwantz]

Put in a removable nose weight system. Can always paper and tape cone while doing the work so you do not bugger up the paint.

 

[Joshua Smith]

Put in a removable nose weight system. Can always paper and tape cone while doing the work so you do not bugger up the paint.

That's a very cool system!

 

[teepot]

For an adjustable weight system I use quick links and 1/2" nuts. I also put a threaded rod down the center of the nose cone with a coupler and an eye bolt.

 

[DMehalko]

Put in a removable nose weight system. Can always paper and tape cone while doing the work so you do not bugger up the paint.

yep, I did this on my warlock after finishing and paint when I decided to stuff a k motor in it, worked great! Slice the bottom of the cone off and build a nose weight system ( I bought the loc rnws)

 

[David Schwantz]

Yup, LOC's is great. kind of where I got the ideaa from

 

[MoreCowbell]

Typically, a rocket that requires nose cone weight to get stable is not a real high-flyer, so when I have a rocket like this I don't bother with an adjustable weight system. I calculate the CG/CP relationship with the largest and heaviest motor that will fit in the rocket. I then mix the required weight of lead shot with epoxy and pour it into the nose cone tip. If you don't have access to lead shot, split-shot sinkers are more readily available where fishing supplies are sold. I then foam the rest of the NC to hold the weight in place.

NOTE: Because of the heat generated while the epoxy cures, it is advisable to suspend the NC in a bucket of cool water--this is especially true for plastic cones, or ones, dare I say, that have already been painted...

 

[David Schwantz]

But now you have just limited the limited the range of your roccket. You fly at a smaller field, higher wind than normal, tree lines, a number of things that could call for the need to fly with a sssssmaller motor.

 

[CPUTommy]

I love the idea of adding nose when needed, some great ideas, let's think about this.

 

[Francisco Garcia]

I built a Madcow 4" Patriot for my L1 cert. Added 16 oz modeling clay to NC (cut off base, used plastic rivets to attach to payload tube). Flew on H115 and H182 with 8 sec delays. Would need another 16 oz. to balance an I280.

Did you keep the stated 28" CP as per instruction with the 16 oz?

 

[David Schwantz]

The CP should not change with any amount of weight. The CG will shift as weight is added or removed.

 

[OzHybrid]

The CP should not change with any amount of weight. The CG will shift as weight is added or removed.

If you apply simple Barrowman CP calculation, where CP is 1/2 the projected area, the CP doesn't change. However,as you go faster, the position of the CP will change. Run RAS Aero on your rocket and it will plot the CP for various Mach's. The Mach shockwave prevents the air from seeing some of the area. This could be more forward or further back. If it's further forward and CP and CG are marginal you end up with a rocket that might have been stable with a low powered motor but stick a more powerful one in it and it becomes unstable when you reach that critical velocity and CG goes behind CP.
So CP is related to velocity and the velocity is related to mass and thrust and drag. And if you are marginally stable, be careful what motor you use.

 

[Francisco Garcia]

Did you keep the stated 28" CP as per instruction with the 16 oz?

Sorry meant 28"CG.....or what was ur CG with this weight.....cuz I'm looking @ 28 oz to make my CG @ the 28" mark!