Nose Cone Purchasing Help

Hello all,

been lurking around the forums for about a year now and finally have a question that I deemed willing to make an account for.

I'm looking into purchasing 2 fiberglass nose cones. Specifically this one: https://rocketrywarehouse.com/product_info.php?products_id=357

It is a 6" 5:1 VK. I have never purchased a nose cone before so I am unsure as to what dimension the 6" is referring to. My gut is telling me it is the ID (or OD of the shoulder). This way I know whether I need to buy a 6" ID or a 5.75" ID fiberglass tube. If any of you have experience with purchasing these I would like your feedback. Thanks!

Welcome to the forum!

Usually, each manufacturer determines those dimensions, and typically you would want to buy the airframes (i.e., tubes) from the same place, to insure proper fit. You can mix/match vendors, but you need to do your homework before hand to make sure they fit.

Regarding their tubes for this vendor:

Inside diameter 6.00 inches

Outside diameter 6.170 inches

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https://rocketrywarehouse.com/product_info.php?products_id=1102

Greg

Thanks Greg for your reply. That helps a ton.

For a clearer picture of my situation: I'm on my university's rocket team and am in charge of the nose cone. So the information of getting a tube from the same vendor is very helpful as I know we are looking to purchase two 10' sections from this manufacturer https://kmac-distribution.com/Plastics/fiberglass-filament-wound-tubes.htm#.VfLuTZdPUXh (stock # KM-24263). Which has a 1/8" thickness and will have an OD of 6.25 which will be a mismatch between the nose cone and tube. And it's a lot more expensive than the tube from rocketry warehouse. I'm going to have to see the trade-offs between the two.

Wow. At that pricing, you could buy Carbon fiber. PML has the 6" heavy wall tubes for $700 for 90" length

https://publicmissiles.com/secure/components.asp?groupid=223200310094593

There isn't much that RW tubing can't handle (I've never seen it fail, actually)

But if they stick to the other tubing, these guys make custom nosecones - https://www.pythonrocketry.com/

Since you are on a university team I assume you are doing some type of special project and you guys don't have a lot of experience with high powered rockets. Remember, tubes of any material are strongest in compression. So unless you have some significant force acting on the sides of your rocket you may be able to use something lighter and less expensive than what you linked to in your post. I've seen videos of people placing a few wine glasses on a flat surface, putting a board on top of them and then standing on the board. A few wine glasses can hold up hundreds of pounds, but hit two of them together a little too hard and they shatter. We don't know what you are doing, so this is just a suggestion.

Emery_Rowe said:

Thanks Greg for your reply. That helps a ton.

For a clearer picture of my situation: I'm on my university's rocket team and am in charge of the nose cone. So the information of getting a tube from the same vendor is very helpful as I know we are looking to purchase two 10' sections from this manufacturer https://kmac-distribution.com/Plastics/fiberglass-filament-wound-tubes.htm#.VfLuTZdPUXh (stock # KM-24263). Which has a 1/8" thickness and will have an OD of 6.25 which will be a mismatch between the nose cone and tube. And it's a lot more expensive than the tube from rocketry warehouse. I'm going to have to see the trade-offs between the two.

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RW 6" airframe has ID = 6.000" and OD = 6.170" so the wall thickness = 0.085", and that's what the RW cones mate to.

The RW airframe is $50/ft. versus K-mac @ $76/ft. The pricing is equivalent on a weight basis as the kmac is 50% thicker, 50% heavier and costs 50% more.

Do some engineering and figure out what wall thickness FG you need and go from there. If you need 0.125" wall then k-mac is ok. If you only need 0.85" wall thickness then you have two options: RW to see if they can supply a 10' length if that's what you need; or ask kmac if they can make a 10' tube that has a 0.085" wall thickness.

Bob

Thanks everyone for the responses. Yes, we do NOT have a lot of experience with high powered rockets. This is only our second attempt (the first was very ugly looking, but did its job). I'll have to talk to some other people I'm working with about this. I do believe that the RW tube would be perfectly fine. I like that it's offered in 1' segments up to 5'. I guess I should have said our rocket isn't going to be one 10' tube (hopefully obvious, but thought I would point it out). That's just what kmac standard lengths are for purchasing.

I don't want to deviate too far from the thread's topic, as it might be confusing for others looking for help.

Next question: Is the metal tip on the nose cone generally glued on or is there a nut/bolt type of connection? We are designing an electronics bay within the nose cone and are trying to find connection points to hold it there. We think attaching everything to the bulkhead would be better. However, we are having trouble designing the bulkhead/nose cone connection right now. So we want to see if we have other options for the electronics bay to use our time wisely. And thanks again for all your help!

Emery,

Check out the National Association of Rocketry and Tripoli Rocketry Association web sites and see if there is a club near you. You can a lot at club launches, and there are often rocket vendors on site that can show you materials and answer your questions. Good luck!

Emery_Rowe said:

Next question: Is the metal tip on the nose cone generally glued on or is there a nut/bolt type of connection? We are designing an electronics bay within the nose cone and are trying to find connection points to hold it there. We think attaching everything to the bulkhead would be better. However, we are having trouble designing the bulkhead/nose cone connection right now. So we want to see if we have other options for the electronics bay to use our time wisely. And thanks again for all your help!

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Those that I have seen are bolted on. The two or three I personally have use 1/4"-20 bolts. I tend to swap the bolt for threaded rod plus an eye-nut. That makes the NC bulkplate removable, gives me one less epoxy joint to worry about, and provides a location for a tracker (when I can afford one).

+1 on finding an NAR or Tripoli section. Not only will they have all the waivers in place for flying, club meetings are a great place to meet people, ask questions, etc.

Emery_Rowe said:

Next question: Is the metal tip on the nose cone generally glued on or is there a nut/bolt type of connection? We are designing an electronics bay within the nose cone and are trying to find connection points to hold it there. We think attaching everything to the bulkhead would be better. However, we are having trouble designing the bulkhead/nose cone connection right now. So we want to see if we have other options for the electronics bay to use our time wisely. And thanks again for all your help!

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You can email Flyodd (RW) directly to check, but all my metal ones are bolted in, with a washer to space it. I knock out the washer, take it off the bolt, then put a rod of all thread into the tip, spacing the washer with nuts. You can also just put a bulkhead on the top of the coupler that goes into the NC, and bolt the lower bulkhead into threaded rods running from the upper bulkhead. Photos tell the story better than I do.

this is the top bulkhead on my 3" darkstar. I epoxied over all the hardware visiable here, then glued the coupler into the nosecone.


fully assembled, bottom bulkhead is removable.


My 2.6" screech, I ran a single allthread down, and used a ubolt. Doing this, you technically don't have to glue the coupler in. I do anyways.




This shows how the washer is spaced inside the nosecone. Here the bolt has been replaced with an eye bolt, as a recovery attachment point (nosecone is used as a payload bay for main chute)

Dave's U-bolt is stronger, but I just attach a forged eye nut to my allthread.

Bat-mite said:

Dave's U-bolt is stronger, but I just attach a forged eye nut to my allthread.

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Honestly I'd have done that if the hardware store had any. much easier with a nut.

Wow! This is all fantastic information. Thanks everyone!

We do have a very knowledgeable contact that comes around every once in awhile if we have questions. I will have to check with him about his clubs' launch dates. However, in Northeast Ohio I doubt any club has a waiver for 10,000'+ in case we would like to test.

NOTRA in Cleveland is hosting BALLS this very month. I don't know the waiver, but the minimum impulse class for BALLS launches is K impulse.

Bat-mite said:

NOTRA in Cleveland is hosting BALLS this very month. I don't know the waiver, but the minimum impulse class for BALLS launches is K impulse.

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??????? Balls is hosted by AHPRA and is located in the Blackrock desert in Nevada!

Dwatkins said:

??????? Balls is hosted by AHPRA and is located in the Blackrock desert in Nevada!

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there's a link to it on their main page..... I think someone got confused https://www.northernohiotra.com/, https://www.balls24.com/

If you need over 10K, We've got an 18K waiver in NY

Our contact actually is the president of NOTRA, and he's attending balls I believe. He's probably getting prepped for the trip. Which might explain why I haven't seen him lately.

Yikes! My bad. :blush:

OAMC near Springfield Ohio has 18,000, so contact me if you need that much airspace. We should be resuming launches in November.