BP Coreburner Rocket Sizes and Payloads

[Ubehage]

I am currently building a pretty huge salute, intended for a rocket.

As I was pasting the shell, I noticed how heavy it feels and I began to wonder if my rocket can lift it.

 

So, I began a long search, and finally found the answer(s) I was looking for.

I thought it would be useful for others if I posted the summary here, so everybody can look up what their rockets can lift.

 

NOTE:

This chart is only for BP core-burners.

If you use whistle or another type of fuel, your rocket may be able to lift more than listed here.

 

First, let's know what size your rocket is.

American rocketeers often describe their rockets in ounces or pounds. Which for me at least, doesn't make any sense.

Like, wtf does 8 ounces mean?

This list will hopefully make that easier to understand.

 

Motor ID Designation Tube Length

3/8-inch ID 2 ounce 3.5 inches

1/2-inch ID 4 ounce 5 inches

5/8-inch ID 8 ounce 6.25 inches

3/4-inch ID 1 pound 7.5 inches

7/8-inch ID 2 pound 9 inches or longer

1-inch ID 3 pound 10 inches

1.25-inch ID 4 pound 12.5 inches

1.5-inch ID 6 pound 15 inches

 

 

Now you know what size your rocket is.

Let's move onto the payload:

 

Rocket Size Maximum Payload

2 ounce 0.5 ounce

4 ounce 1 ounce

8 ounce 2-3 ounce

1 pound 4-6 ounce

2 pound 8-10 ounce

3 pound 12-14 ounce

4 pound 16 ounce

6 pound 18-24 ounce

 

This list is the maximum payload that can be safely lifted to a decent height.

Feel free to experiment, but remember to stay safe.

 

 

Now, some of you may wonder "WTF is an ounce?"

1 ounce is 28.34 gram.

1 pound is 453 gram.

 

 

Some of the information in this post was gathered from an earlier post on APC. Many thanks to APC-member Pretty Green Flame for providing the list of payloads.

The rest of the information is from Ned Gorski.

Edited June 7, 2020 by Ubehage

[BetICouldMake1]

My 1lb coreburners can easily lift 16oz headers using 70-20-10 fuel. A list like that is handy but lifting ability is highly dependant upon the fuel used, both the charcoal and the ratio. Never a bad idea to err on the safe side, but these seem like very low estimates to me, by about 50%.

[SharkWhisperer]

My 1lb coreburners can easily lift 16oz headers using 70-20-10 fuel. A list like that is handy but lifting ability is highly dependant upon the fuel used, both the charcoal and the ratio. Never a bad idea to err on the safe side, but these seem like very low estimates to me, by about 50%.

ABSOLUTELY your rocket efficiency and ultimate payload is entirely dependent on the characteristics of your BP, which vary wildly from person-to-person, depending on not only starting materials but technique. Not to mention rocket building expertise and results.

 

Uberhage, you mean well and your description of "standard" rocket tube diameters vs lengths are an excellent starting guide (but by no means the rule--I use various tube lengths for a given diameter to achieve different effects, all the time; others do, too).

 

But posting payloads per rocket size is fraught with potential accidents. Imagine a newbie with poorly tested, or untested, or insufficiently tested/consistent rockets trying to launch a shell with some crappy BP, as is usually the case with first timers. That could spell a disaster.

 

Ranges of payloads are highly variable and BP and rocket construction-dependent. New guys: launch a few rockets with no payload. If they don't perform nearly identically, then you have work to do before going to the next step. Once they perform consistently, and I mean consistently, then attach an inert payload (bag of sand, ffs--I don't care), and repeat until you have consistency and predictability. Only then, please, start loading hot payloads, and please start small.

 

If you get 1 of 5 or 1 of 10 rockets cato'ing on the pad or soon after, that's unacceptable risk to attach a pyro payload. You will possibly blow up yourself and your friends.

 

The payload chart is not gospel. In fact, I consider it dangerous. As BCM1 stated, his results greatly vary from your "guidelines", which I'm sorry to say, I consider misleading and potentially dangerous. That chart needed a clear disclaimer that this is for "hot BP, well-tested & well-constructed, consistently replicated core-burners and are only loose estimates and ballpark figures to consider what to begin with (AFTER you have a reliable delivery system, aka rocket !!!).

[dynomike1]

Thanks Ube now i know why i was getting catoes with payload.

[Bourbon]

Question for anyone here as I am still extremely new to this. I see in these charts that a 1 pound rocket is 7 1/2" long. I've started my venture into rockets with Stingers. My tooling is for 1# Stingers but the tubes are only 3 3/4". Why do they still consider this a 1# ? Why is it all based on the ID of the motor?

[SharkWhisperer]

Question for anyone here as I am still extremely new to this. I see in these charts that a 1 pound rocket is 7 1/2" long. I've started my venture into rockets with Stingers. My tooling is for 1# Stingers but the tubes are only 3 3/4". Why do they still consider this a 1# ? Why is it all based on the ID of the motor?

"Poundage" is an archaic term related to barrel diameter, and you'll find many threads with speculation (some more confident than others about specific details) regarding how it was decided based on how many metal (lead) balls of a certain diameter would fit inside a given length. The explanations don't always jibe with one another.

 

In my opinion, it is archaic terminology with limited practical utility. Most pyros know a 1-lb rocket is 3/4" ID and a 3-pounder is an even inch. Outer diameter is not considered, nor is length. Many of us roll our own tubes or cut commercial lengths to the size we desire. The basic ID/length ratio for core-burners in pyro is length = 10x ID; hence your 3/4" ID "standard" rocket tube is 7.5" long, and commercial tooling (for rockets) reflects this. That said, I often make 3/4" motors for semi-endburners (slight core) that are longer or shorter than 7.5", depending on what I'm using them for (I make hybrid finned "model" rockets powered by homemade BP motors). Unless you're making endburners or your own tooling, most tube and tool vendors stick pretty closely to the typically used length charts that was posted above. This is not gospel, however, and your stingers are still using 1-lb rocket tubing and tooling, just shorter than standard full-size tooling.

 

Don't make yourself crazy over this aberrant terminology. Just enjoy using what works for you (I've made 4" and I've made 10" motors from 3/4" tubing, in addition to the most common 7.5" size, all successfully but with different burn characteristics for different purposes.

 

There are many well-established comps and ratios in pyro, but very few are immune to re-thinking/modification/experimentation, which makes the hobby that much more interesting and flexible.

 

Stingers are a hoot, so have fun!!

[Bourbon]

"Poundage" is an archaic term related to barrel diameter, and you'll find many threads with speculation (some more confident than others about specific details) regarding how it was decided based on how many metal (lead) balls of a certain diameter would fit inside a given length. The explanations don't always jibe with one another.

 

In my opinion, it is archaic terminology with limited practical utility. Most pyros know a 1-lb rocket is 3/4" ID and a 3-pounder is an even inch. Outer diameter is not considered, nor is length. Many of us roll our own tubes or cut commercial lengths to the size we desire. The basic ID/length ratio for core-burners in pyro is length = 10x ID; hence your 3/4" ID "standard" rocket tube is 7.5" long, and commercial tooling (for rockets) reflects this. That said, I often make 3/4" motors for semi-endburners (slight core) that are longer or shorter than 7.5", depending on what I'm using them for (I make hybrid finned "model" rockets powered by homemade BP motors). Unless you're making endburners or your own tooling, most tube and tool vendors stick pretty closely to the typically used length charts that was posted above. This is not gospel, however, and your stingers are still using 1-lb rocket tubing and tooling, just shorter than standard full-size tooling.

 

Don't make yourself crazy over this aberrant terminology. Just enjoy using what works for you (I've made 4" and I've made 10" motors from 3/4" tubing, in addition to the most common 7.5" size, all successfully but with different burn characteristics for different purposes.

 

There are many well-established comps and ratios in pyro, but very few are immune to re-thinking/modification/experimentation, which makes the hobby that much more interesting and flexible.

 

Stingers are a hoot, so have fun!!

I didn't realize I could be so universal with the given tooling I have. Thanks for the explanation and hints!