37 replies to this topic

[Pretty green flames]

Hey

What's the general known payload weight for a 4oz. rocket. I've been reading and some say 60grams other 15-30grams.

Will it carry a 2inch ball shell to 90-100feet.

Which BP based propelant would be the best to get as much power as possible out of the motor.

Thanks for your answers.

[JamesH]

My 4oz BP end-burning rocket motors will carry a 2" round shell weighing 45g straight up without a struggle. It will lift more, but I haven't determined their safe upper limit yet.
I have a few pictures of such a rocket here: -
http://photobucket.c...s/a152/jamesh22

[Pretty green flames]

Which propelant do you use, 6:3:1 ?

[JamesH]

75/15/10 black powder made with willow charcoal. Since it's an end-burning rocket the fuel needs to be very fast burning.

Are you intending to use an end-burner or a core-burner?

[Pretty green flames]

Core burner.

[JamesH]

I should imagine a 6/3/1 propellant would be a good starting point for a 4oz coreburner.

[Pretty green flames]

Thanks for your help JamesH

[Yugen-biki]

This was posted on this forum a long time ago. I don't remeber who it was. But here it is again.

Okay, here are recommended safe payloads.
For those who can?t handle UK numeric system ? like myself, 1 pound (lb) is about 450grams.
There are 16 ounces (oz) to a pound, so an ounce is about 28g and change:

Rocket size ? Payload
2oz ? 1/2oz
4oz ? 1 oz
8 oz ? 2-3oz
1lb ? 4-6oz
2lb ? 8-10oz
3 lb ? 12-14oz
4 lb ? 16oz
6lb ? 18-24oz


Q: What is the source for this numbers:
A: Wolter Pyro Tools technical documentation,
although it is similar and has been verified with other tool makers.

Q: Is the range of payload weight represent minimum maximum payload?
A: No. The upper end of the range represent the maximum payload you can shoot safely,
but the left represent a recommended usage minimum. If you want to put a payload
smaller then the minimum then you can, but it will be cheaper to build a smaller
rocket that can handle that weight.

Q: So I should never go above the maximum?
A: Well, every composition is different, and of course,
if you manage to create a procedure that consistently allows you to lift a bigger
payload to a safe height, then that?s great. But play safe and test many times before
deciding to send your bigger rockets to the local show.

Q: Is this valid for other type of fuel or stabilizing arrangement?
A: No. This is specifically for CORE-BURNING bp composition type rockets.
Any rockets that use whistle, KNO3/Sercose, end burning, fin stabilized,
spin stabilized etc has different payloads. P.S. It is considered to be
unsafe to put a payload on any spin stabilized rocket? but this really has
nothing to do with the question

[Pretty green flames]

Thanks yugen, that's the kind of information i was looking for, somehow i couldn't find it here.

Now i'm 1 step away from firing my first rocket with a header attached. And that one step is Sulfur.
I'm all out so no propelant.

[raiderzone]

My 4oz BP end-burning rocket motors will carry a 2" round shell weighing 45g straight up without a struggle. It will lift more, but I haven't determined their safe upper limit yet.
I have a few pictures of such a rocket here: -
http://photobucket.c...s/a152/jamesh22

Hey James,

Nice pictures. I've noticed that on the 4oz rocket ball shell you have a small device on top (crossette or salute?) that is fused from the bottom of the rocket. Can you explain conceptually what is going on here? I have seen this device and type of fusing used on Tom Rebenklau's rockets and was curious as to what it was and how it worked. Thanks!

[JamesH]

Its a D1 glitter comet as a rising tail that is burn inhibited on the outer surface. I do this rather than add spark ingredients to the BP since endburners need a very fast burning propellant. The motors themselves give very little tail.

Edited by JamesH, 05 November 2005 - 05:22 PM.

[raiderzone]

Its a D1 glitter comet as a rising tail that is burn inhibited on the outer surface. I do this rather than add spark ingredients to the BP since endburners need a very fast burning propellant. The motors themselves give very little tail.

Thanks for the response. This should've been obvious to me, but it still doesnt explain why Tom R. has them on his rockets. AFAIK all his rockets are 1lb core burner rockets that have the glitter effects (Winouker 39j) in the delay section of the rocket.

[Maineiac]

Raiderzone,
What pics (or where) are you seeing this comet attachment on Tom R's rockets? Let me know and I can more than likely clear it up for you.

[raiderzone]

Raiderzone,
What pics (or where) are you seeing this comet attachment on Tom R's rockets? Let me know and I can more than likely clear it up for you.

Hey Maineiac,

In the following photo, I see at least 3 examples of a device attached to the heading that has a fuse leader that follows a path down the side of the rocket to the nozzle area.

http://www.osff.net/rocketslarge.jpg

Appreciate your help on chiming in to clarify!

[Maineiac]

These are simply large comets hot melt glued on the top of the rocket for added rising effect at launch. You're right, Tom does use either 39 or 39J as his delay comp but that is rather sparse by the time it kicks in. The comets leave a nice big bright tail all the way up.