Smoke trail

[Merlin]

For homemade BP rockets using modified Estes type engine. Does anyone have ideas for creating a smoke trail to track rocket? Edited April 10, 2016 by Merlin

[OldMarine]

Add a comet to the side/top of the motor?

[schroedinger]

Put a Smoke comp comet on top. Either use a pressed comet made of naphtalene comp or a comet made out of a punctuated tube filled with granulated comp. For tracking a rocket i would granulate really big 10 - 14 mm (just cut or pump)

Else you could also try add naphtalene to the delay comp.

[FlaMtnBkr]

If it's similar to an Estes then it is an end burner? I would pick out a smoke formula and make cut stars maybe 3/8" big and prime with screen mixed BP. Then roll a can from kraft paper and maybe take a hole punch and put some holes around the top of the perimeter of the can. You could glue a piece of zip lock type bag that is thicker than plastic/saran wrap on the inside that covers the holes if worried about air getting in. Then put a bag in the can and fill with stars and pipe some quickmatch into the stars and tie the bag shut around the match and close it up. Put the other end under the nozzle so it's lit with either the fuse or the rocket exhaust which then near instantly lights the stars.

 

You don't want the can to burst but to light and spray lots of smoke out of the holes which the first bit of flame melts the plastic away and opens the holes. Also why you want to use a real slow prime on the stars so they light more slowly without breaking up the can.

 

That is basically what I would try. Any smoke comp pressed in the top of the engine will burn slow and not put out lots of smoke and with a rocket that's moving fast it will be a thin wisp of smoke. You need something that will produce lots of smoke over a few seconds. A solid grain will burn too slow and granulated comp will probably burn a bit too quick which is why I suggest cut stars which are in the middle.

 

Just what I would try. Good luck!

[Merlin]

Thanks. I will give it a try. The Estes motors seem to have a smoke comp added to the delay so when the delay burns through the parachute ejection charge fires releasing a puff of smoke to help locate the model in the sky to aid in retrieving. Your idea seems like it would work well for a header on a daytime stick rocket to leave a good smoke trail.

[schroedinger]

The ejection charge is normal bp grains. If it burns it produces a good ammount of smoke.

[FlaMtnBkr]

Are you just looking for something to locate the rocket at it's apex? If so there is probably something much more simple. I thought you wanted a trail of smoke to be able to follow it all the way up.

[Merlin]

Thanks. Yes I just need a bit of smoke in the delay. If a small rocket gets to 1500 feet it becomes a tiny speck. I thought a smoke mix that served as the delay would be two birds for one bullet.(never had much luck with stones!)

[FlaMtnBkr]

You probably want something that ignites all at once after a few seconds to give the rocket time to slow down. If the rocket is still moving quickly it gets 'diluted' a lot and just get that thin wispy trail I mentioned. I bet what you see with an Estes engine is the ejection charge.

 

What works for me is putting a report at the end. It doesn't have to be crazy or fancy. Just a gram of flash in the end of the tube above the propellant grain with a couple pieces of tape. It's all you need for a bottle rocket type report and gives a good bright flash that is easy to locate and leaves a puff of smoke.

 

If you don't want to work with flash or any noise, then something that will probably also work well enough is to do the same thing but with a tablespoon or so of BP. You probably won't have enough space though and will need to put a couple turns of pasted paper or gummed tape hanging off the end of the tube to make extra room. Something that would work even better is to take a nitrate based smoke formula and granulate just like BP and use it instead.

[Merlin]

Thanks. I have made a number of 4 and 8oz stick rockets with report and with headers containing stars. The model rocket is different because everything I contained inside the model. A delay is used above the rocket fuel and a small BP ejection charge deploys the parachute. Stick rockets don't have to be recovered but the models are recovered and reused. I have heard napthalene, star comp, and slow BP for the delay. This year I am going to use a hydraulic press to make rockets.

[lloyd]

Just "slow BP" will make enough of a smoke trail to track. I've made many "Estes-like" motors for my own stock Estes kits (starting at age 15 or 16, and I'm 67 now! <G>) I (we) made them for years for my kids, too, not wishing them 1) to spend that much money on six seconds of flight, and 2) wanting to teach them pyro, also. My daughter ended up being "the pyro".

 

Just take regular BP, up the sulfur and charcoal relative to the KNO3 until you get the burn rate you enjoy, and it will make enough smoke to track to apogee.

 

Lloyd

Edited April 12, 2016 by lloyd

[FlaMtnBkr]

I didn't know you were actually using them in models but describing the motor construction type.

 

In that case my suggestions don't make much sense. Do as Lloyd suggests and make a fuel rich BP that will leave lots of partially burnt fuel in the exhaust aka smoke. I was trying to suggest a way to make lots of smoke and didn't realize it needed to fit in and not destroy a model.

 

A smoke formula might get you more smoke but will probably just take some experimenting on your end. Or the fuel rich BP, which is similar to some nitrate smoke formulas, may provide all the smoke you need.

 

Let us know how it works out.

[MadMat]

You might try using rcandy with 10% sodium bicarbonate added for your delay. That will produce a lot of smoke.