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Using 2 motors for one rocket


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#1 Freese

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Posted 14 June 2006 - 06:01 PM

I just saw a picture of a rocket, looks like a 1lb. BP rocket, with a smoke tube taped along side and fused for simultaneous ignition.

Now the smoke won't provide any additional lift, just the added effect. Now I'm wondering - what if I taped a whistle motor tube to a BP rocket. The idea being you get the tail of the BP motor and the whistle from, well, the whistle motor.

Since both motors will provide simultaneous thrust, do you think the rocket will travel true (assuming that one uses the correct size stick for stabilization)? Or will the thrust from one motor cause an imbalance, perhaps because one motor give more thrust than the other.

Just an idea from a warped mind. I suppose one could just use a very small whistle, but what fun would that be... :rolleyes:

Any ideas?

Fred

#2 fishy1

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Posted 14 June 2006 - 09:46 PM

In theory, I'd imagine it could work, but in practise I would imagine that the roar from the 1lb BP rocket would drown out a small whistle rocket.

#3 BigG

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Posted 15 June 2006 - 07:01 AM

Using simultaneous ignition in a pyrotechnic rocket is not advised. The aim of the motor in this case is (beside providing a sound effect and maybe a trail) to bring the rocket to an optimum height were it could dispose of the pyrotechnic effect. Since this height is quite low ? the need for multiply engines is non-existant, and adding more motors brings a level of instability to the device (which we try to minimize in pyrotechnic).

A small whistle will do nicely (open, where it is not adding/adding tiny thrust) ? and it will be heard quite well above the noise of a 1 (or 2 or 3) pound rocket. Another way to go about it is to have one whistle rocket providing the lift and the sound.

#4 Night Owl

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Posted 15 June 2006 - 12:51 PM

Sorry for promoting my web site guys but look at the second pic down, why not try this idea, I dont claim to be the only person to try or use these, it works great and looks excellent when rising, but really only best in day time displays http://pulsar46.tripod.com/id6.html

#5 rocket rod

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Posted 18 June 2006 - 08:04 PM

If you are talking about model rocketry rather than pyros, then firing two motors simultaneously is fairly easy and is done regularly at UKRA events. In the US, they use multiple igniters with a big power source. In the UK we tend towards using single igniter and quick match.I put one strand of quick match into the nozzle of each moter and add some BP to help ignition. Tape the QM onto the motors with masking tape. I also add some BP to the area of the igniter. Once I fired seven motors simulateously.

#6 Freese

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Posted 19 June 2006 - 04:49 PM

Sorry for promoting my web site guys but look at the second pic down, why not try this idea, I dont claim to be the only person to try or use these, it works great and looks excellent when rising, but really only best in day time displays http://pulsar46.tripod.com/id6.html


It was your website that gave me the idea (thought I wrote that in the post, should have been clearer to give credit where due :blush: )

Thanks for the input. This is, as Justice Holmes would put it, a marketplace of ideas.

#7 Night Owl

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Posted 19 June 2006 - 11:33 PM

Glad I gave some idea's by the way if anyone needs the deets on 2 stage rocket building I can advise through PM or web site contact http://pulsar46.tripod.com by 2 stage I mean one motor burns then second kicks in when first finishes, I've done a few their quite good :P

#8 al93535

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Posted 16 September 2006 - 09:08 AM

1lb BP rocket with a sali whistle on the side.

http://img.photobuck...bandwhistle.jpg

http://www.apcforum....bredstrobes.wmv
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#9 The Swedish Scientist

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Posted 22 May 2007 - 02:05 PM

I just saw a picture of a rocket, looks like a 1lb. BP rocket, with a smoke tube taped along side and fused for simultaneous ignition.

Now the smoke won't provide any additional lift, just the added effect. Now I'm wondering - what if I taped a whistle motor tube to a BP rocket. The idea being you get the tail of the BP motor and the whistle from, well, the whistle motor.

Since both motors will provide simultaneous thrust, do you think the rocket will travel true (assuming that one uses the correct size stick for stabilization)? Or will the thrust from one motor cause an imbalance, perhaps because one motor give more thrust than the other.

Just an idea from a warped mind. I suppose one could just use a very small whistle, but what fun would that be... :rolleyes:

Any ideas?

Fred


What about using a whistle tube rather than a whistle engine?

If you fire enough rockets, sooner or later the whistle engine is going to come off. I personally don't like the idea of being chased by a loose engine. I imagine you would get a more straight trajectory without the second engine.

By using a thick walled tube the heat generated by the whislte would not affect the BP engine.
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If you make it waterproof they'll just make a deeper ocean.
If you make it foolproof... They'll just find 'emselves a redneck!

#10 cplmac

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Posted 27 July 2007 - 08:35 PM

What about using a whistle tube rather than a whistle engine?

That's exactly what I was thinking. Just use a whistle motor but press it as an insert, ie no core. It would provide very little thrust, maybe enough to push itself without a stick at best and it would scream like a banshee, no way a BP motor would be near as loud.




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