combining different motor types in one rocket?

[rocketsonly]

Hello. Just wondering if combining composite and black powder motors on a rocket would be practical. I know the space shuttle uses 2 solid boosters and a liquid based motor (forgot the exact term).

Do black powder motors give off more smoke than blue thunder or white lightning motors?

Thanks.

 

[lalligood]

Mixing propellants is a tricky science.

The short version is this:

When mixing BP & composite motors, you want to ignite the composite motor first because BP comes up to pressure much quicker.

Mixing different composite propellants is usually frowned upon only because it is more difficult to light some propellants (like Black Jack) than others (like White Lightning and/or Blue Thunder).

Now the real question is "how do you to light the different propellant types at different times?" Well, I'm going to leave that to someone else...

And BP motors pretty much give off more smoke than Blue Thunder (which has almost no smoke trail), but White Lightning gives off a LOT more than BP!

HTH,

 

[havoc821]

I was curious about that too. My Saturn V was going to lift off on a F40 or G64 and 4 C6 motors. How would I do this where all light at the same time? Could I just light the composite and light the BP motors with the thermAlight so that they at least get lighted while the rocket is fairly close to the ground. You know for the whole effect thing.

 

[hokkyokusei]

Ignite the composte motor in the usual way, and the use electronics to air start the black powder motors, ignition being trigged by a g-switch.

Over here in the UK you could also use quickmatch to ignite the BP motors, the quick match being lit from the composte motor.

 

[Ray Dunakin]

Originally posted by havoc821
I was curious about that too. My Saturn V was going to lift off on a F40 or G64 and 4 C6 motors. How would I do this where all light at the same time? Could I just light the composite and light the BP motors with the thermAlight so that they at least get lighted while the rocket is fairly close to the ground. You know for the whole effect thing.

Yes, if you have access to Thermalite that's the simplest and most reliable way to do it. Otherwise, you can use a timer such as the PerfectFlight timer. However, timers usually don't put out a lot of power, so test it on the ground first to see if it will light all four igniters. If it won't light the Estes igniters you could use e-matches.

 

[havoc821]

I was going to order about 5 feet of the timing fuse from Pyrotek that you revied in a previous Extreme Rocketry. Good article by the way!