Fast airstart ignition of K550W ? ?

[DMcCauley]

Anyone have any recommendations on how to quickly (and reliably) fast start a K550W without having to make a thermite mixture?

Basically, i'll be airstarting (2) K550Ws using a breakwire timer device (PerfectFlight) which will need to initiate just after the central M650W motor ignites and the rocket starts moving.

Thanks
Dan

 

[AHansom]

For my air starts I have been gluing a Pyrodex pellet in the core at the top of the motor. I have seen several people at our local club launchs using this technique and it always seems to work.

https://www.youtube.com/watch?v=248ZLdN4Gis&feature=channel_page

 

[highpowerrocket]

Pyrodex pellet is an excellent way to go. Another option is to dip an electric match in pyrogen and attach a small sliver (or two) of Blue Thunder propellent to the igniter with thread.

 

[FROB]

Richard Nakka has a great article /discussion on the subject here:
https://www.nakka-rocketry.net/igniter.html

 

[Obi-Wan]

harvesting Al Flake - right on!

 

[FROB]

Tell me about it- i just discovered i could make decent propellant from dollar store "ingredients" gotta love it

 

[ben_ullman]

Tell me about it- i just discovered i could make decent propellant from dollar store "ingredients" gotta love it

just wait untill you realize how awesome HTPB propellants are

Ben

 

[cjl]

I've had excellent success with the slivers of blue thunder method. I just use an F39, and cut the grain lengthwise into 5 or 6 slivers of propellant. Add 1 or 2 to your igniter, and it WILL light, nearly instantly.

 

[DMcCauley]

Will an electric match light the blue thunder slivers instantly?

 

[cjl]

Not reliably, unless it is dipped. They aren't hard to light, but I wouldn't trust them to light on something as quick as an e-match.

 

[ben_ullman]

Not reliably, unless it is dipped. They aren't hard to light, but I wouldn't trust them to light on something as quick as an e-match.

Unless you get the Ematches the BURN not POP. Then you have a good chance.

Ben

 

[cjl]

Unless you get the Ematches the BURN not POP. Then you have a good chance.

Ben

E-matches pop. It's how they work.

Yes, some pop slower than others, but they will never burn as slowly as a typical igniter.

 

[ben_ullman]

E-matches pop. It's how they work.

Yes, some pop slower than others, but they will never burn as slowly as a typical igniter.

I know the Davey Fires Hold fire long enough to light slivers and pellets. They hold fire longer than say an Mtek

Ben

 

[cjl]

Well, if by pellets you mean pyrodex, it is quite easy to light. Any e-match will do. Propellant slivers are harder to light though, at least from my experience.

 

[DMcCauley]

I know the Davey Fires Hold fire long enough to light slivers and pellets. They hold fire longer than say an Mtek

Ben

And just where can you find a Davey Fire these days . . .