[RocketsNW] IGNITERS

[Scott T Bowers]

One word...

Copper oxide thermite.

Wait, that's three words. Cheap, easy, safe, and works VERY well.

Crap, that's seven words, unless these words count, then....never mind. 


Scott T. Bowers
www.scottsrockets.com
 

-----Original Message-----
From: rockets-bounces at rocketsnw.com [mailto:rockets-bounces at rocketsnw.com]
On Behalf Of Robert Krausert
Sent: Thursday, April 09, 2009 3:39 PM
To: Gary Harris; rockets at rocketsnw.com; Paul Bogdanich
Subject: Re: [RocketsNW] IGNITERS

I'd like an opinion here. For 38mm and larger, I've been more successful
adding a sliver of Blue Thunder to the ignitor. I simply take a grain of BT,
and cut a chunk out and use kite string to secure it to the ignitor head. 
When I've done this, all motors have started fine. My question is, is adding
the BT sliver really helping, or would the large ignitor with pyrogen have
been fine alone?

Curious.

Cheers,
Robert


----- Original Message -----
From: "Gary Harris" <bphlat234 at comcast.net>
To: <rockets at rocketsnw.com>; "Paul Bogdanich" <jhadv at pacifier.com>
Sent: Thursday, April 09, 2009 3:06 PM
Subject: Re: [RocketsNW] IGNITERS


> Paul gave me one of his low-pressure and high heat producing thermite
> ignitors mentioned below last october to use in a 11-year old J350.  It
> started up instantly like an Estes motor.
>
> Gary Harris
>
> ----- Original Message ----- 
> From: "Paul Bogdanich" <jhadv at pacifier.com>
> To: <rockets at rocketsnw.com>
> Sent: Tuesday, April 07, 2009 12:30 PM
> Subject: [RocketsNW] IGNITERS
>
>
>> At 11:27 AM 4/7/2009 -0700, you wrote:  "...there's likely no basis for
>> regulating an ignitor which is used with a non-explosive device. 
>> Igniters
>> packaged with unregulated motors (and replacement ignitors) were
>> themselves
>> considered unregulated."
>>
>> I think you said it in your e-mail when you said igniters, "packaged with
>> unregulated motors..."  The only problem being that said devices are, in
>> the opinion of some, very low performance devices so much so as to be 
>> just
>> barely functional.  People of this opinion would point to all the 
>> chuffing
>> and recycling one witnesses at almost any launch.  Such devices (total
>> calorific output of less than .5 kcal) probably do qualify as "motor
>> starters" and may very well be able to be unregulated.  I certainly don't
>> see why they should be regulated as some safety match heads with the
>> pyrogen scraped off, dissolved in a solvent and cast around a bridge wire
>> would produce more heat.  We don't regulate books of matches do we?
>> I myself, however, would like to see an "igniter" that can add between 6
>> and 10 calories per cc of propellant surface, generate enough gas 
>> products
>> to put the motor interior at >= 200 psi but < 400 psi, totally burn well
>> within 100 ms, and achieve a flux rate of greater than 100 cal/cm2/sec 
>> for
>> a 38mm motor (this last metric can change with motor size and propellant
>> characteristics).  That's an igniter and I think you're still going to
>> need
>> a permit for those.  A NASA Standard would be an example of such an
>> igniter
>> albeit for a much larger motor than a 38mm.
>> Whether or not a thermite (where such term includes thermate and
>> thermalite) based igniters should be restricted is an open question as
>> those lie between the two classes of devices already mentioned (they
>> generally do not pre-pressure the motor nor create a shock wave).  I
>> suspect however, that the BATFE position would be that thermite, thermate
>> and thermalite are definitely regulated as they are included in the
>> definitions section of the statute whereas APCP was not.
>>
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>
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