[SS-VehDev] Re: [SS-Main] Igniters

[william colburn]

Andrej,

For the full scale, if you can create the pyrogen to
accept a 1/2-20 NF class 2 male igniter thread, I can
supply qualified 1 amp/1 watt initiators which are
range-safe.  But we also need them to thread into
essentially a 3-way valve that will act as a manual
safe-arm. This can be manually operated from outside
the vehicle at the last minute, or turned
electromechanically to arm the second phase just prior
to launch.

Appreciate the thought on the bulkhead, it looks great
for the 1/4 scale.

I am copying Rich as this is really his bailiwick.
Safety should also be on baord with this issue too.

BC

--- Andrej Vrbec <andre09091978 at yahoo.com> wrote:

> Hi Guys
> 
>  
> We determined basic igniter configuration. 
> Second phase igniter will be classic pyrogen
> igniter.
> For 1/4 scale motor it will use single unrestricted
> grain (KN-Dextrose doped with Fe2O3). Burn time is
> 0,2
> seconds. For full scale motor, geometry of the grain
> will be modified to achieve the same burn time.
> Igniter will be retained in the forward bulkhead by
> a
> snap ring (see drawing). Seal will be provided by
> O-rings. Igniter grain will be ignited with a
> primer:
> 60% black powder, 40% magnesium powder. 
> First phase igniter is a bit tricky. It will have to
> be casing-less in order not to block any flow from
> the
> second phase. Plan is to use a fast burning grain
> which would be glued to the RNX delay plug. Grain
> will
> be cast of modified KN-Dextrose (certain additive
> will
> have to be added to increase burn rate at atmosferic
> pressure- magnesium powder shows promising results).
> Another problem is how to attach the igniter leads.
> Due to poor mechanical strenght of the propellant we
> recommend that igniter leads would be secured with
> screw or glue so that they can't be accidentaly
> pulled
> out. 
> I attached a drawing of forward bulkhead for 1/4
> scale
> motor with measurements of cavity where the igniter
> will be placed. We would also like to know, if we
> send
> you igniter casing or do you prefer to machine it
> yourself.
> When is 1/4 scale motor planed to be static tested?
> We
> will test both types of igniters in the following
> days
> and let you know about the results.
> 
> Andrej
> 
> 
> 
> 	
> 		
>
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