how are military solid rockets ignited, same as ours?

The Rocketry Forum

Help Support The Rocketry Forum:

soopirV

Well-Known Member
Joined
Sep 1, 2010
Messages
1,157
Reaction score
6
I was reading up on the sidewinder AIM-9, and wasn't able to determine how they are ignited...is it just an ematch-like igniter?
 

Zeus-cat

Well-Known Member
Joined
Mar 14, 2009
Messages
4,680
Reaction score
921
Copperheads!

Actually, I would think they would use something very energetic to ensure ignition. They can't swap out the igniter if it fails!
 

rstaff3

Oddroc-eteer
Joined
Jan 18, 2009
Messages
11,763
Reaction score
22
Head end pyrogen plug per their spec sheets.
 

ECayemberg

Well-Known Member
Joined
Jan 21, 2009
Messages
2,672
Reaction score
298
I lit my Sidewinder motor with a Firestar igniter taped to a 6' stick and probably augmented with scrap propellant. It lit easily and pressurized immediately. Nice motor.

But yes, the military version is a bit different as far as ignition goes. Doesn't take much to get that propellant going!

Eric
 

stealth6

insert witty tagline here
Joined
May 1, 2011
Messages
2,718
Reaction score
296
Well they used to use Q2G2s, but.........

s6
 

soopirV

Well-Known Member
Joined
Sep 1, 2010
Messages
1,157
Reaction score
6

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
7,060
Reaction score
4,105
Location
Butte, Montana
Thank you to you and Rstaff3 for the needed details, and the rest for the laughs! I had assumed (hoped?) that the military had something more elegant (and of course expensive) than an e-match, but couldn't find any specifics!
It's quite different from an ematch; higher current (nobody wants a Sidewinder going off accidentally), matched to the 28 volt DC aircraft power bus, less sensitive to physical and electric shock.
The new head end igniter system from Aerotech shares some features.
 

ECayemberg

Well-Known Member
Joined
Jan 21, 2009
Messages
2,672
Reaction score
298
...except I was serious:

[video=youtube;nylUXEGtpgU]https://www.youtube.com/watch?v=nylUXEGtpgU[/video]

unless I'm mistaken in that the O25k is a commercial HPR version of the Aim-9 motor:confused:
 

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
7,060
Reaction score
4,105
Location
Butte, Montana

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
7,060
Reaction score
4,105
Location
Butte, Montana

DavidMcCann

Well-Known Member
Joined
May 15, 2016
Messages
2,656
Reaction score
172
They're ignited by the sheer anger of the pilot at his target
 

Worsaer

Amateur Propulsionist
TRF Lifetime Supporter
Joined
Jan 11, 2012
Messages
1,828
Reaction score
128
Location
Central Virginia
Adapting these to HPR Head-End-Ignition (HEI), as Aerotech is pursuing, also requires some thought to safety. If you review the linked PDF, you'll see a schematic that requires two independent 'arm' inputs plus a 'fire' signal to initiate ignition. For a two-stage configuration, with HEI for the upper stage, this adds an interesting margin of safety.

https://www.e2v.com/resources/account/download/28
 

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
7,060
Reaction score
4,105
Location
Butte, Montana
Adapting these to HPR Head-End-Ignition (HEI), as Aerotech is pursuing, also requires some thought to safety. If you review the linked PDF, you'll see a schematic that requires two independent 'arm' inputs plus a 'fire' signal to initiate ignition. For a two-stage configuration, with HEI for the upper stage, this adds an interesting margin of safety.

https://www.e2v.com/resources/account/download/28
Absolutely correct! Although we don't require that many inhibitors, we still require that whether the igniter is inserted head end or aft end the connection of the circuit that powers the igniter is required to be made either at the pad or at a preparation area that is away from uninvolved persons and must not be armed until the rocket is on the pad and near vertical.
 

UhClem

Well-Known Member
Joined
Feb 6, 2009
Messages
1,874
Reaction score
303
Help me understand Kurt. BKNO3 is used for rocket ignition, isn't it?
Rocket motor igniters come in at least two parts: initiator and pyrogen. The initiator is the (usually) electrically activated bit that kicks things off. Usually a 1 Ohm/1 Watt device. (Must be able to withstand the application of 1 Watt for 5 minutes without doing anything.) This is followed by a pyrogen which does the heavy lifting of generating heat/gas. Popular pyrogens are BKNO3 and Magnesium Teflon among others.

There may also be an integrated arm/fire device with safety features that receive very careful review.
 

ksaves2

Lifetime Supporter
TRF Lifetime Supporter
Joined
Nov 25, 2009
Messages
6,267
Reaction score
491
Location
Central Illinois
Help me understand Kurt. BKNO3 is used for rocket ignition, isn't it?
Yes BKNO3 is used for ignition. I've been told the zirconium can be very dangerous and powdered Boron is quite pricey. That's where "don't go there" came from as far as hobbyists are concerned. The government, NASA and the military have the means to do what they want and pull it off.

It's ok to click on the link, just don't get any ideas of trying to reproduce what the "big boys" do as it's not fun getting hurt. MTV igniters are doable and reasonably safe as long as one is well-versed with the safety of dealing with magnesium powder. Raw viton can be hard to find as one can't just chop up a cured viton gasket and get it to dissolve in anything. Teflon is easy to find. A first dip with a commercially available product is advisable and then the MTV. Note, I didn't discuss proportions here so not violating the rules. Oh, the commercially available igniter kits are reasonable too if one doesn't want to mess with the hassle of looking up recipes and trying to acquire the components. Or if one just flies certified loads, just use what's provided (except
I think I have to use my own igniters for Loki loads which is fine by me)

I realize the original question is, "What does the military use?" I just want to caution it isn't necessary for a hobbyist to attempt to emulate it, that's all. Kurt

Kurt
 

Worsaer

Amateur Propulsionist
TRF Lifetime Supporter
Joined
Jan 11, 2012
Messages
1,828
Reaction score
128
Location
Central Virginia
Thanks Kurt, got it. I assumed you were talking about safety concerns, sorry.

I noticed the instructions on the component available from RCS (made by Triton Space) that we may see in wider use in our hobby some day, and BKNO3 was included (below). Your point about cost, availability, and practicality of BKNO3 is well taken.



 

Latest posts

Top