[AR] Re: Hypergolics with N2O?

  • From: eric.pillai01@xxxxxxxxx
  • To: arocket@xxxxxxxxxxxxx
  • Date: Fri, 24 Feb 2023 08:23:04 -0800

If the goal is hypergolic ignition of a nitrous + conventional fuel engine, maybe the better approach is a hypergol with the fuel? 
Nitric acid isn’t exactly fun stuff but it’s been used successfully in amateur rockets (Tom Mueller’s Micro Rocket) and would be a hypergol with many conventional fuels. Micro rocket seems like a decent template for what a hypergolic ignition system on a bigger liquid biprop might look like.
Eric

Then there was the HLR-25, a hypergolic propellant 25 pound thrust rocket, possibly the smallest liquid rocket ever flown? It burned anhydrous nitric acid (white fuming) and furfuryl alcohol. It was so small and fast no one got a clear picture of the launch!
Tom Muellertwitter.com


On Feb 24, 2023, at 6:36 AM, Ben Brockert <wikkit@xxxxxxxxx> wrote:

I'd expect that anything that is usefully hypergolic with oxidizers
like LOX or nitrous has to be pyrophoric as well. TEA/TEB will
autoignite in air. Anything that can strip oxygen off liquid nitrous
is probably going to be happy to burn in 21% oxygen gas.

How does a silane leak demolish a building, rather than burning at the
leak location?

I wonder if white phosphorus is hypergolic with nitrous. Also quite
unpleasant and difficult to get. There is the classic chemistry demo
of cooking iron oxalate powder to form extremely fine iron dust that
will ignite in air, I've wondered if it would still burn if mixed with
a fuel. Probably difficult to keep it suspended in a liquid. NaK?
Relatively easy to make, liquid, great density, slightly crazy to work
with.

On Fri, Feb 24, 2023 at 1:51 PM Jim <jmrosson@xxxxxxx> wrote:

Beware – Silane gas is pyrophoric, I.E. explodes on contact with oxygen.  It is also toxic too.

Silane is nasty, NASTY, stuff; and never recommended for DIY.



Silane stories:



Fill a 2-3” water balloon with silane, and pop the balloon (3 feet away); sounds like a M-80, and feels like it too. 😉



A single silane cylinder with a leak; removed an entire 1000sqft 2nd story laboratory, from a top of the building I worked in during late 80’s.  This was a newly built professional chemical/biological lab facility,  built as blocks of self-contained, fully isolated concrete safety boxes for each lab; surrounded by employee cubicles on outside of lab core.   After the explosion, there was nothing left of the top corner of the building.  All of the adjacent labs were damaged as well.  Thankfully, explosion happened several hours after everyone left for the day; and janitorial staff was cleaning in another building at time.



Indoor storage of silane gas for semiconductor processing, is generally done with a solid concrete/steel vault like blast cabinet box with open top to vent the blast pressure.   Bottle change is a scary affair; requiring nitrogen purge, and proper PPE.  One fine day at work: a pallet rack of silane storage bottles in a cabinet, had a valve leak that blew up.  The rain cover structure for blast cabinet was found in a parking lot ¼ mile away.  The concrete/steel blast box was destroyed and had to be replaced too.  Blast registered on University seismographs 30 miles away.



Most of the liquid silicon derivative’s available are flammable liquids, reasonably stable with oxygen; and only go boom when heated dramatically above boiling point and mixed with catalyst.  IMHO would be better just using a known poisonous catalyst instead.



YMMV



Cheers,

Jim



From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> On Behalf Of Bruno Berger ("bruno.berger")
Sent: Thursday, February 23, 2023 11:04 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Hypergolics with N2O?



Does anybody know about chemicals which are hypergolic with N2O? I know TEA and TEB are, but that's nasty stuff. Someone told me that Silane (SiH4 and the heavier molecules) may be hypergolic as well. That's also nasty stuff, but more available that TEA. It might be soluble in conventional fuels like Ethane/Ethene/Propane etc. But I haven't found much about the hypergolic behavior...

Cheers Bruno



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