The thermochemistry of Jetex propellant is both complex and fascinating, quite unlike any other solid rocket formulation. We're reinventing this esoteric energy source, from scratch, in a little desert laboratory near Mojave, California. If you have an interest or curiosity about the chemical sorcery, join the conversation. Arm-chair engineers and retired chemists are likewise welcome.
The key ingredients for making Jetex propellant have become available again in America, and I've dusted off the lab bench and reopened the Jetex Propulsion Lab, which I co-founded with Carlo Godel in 1999. Carlo and I spent some years getting near success with replicating the old Imperial Chemical Industries formulae of the 1930s, but lack of guanidine nitrate and other essentials kept us at bay. That has changed, though Carlo has passed, and JPL is again open, and setting up for scientific experiments.
My personal forté is gas generator solid propellant development, and my experience dates to projects with long- and slow-burning formulations for Navy target drones, in 1957. And this isn't a trivial or simple effort. To make it happen, I need support, associates, assistants, and contributions.
Can't say I'm the slightest bit chemical, but I do realise exactly what is needed from the formulation. If we look at it from a layman's point of view (mine), we need a low flame temperature which means our motors won't melt or have case failure. Then we need duration of ten seconds or preferably more. We also need a guaranteed lack of explosion from the chemistry. If it's fuel in the form of pellets it needs low toxicity so it can be safely handled and when burned preferably the same would apply.
The original ICI pellets had 0.5 % asbestos in the mixture to provide a spine for catalasis to take place, this too would have to be addressed.
Whichever way you slice it, it's a mass of contradictions and trade offs, it also has to have a coating to keep the moisture out and on top of that has to have consistent properties time after time after time.
Well said, Andy. And as Uncle Al once said: "Any intelligent fool can make things bigger and more complex and more violent. It takes a touch of genius and a lot of courage to move in the opposite direction." --Albert Einstein
I started Jetex.org and the Jet-Ex-Press egroup about 15 years ago, before it moved to Yahoo, and
for that decade plus we've talked and talked and talked about how we needed guanidine nitrate CH6N4O3 (GN) to make Jetex propellant. And
for 15 years or so, GN has been "unavailable," in small amounts, for experimenters.
Until today! A couple of hours ago, a shipment arrived with enough chemically-pure GN powder to make ... well, what's a Jetex pellet
weigh, maybe 3 grams? Thanks to the several generous folks who contributed cash to make this possible, JPL now has in stock nearly
1.5-kg of this secret sauce.
Our purveyor back-ordered three other key ingredients alas and alak, but after waiting for a decade, I guess another few days won't ruin
Without going into details here, suffice to say that JPL now has almost all the makings for both Jetex pellets and Rapier motors
(except for some few grams of fine asbestos fibers, and a couple other condiments to make them work correctly).
Also in the parcel is a large container of chemically pure 2,4-DNT, a substitute for the usual 2,4-DNR Jetex catalyst.
I've a copy of Dr James Taylor's "Solid Propellent [sic] and Gas Generating Compositions" open on the lab bench, reviewing the ICI
thermochemistry and patents for the ump-teenth time.
Thrilled and enthused as I am with this good news, the fact remains that until JPL can setup a suitable, simple, easy-to-use static test
rig to evaluate the ballistics of these formulations carefully, perfecting the compositions will be impossible.
But, for now, let's pop a cool one and celebrate the reality that we Jetex-lovers now have a mini lab, a dedicated chemist, and most of the
essential reagents in hand. We've come a long, long way since imagining this grand project.
JPL-Mojave ain't Imperial Chemical Industries, not by a long shot, and at the same time, I can't imagine Dr Taylor et al being less
enthusiastic that I am today.
All the best to one and all, with continued thanks and appreciation to all who have contributed!
via the Jetexpress group I hear Dr. EdwardJones of JPL is making good progress with a Rapier L-2 type motor, which burns for or 20 sec or so This is impressive!
Edward says he hasn't tested their thrust . I don't think he is too impressed with my test rig consisting of digital scales and a helper with a digital camera, though it has given adequate results for me to compare motors and pellets in 2012:
and test Claudio Bormida's new Jetex 50-size motor:
Edward opines that developing a Jetex pellet formulation will be much more difficult than making a Rapier type propellant, and with this I concur. Claudio had success with a formulation based on the later Sebel pellets, which contain dichromate and Kaolin; Edward is 'going for broke' and attempting to recreate the ICI type pellets, which, I think we can agree, were superior (and fetch high prices on eBay!).
I do hope Edward can sort out a test rig soon so we can chart progress.
Claudio initially had problems with his motors, so it may be better to go back to the original ICI motor patent - a 'one shot' cardboard-bodied motor. The ICI motor had a metal end cap and nozzle, but ceramic may be just as good, though thought needs to be given to a 'safety valve'.