
How to Design, Build and Test Small Liquid-Fuel Rocket Engines (1967) - areoform
http://www.risacher.org/rocket/
======
helldritch
This book is a great resource, and I would recommend it to to any amateur
model rocketry fan.

I'm starting University in September as an adult student of Computer Science
and I'm planning to start a model rocketry society with the goal of putting a
9ft tube above the Karman line and recovering it safely.

I'm still deciding on fuels, but I'm strongly considering a hypergolic
combination of catalyzed pure hydrogen peroxide and kerosene (I've already
been granted a recipient competent authority from the explosives department
for the storage and transport of usable quantities these for the use in a
model rocket).

The primary reason for hypergolic fuels is because it doesn't require a
complex combustion chamber / ignition set up. You can mix them together at
ambient pressure and temperature and they will spontaneously combust producing
heat, steam and pressure. If you can safely handle the dangerous fuels it's a
much easier route to a liquid fueled rocket engine.

One of the difficulties in the UK is going to be finding somewhere to launch
from: we don't have large swathes of unowned, unmonitored land and the
restrictions the CAA (rightfully) place on launching near cities means that
it'll have to be out in the sticks somewhere. I'll probably have to convince a
farmer to let us blow up a couple rockets on the back of a fallow field a few
times before we get a successful launch off the ground.

I'm trying to plan as much as possible and get all the requisite licenses (I
already have a CAA unmanned surveillance drone operator ID, as well as
exemption from the need for a flyer ID because I have my flight competency
certificates, and exemption from the 400ft amateur flight ceiling as long as I
issue a NOTAM (notice to airmen) 1 week before any test flights, and I'm
insured by the UK Rocketry Association) in the hopes that people will "take me
seriously" when I found the society.

I'm also working behind the scenes to set up partnerships. I've been in
contact with Starchaser Industries and a few other aerospace companies nearby
to have them sponsor the program, show us around their rocketry factories and
hopefully give us contacts at their company we can bounce ideas off to see if
there's anything we've missed, or any hazards we are hugely mispredicting.

~~~
hoorayimhelping
> _If you can safely handle the dangerous fuels it 's a much easier route to a
> liquid fueled rocket engine._

This kind of glosses over the whole hypergolic fuels are necessarily poisonous
toxins that boil your skin if you touch them. To react with each other so
quickly, they basically have to react with just about everything else as well
- including human saliva, the liquid on eyeballs, and the liquid in your
lungs.

This (extremely 60s styled) video is full of useful information about how
dangerous hypergols are: [https://www.youtube.com/watch?v=Zha9DyS-
PPA](https://www.youtube.com/watch?v=Zha9DyS-PPA)

~~~
helldritch
In general, I would agree with you.

If you're dealing with umsymettrical-dimethylhydrazine and dinitrogen
tetroxide, you're going to be in a world of pain trying to produce them,
handle them and get them close enough to use in an engine without being so
close that the fumes spontaneously ignite. Not to mention that the dinitrogen
tetroxide boils at ambient temperatures, etc, etc.

Obviously, I was glossing over the danger (not something I do in real life
when handling dangerous fuels, but probably something I do when writing a
short comment on Hacker News) and anyone seeking to work on Rocket Engines
needs to ensure that they consult with subject matter exports before, during
and after any construction or launch preparations begin.

... With that disclaimer out of the way, in the grand scheme of dangerous fuel
and oxidisers combinations, Kerosene and Hydrogen Peroxide are _significantly_
safer to handle than traditionally used hypergolic mixtures:

\- They are both liquids at ambient pressures and temperatures (don't
underestimate the value of not needing highly pressurised canisters - above
2000psi in many cases - and cryogenic equipment, that's all mass you don't
need to lift and failure states you don't need to control for)

\- Storage and deployment of AVTUR (Aviation Turbine Fuels) is a well
understood procedure with pre-certified canisters.

\- Hydrogen Peroxide at sub-90%, and especially at sub 70%, purities is
reasonably safe to store and handle, especially if you store it in an
inhibited state and you're willing to have a suboptimal hypergolic reaction in
return for a safer handling procedure.

\- The pressures and temperatures created when reacting these two liquids
together in a combustion chamber are extreme, but not so extreme as to be
outside the remit of an amateur team.

This all doesn't mean that these are safe to handle - and failing to properly
respect rocket fuel results in death for yourself and others - but it does
mean that they're safer to handle.

In a perfect world I would manufacture solid state rocket propellants, but in
addition to the negatives of not being throttle-able and being hard to early-
terminate, manufacture of solid rocket motors is a criminal offence in the
United Kingdom and getting an explosives certificate is a long, daunting task.

~~~
jabl
> in the grand scheme of dangerous fuel and oxidisers combinations, Kerosene
> and Hydrogen Peroxide are significantly safer to handle than traditionally
> used hypergolic mixtures:

Are they? AFAIU the propensity for HTP to exothermically decompose was the
main reason why it was abandoned in favor of IRFNA/NTO. I mean, if you're
switching to something as nasty as NTO or IRFNA for safety reasons, whatever
you're switching from has to be pretty bad!

See also the Kursk submarine disaster.

> Hydrogen Peroxide at sub-90%, and especially at sub 70%, purities is
> reasonably safe to store and handle, especially if you store it in an
> inhibited state and you're willing to have a suboptimal hypergolic reaction
> in return for a safer handling procedure.

IIRC in Clark's Ignition the opposite was mentioned, namely that higher
concentrations have better resistance to decomposition, presumably due to
lower amounts of impurities which can get the decomposition reaction started.

~~~
avmich
> Are they? AFAIU the propensity for HTP to exothermically decompose was the
> main reason why it was abandoned in favor of IRFNA/NTO. I mean, if you're
> switching to something as nasty as NTO or IRFNA for safety reasons, whatever
> you're switching from has to be pretty bad!

I'm not sure the switch to IRFNA/NTO is for safety reasons. There is
simplicity involved - you don't need catalyst with them. The components
themselves are easier to get by and to store. They however have their own
nasty properties regarding safety. Also historically nitric acid was initially
used with turpentine, which is a hypergolic pair.

Here are some comments on safety.

[https://yarchive.net/space/rocket/fuels/peroxide.html](https://yarchive.net/space/rocket/fuels/peroxide.html)

~~~
jabl
> I'm not sure the switch to IRFNA/NTO is for safety reasons. There is
> simplicity involved - you don't need catalyst with them.

Yeah, good point, that's certainly an advantage.

> Here are some comments on safety.

>
> [https://yarchive.net/space/rocket/fuels/peroxide.html](https://yarchive.net/space/rocket/fuels/peroxide.html)

Coincidentally(?) those comments stop in the year 2000, when the Kursk put a
dent in HTP enthusiasm. For a while at least.

Not that I have any good solution either. Seems all high performance liquid
rocket fuels have some nasty downsides.

For small scale applications N2O + some light hydrocarbon like propane or
ethane could be interesting. But that seems to be quite immature, so could be
some showstoppers ahead in that path.

------
jccooper
Perhaps worth noting that this is not the Rocket Lab launching small liquid
fuel rockets today. This Rocketlab seems to have been a mail-order publisher
mostly of NASA public domain stuff, with some original material and other
authors. This book would seem to be their magnum opus and one of their more
popular products.

They sold this book and Apollo photos and other things out of the back of
hobby magazines in the 60s and 70s. China Lake is home to a Naval Air Station,
a major R&D location for rockets and other flying things, so it's possible it
was a side gig by some rocket scientists there, but that's just a wild guess.

~~~
jeffreyrogers
There is a great book that covers the development of the Sidewinder missile at
China Lake[0]. Really interesting discussion of the management/organization of
the missile program and how it was so successful given it's small size and
limited resources.

[0]: [https://www.amazon.com/Sidewinder-Creative-Missile-
Developme...](https://www.amazon.com/Sidewinder-Creative-Missile-Development-
China/dp/1591149819)

------
Certified
As someone who attempted to build a small liquid fueled rocket engine in high-
school, this was one of the only texts I could find at the time that went into
the subject in enough detail to be useful. (circa 2007)

~~~
FlyMoreRockets
See also: "Rocket Propulsion Elements", by George Sutton. Now in its 9th
edition.

------
avmich
A great historic document. Today some better ways, in some aspects, could be
proposed, but this is still a workable recipe.

~~~
jeffreyrogers
Do you know of any more recent resources than this one?

~~~
FlyMoreRockets
The standard text on the matter is "Rocket Propulsion Elements", by George
Sutton. Another recommended reference is "Design of Liquid Propellant Rocket
Engines" by Dieter K.Huzel and David H.Huang.

------
georgeecollins
What depresses me is the section on "The Law". I did a lot of model rockets
(just the regular solid fuel type) with my son. A fun educational hobby. There
are very few place in Southern California where you can legally launch a
rocket, even though they are extremely safe in comparison to the ones
described here.

------
_n_b_
Related (but sadly sold out) plans for a home rocket engine for your bicycle
or go-kart:
[http://unitednuclear.com/index.php?main_page=index&cPath=28_...](http://unitednuclear.com/index.php?main_page=index&cPath=28_47)

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praveen9920
Seems like a great resource for rocket engines.

Having a simulator to try these out would be very useful before trying
anything practical. I'm sure it will be a complicated piece of code with heavy
computation requirements

~~~
uponcoffee
Simulation and validation is a touch improved, when I did this in college we
used Ansys supplemented with data from NASA's CEA (Chemical Equilibrium and
Applications) utility for validation. Once you get the work flow figured out
it's not terrible.

Simulating cooling channels//ablation for larger scale rockets is a major PTA
though.

------
jcims
This reminded me of the Popular Mechanic's encyclopedia set we had growing up.
Basically an encyclopedia of DIY projects. Looking back it's something i
definitely did not appreciate enough.

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larrydag
Is it easy to procure liquid oxygen as an amateur builder? The guide looks
like it recommends using gaseous oxygen and gasoline since it is readily
available.

~~~
helldritch
The typical way to produce small scale liquid oxygen (LOX) requires liquid
nitrogen (you use the liquid nitrogen to cool the gas as it passes through
some transport medium like a copper pipe and collect the cooled liquid).

Purchasing LOX isn't too difficult, there are many vendors willing to supply
large amounts of it, and a few vendors willing to supply small (experimental)
amounts of it.

Storing LOX is the real challenge, you need to keep it at ~310f (~-190c) which
requires a well insulated cryogenic storage chamber. Typical industrial sized
storage tanks have a few metres of insulation to keep the heat out, and
typical small-scale tanks have around 1-2 feet of insulation.

You're probably looking at a viable minimum storage container size of between
500-1000 litres (any smaller and your insulation layer will be so thin that
you'll lose 10-20% of your stored oxygen as gases per day), with the typical
minimal size being in the 2,500 litres range (which normally lose 1-2% of
stored oxygen to gas per day)

You can buy very small containers (2l, 5l, 25l, etc, these are for nitrogen
but you can get them for oxygen too):
[https://uk.vwr.com/store/product/2104367/liquid-nitrogen-
dew...](https://uk.vwr.com/store/product/2104367/liquid-nitrogen-dewars-for-
storage-and-transport-ld-series) but these lose the liquid _very_ quickly and
you would likely want them delivered the same day you need them, resulting in
a just-in-time delivery failure point.

------
discordance
Interesting material but shame it uses imperial units

