Rocket Fuel Injectors Explained

A nice video from Scott Manley explaining rocket injectors, worth a watch!

Video Caption: Rocket Propellent Injectors are critical parts of the engine design, they take the propellents and mix them so that they can quickly burn in the combustion chamber. Injectors can make or (literally) break a rocket design, and over the years we’ve seen rocket engines move from injector plate designs to more efficient options as engineers have come to understand what works well.

Thanks to Copenhagen Suborbitals for sharing some video of their injectors being tested, I hope to get to see some more flights with these:

Instagram Pic of the Week

BURPG Updates

Some twitter updates from Boston University Rocket Propulsion Group, the group are working toward the first firing of their Iron Lotus and Lotus Dev 2 rocket engines.


2016 Year in Review

Well, what a year it has been! This year we have seen many teams and groups finally launching their rockets after delays, new altitude records broken and the odd hiccup along the way. Never the less 2016 has turned it on in the amateur rocket world :).

A few of my highlights.

The Launch of Vulcan 1

For me the big one of 2016 was finally seeing SEDS UCSD launch their Vulcan rocket, this rocket was powered by the groups 3D printed liquid-fueled engine and finally launched on May 21st. I originally supported the team with their Kickstarter campaign, so it was great to see them finally succeed with the launch, although recovery malfunctioned I think the team can still walk away having achieved a great deal. Good work guys and girls!


A New European Student and Amateur Altitude Record

2016 also saw the fall of the European student and amateur altitude record, previously held by Delft Aerospace Rocket Engineering students and their Stratos II+ rocket with an altitude of 21.5km. The record was broken by students at the University of Stuttgart with their HyEnD HEROS 3 rocket, which achieved an altitude of 32.3km. This was only after the team had launched an identical rocket HEROS 2, which unfortunately ran into telemetry problems which likely caused recovery issues, therefore, unable to be located. I hope in the summer they can find it, or what is left and get some data, who knows it may have reached a similar altitude!

ULA Interns Launch Worlds Largest Sport Rocket

This was just impressive, 50ft tall rocket, 1245lbs weight, 6600lbf thrust at liftoff! Always fun to watch this video over and over!


Copenhagen Suborbitals

CS had a pretty full on year, with continued testing of their BPM 5 rocket engine, which included gimbal testing to eventually move away from jet vanes and of course the big event of 2016, the launch of Nexo 1, which did not exactly go to plan.

Nexo 1 launch (Credit: Copenhagen Suborbitals)
Nexo 1 launch (Credit: Copenhagen Suborbitals)

Unfortunately, GOX flow through the engine injector lowered the overall mass flow rate causing a fuel rich burn and lowered thrust, this had the snowball effect of not activating the recovery system and the rocket plummeted into the ocean after only reaching 1514m in altitude.

The team still soldiers on and 2017 should see the flight of Nexo 2 and hopefully some BPM 100 rocket engine news and hardware :).


PSAS 3D Printed Engine

Portland State Aerospace Society made big strides this year as they continue working towards sending a rocket 100km. The team designed and printed their first ever liquid fuelled rocket engine, running on ethanol and liquid oxygen the engine is designed to develop 500lbf of thrust. Hopefully, this will be test fired sometime in 2017, looking forward to it!

Remember to donate towards the teams crowdfunding campaign so we can all see this fire next year!!

BURPG Lotus engine testing with more to come

This year the students of Boston University Rocket Propulsion Group test fired their Lotus rocket engine, designed to power their Starscraper rocket to over 100km, this was another Kickstarter campaign that I supported. Unfortunately during testing the rocket engine over pressurized leading to the failure of the retaining ring holding in the inner chamber, allowing it to exit.

Egnine liner exiting Lotus (Credit: BURPG)
Egnine liner exiting Lotus (Credit: BURPG)

The team have since gone back to the drawing board and redeveloped the engine as Lotus Dev 2, increasing thrust from 1500lbf to 2500lbf and fixing the issues they had with the first version.

Lotus Dev 2 (Credit: BURPG)
Lotus Dev 2 (Credit: BURPG)

Engine testing is slated to begin early next year.


There were so many more cool projects going on for 2016, I could go on and on, but to wrap things up I’d like to finish with the epic on board GoPro footage of the UP Aerospace SL-10 launch, which was released this year.

Happy holidays and see you all in 2017!

PSAS 3D Printed Engine

As soon as I post about Portland State Aerospace Society developing a 3D printed rocket engine they go and post a picture of the actual engine all printed up and done! Looks good team!

Rocket Engine Pump Design

Although not a new technology for rockets, the propellant pump is one thing experimental rocketeers could well do with.
Unfortunately on the scale of size that most amateur liquid fuelled rocket builders are going for, the pump becomes a very complicated matter, it is often just as easy to use an onboard pressurization system, or run the rocket in blowdown mode (tanks filled to ~60% then pressurized with an external source before flight).

But with new technologies and 3D printing metal, small scale pumps may be in the realms of amateurs, this technology has notably been pursued by Ventions and Rocket Lab in the form of electric driven pumps. More so, Ventions who have been in the game a bit longer than Rocket Lab specialize in developing electric and turbine driven pumps as well as rocket engines on a small scale, news is generally few and far between, but one can find patents on the hardware never the less to get an idea of some of the things they are up to.

Rocket Lab Rutherford Lox/Rp-1 Rocket Engine

Other notable pump technologies is the piston pump from Xcor Aerospace, the pump will power their Lynx space plane on its suborbital flights.

More info can be found here.

Current Amateur Pump Work

There has been a little bit of pump work going on in the amateur community, I’ll try to detail some below, there may well be projects I have missed and or do not know about so do drop me a line to tell me!

Back in 2008 Paul Breed of Unreasonable Rocket looked into a geared Hydrogen Peroxide  electric pump when doing an  analysis for his NGLLC Level 2 vehicle, Paul went as far as building a pump system but as far as I can tell did not test it.
You can find the specific blog posts here, Why I like this project…andMerry Xmas

Not really amateur so to speak but Nadir Bagaveyev of Bagaveyev Corporation has been doing work with small-scale 3D printed pumps. Information is few and far between, but Nadir does have some good youtube videos of his work so far.

This is only one of many, make sure to check out his youtube profile.

Another project that got to testing phase is from Andrew Burns. Andrew set out to make a small electric centrifugal pump, pumping 0.3kg/s at 800psi using a Barske impeller design, the pump fluid power output is 1.5kW and runs as 40% efficient. I am not sure the current state of Andrews work, but never the less he shows what can be made with limited machining capabilities.

And lastly, a group of enthusiasts, professionals, and amateurs on the Arocket mailing list over the past few months have been working towards building a hydrogen peroxide and gasoline electric centrifugal pump. The project is utilizing minds and expertise from all over the world so it will be interesting to see how it progresses. Clicking on the link provided and going through the 2015 archives will put you in the right place to find out more without myself doing a huge info dump here.

Design your own pump

It may be up to you to help us amateur experimental rocketeers prgress more in the pump world so here is the literature and help needed to get started.

Design of Liquid Propellant Rocket Engines, a very comprehensive section on pumps, if you feel like it in hard copy, you can get it here, worth every dollar.
Centrifugal Pumps – Design and Application, recommended by others in the rocket world.
Centrifugal Pump Design, again recommended by others in the rocket world.
And lastly Lloyd Droppers of Project Earendel has been posting on pump design,

Roberts Rocket Project Update

One of the many great rocket projects out, there, is Roberts Rocket Project.

This one specifically is a must read for anyone wanting to build and test their own liquid-fueled rocket engine. Over the year’s Robert has built and tested cooled and uncooled rocket engines, his latest prototype engine produces 250lbf (1112N) of thrust, burns liquid oxygen and kerosene, is regeneratively cooled and is machined from aluminium.

His work is very thorough and at a very professional level that is impressive to see come together, there are no shortcuts on this project. This can be seen in the design spreadsheets that he has made available to download, tweak for your own good and use.

Robert has been working on getting his 250lbf regen engine to a point where he is happy with it and work now commences on a rocket that this engine will power.

His latest update from April 5th, 2015 goes into a bit more detail about this rocket and work done so far.