Hybrid Rocket Shop Tour

Alex has built a 4″ hybrid that with a minimal oxidiser load comes out to an N10,000 and with a full load to the mid to upper O range. The launch and ground infrastructure is also worth noting, custom rail with integrated load cell, turbine flow meter and pressure sensor with a ground monitoring station, this is what amateur rocketry is all about, it is good to see people going the extra mile.

His larger rocket is equivalent to an R10,000 and holds 200 lbs (90.7 kg) of oxidiser this will be impressive to see launch!

2019 Year in Review

Photo by NordWood Themes on Unsplash

2019 turned out to be another great year in the realms of amateur experimental rocketry, so without further ado let’s look at how 2019 shaped up.

The year of the student Spaceshots…again
The year kicked off with UC Aerospace (from New Zealand) attempting to launch their two-stage ‘Into The Black’ rocket to 100km in March, hoping to beat USCRPL and become the first student team to launch a rocket beyond the Karman line. Unfortunately, the 2nd stage encountered an ignition problem leaving the team short of their goal.

Come in USCRPL with their 4th space shot attempt and it looks like 4th time was a charm for the team. After 3 unsuccessful launches over the years, the team finally reached space with their Traveler IV rocket in April, thus becoming the first student team to launch a rocket beyond the Karman line. Traveler IV reached 103.5 km and was recovered successfully.

Once again Princeton Spaceshot made it to the pad again this year, this time with two identical rockets hoping for the chance one of them would reach space. The first launch at the end of May from Spaceport America was a success with the rocket being fully recovered, the second rocket was launched a few days later but the second stage failed to ignite.
Unfortunately, Princeton Spaceshot went quiet after these attempts, so either the rocket did not perform as planned or no data was recovered or maybe they just have not got around to filling us all in.
If any members read this, then drop me a line!

2019 also saw the return of the TU Wien Space Team to the Black Rocket Desert to launch their ‘Hound’ rocket with the hope of not only breaking the current European student altitude record but also to reach space. Unfortunately, the rocket broke apart at booster burnout and although the team had a backup rocket, without knowing the cause, did not launch it.

USCRPL remains the only student team have launched a rocket into space.

Liquid Fueled Rocket Palooza!
With the advent of the Base 11 Space Challenge, the FAR MARS Prize and the FAR DPF Challenge, the number of student teams building and firing liquid-fuelled rocket engines and rockets has increased dramatically. Not only are teams firing the conventional LOX/Kero,  LOX/Ethanol engines but more and more are experimenting with LOX/LCH4 (Methane) engines. A part of this comes from the FAR MARS Prize where part of the prize money goes towards a team who flies a LOX/LCH4 rocket, as methane can be found on Mars, advances in these engines might end up helping crewed flight in the years to come.

To list a few of the teams (that have flown and or hot fired),

If I missed your team, drop me a line on the contact form!

All the rest!
Copenhagen suborbitals started to bend metal for their large crewed Spica rocket, I featured on a Claymin’ Space podcast talking all things rocketry, Joe from BPS Space flew his Falcon Heavy for the second time and made some epic silo launched rockets, DARE unveiled their Stratos IV rocket and continued engine testing, Charlie Garcia released a bunch of liquid rocket engine how-to videos, MIT Rocket team tested a P9100 solid-fueled rocket motor plus much more! Click the links on the side to find out what else everyone has been up to.

To 2020 and beyond
Having now graduated from university and working full time, amongst other things I have been finding it difficult to find time to keep my blog updated. I want to keep it updated in a sense of providing you the reader with more than just a copy/paste of a rocket update. I have been trying to figure out where to take it for the future, some ideas are more mechanically minded posts, possibly delve into the realm of ‘newspace’, more libraries of documents, so if you have any ideas of what you want or like to see then let me know on the contact form.

Thanks for all the support and here is to many more rocket launches in 2020!

TU Wien Space Team Aim for the Karman line and European Altitude Record

Vienna (TU WIEN) – The Space Team of the Vienna University of Technology wants to know it again: in Nevada (USA) two rockets are launched, which are to reach record-breaking heights.

If everything works out perfectly, the rocket should reach a height of over 100 km – the area where the atmosphere gets thin and space begins. The Space Team of the Vienna University of Technology, an association made up of students from different TU disciplines, will attempt to break records in the Nevada desert with two self-developed two-stage rockets. The previous European record for student teams is 32.3 km.

In the last attempt last year, the goal could not yet be achieved. Now the team tries again. The launch is scheduled between 20.9 and 22.9 – updates are posted on the Space Team’s website.

Much know-how at the Vienna University of Technology

The Space Team has already made a number of remarkable achievements. Various rockets have been successfully launched, a mini-satellite has been built and is still sending data from its orbit, a novel mountain system has been developed, with the probes without parachute unscathed from space to return to Earth.

The technical challenges that needed to be overcome for the record attempt are huge:

For about three and a half seconds, the first stage of the rocket burns. This is then separated from the rest and the upper stage continues for fifteen seconds, until it is then ignited at a height of about twelve kilometers. This is made possible by a sophisticated electronics system, which was developed and built by the Space Team.

“This is a challenging task, and there are countless things to consider such as safety and reliability,” says Project Manager Christoph Fröhlich. “The last time we tried a security mechanism was not wired correctly, this year we will launch the rocket again, and in addition we will try a second improved missile in detail, especially the electronic systems and the upper stage ignition have been revised.”

Both rockets are each just under four meters long and weigh (including fuel) each about 30 kg. In the development, it was important to choose the right materials that could withstand extreme loads – such as special glass fiber reinforced polymers. Due to the strong air resistance, the rocket is extremely hot. At atmospheric pressure at sea level, such a rocket would burn, but as the air pressure and thus also the air resistance decreases, the team hopes to surpass the previous European record for student teams of 32.3 km. Achieving a world record is possible, albeit difficult: a team from the University of Southern California has now reached 100 km. “What height we can ideally achieve is hard to say because the simulations come to quite different results. Ultimately, we will only know when we analyze the sensor data after the flight, “says Christoph Fröhlich.

Video Caption: In September of 2018 the TU Wien Space Team launched the two-staged rocket “The Hound” in Nevada, USA. More information under http://spaceteam.at/2018/10/20/the-ho…

CS: DIY Parachutes Part II

Video Caption: This is a follow up video to our June 29th Spica space capsule ballute and parachute system tests. Here we talk about the data we got from those jumps. If you haven’t seen the first part of this video, you can watch it here: https://www.youtube.com/watch?v=4SQet…

Copenhagen Suborbitals is the world’s only manned, amateur space program, 100% crowdfunded and nonprofit. In the future, a volunteer will fly to space on our home-built rocket.

If you like the video and what we do in general, please go to http://www.copsub.com/support-us and support our project. Donations start from as little as a coffee a month. Compliment us by wearing our apparel: https://www.zazzle.com/store/copsub

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Why Tolerances are Important

As rocket projects become more complicated and with the advent of cheap and readily available machinery, and machinery services (3D hubs for example) a lot of people are starting to push the limits with what is being made in the garage.

When it comes to rockets you are never going to get it right first time and you will soon find yourself in the iteration process as you improve on your designs. If you are having to remake parts from rough or non-existant drawings you may find yourself in a dilemma with parts not fitting and potentially botching a few.

From a mechanical standpoint, there are a few things you can do to make your life easier, a simple tolerance is one of them.

We must first understand what a tolerance is, in engineering, a tolerance is the limit or variation of a physical dimension. This can be set by yourself on how accurate you want your part or it is sometimes set by the machine used, a bad operator can also play a part but for this write up I will not consider this.
As a general rule the higher the tolerance you put on your part the more it will cost, if I wanted a shaft with a diameter of 20 mm ±0.1 mm (19.9 mm to 20.1 mm) this would be easily achievable on a lathe with no extra tooling. If I was to make this ±0.01 mm (19.99 mm to 20.01 mm) then things start getting harder, the shaft would now require a grinding process to achieve this, meaning more time and man-hours and thus a more expensive part.

Not only is cost a factor, but also the fit of the part, which is what we probably really care about matters. If my 20 mm diameter shaft had to fit inside a hole, a bushing for example, and if there were no tolerances involved then how would I know it would fit every time? It could be oversized, undersized or it could be ok.

Luckily for shafts and holes (or anything concentric like a rocket tube and bulkhead), there is a simple ISO tolerance letter/number designation system to make life easy, shown below.

Fits (Credit: Machinery Handbook 29th Edition)

To go along with this, there is a handy Limits, Fits and Tolerance calculator from Amesweb which makes this ISO system easy to understand.

Let’s look at out 20 mm diameter shaft and the bushing it must go into. From the above chart I’d like a sliding fit, with a basis on the hole (hole limits are maintained but shaft limits can vary), therefore I want a H7/g6 tolerance on the shaft and hole.
Plugging this into the above-mentioned calculator yields the following,

As can be seen, I have a nice tolerance dimension that will always enable a sliding fit, but what are these dimensions?

My bush dimension becomes 20 mm -0 mm on the lower end and 20 mm +0.021 mm on the upper end, while my shaft diameter becomes 20 mm -0.020 mm on the lower end and 20 mm -0.007 mm on the upper end.
This gives me a range that I can make each part too, and as long as each part is within that range I will always have a sliding fit, no matter who or where it is made.

This is a very basic introduction, more specifically relating to cylindrical components and fits. In a future post, I’ll go into a bit more detail into the next steps you can take to ensure your parts are concentric and cylindrical using the Geometric Dimensioning, and Tolerance (GD&T) language as well as covering the three basic types of tolerances you may see on a drawing.

BPS.space on TMRO

Video Caption: Joe Barnard of BPS.space joins us to talk about his work in making model rockets emulate larger, liquid fueled vehicles such as Falcon and Electron. He has created many amazing models and has been working on thrust vector control (TVC) steering of models as well as being able to stage and even land model rockets. This is his story.

If you would like to continue the conversation we have a few great ways to do that: – Comment right here on YouTube. We’ll comment back or even feature it in the show – Create a new post on our community forum at https://community.tmro.tv – Head over to our real-time Discord channel here: https://discord.gg/9NkkFWD

DARE: Parachute Research Group News

As well as designing the recovery systems for the upcoming Stratos IV flight, the team will get a chance to test their systems in the REXUS/BEXUS program, first flight in 2020.

From the REXUS/BEXUS website,

The REXUS/BEXUS programme allows students from universities and higher education colleges across Europe to carry out scientific and technological experiments on research rockets and balloons. Each year, two rockets and two balloons are launched, carrying up to 20 experiments designed and built by student teams.